What is the chest? |

Structure and Functions

The chest, or thorax, consists of those parts of the body lying between the diaphragm and the neck. Included here are the rib cage, diaphragm, heart, lungs, chest muscles, and breasts.

The skeletal support of the chest consists of the thoracic vertebrae and rib cage. In humans, there are usually twelve pairs of ribs and twelve thoracic vertebrae. Each thoracic vertebra consists of a cylindrical portion, the centrum or body, and a neural arch attached to the dorsal side of the centrum. The neural arch surrounds and protects the spinal column. A spinous process extends dorsally from the neural arch of each thoracic vertebra and serves as a site for muscle attachment. Near the base of each neural arch are two pairs of articular processes (zygapophyses). The superior pair of one vertebra face toward each other and articulate with the inferior articular processes of the adjacent vertebrae.

Attached to each thoracic vertebra is a rib. There are usually twelve pairs of ribs, but this number occasionally varies. Each rib consists of a bony portion and a cartilaginous extension, the costal cartilage. At its vertebral end, each rib has two articulating processes, the head (capitulum) and the tubercle (tuberculum). The costal cartilages of the first seven ribs (the number occasionally varies) extend all the way to the sternum. The next two or three ribs have costal cartilages that attach to the costal cartilage above them. The remaining ribs have costal cartilages that are “floating” and have no attachments. Together, the ribs make up a cagelike structure called the rib cage, which shapes the chest and protects the heart and lungs from injury.

The sternum, or breastbone, runs along the front of the chest in the midline of the body. It consists of a flattened top portion called the manubrium; a long, extended body (corpus); and an extension called the xiphoid process, which is made mostly of cartilage. The manubrium has notches for the attachment of the clavicle and the first rib on either side. The attachment for the second rib lies between the manubrium and corpus and is shared by both bones. The corpus of the sternum is formed by the fusion of five individual parts called sternebrae. The costal cartilages of the second through seventh ribs articulate with the corpus of the sternum and mark the boundaries between the individual sternebrae. Beyond the notch for the attachment of the seventh costal cartilage, the xiphoid process extends downward along the midline.

A muscular diaphragm marks the boundary between the chest cavity and the abdominal cavity. Although it is located at the lower end of the chest cavity, it originates in the neck region and derives its nerve supply, the phrenic nerve, from within the neck. The diaphragm is the principal muscle used in breathing. Normally dome-shaped and bowed upward, the diaphragm flattens when its muscles contract, expanding the chest cavity and resulting in the inhalation of air. Relaxation of the diaphragm returns the curvature of the dome upward, compressing the chest cavity and resulting in the exhalation of air. The diaphragm has openings for the passage of the esophagus and the major blood vessels, especially the descending aorta and inferior vena cava.

The heart and major blood vessels lie within the chest cavity and are protected by the rib cage. The heart
is a muscular pump that has four chambers (two atria and two ventricles). The right atrium receives oxygen-poor blood from the body’s organs via the superior vena cava (from the head and upper extremities) and the inferior vena cava (from the abdominal region, pelvic region, and lower extremities). Blood from the right atrium passes through the tricuspid valve to the right ventricle, from which it is pumped into the pulmonary artery. The pulmonary artery then divides in two branches that run separately to each lung. Oxygen-rich blood from the lungs returns to the heart by means of the pulmonary veins, which empty into the left atrium. Blood from the left atrium passes through the bicuspid valve and empties into the left ventricle, which has an extremely thick, muscular wall. Contraction of the left ventricle propels the blood out of the aorta and through the body via the arteries.

Contractions of the heart originate in a location known as the sinoatrial node, located on the surface of the right atrium. From this point, contractions spread to the atrioventricular node, located at the point where all four chambers meet. The wave of contraction then spreads rapidly down the septum between the two ventricles and up the side walls of each ventricle. A specialized bundle of cardiac muscle called the bundle of His, composed of modified muscle fibers (Purkinje fibers), is responsible for this rapid conduction.

Except for the pulmonary arteries, the arteries of the chest region are all branches of the aorta, the major artery that flows out from the left ventricle of the heart in an upward direction. The aorta can be subdivided into an initial portion (the ascending aorta), an aortic arch, and a longer descending aorta which extends from the thoracic region into the pelvis. The coronary arteries are small but important branches that arise from the ascending aorta as it leaves the heart. These arteries supply blood to the muscular wall of the heart itself. From the arch of the aorta, the most common pattern of branching is that of a brachiocephalic trunk, which then splits into a right common carotid and right subclavian artery, followed by a left common carotid artery and then a left subclavian artery. There is considerable variation, however, in this pattern of branchings. The carotid arteries run up the sides of the neck to supply blood to the head and neck.

The subclavian arteries of either side run first upward and then laterally through the chest cavity, continuing toward the upper extremity as the axillary artery. Along its course, each subclavian artery gives off the following branches: vertebral artery, thyrocervical trunk, internal thoracic artery, costocervical artery, and descending scapular artery. The vertebral artery, the largest branch, supplies blood to the vertebrae of the neck region and ultimately to the base of the brain. The short thyrocervical trunk divides almost immediately into three branches: an inferior thyroid artery to the larynx, trachea, esophagus, and surrounding muscles; a suprascapular artery to the subclavius and sternocleidomastoid muscles and to the overlying skin; and a transverse cervical artery to the muscles of the shoulder region.

The right and left internal thoracic arteries (also called internal mammary arteries) run along the ventral side of the chest, just beneath the costal cartilages and just to either side of the sternum. Each internal thoracic artery gives off branches to the diaphragm, the pleura, the pericardium, the thymus, the transverse thoracic muscle, the ribs and intercostal muscles, the pectoral muscles, and the mammary glands. Beyond the sixth rib, each internal thoracic artery divides into a musculophrenic branch to the last six ribs and the diaphragm and a superior epigastric artery, which descends along the abdominal surface, supplying the muscles of this region before meeting the inferior epigastric artery that ascends from the pelvic region.

The veins of the chest region include the external and internal jugular veins, draining the head and neck, and the subclavian veins, draining the upper extremities. These veins come together to form the right and left brachiocephalic veins, which then drain into the superior vena cava. The superior vena cava also receives several smaller tributaries, including the azygos vein, the paired internal thoracic and inferior thyroid veins, the highest intercostal vein, and several smaller veins of the vertebral column. The azygos vein (on the right) and the hemizygous vein (on the left) run parallel to each other on either side of the vertebral column along the dorsal or rear wall of the chest cavity, draining blood from the muscles of the back, the bronchi, the ribs, and the mediastinum. The right and left internal thoracic veins receive tributaries from the ribs and intercostal muscles as well as the diaphragm, pericardium, and mediastinum. The highest intercostal veins drain the first two or three intercostal spaces on either side, also receiving smaller tributaries from the bronchi and the upper portion of the diaphragm. The inferior thyroid veins drain the thyroid gland, esophagus, trachea, and larynx. In addition to the veins listed above, the veins of the heart muscle all drain into a coronary sinus, which runs between the left atrium and ventricle, then drains directly into the right atrium near the inferior vena cava.

The lungs, the principal organs of respiration, consist of several lobes. The right lung has superior, medial, and inferior lobes; the left lung has superior and inferior lobes only. Inhalation of air, or inspiration, is brought about by the lowering (contraction) of the diaphragm and by the raising and outward expansion of the rib cage. Exhalation of air, or expiration, is brought about by the raising (relaxation) of the diaphragm and by the relaxation of the intercostal muscles, lowering and contracting the rib cage. Under most conditions, inspiration is an active process requiring muscular contraction, while expiration takes place passively as the muscles relax.

Together, the heart, the lungs, and the thoracic portion of the esophagus occupy the thoracic cavity, or chest cavity. Each of these organs is surrounded by a thin membrane, the visceral pleura. This membrane is continuous with the parietal pleura, another thin membrane that lines the outer walls of the chest cavity. The right and left visceral pleura come together to form a septum called the mediastinum, which separates the bulk of the thoracic cavity into right and left pleural cavities, each containing one of the lungs. The pericardial cavity, containing the heart, is inserted between the layers of the mediastinum. Also occupying part of the thoracic cavity is a large mass of lymphoid tissue, the thymus body. The thymus is irregular in shape and occupies the highest portion of the thoracic cavity above the heart.

Muscles of the chest region may be divided into those associated developmentally with the upper extremity and those that are associated with the trunk of the body. One muscle, the trapezius, is a modified gill muscle that belongs developmentally to neither group. Fibers of the trapezius muscle originate from the cervical and thoracic vertebrae, including the adjoining ligaments and the adjacent part of the skull. These fibers converge onto the spine and acromion of the scapula and onto the clavicle. The muscles associated with the trunk of the body are called axial muscles. Of those in the chest or thoracic region, four are responsible primarily for movements of the shoulder blade (scapula), twelve for movements of the rib cage, and another eleven for movements of the vertebral column.

The levator scapula runs from the transverse processes of the first four cervical vertebrae to the vertebral border of the scapula; by contracting, it raises and rotates the scapula. The two rhomboid muscles run from the vertebral column to the vertebral border of the scapula. The rhomboideus minor originates from the spinous processes of the seventh cervical and the first thoracic vertebra and from the nuchal ligament that runs from these spinous processes to the skull. The rhomboideus major originates from the spinous processes of the second through fifth thoracic vertebrae. Both rhomboideus muscles run diagonally from the vertebral column to the vertebral border of the scapula, including the base of the scapular spine. The serratus anterior, also called serratus ventralis, is a sheetlike muscle that lies between the scapula and the rib cage. Its fibers originate from the ribs as a series of strips that converge slightly; they all insert onto the vertebral border of the scapula. The attachments of this muscle to the ribs resemble a series of angular sawteeth (serrations) that give the muscle its name. The four preceding muscles all share a common embryological origin, and all have a common nerve supply from the dorsal scapular nerve.

The axial muscles associated with movements of the rib cage include the scalenus anterior, scalenus medius, scalenus posterior, intercostals, subcostals, levatores costarum, transversus thoracis, serratus posterior superior, serratus posterior inferior, rectus abdominis, and diaphragm. The three scalene muscles, as their name implies, are all shaped like elongated scalene triangles (with three sides of different lengths). The scalenus anterior arises from the transverse processes of the third through sixth cervical vertebrae and inserts (attaches) onto the first rib. The largest of the scalene muscles is the scalenus medius, which runs from the transverse processes of the last six cervical vertebrae to an insertion on the first rib. The scalenus posterior arises from the transverse processes of the last two or three cervical vertebrae and inserts onto the second rib.

The intercostal muscles run between the ribs in two sets of fibers. The external intercostals run from each rib to the next in a diagonal direction; the upper end of each fiber is situated closer to the vertebral column than is the lower end. The internal intercostals also run diagonally from each rib to the next, but deep to the fibers of the external intercostals and perpendicular to them, so that the lower end of each fiber is closer to the vertebral end of each rib than is the upper end. Both sets of intercostals are broad, extending nearly along the entire extent of each rib, but the fibers are in each case short, extending only from one rib to the next. The subcostals are similar in position and orientation to the internal intercostals, except they are usually confined to the last few ribs and they span two or three intercostal spaces at a time. The levatores costarum are a continuation of the external intercostals onto the transverse processes of the vertebrae, from the last cervical vertebra to the eleventh thoracic vertebra. Each levator costarum is a triangular slip located in the angle between one of the ribs and the vertebra in front of it, running from the transverse process of the vertebra onto the rib.

The transversus thoracis is a flat muscle that covers part of the inside of the rib cage. Its fibers originate from the corpus and xiphoid process of the sternum; these fibers radiate both horizontally and diagonally upward to insert on the deep surfaces of the second through sixth ribs. The serratus posterior superior arises from the spinous processes of the first few thoracic vertebrae and the seventh cervical vertebra, as well as from the ligaments connecting these spinous processes with one another and with the skull. The fibers converge only slightly and are inserted in four separate slips onto the superior margins of the second through fifth ribs. The serratus posterior inferior is a similar but broader muscle located farther down the spine. It arises from the spinous processes of the last two thoracic and first few lumbar vertebrae, runs diagonally upward, and divides into four separate slips that insert onto the inferior margins of the last four ribs. The rectus abdominis, obliquus externus, obliquus internus, and transversus abdominis are abdominal muscles that pull down on the chest and particularly on the rib cage. The rectus abdominis consists of a strip of muscle fibers running vertically along the ventral midline. The other abdominal muscles are sheetlike and cover the majority of the abdominal surface. Contractions of these muscles generally pull downward on the ribs and oppose the expansion of the rib cage.

The diaphragm is also an axial muscle of the chest cavity. Its muscle fibers originate from the inside of the xiphoid process of the sternum (the sternal portion), from the inner surfaces of the last six ribs and their costal cartilages (the costal portion), and from two muscular arches and two tendinous crura that make up the lumbar portion. The medial lumbocostal arch forms a passage for the greater psoas muscle, while the lateral lumbocostal arch forms a passage for the lumbar quadrate muscle. The right and left crura arise from the ventral surfaces of the first few lumbar vertebrae. Together, the sternal, costal, and lumbar portions of the diaphragm converge upon a sheetlike central tendon, which is divided into large left and right leaflets and a small middle leaflet.

The axial muscles concerned with movements of the thoracic vertebrae include the longus and splenius muscles and the muscles of the erector spinae complex. The longus colli arises from the centra of the last few cervical and first few thoracic vertebrae along their ventral surfaces; it runs upward to insert onto the bodies of the first four cervical vertebrae and the transverse processes of the fifth and sixth cervical vertebrae. The splenius capitis originates from the spinous processes of the last cervical and the first three or four thoracic vertebrae and from the ligaments connecting these processes to one another and to the back of the skull. The muscle inserts onto the occipital and temporal bones on the back of the skull, including the mastoid process. The splenius cervicis arises from the spinous processes of the third through sixth thoracic vertebrae and runs to an insertion on the transverse processes of the first few cervical vertebrae. The muscles of the erector spinae complex include the iliocostalis, longissimus, spinalis, semispinalis, multifidius, rotatores, and intertransversarii. Collectively, these muscles are responsible for dorsal movements (extension) of the vertebral column throughout the lumbar, thoracic, and cervical regions.

The muscles associated developmentally with the extremities are called appendicular muscles. Appendicular muscles of the chest region include the pectoralis, latissimus dorsi, and subclavius. The pectoralis major is triangular in shape; it originates from the sternum, costal cartilages, and a portion of the clavicle, from which its fibers converge toward an insertion onto the greater tuberosity of the humerus. The pectoralis minor originates from the third through fifth ribs and inserts onto the coracoid process of the scapula. The latissimus dorsi is a broad, flat muscle that originates from the lower half of the vertebral column (and part of the ilium) by way of a tough tendinous sheet (the lumbar aponeurosis); it inserts high on the humerus. The subclavius muscle runs from the bottom surface of the clavicle diagonally onto the first rib. Upon contraction, this muscle helps pull the shoulder inward and the rib cage upward.

Each of the paired breasts consists of a mammary gland, nipple (papilla), areola, and surrounding fat tissue. The breasts are small in children and remain small in most adult men, but they become larger during puberty in women and enlarge even more during late pregnancy and throughout lactation. Toward the end of pregnancy, the gland begins to secrete milk, a white, nutritive fluid containing lactose (milk sugar), proteins, and some fats (more sugar and less fat than in cow’s milk). The secretion of milk is known as lactation. During lactation, the mammary gland continues to secrete milk as long as the baby continues nursing. When the child is weaned, the mammary gland undergoes a process of involution (shrinkage). The smaller ducts of the mammary gland collect into larger ducts, each draining a wedge-shaped section of the breast. These larger ducts converge toward a raised nipple (papilla) from which the milk exudes. The nipple is surrounded by a circular area, the areola, characterized by thin skin which is a bit more heavily pigmented (usually redder) than the remainder of the breast.

Agur, Anne M. R., and Arthur F. Dalley. Grant’s Atlas of Anatomy. 13th ed. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins, 2012.

"Chest Pain: First Aid." Mayo Clinic, February 3, 2012.

Crouch, James E. Functional Human Anatomy. 4th ed. Philadelphia: Lea & Febiger, 1985.

Marieb, Elaine N. Essentials of Human Anatomy and Physiology. 10th ed. San Francisco: Pearson/Benjamin Cummings, 2011.

Rosse, Cornelius, and Penelope Gaddum-Rosse. Hollinshead’s Textbook of Anatomy. 5th ed. Philadelphia: Lippincott-Raven, 1997.

Standring, Susan, et al., eds. Gray’s Anatomy. 40th ed. New York: Churchill Livingstone/Elsevier, 2008.

What is Behçet's disease? |

Causes and Symptoms

Behçet’s disease, or Behçet’s syndrome, usually appears in early adulthood with painful aphthous ulcers
(similar to canker sores) in the mouth and genitals. These ulcers generally subside after one to two weeks, but they recur throughout the course of the disease. Some patients also have painful skin nodules known as erythema nodosum. Brief periods of joint pain are also common. Rarely, the ulcers of Behçet’s disease are found in the gastrointestinal tract. Involvement of the central nervous system causes a variety of symptoms ranging from mild confusion to paralysis. However, the most serious complication of Behçet’s disease is involvement of the eyes, since this may progress to blindness. Patients also have an increased predisposition for the formation of blood clots, usually in the venous system. These clots can be
life-threatening if they migrate to the lungs.

The common factor underlying these diverse manifestations of Behçet’s disease is inflammation of the small blood vessels, but it remains unclear what environmental or genetic factors trigger this inflammation. Rare reports have been made of familial forms of the disease, raising the possibility of a genetic basis, but this remains under investigation. Diagnosis is made on clinical grounds.

Treatment and Therapy

Behçet’s disease is a chronic condition, but the severity of the disease generally lessens over time. Ulcers are first treated with topical glucocorticoids, in the form of either mouthwash or paste. Refractory cases may require thalidomide, a drug that must be used with extreme caution because of its ability to cause birth defects. Because of the risk of blindness, ocular and central nervous system disease is managed more aggressively with oral steroids (such as prednisone), along with azathioprine or cyclosporine.

Apart from the above complications, the long-term prognosis of Behçet’s disease is quite good, and the life expectancy of patients is comparable with that of the general population.

Perspective and Prospects

The first description of Behçet’s disease appears in the writings of Hippocrates in the fifth century b.c.e., but it was first recognized in the modern era by the Turkish physician Hulusi Behçet in 1937. Although Behçet’s disease is seen throughout the world, the highest prevalence is in countries along the ancient Silk Road, a trading route extending from the Far East to the Mediterranean Sea.

Bibliography:

"Behçet’s Disease." National Institute of Arthritis and Musculoskeletal and Skin Diseases, Apr. 2012.

"Behçet’s Syndrome." MedlinePlus, Mar. 14, 2013.

"Common Symptoms and Signs of Behçet’s Disease." American Behçet’s Disease Association.

Lee, Sungnack, et al., eds. Behçet’s Disease: A Guide to Its Clinical Understanding. New York: Springer, 2001.

Parker, James N., and Philip M. Parker, eds. The Official Patient’s Sourcebook on Behcet’s Disease. San Diego, Calif.: Icon Health, 2002.

Plotkin, Gary R., John J. Calabro, and J. Desmond O’Duffy, eds. Behçet’s Disease: A Contemporary Synopsis. Mount Kisco, N.Y.: Futura, 1988.

Zeis, Joanne. Essential Guide to Behçet’s Disease. Uxbridge, Mass.: Central Vision Press, 2002.

Describe the scene of leaving the ghetto in Night by Elie Wiesel.

In Night by Elie Wiesel, the Jewish people of the town Sighet in Transylvania were forced to leave the ghetto they had been forced into earlier when the Nazis took over the town. They left on Saturday, the Jewish Sabbath, as the sun was coming up. The people gathered in the streets, ready to go. The local Jewish Council had made a deal with the Hungarian police that the Jews would organize their own departure. 

...

In Night by Elie Wiesel, the Jewish people of the town Sighet in Transylvania were forced to leave the ghetto they had been forced into earlier when the Nazis took over the town. They left on Saturday, the Jewish Sabbath, as the sun was coming up. The people gathered in the streets, ready to go. The local Jewish Council had made a deal with the Hungarian police that the Jews would organize their own departure. 

The townspeople went to their main synagogue, the Jewish place of worship, which had been vandalized and desecrated by the Nazis. They stayed there all day and night, crowded together.

"There were so many of us that we could scarcely breathe. We spent a horrible twenty-four hours there. There were men downstairs; women on the first floor. It was Saturday; it was as though we had come to attend the service. Since no one could go out, people were relieving themselves in a corner" (Wiesel 20).

The next morning the Jewish people of Sighet walked to the train station. They were forced into cattle cars--80 people to a car and given some bread and pails of water. They were warned that if anyone tried to escape, he/she would be shot.

"Two Gestapo officers strolled about on the platform, smiling: all things considered, everything had gone off very well.

A prolonged whistle split the air. The wheels began to grind. We were on our way" (Wiesel 20).

What is the dramatic significance of the subplot in King Lear?

Gloucester acts as a foil to Lear. This means that he provides a mirror to the main character, whose traits are then highlighted for dramatic purposes. In structural terms, there are great similarities between the two men and their respective fates. Both come to grief through a naive trust in their children; both suffer appalling pain: mentally in the case of Lear, physically and mentally in the case of Gloucester; both realize, all too late,...

Gloucester acts as a foil to Lear. This means that he provides a mirror to the main character, whose traits are then highlighted for dramatic purposes. In structural terms, there are great similarities between the two men and their respective fates. Both come to grief through a naive trust in their children; both suffer appalling pain: mentally in the case of Lear, physically and mentally in the case of Gloucester; both realize, all too late, which family member was the one who really loved and cared for them.

Yet there are important differences between plot and subplot. Gloucester's suffering is more recognizably human than the mental anguish endured by Lear. Lear remains a larger-than-life character throughout the play; he may have renounced his kingdom, but he still acts and feels like a king. His lapse into insanity stems largely from his inability to come to terms with his humiliating status as a king without a throne.

Gloucester is more human and less exciting as a character, perhaps, but none the worse for that. And unlike Lear, he gives—not out of an insecure need to be loved, but out of a genuine sense of humanity. Both men ultimately fall, but for different reasons: Lear cannot live in a world in which he has no place because he is too God-like; Gloucester, a mere mortal, cannot live there either, but because he's all too human. The Gloucester subplot reminds us that what happens to Lear can happen to any of us, albeit for different reasons. 

What are omega-3 fatty acids? Can they help prevent cancer?

Cancers treated or prevented: Colon cancer, breast cancer, prostate cancer, pancreatic cancer

Delivery routes: Oral by food, capsule, or liquid

How this substance works: Omega-3 fatty acids are highly concentrated in the brain and appear to play an important role in cognitive and behavioral functions, as well as normal growth and development. Research indicates that these acids are important in numerous physiological functions, particularly muscle contraction and relaxation, movement of calcium and other material into and out of cells, regulation of blood clotting, and secretion of substances including hormones and digestive enzymes. They also play a role in controlling cell division and fertility, indicating their possible importance in protection against certain types of cancer. Omega-3 fatty acids seem to reduce inflammation and retard tumor growth. On the other hand, omega-6 fatty acids, which are found in sunflower oil, safflower oil, and most saturated fats and vegetable oils, promote inflammation and feed tumor growth. An appropriate balance between omega-3 and omega-6 fatty acids is necessary to promote good health.

Some research indicates that omega-3 fatty acids help to prevent certain chronic diseases, including heart disease and some cancers. EPA appears to be important in cancer prevention by affecting the production of cytokines and the tumor necrosis factor (TNF). Other research indicates that omega-3 fatty acids may play an adverse role in treating some cancers. If the latter is true, then these acids still play an indirect role in cancer prevention if cold-water fish, such as salmon, halibut, and tuna, are substituted for red and processed meats, which are known to increase the risk of colon and prostate cancers.

Side effects: The consumption of omega-3 fatty acids and cancer incidence have had unfavorable associations in some case studies. One study on skin cancer and another on lung cancer showed that these fatty acids increased the risk for developing these cancers. A study on prostate cancer showed that ALA increased its risk, while EPA and DHA reduced the risk. A 2013 study published in the Journal of the National Cancer Institute also found that prostate cancer, especially aggressive prostate cancer, was associated with higher intakes of oily fish and fish oil supplements. More specific case studies need to be conducted in order to build a significant statistical database.

Bibliography

Calviello, Gabriella, and Simona Serini, eds. Dietary Omega-3 Polyunsaturated Fatty Acids and Cancer. Dordrecht: Springer, 2010. Print.

De Meester, Fabien, Ronald Watson, and Sherma Zibadi, eds. Omega-6/3 Fatty Acids: Functions, Sustainability Strategies and Perspectives. New York: Springer, 2012. Print.

"Fish Oil." MedlinePlus. US Natl. Lib. of Medicine, 21 Aug. 2014. Web. 12 Nov. 2014.

"Omega-3 Fatty Acids." Cancer.org. Amer. Cancer Soc., 17 Jan. 2013. Web. 12 Nov. 2014.

"Omega-3 Supplements: An Introduction." National Center for Complementary and Alternative Medicine. Natl. Inst. of Health, US Dept. of Health and Human Services, June 2013. Web. 12 Nov. 2014.

Simon, Stacy. "Omega-3 Fatty Acids Linked to Increase in Prostate Cancer Risk." Cancer.org. Amer. Cancer Soc., 17 July 2013. Web. 17 Nov. 2014.

Why was Macbeth afraid of Banquo?

Macbeth’s fear of Banquo stems from the witches’ prophecies in Act I, Scene 3.  Of course, Macbeth is originally enraptured by the witches’ startling predictions that he will become Thane of Cawdor and King. However, when Banquo inquires about his destiny, the witches’ three-line response slowly destabilizes Macbeth and leads him to murder his former confidant and best friend.

The first witch tells Banquo that he will be “lesser than Macbeth but greater” (1.7.66). The...

Macbeth’s fear of Banquo stems from the witches’ prophecies in Act I, Scene 3.  Of course, Macbeth is originally enraptured by the witches’ startling predictions that he will become Thane of Cawdor and King. However, when Banquo inquires about his destiny, the witches’ three-line response slowly destabilizes Macbeth and leads him to murder his former confidant and best friend.

The first witch tells Banquo that he will be “lesser than Macbeth but greater” (1.7.66). The second witch tells him that he will be “Not so happy, yet much happier” (1.7. 67). Finally, the third witch tells him that “Thou shalt get kings, but thou shall be none” (1.7.68). This final line means that while Banquo himself will not be king, his sons will rule. Consequently, Macbeth agonizes over the fact that he killed Duncan and consigned himself to hell only to see Banquo’s children take control of the throne. He worries that Banquo and his son Fleance will pose a grave threat to his power and life. In fact, the threat of Banquo’s children continues to haunt Macbeth even after Banquo’s death; in Act IV, Scene I, the witches show Macbeth a line of kings followed by Banquo’s ghost. This is a clear sign to Macbeth that Banquo’s children will form a dynasty.

In fact, one could even argue that Macbeth is not afraid of Banquo; Macbeth is terrified of Banquo’s children.

How can I give a speech about how Cristiano Ronaldo achieved his dreams by overcoming adversity?

This sounds like the speech of appreciation that I make my public speaking students perform.  It sounds like you need to explain why you appreciate Ronaldo, which means you are going to mix informational facts about him and persuasive opinions of your own.  The persuasive opinions of your own will be easy to do by simply concentrating on the positive aspects of him.  

Before you begin outlining your speech, pick three events in Ronaldo's...

This sounds like the speech of appreciation that I make my public speaking students perform.  It sounds like you need to explain why you appreciate Ronaldo, which means you are going to mix informational facts about him and persuasive opinions of your own.  The persuasive opinions of your own will be easy to do by simply concentrating on the positive aspects of him.  

Before you begin outlining your speech, pick three events in Ronaldo's life that you believe helped shape him into the person/player that you admire so much.  Your speech will contain those three items, and it covers the teacher's requirement to talk about specific events.  Because you chose major events that helped make Ronaldo great, you have built in the ability to conclude with your own opinion about achieving your goals by following his example.  

To start your speech, you need an "attention getter."  Some teachers call it the hook.  Regardless, the first words out of your mouth need to get your audience interested.  If they are not, they will not listen. I teach five attention-getting tools.  

1. Make a bold statement.  Lean toward opinion here.  Facts are seen as boring. 


2. Use a quote.  For you, I recommend using something Ronaldo said or a famous quote about achieving your goals.  


3. Give a definition.  I don't see how this would work well for your speech.  Stay away. 


4. Ask a question.  It's simple and effective, because it forces your audience to immediately engage mentally with your speech. 


5. Use an anecdote.  Tell a brief story that ties into your speech topics.  

After your opening attention getter, then you will move into the body that contains the three main things about Ronaldo that you want to talk about.  Pre-plan your transitions that move you from main point to main point.  Those must be smooth.  In your conclusion, emphasize why Ronaldo matters to you and why his example can inspire your audience as well.  Good luck and have fun! 

Why do some windows have two panes of glass?

There are several possible answers, and the circumstances would have to be more specifically defined to identify the most likely explanation.

Some windows are double-paned to provide soundproofing. The second pane essentially provides a barrier and additional layer of material through which the sound waves, which are just vibrations in air molecules, need to pass before they can reach you. The more material they have to pass through, the lower the energy by the time...

There are several possible answers, and the circumstances would have to be more specifically defined to identify the most likely explanation.

Some windows are double-paned to provide soundproofing. The second pane essentially provides a barrier and additional layer of material through which the sound waves, which are just vibrations in air molecules, need to pass before they can reach you. The more material they have to pass through, the lower the energy by the time you hear it, and therefore the quieter the sound. 

Double-paning can also provide insulation, especially if the space between the panes is filled with some kind of transparent insulating material—some inert gases such as krypton are used in commercial products. As with the sound waves, the gap provides an additional layer of material which any heat must excite and pass through, which can serve to prevent heat from entering or escaping. 

Finally, double paning can provide some degree of shatter resistance, especially if one or both panes are made out of different materials, such as plexiglass. This is simply a matter of the second pane being a "backup" in the event of the first breaking, and so this would be more likely to be seen in situations where safety is a concern, such as on airplane windows. 

What is giftedness, and how is it related to cognitive development?

Introduction

Modern studies of giftedness have their origin in the work of Lewis Madison Terman
at Stanford University, who in the 1920s used intelligence test scores to identify intellectually gifted children. His minimal standard for giftedness was an intelligence quotient (IQ)
of 140 on the Stanford-Binet test, a number at or above which only 1 percent of children are expected to score. (The average IQ score is 100.) Terman and his associates identified more than fifteen hundred children in California as gifted, and follow-up studies on the Terman gifted group were conducted throughout their adult lives. Although individuals in the gifted group tended to achieve highly in school and in their careers, they were not greatly different from average scorers in other ways. Terman’s research dispelled the myths that high scorers on IQ tests were, as a group, socially maladjusted or “burned out” in adulthood. They were high achievers and yet normal in the sense that their social relationships were similar to those of the general population.

By the time the Terman gifted group reached retirement age, it was clear that the study had not realized the hope of identifying eminence. None of the children selected had, as adults, won the Nobel Prize, although two children who were rejected for the study later did so (physicist Luis Alvarez and engineer William Shockley). Nor did high IQ scores seem to be characteristic of artistic ability. Apparently, an IQ score of 140 or above as a criterion for giftedness in children was not able to predict creative accomplishments in later life.

Studies conducted in the 1950s under the direction of Donald MacKinnon at the University of California, Berkeley, tended to confirm this conclusion. Panels of experts submitted the names of whomever they believed to be the most creative architects, mathematicians, and research scientists in the United States; then these individuals were invited to take part in assessments, including measurement of their intelligence through the Wechsler Adult Intelligence Scale. The IQ scores of these highly creative individuals ranged from 114 to 145, averaging around 130, significantly below Terman’s criterion for giftedness. No one knows how these adults would have scored on the Stanford-Binet as children or how creative adults in other domains would have scored, but the results confirmed that a score of 140 on an intelligence test is not a prerequisite for outstanding creative accomplishment.

More recent studies have cast light on the importance of nurture in the development of a broader range of talent. A team of researchers at the University of Chicago headed by Benjamin Bloom investigated the lives of 120 talented adults in six fields: concert piano, sculpture, swimming, tennis, mathematics, and research neurology. They found that in most cases, accomplishments on a national or international level by the age of forty had their origin not in a prodigious gift, but in child-centered homes. The child’s early experiences of the field were playful, rewarding, and supported by parents. Rapid progress was due to a work ethic instilled by parents (“always do your best”) and by increasingly expert and selective teachers, whom parents sought out. Bloom’s findings did not exactly contradict those of Terman (no testing was done), but they suggested to the researchers that nurture and motivation play the lead and supporting roles in the development of a wide range of talent.

Just what general ability IQ tests measure remains uncertain, but increasingly, psychologists and educators have conceptualized giftedness as a function of specialized capabilities and potential for performance in specific fields such as mathematics, biology, dance, or visual arts. A definition of giftedness first offered in a 1971 report to the Congress of the United States by Sidney P. Marland, then commissioner of education, indicates a much broader concept of giftedness than high IQ scores have been found to measure. “Gifted and talented children are those identified by professionally qualified persons who, by virtue of outstanding abilities, are capable of high performance.” He defined gifted children as those with demonstrated achievement or potential ability in the following areas, singly or in combination: general intellectual ability, specific academic aptitude, creative or productive thinking, leadership ability, visual or performing arts, and psychomotor ability. This definition of giftedness, known as the Marland definition, does not distinguish giftedness from talent and includes performance capabilities that are sometimes related only distantly to performance on an IQ test. Nevertheless, the legacy of the Terman study of giftedness is that high IQ test scores remain one among several ways for psychologists and educators to identify intellectual giftedness among children in the general population. Giftedness in academic, creative, leadership, artistic, and psychomotor domains, however, is generally identified in other ways.

Identification of Giftedness

Different percentages of the general population have been identified as gifted, depending on the definition of giftedness. Terman’s use of IQ scores of 140 or above identified 1 percent of scorers as gifted. The common, contemporary indicator of intellectual giftedness is a score of 130 or above on a standardized, individually administered intelligence test, which is achieved by the top 2.5 percent of scorers. By the broader Marland definition, some form of which has been enacted through legislation by most states that have mandated gifted education programs, a minimum of 3 to 5 percent of school children are estimated to be gifted. Other definitions would identify as many as 10 to 15 percent of schoolchildren as gifted or as many as 15 to 25 percent in a talent pool. Gifted and talented students receiving services in schools in the United States constitute about 6 percent of all children who are enrolled.

By almost any definition, giftedness is very difficult to identify during infancy. Most researchers would agree that giftedness has a biological foundation, but whether this foundation exists as a general or a specific capability is unknown. One of the earliest indicators of many forms of giftedness is precociousness, or unusually early development or maturity. During preschool years, precociousness can generalize across several domains, such as the use of logic with an extensive vocabulary, or it can be more specialized, such as drawing realistic pictures of animals or objects or picking out a tune by ear on a musical instrument. Development does not seem to proceed in all areas at the same pace, however, so a young child may develop early in one or two areas but still behave in many ways like other children of the same age. Because of such asynchronous development, parents should not assume that a child who can master the moves of checkers at four years old, for example, will accept losing a game any better than the average four-year-old.

There has been debate regarding whether giftedness is the result of intense practice. Children with talents in specific areas, such as math or tennis, are seen to practice these skills very often and intensely. Often, giftedness in a specific domain is identified after much practice has occurred.

A surprising number of gifted children are their parents’ only children or first-borns, but this fact reveals only that their precocious development is due, at least in part, to learning from the models in their early environment, who are adults rather than age-mates. As Bloom’s study suggested, parents or other adult caretakers provide opportunities, resources, and encouragement to learn. Whatever reading ability a child may have, for example, can be nurtured by adults who read both to and around the child, who provide appropriate materials to read, and who show interest in the child’s spontaneous efforts to read.

A child who is developing a talent early often will tend to rehearse it spontaneously or call for repeated performance or for explanation by the parent (or other model) to review or understand what the child wants to learn. The products and performances of gifted children in elementary school are often similar to the products and performances of skilled but less gifted adolescents. For this reason, gifted children are often bored when instruction is designed for their age level rather than for an advanced level and rapid pace of learning.

By the school years, children’s giftedness can be assessed reliably in ways other than observation of precociousness. Assessment usually begins with nomination by a teacher, parent, or school social worker. Teacher nominations cannot be the sole indicator of who is gifted, however, because studies have shown them to miss about half of all gifted children. Nominations by teachers and others are often supported by academic marks during the previous year, often supplemented by standardized test scores. These scores can result from individual or group assessments of intelligence, school ability, cognitive abilities, academic aptitudes or achievements, and creative or productive thinking abilities. Since tests themselves have been found to identify only half of all gifted children, test scores are sometimes supplemented by scores from other types of instruments (such as checklists), ratings of portfolios or performances, or interviews to complete the assessment process. No single assessment technique or instrument has been found to satisfactorily identify all types of giftedness outlined in the Marland definition. Underrepresentation of African American, Latino, and Native American children in gifted education programs in the United States is largely a problem of identification. Some gifted children do not meet cutoff scores yet still have exceptional abilities. Other gifted children have poor test-taking skills, which highlights the need for multiple methods of identification of gifted children.

Instruction of Gifted Children and Adolescents

Eligibility for a gifted education program may be decided as a result of the process of identification, but the design of a program of instruction for each child is often a separate set of decisions, sometimes requiring further assessments. It must be decided whether a child who is nearing the end of first grade but who has performed at the seventh-grade level on a standardized achievement test should be promoted to a much higher grade level the next year. An adolescent who is writing commercial music and who is successfully performing it on weekends might be allowed to leave school during the day to make a recording. The programming decisions to be made are as diverse as the talents of the children themselves.

It is not surprising, then, that no single strategy for teaching the gifted child has been found to be the best. Rather, broad strategies of intervention can be classified as modifications in curriculum content or skills and modifications in school environment. Modifications in curriculum content for gifted students might include content acceleration (such as early admission, grade skipping, or telescoping two years into one), content enrichment (materials to elaborate on basic concepts in standard programs), content sophistication (more abstract or fundamental considerations of basic concepts), and content novelty (such as units on highly specialized topics). Modifications in skills include training in component skills of problem solving, various forms of problem solving (such as creative, cooperative, or competitive), and development of creativity. A program for the first-grader who is performing on achievement tests at the seventh-grade level, for example, might call for placement in a higher grade level (grade skipping), although which grade level is appropriate for placement would have to be determined using teacher observations, interview results, and diagnostic tests.

Possible modifications in the school environment include provisions for enrichment in the regular classroom (such as access to special equipment), a consultant teacher (who helps the classroom teacher develop lessons), a resource room (or “pullout” program), mentoring (often by a professional in the community), independent study (often a special project), special-interest classes (such as creative writing), special classes (such as advanced placement biology), and special schools (such as a statewide math and science school). A program for the musically creative adolescent might incorporate mentoring by a music professional, who would report to the school on a regular basis about work completed by the adolescent at a recording studio or while otherwise away from school during school hours.

Legal Aspects

No federally accepted definition of giftedness exists within the United States and Canada. In the United States, definitions of giftedness are left up to individual states and most gifted programming is left to individual school districts. This has created wide variance in services. Although the No Child Left Behind and Race to the Top legislation both mandated support to help struggling students, there is no mandate to support gifted children. Moreover, the extra support for struggling students often comes at the expense of gifted students. Although children who are labeled as learning disabled or developmentally delayed are entitled to extra resources, gifted students are often neglected. Likewise, while Common Core State Standards are being implemented in many states to improve the rigorousness of general education course, they specifically do not outline options for gifted students.

Most states require that children identified as gifted, just like those identified as delayed, have an individualized education plan (IEP) in place. This plan outlines how the gifted child is to be educated during the following year and is typically constructed and agreed on by teachers in conjunction with the parents of the gifted student and sometimes also with the gifted student.

Counseling Gifted Learners

Beginning in the 1920s, Leta Anna Stetter Hollingworth
at Columbia University investigated characteristics of children who scored over 180 on the Stanford-Binet test. Her study of twelve children (eight boys and four girls) suggested that despite their overall adjustment, children who were highly intellectually gifted tended to encounter three challenges not encountered by most other children. The first was a failure to develop work habits at school because of a curriculum paced for much less capable learners. The second was difficulty in finding satisfying companionship because of their advanced interests and abilities in relation to their age-mates. The third was vulnerability to frustration and depression because of a capacity to understand information on an adult level without sufficient experience to know how to respond to it.

Hollingworth suggested that the problem of work habits could be addressed by a combination of acceleration and enrichment. The problem of loneliness could be solved by training gifted children in social games—such as checkers or chess—that could be played by people of any age, and the problems of frustration and depression by careful adult supervision and patience. Research has tended to confirm that the problems Hollingworth identified often need to be addressed not only in cases of extreme precociousness but also, to a lesser extent, in the lives of many people identified as gifted.

If underachievement by a gifted child has its source in an unchallenging or otherwise inappropriate educational program, the recommended action is to assess strengths and weaknesses (a learning disability may be the problem), then design a more appropriate program or place the child in one that already exists. If the source of underachievement is low self-esteem, the home environment may be unlike that found by Bloom to nurture talent. In this case, family counseling can often reverse underachievement.

To help a gifted child with peer relations,
group therapy with other gifted children can be particularly beneficial. Group members not only can share their experiences of being gifted but also can establish and maintain friendships with those who have similar (or sometimes quite different) exceptional abilities. Group counseling sessions can be both therapeutic and developmental.

At least some of the emotional challenges facing gifted children develop from their emotional sensitivity and excitability. Because parents and siblings often share these characteristics, the stage is set for conflict. What is surprising is that conflict does not create unhappiness more often. In the main, gifted people report satisfaction with their home lives. If tensions in the home arise more often than in the average home, the parents of gifted children and the children themselves may need to develop more effective conflict resolution strategies and higher levels of self-understanding. Developmental counseling can assist parents and children in making these changes. Research has shown that gifted children do not have a higher level of psychopathology than do nongifted children. However, it is often assumed that because of their abilities, these children can find their way on their own.

It has been suggested that modern psychology could have much to offer the field of giftedness. Steven Pfeiffer of the Talent Identification Program at Duke University conducted a study to identify how the field of psychology could contribute to the study of giftedness and to gifted individuals. Psychologists could help build consensus around a definition of giftedness. After almost a century of work and research in giftedness, there is still no single definition to which all practitioners can turn. Although many schools use standardized intelligence tests to identify gifted students, there is considerable debate regarding the best way to test and measure giftedness. A considerable problem exists, especially in the identification of gifted minorities, who remain underrepresented in the gifted population. Psychologists could become more involved in the debate concerning how to identify all children who are gifted, regardless of race, gender, and ethnic background. Finally, there are still problems addressing the needs of gifted students within the classroom setting. Most teachers are unprepared by their schooling to meet the needs of gifted children. It is not merely a matter of giving gifted students more work, but different work that uniquely suits their abilities.

Bibliography

Colangelo, Nicholas, and Gary A. Davis, eds. Handbook of Gifted Education. 3rd ed. Boston: Allyn, 2002. Print.

"Common Core State Standards and Gifted Education." National Association for Gifted Children. National Assn. for Gifted Children, 2008. Web. 20 May 2014.

Gallagher, James, and Shelagh Gallagher. Teaching the Gifted Child. 4th ed. Boston: Allyn, 1994. Print.

Gavin, Mary L. "Gifted Education." KidsHealth.org. Nemours Foundation, Apr. 2014. Web. 15 May 2014.

MacKinnon, Donald W. In Search of Human Effectiveness. Buffalo: Creative Education Foundation, 1978. Print.

Marland, Sidney P. Education of the Gifted and Talented. Washington: GPO, 1971. Print.

Mendaglio, Sal, and Jean Sunde Peterson. Models of Counseling Gifted Children, Adolescents, and Young Adults. Waco: Prufrock, 2006. Print.

Morrissey, Annie-Marie, and Anne Grant. "Making a Difference for Young Gifted and Talented Children." Education.vic.gov.au. Dept. of Education and Early Childhood Development, State Government of Victoria, 21 Mar. 2014. Web. 15 May 2014.

Pfeiffer, S. “Professional Psychology and the Gifted: Emerging Practice Opportunities.” Professional Psychology: Research and Practice 32.2 (2001): 175–80. Print.

Rivero, Lisa. "Many Ages at Once." Psychology Today. Sussex Publishers, 24 Jan. 2012. Web. 15 May 2014.

Sawyer, R. Keith. Explaining Creativity: The Science of Human Innovation. 2nd ed. New York: Oxford UP, 2012. Print.

Shurkin, Joel N. Terman’s Kids: The Groundbreaking Study of How the Gifted Grow Up. Boston: Little, Brown, 1992. Print.

Winner, Ellen. Gifted Children: Myths and Realities. New York: Basic, 1996. Print.

How are bacterial infections prevented?

Definition

Bacterial infections are infections that are caused by microorganisms called
bacteria. Common bacterial infections include
urinary tract
infection (UTI), strep throat, tuberculosis
(TB), Helicobacter pylori infection, and
methicillin-resistant Staphylococcus aureus (MRSA).

Types of Bacterial Infection

UTI is a bacterial infection of one or more parts of the urinary system. Most UTIs originate in the bladder or urethra, but they also can begin in the kidneys or ureters. Strep throat is an infection of the throat that is caused by the group A Streptococcus (GAS) bacterium. TB is a bacterial infection that affects the lungs. H. pylori is a bacterium that affects the intestinal tract. It causes chronic gastritis and duodenal and gastric ulcers, and it may contribute to the development of gastric cancer. MRSA is a staph infection that has become resistant to the antibiotics that are normally used to treat staph infections.

Prevention

UTIs most commonly occur when bacteria that normally live in the intestine enter the urethra. Other sources of bacteria that can cause UTIs are sexual intercourse, urinary catheters, and obstruction, such as kidney stones or prostate problems.

No vaccine exists for the prevention of UTI. However, one can take the following measures to reduce the risk for UTIs: Drink a minimum of eight glasses of water per day, urinate as soon as possible after intercourse, take showers instead of tub baths, wipe from front to back after urination or bowel movement, avoid spermicidal foams or jellies, and avoid feminine hygiene sprays or douches.

Strep throat is spread through droplets in the air when an infected person sneezes or coughs or by contact with infected objects. As with UTIs, no vaccine exists for the prevention of strep throat. One should take the following measures to reduce the risk of contracting strep throat: Wash hands frequently, especially before preparing or eating food; when possible, avoid contact with people who have strep infections; and avoid sharing personal items such as drinking glasses, eating utensils, and toothbrushes.

TB is spread through droplets in the air when an infected person sneezes or coughs. Although a vaccine has been developed for the prevention of TB, it is not commonly used in the United States. The TB vaccine, which is also known as the Bacillus Calmette-Guérin (BCG) vaccine, does not always protect against TB and could cause a false-positive result in people who are later tested for TB.

Even without the use of the BCG vaccine, there are still some things one can do to prevent the spread of TB. One method is to treat TB-infected persons before their disease becomes active. This involves regular testing of people who may be at risk. For persons who test positive for TB infection, certain medications can be prescribed by doctors to help prevent active disease. Other methods of preventing the spread of TB include covering the nose and mouth with a tissue when coughing or sneezing, opening windows to ventilate rooms if the weather permits, avoiding the workplace when sick, wearing a mask around others, and avoiding close contact with family members for the first few weeks of treatment.

It is not known how H. pylori infection is contracted, so
there are no specific recommendations for prevention. However, to prevent
complications of H. pylori infection, persons with symptoms of
gastritis or gastric or duodenal ulcers are frequently
tested for H. pylori and are treated if found to be infected.

MRSA can be acquired in hospitals and other healthcare settings, and in specific communities, such asnursing homes. MRSA infection is spread through contact with a contaminated person or object. In the health care setting, MRSA is frequently prevented through isolation of infected persons and through practicing standard precautions, such as handwashing and wearing protective gloves and clothing.

There are several measures that one can take to prevent the spread of MRSA in the community setting. These measures include covering wounds with clean, dry bandages until they have healed; frequent handwashing; not sharing personal items, such as towels, wash cloths, or razors; periodic cleaning of frequently touched surfaces with disinfecting wipes; and washing bed linens in hot water.

Impact

According to the National Institute of Diabetes and Digestive and Kidney
Diseases, UTIs account for more than 8 million doctor visits each year in the
United States. UTI is more common in women, and one in five women will get a UTI
at least once during her lifetime. The Centers for Disease Control and Prevention
(CDC) reports that between 9,000 and 11,500 cases of invasive
GAS disease occur each year in the United States, resulting in 1,000 to 1,800
deaths annually.

The World
Health Organization estimates that one-third of the world’s
population is infected with TB at any given time, and that 5 to 10 percent of
infected persons will develop active TB in the future. In 2009, about 1.7 million
people died from TB.

The CDC estimates that approximately two-thirds of the world population is infected with the H. pylori bacterium, and that between 2 and 20 percent of those persons infected will develop ulcers. Furthermore, CDC statistics show that in 2005, more than 94,000 people developed a serious MRSA infection and more than 18,000 people died during a hospital stay related to these infections.

Bibliography

Brachman, Philip S., and Elias Abrutyn, eds. Bacterial Infections of Humans: Epidemiology and Control. 4th ed. New York: Springer, 2009.

Brogden, K., et al. Virulence Mechanisms of Bacterial Pathogens. 4th ed. Washington, D.C.: ASM Press, 2007.

Centers for Disease Control and Prevention. “ Helicobacter pylori: Fact Sheet for Health Care Providers.” Available at http://www.cdc.gov/ulcer/keytocure.htm.

Mayo Foundation for Medical Education and Research. “Tuberculosis.” Available at http://www.mayoclinic.com/health/tuberculosis/DS00372.

_______. “Urinary Tract Infection.” Available at http://www.mayoclinic.com/health/urinary-tract-infection/DS00286.

“Strep Throat.” Available at http://www.webmd.com/oral-health/tc/strep-throat-topic-overview.

What is cardiopulmonary resuscitation (CPR)?

Indications and Procedures

Cardiopulmonary resuscitation (CPR) is generally performed on a person who is in cardiac arrest. In the United States, someone dies from sudden cardiac arrest (SCA) every two minutes. Cardiac arrest occurs when a person has no heartbeats or insufficient heartbeats to pump blood to the brain and other vital organs. Without sufficient blood flow, these organs do not receive enough oxygen to function normally; after about four minutes, they begin to die. This life-threatening situation requires immediate attention to keep the person alive. If medical personnel are not immediately available, then emergency medical services (EMS) should be called and CPR should be initiated.

Cardiac arrest can have many causes. The most common is a severe heart attack. Many heart attacks do not require CPR, but if a person is unconscious with no pulse, then CPR should begin as soon as possible. Other causes of cardiac arrest that may require CPR are drowning, suffocation, drug overdose, electrocution, stroke, and other types of brain damage. In each of these situations, the heart is not contracting and pumping blood.

CPR includes two distinct operations, breathing air into the person’s lungs and compressing the chest. In mouth-to-mouth breathing, sometimes called artificial respiration,
the rescuer breathes air into the person’s lungs, causing the chest to rise and fall with each breath. The rescuer’s expired air is 16 percent oxygen, as compared with 21 percent oxygen in room air. This expired air has enough oxygen to maintain life. It is recommended that an individual providing mouth-to-mouth breathing use a protective device, such as a CPR mask or shield, to avoid transmission of potentially infectious body fluids. The mask or shield devices can be purchased for a small cost online or from uniform stores or university medical bookstores.

Chest compressions involve the application of pressure to the lower half of the breastbone. The external pressure increases the pressure in the chest, pushing blood to the brain and the rest of the body. Although this procedure circulates only 25 to 33 percent of normal blood flow, it is sufficient to keep the person alive when used in conjunction with mouth-to-mouth breathing.

In an emergency situation, CPR can be administered by one or two people. One person can alternate mouth-to-mouth breathing and chest compressions. Performing CPR for several minutes, however, can be exhausting. If two certified rescuers are present, one can do the mouth-to-mouth breathing while the other performs chest compressions. Two people can do the procedure more efficiently and for longer periods of time.

Uses and Complications

Cardiopulmonary resuscitation should be used only if a person is suffering from cardiac arrest. There are no other applications. Even when CPR is correctly performed by experienced, certified medical personnel, injury can occur to the individual receiving CPR. These injuries may include broken ribs, bruising of the heart, and tearing of the liver and/or the spleen. However, these injuries should not deter an individual from performing CPR. Cardiopulmonary resuscitation is only performed when a person is clinically dead, without a pulse or respiration. Individuals should take a course and become certified to learn the most effective and safest techniques.

Effective CPR sends oxygen to the vital organs to prevent permanent tissue death, but it cannot alter abnormal electrical energy that may be occurring in the heart muscle. This abnormal electrical energy does not allow the heart to pump blood adequately throughout the body. Medical attention is generally needed to restart the heart contractions, and CPR must be continued until EMS personnel arrive. Emergency medical personnel will defibrillate the heart by sending an electric shock through the chest in an attempt to correct the abnormal electrical energy in the heart so that it can resume normal contractions.

Almost anyone can become certified in CPR. The American Heart Association and the American Red Cross offer classes with certification. These organizations are also involved in campaigns to have as many people certified as possible because CPR doubles a victim’s chances of sudden cardiac arrest survival. Therefore, the more people that are certified, the more likely it is that someone can perform CPR in an emergency and the more likely it is the victim will survive.

Another program to reduce deaths from sudden cardiac arrest includes the use of automated external defibrillators (AEDs). These units are computerized and allow a person with minimal training to defibrillate a heart. An AED unit has simple steps to follow with voice and print instructions. The machine has built-in safety features to prevent a person from receiving defibrillation that is not needed. AED units have been placed in work sites, stadiums, airports, and other places where large numbers of people are found. Designated people in these areas are trained to use the AEDs. If the first defibrillation shock is administered within six minutes, then the victim has an approximately 45 percent chance of survival.

Perspective and Prospects

Mouth-to-mouth breathing dates to biblical times, when it was used by midwives to resuscitate newborns. However, it fell out of practice until the 1950s, when it was rediscovered by James Elam and Peter Safer. In 1960, other physicians found that chest compressions could attain sufficient circulation, and these compressions were combined with mouth-to-mouth breathing to create a CPR procedure similar to what is used today.

Bibliography

American Academy of Orthopaedic Surgeons and Alton L. Thygerson. First Aid, CPR, and AED. 6th ed. Sudbury, Mass.: Jones and Bartlett, 2011.

American Heart Association. “2005 AHA Guidelines for CPR and ECC.” http://www.americanheart.org, 2013.

American Red Cross.American Red Cross First Aid: Responding to Emergencies. 4th rev. ed. Yardley, Pa.: StayWell, 2007.

Bergeron, David J., et al. First Responder. 8th ed. Upper Saddle River, N.J.: Pearson/Prentice Hall, 2009.

“CPR: Are We Doing It Wrong?” Harvard Health Letter 30, no. 7 (May, 2005): 1–3.

Finucane, Brendan T., and Albert H. Santora. Principles of Airway Management. 4th ed. New York: Springer, 2011.

Kohnle, Diana. "Cardiopulmonary Resuscitation for Children Age 1 to Early Teens." Health Library, March 15, 2013.

Kohnle, Diana. "Cardiopulmonary Resuscitation for Infants." Health Library, March 15, 2013.

Kohnle, Diana. "Cardiopulmonary Resuscitation for Teens and Adults." Health Library, March 15, 2013.

MedlinePlus. "CPR." MedlinePlus, May 22, 2013.