Embryology

Question 1

A zygote is

Answer 1

a combination of 2 cells, sperm and ova

Question 2

an embryo is

Answer 2

4 to 8 weeks old

Question 3

a fetus is

Answer 3

past 8 weeks

Question 4

what is the 16-cell stage of life called

Answer 4

morula

Question 5

Cytogenesis is

Answer 5

development of cells

Question 6

histogenesis is

Answer 6

formation of cells into tissues

Question 7

organogenesis

Answer 7

formation of organs from tissues

Question 8

what are the ectoderm, mesoderm, endoderm. What organs do each develop?

Answer 8

the three layers that the embryo consists of. Ectoderm develops the CNS, Mesoderm develops the circulatory/urinary sytems. the Endoderm develops the lungs and intestines.

Question 9

Why does it take 2 weeks after menstruation for the conception to take palce

Answer 9

the ova is not released until ovulation

Question 10

what is a yolk sac

Answer 10

the pre-placenta that provides the fetus with nutrients

Question 11

what is the first system to become functional in the embryo? when?

Answer 11

the cardiovascular system. 5-6 weeks

Question 12

what does the umbilical vein do?

Answer 12

brings oxygenated blood with nutrients from the placenta to the fetus

Question 13

what do the 2 umbilical arteries do?

Answer 13

they bring deoxygenated blood from the fetus to the placenta

Question 14

What do the vitelline veins become?

Answer 14

The IVC, SMV, IMV, Hepatic and Portal Veins

Question 15

What does the portal vein develop from? When does it form?

Answer 15

The portal vein develops at week 8 from the vitelline veins.

Question 16

What do the vitelline arteries become?

Answer 16

SMA, IMA, Celiac

Question 17

Which section of the IVC originates from the proximal vitelline vein

Answer 17

hepatics

Question 18

Which 2 sections of the IVC originate from the subcardinal vein

Answer 18

Prerenal and Renal sections

Question 19

Which 2 sections of the IVC originate from the supracardinal vein

Answer 19

renal and postrenal sections

Question 20

When and where does the liver begin formation

Answer 20

Formed at 4 weeks by the ventral diverticulum

Question 21

What is Ductus venosus? Where is it located

Answer 21

It is a duct in the liver that connects the umbilical vein and IVC.

Question 22

What is the gallbladder formed by? Is it visible sonographically?

Answer 22

It is formed by the hepatic diverticulum. It is present in sonography but nonfunctional.

Question 23

which vein becomes ligament teres after birth? Which becomes ligament venosum?

Answer 23

The umbilical vein becomes ligament teres and ductus venosus becomes ligament venosum.

Question 24

What do the dorsal and ventral buds come from

Answer 24

the primitive foregut

Question 25

What does the dorsal bud of the pancreas do?

Answer 25

the dorsal portion forms the body and tail of the pancreas.

Question 26

What does the ventral bud of the pancreas do?

Answer 26

The ventral bud forms the head of the pancreas. It rotates to fuse with the dorsal portion.

Question 27

When does the spleen form? When does it start producing red and white blood cells?

Answer 27

It forms at week 5 of gestation and starts hematopoesis at week 11

Question 28

Where do the kidneys form?

Answer 28

In the pelvis. They migrate up.

Question 29

What are the 3 stages of kidney development and when do they occur?

Answer 29

Pronephros- week 4, mesonephros and metanephros at week 5 but they don't become functional until week 8

Question 30

What does the Foregut form?

Answer 30

mouth, stomach, liver, pancreas

Question 31

What does the Midgut form?

Answer 31

distal duodenum, proximal colon

Question 32

What does the Hindgut form?

Answer 32

remainder of the colon

Question 33

When does the herniation of the midgut occur? How does it appear sonographically?

Answer 33

Week 5-10. The midgut herniates out of the abdomen and rotates before returning to the abdomen.

Question 34

Are the Wolffian ducts part of the male or female genital tract

Answer 34

male

Question 35

Where do the testicles develop

Answer 35

in the upper abdomen near the kidneys

Question 36

How and When do the testicles get to their final location

Answer 36

In month 4, the testes descend to the level of the bladder until month 7 when they descend into the scrotum.

Question 37

Where do congenital malformations of the uterus come from?

Answer 37

They result from the incomplete fusion or agenesis of the Mullerian ducts

Question 38

When do mammary ridges develop?

Answer 38

They are visible by week 6 and have buds by week 8.

Question 39

What part of the primitive brain is formed at 3-4 weeks?

Answer 39

the neural tube

Question 40

What does the forebrain develop

Answer 40

Olfactory bulbs, optic tracts, pituitary glands

Question 41

What does the midbrain develop?

Answer 41

Thalamus and Hypothalamus