test questions

Question 1

Pathway of O2 from mother to foetus via placenta

Answer 1

• Placenta is attached to foetus by umbilical cord
• Inside umbilical cord are two uterine arteries which carry blood to the capillaries of the chorionic villi.
• A single umbilical vein carries blood from placenta, through the umbilical cord, back to foetus.
• On the maternal side, oxygenated blood from the mother enters the placenta through the uterine arteries, flows through the blood spaces where exchange of nutrients and wastes occurs and then leaves again through uterine veins.

Question 2

List 2 foetal heart features

Answer 2

Blood returning to foetal heart enters right atrium. As lungs are collapsed and not functioning at this stage, they offer considerable resistance to blood flow and little blood reaches the lungs. Most of the blood flows through the ductus arteriosus to the aorta. The ductus arteriosus is a vessel that bypasses the lung, allowing blood in pulmonary to flow directly into the aorta.

Blood entering right atrium might flow through to left atrium through an oval opening between the two chambers. This opening is called the foramen ovale. This is located so that most of the blood entering right atrium goes through it. Beneficial as blood coming from placenta is highly oxygenated and can flow to developing foetal tissues via aorta very quickly.

Question 3

Immune, nutritional, and respiratory role of placenta

Answer 3

Immune - transports antibodies from mother into he foetal blood supply so that the foetus has immunity to some infectious diseases

nutritional - transports nutrients and minerals from mothers blood to foetal blood.

respiratory - transports O2 from mother to foetus and CO2 from foetus to mother.

Question 4

what happens at the 4th month of pregnancy

Answer 4

• expansion and noticeable bulge of womans abdomen

- mother may begin to detect movements such as stretching of arms and legs