19. Which of the following is the first step of hemostasis? A) formation of a pl

Question

19. Which of the following is the first step of hemostasis? A) formation of a platelet plug B) formation of a blood clot C) formation of a fibrin clot D) vascular spasm E) secretion of histamine 20. The coagulation cascade is essential in the formation of the platelet plug. A) True B) False 21. The formation of a platelet plug is inhibited by healthy endothelial cells through their release of- A) nitric oxide B) thromboxane A2 C) prostacyclin D) both A and B E) both A and C 22. Which of the following processes is NOT a part of external respiration? A) the movement of air into and out of the lungs by bulk flow B) the exchange of oxygen and carbon dioxide between the lungs and blood by diffusion C) the transportation of oxygen and carbon dioxide between the lungs and body tissues by the blood D) the exchange of oxygen and carbon dioxide between the blood and tissues by diffusion E) the use of oxygen and generation of carbon dioxide by the mitochondria during energy metabolism 23. The upper airway refers to the passageway for air that is located within the head and neck A) True B) False 24. The difference between what two pressures drives air into and out of the lungs? A) pulmonary venous and atmospheric B) central venous and intracoronary C) intrapleural and intra-alveolar D) atmospheric and intra-alveolar E) atmospheric and intrapleural

Explanation / Answer

Ans 19-. The term hemostasis means prevention of blood loss. Whenever a vessel is ruptures the first step is

D) vascular spasm then , formation of a platelet plug progressing to formation of a blood clot as a result of blood coagulation and lastly eventual growth of fibrous tissue into the blood clot to close the hole in the vessel permanently.

Ans 20- B) False because when platelets comes in contact with a damaged vascular surface such as the collagen fibers, they begin to swell; their contractile proteins contract forcefully and cause the release of granules that contain multiple active factors; they become sticky and adhere to collagen and to a protein called Von Willen rand factor that spreads throughout the plasma; they secrete large quantity of ADP and their enzymes form Thromboxane A2. The stickiness of these additional platelets causes them to adhere to the originally activated platelets. Therefore, at the site of any rent in a blood vessel wall, the tissues elicit activation of increasing numbers of platelets that themselves attract more platelets, forming platelet plug.

Ans 21) E) Both A & C

Ans 22). E) The use of oxygen and generation of carbon di oxide by the mitochondria during energy metabolism.

Ans 23) A) True

Ans 24) C) Intrapleural and intraalveolar are the two pressures also called transpulmonary pressure that drives air into and out of the lungs.

Ans 25) E) Atmospheric pressure is constant during the respiratory cycle.

Ans 26) B) Rebound pressure (elastic recoil) is the distending force on the lungs and also causes lung expansion and contraction.

Ans 27) E) Total lung Capacity is the tidal volume+inspiratory reserve volume+expiratory reserve volume+residual volume.

Ans 28) A) Each gas acts independently and diffuses down it's own partial pressure gradient best describes why oxygen and carbon di oxide can both be exchanged simultaneously.

Ans 29) A) Hyperventilation is an increase in alveolar ventilation to match the demands of increased metabolic activity in the cells.

Ans 30) The majority of oxygen present within the blood is

B) Bound to hemoglobin in Red Blood Cells I.e, 4 oxygen bounded to one hemoglobin.

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