Clinically Oriented Anatomy
Keith Leon MooreSözler ve Alıntılar
Two heart sounds are heard with a stethoscope: a lub (1st) sound as the blood is transferred from the atria into the ventricles, and a dub (2nd) sound as the ventricles expel blood from the heart. The heart sounds are produced by the snapping shut of the one-way valves that normally keep blood from flowing backward during contractions of the heart.
Sayfa 357
Stomach
The stomach acts as a food blender and reservoir; its chief function is enzymatic digestion. The gastric juice gradually converts a mass of food into a semi-liquid mixture, 'chyme', which passes fairly quickly into the duodenum. An empty stomach is only of slightly larger caliber than the large intestine; however, it is capable of considerable expansion and can hold 2-3 L of food.
Sayfa 453
Gastric ulcers
Most ulcers of the stomach (gastric ulcers) and duodenum are associated with an infection of a specific bacterium, "Helicobacter pylori" (H. pylori). People experiencing severe chronic anxiety are most prone to development of peptic ulcers. They often have gastric acid secretion rates that are markedly higher than normal between meals. It is thought that the high acid in the stomach and duodenum overwhelms the bicarbonate normally produced by the duodenum and reduces the effectiveness of the mucous lining, leaving it vulnerable to H. pylori. The bacteria erode the protective mucous lining of the stomach, inflaming the mucosa and making it vulnerable to the effects of the gastric acid and digestive enzymes (pepsin) produced by the stomach.
Sayfa 479
Alveoli
The pulmonary alveolus is the basic structural unit of gas exchange in the lung. Due to the presence of the alveoli, the respiratory bronchioles are involved both in air transportation and gas exchange... New alveoli continue to develop until about age 8 years, by which time there are approximately 300 million alveoli.
Sayfa 336
Epistaxis (nosebleed)
Epistaxis (nosebleed) is relatively common because of the rich blood supply to the nasal mucosa. In most cases, the cause of nosebleed is trauma and the bleeding is from an area in the anterior third of the nose (Kiesselbach area). Epistaxis is also associated with infections and hypertension. Spurting of blood from the nose results from rupture of arteries. Mild epistaxis may also result from nose picking, which tears veins in the vestibule of the nose.
Sayfa 972
Dextrocardia
Abnormal folding of the embryonic heart tube to the left instead of the right may cause the position of the heart to be completely reversed so that the apex is misplaced to the right instead of the left-- dextrocardia. This congenital anomaly is the most common positional abnormality of the heart, but it is still relatively uncommon. Dextrocardia is associated with mirror image positioning of the great vessels and arch of the aorta.
Sayfa 354
The circulatory system of the myocardium is unique in that the coronary arteries fill during ventricular diastole as a result of aortic recoil. They are typically (but not necessarily) functional end arteries.
Sayfa 381