Author Question: A student has read that hematopoiesis occurring in the wall of the yolk sac declines after the ... (Read 54 times)

audragclark · **on:** Jun 28, 2018

A student has read that hematopoiesis occurring in the wall of the yolk sac declines after the eighth week of gestation and asks the instructor for clarification. What statement by the faculty member is most accurate?

A.
All of the blood needed is transported across the placenta.
B.
Bone marrow production of blood begins in week 8.
C.
The fetal liver takes over that function then.
D.
You must have misread that information.

Question 2

A couple wishes to know the chances of passing on an X-linked dominant heritable disorder to their four sons. The father's family has the disorder.

The sons appear healthy, but the couple wants to be prepared for possible future events related to the disease. What information does the nurse give them?

A.
All of them will be affected.
B.
Half of them will be affected.
C.
None of your sons will be affected.
D.
One of the four will be affected.

Brenm · **Reply #1 on:** Jun 28, 2018

Answer to Question 1

ANS: C
Formation and development of red blood cells (hematopoiesis) occurs in the wall of the yolk sac beginning in the third week. The function gradually declines after the eighth gestational week when the fetal liver begins to take over this process.

Answer to Question 2

ANS: C
An X-linked dominant inheritance disorder is the result of an alteration in a gene located on an X chromosome. None of this couple's sons can be affected because boys get a Y chromosome from the father, whereas all of a man's daughters will have it.