Describe the cardiac cycle
What will be an ideal response?
During ventricular filling, the AV valves are open and the semilunar valves are closed. Blood is returning to the atria and passively flowing into the ventricles. As blood accumulates in the ventricle, pressure increases and blood flow into it slows down. At this point the SA node fires, P wave occurs, atria are depolarized and contract pushing more blood into the ventricle. Electrical impulse travels through the AV node, AV node fires, QRS complex occurs, ventricles contract, pressure rises in ventricles, AV valves are forced closed, first heart sound occurs. Ventricle continues to contract, pressure rises and forces semilunar valves open, blood leaves the ventricles. T wave occurs, ventricles repolarize and relax. Pressure in ventricles falls, blood starts to fall back toward the heart, semilunar valves close to prevent backflow into ventricle, second heart sound occurs. During ventricular relaxation the atria are filling with blood and pressure in the atria is rising. When atria pressure exceeds ventricular pressure the AV valves are forced open and the cycle repeats
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The respiratory system
a. obtains oxygen from and eliminates carbon dioxide to the internal environment. b. consists of the heart, blood vessels and lungs. c. plays an important role in maintaining the proper pH of the internal environment by adjusting the rate of removal of acid-forming carbon dioxide. d. both (a) and (c) above. e. all of these answers.
A muscle twitch differs from a tetanic contraction in that:
A) the tetanic contraction is considered abnormal, while the twitch is a normal muscle response B) the tetanic contraction is caused by a single stimulus, while the twitch is caused by very rapid multiple stimuli C) the muscle twitch is prolonged and continuous while a tetanic contraction is brief and jerky D) the muscle twitch occurs only in small muscles while a tetanic contraction occurs in large muscle groups E) the muscle twitch is a brief and jerky movement, while the tetanic contraction is prolonged and continuous
A 58-year-old man is admitted to a hospital with severe abdominal pain, nausea, and vomiting resulting in dehydration. Emergency CT scan reveals a tumor located between the celiac trunk and the superior mesenteric artery. Which of the following structures is likely compressed by this tumor?
(A) Fundus of the stomach (B) Neck of the pancreas (C) Transverse colon (D) Hepatopancreatic ampulla (E) Duodenojejunal junction
What is epidemiology?
A. How widespread the occurrence of the disease may be B. The rate and range of the occurrence of the disease C. The study of how disease affects the overall health and well-being of a population D. None of these answers are correct