Question

vessels is found in which of the following layers? A. tunica adventitia (B,tunica media C. tunica intima D. all of the above 35.The most important mechanism of exchange between blood and tissue fluid is: A. transcytosis B. diffusion C. filtration D. active transport 36. Blood vessels that connect two capillary networks are called: A. portal systems B. anastomoses C. arterial systems D. veins 37. Vasodilation may be brought about by A. Histamine C. high blood carbon dioxide D. angiotensin II B. high blood oxygen 38. When net filtration capillary than leaves it A. True B. False pressure is greater than net re-absorption pressure more fluid enters the 39. This into the superior vena cava: A. azygos vein hemiazygous vein E.right internal jugular vein vein receives blood returning from all areas of the posterior thoracic wall before it empties D. accessory C. hemiazygos vein B. right brachiocephalic vein 40. These structures, present in medium-sized veins, prevent backflow of blood: A. precapillary D. fenestrations C.skeletal muscles B. venous tunica E. venous valves sphincters 41. A fetal heart structure that allows blood to bypass the pulmonary circulation is the: A. foramen spinosum B. foramen ovale C. ductus venosus D. umbilical veins 42. Which of the following is not an example of a teratogen? A. virusB. pesticides C.alcohol D. cigarette smoking
35-42

Answer 1

35. Answer: B

• Diffusion is Physical movement of molecules or ions, from higher concentration to lower concentration.
• Molecules diffuseto and from blood and tissues.

36. Answer: A

• Portal system connects capillaries with other capillary systems.

• Hepatic portal venous system circulation includes capillary bed pools into another capillary bed through veins, without first going through the heart.

37. Answer: A

• Histamines are generated by basophils and mast cells in body.
• They are nitrogenous compounds stimulating hypersensitivity reactions like vasodilation.

38. Answer B.

• Net filtration pressure: It is the interaction of hydrostatic pressure, blood colloid osmotic pressure and interstitial fluid osmotic pressure.
• Re-absorption pressure: pressure that mediate movement of fluid back to the capillaries. It is mainly osmotic pressure.
• When re-absorption is occurring, net filtration pressure is negative.
• Higher NFP drives fluid out.
• NFP = Filtration -reabsorption (filtration referring to movement of fluid out of capillary).

39. Aswer: A

• Azygos vein is a part or extension of ascending Lumbar vein.
• The branches of the azygous vein receives blood from the thoracic region and joins the superior vena cava.

40. Answer: E

• Medium sized veins contain venous valves.
• These valves prevent back flow of blood under pressure or ascending limbs.

41. Answer: B

• Foramen ovale is an oval opening connecting two atria to bypass pulmonary circulation.
• Foramen ovale should naturally closed after birth.

42. B

• Teratogens are agents that cause fetal deformation when exposed during pregnancy.
• Virus like Rubella, CMV, HIV are teratogenic.
• Alcohol and nicotine use during pregnancy may cause teratogenic effect.
• Chemical agents acting as teratogens are PCB, herbicide.
• Fluoride or fluorinated pesticides may be teratogenic.
• Possible effect of pesticides as teratogens are under evaluation.