Embryology Practice Questions With Answers |120 Questions| With Correct Answers.

73. The remnant of the first aortic arch artery is: A. stapedial artery B. internal carotid artery C. maxillary artery D. common carotid artery E. the 1st arch artery regresses without remnants {Ans: C. is correct. First arch becomes maxillary; 2nd arch remnants are stapedial and hyoid arteries; 3rd arch becomes common and proximal internal carotid arteries; 4th arch becomes proximal right subclavian and part of arch of aorta; 6th arch becomes proximal pulmonary arteries and ductus arteriosus.}80. Abnormal intestinal rotation during fetal development may produce the following: A. congenital umbilical hernia B. annular pancreas C. infarction and gangrene D. diaphragmatic hernia E. Meckel's diverticulum or diverticulum ilei {Ans: C. is correct. Abnormal rotation of the intestinal loop causes it to return to the abdomen in a different order, with the colon being the first to return to the gut. This positions things backwards, and the gut may twist abnormally. Such twisting or volvulus can obstruct the blood supply to the gut, resulting infarction and gangrene.}7. Capacitation of the sperm: A. is caused by the zona pellucida B. occurs in the male C. prevents polyspermy D. is essential for fertilization E. removes the head of the sperm