Lesson 3A (Part 3)

Question 1

What happens during the feto-placental circulation (fetal aspect)? (2)

Answer 1

1. The umbilical cord will develop fetal capillaries which extend into the terminal villi
2. The membranes of the terminal villi are very thin, and allow the transfer of gases (O2 and CO2) and nutrients

Question 2

When does the umbilical cord develop?

Answer 2

In the 6th weeks

Question 3

What does the umbilical cord contain? (2)

Answer 3

1. 1 umbilical vein

2. 2 umbilical arteries

Question 4

What kind of blood is in the umbilical vein?

Answer 4

Oxygenated

Question 5

What kind of blood is in the umbilical arteries?

Answer 5

Deoxygenated

Question 6

What happens if villi go into the basilis layer?

Answer 6

It will cause pathology

• cause damage to the uterus
• creates abnormal bleeding

Question 7

What does gastrulation involve?

Answer 7

The changing of the epiblast of bilaminar disk into a 3 layer gastrula

Question 8

What does gastrulation begin with the formation of?

Answer 8

With the formation of a primitive streak

Question 9

What does the formation of the primitive streak give the embryo? (2)

Answer 9

1. A midline and allows symmetrical growth

2. A specific cephalad-caudad or dorsal-ventral orientation

Question 10

What does gastrulation result in? (3)

Answer 10

1. Ectoderm
2. Mesoderm
3. Endoderm

Question 11

What does the endoderm form? (9)

Answer 11

1. GI tract
2. Liver
3. Pancreas
4. Urinary bladder
5. Epithelial parts of trachea
6. Lungs
7. Pharynx
8. Thyroid
9. Parathyroid

Question 12

What does the mesoderm form? (8)

Answer 12

1. Kidneys
2. Gonads
3. Cartilage
4. Skeletal muscle
5. Dermis
6. The circulatory system
   - including the heart
7. Spleen
8. The wall of the gut

Question 13

What does the ectoderm form? (13)

Answer 13

1. Nervous system
2. Epidermis
3. Hair
4. Nails
5. Lens of the eye
6. Sebaceous glands
7. Cornea
8. Tooth enamel
9. Epithelium of mouth and nose
10. Adrenal medulla
11. Melanocytes
12. Facial cartilage
13. Retina