Book Questions

Question 1

During spermatogenesis histone is replaced by what to allow for better packing of condensed chromatin ?

Answer 1

Proamine

Question 2

What cell type is located outside the blood testis barrier?

Answer 2

Primary spermatocyte

Question 3

Which of the following cells normally participates in mitotic divisions?

a. primary oocyte
b. oogonium
c. primary spermatocyte
d. spermatid
e. secondary spermatocyte

Answer 3

oogonium

Question 4

In a chest x ray the radiologist sees what looks like teeth, what is the probably embryological explination?

Answer 4

Primordial germ cells did not migrate correctly leading to a mediastinal teratoma.

Question 5

When does meiosis begin in the female and in the male?

Answer 5

In females meiosis begins during embryonic life and in males it begins at puberty.

Question 6

What stage in meiosis is oogenesis arrested in ?

Answer 6

Diplotene stage shortly after birth up until puberty. After puberty at the beginning of each cycle some will resume meiosis until metaphase II.

Question 7

What is the underlying cause of spontaneous abortions in early weeks of pergnancy?

Answer 7

Chromosome abnormalities

Question 8

What is the difference between spermatogenesis and spermiogenesis?

Answer 8

Spermatogenesis is the entire process of sperm formation from a spermatogonium, including two meiotic divisions and spermiogenesis. Spermiogenesis is the process of transformation from a postmeiotic spermatid to a highly specialized spermatozoon.

Question 9

The actions of what hormones are responsible for the changes in the endometrium during menstrual cycle?

Answer 9

Estrogen secreted by the ovary support proliferative phase. Progesterone is secreted by CL and responsible for secretory phase which prepares for implantation.

Question 10

Sertoli cells in the testis are stimulated by what two major reproductive hormones?

Answer 10

FSH from AP and testosterone secreted by the Leydig cells of the testis

Question 11

Of the barriers to sperm survival and transport within the female tract, low pH is most important in what structure?

Answer 11

Vagina

Question 12

The principal energy source for ejaculate spermatozoa is?

Answer 12

Fructose in the seminal vesicle fluid

Question 13

What is the principal hormone stimulus for ovulation?

Answer 13

Surge in LH

Question 14

What is capacitation?

Answer 14

Step required for sperm to undergo acrosomal reaction, it requires the binding of sperm to tubal epithelium and removes cholesterol from sperm

Question 15

Name two functions of ZP3 protein of the Zona Pellucida?

Answer 15

1. stimulates acrosomal reaction through G proteins

2. Exchanges sodium and hydrogen ions to increase pH

Question 16

What is polyspermy and how is it prevented after spermatozoon enters?

Answer 16

Polyspermy is when multiple sperm fertilize the egg. It is blocked by fast electrical block and then slow block or zona reaction that releases granules to inactivate sperm receptors in the ZP.

Question 17

A woman gives birth to septuplets, what is the likely reason for multiple births?

Answer 17

She most likely took clomiphene to stimulate ovulation. Natural septuplets arent seen often.

Question 18

When multiple oocytes obtained by laparoscopy are fertilized in vitro why are up to three embryos implanted and why are others frozen?

Answer 18

Multiple embryos are implanted to enhance the chances of the embryo surviving until birth. The remaining are frozen in case pregnancy does not result the first time it can be re done.

Question 19

What are some functions of the zona pellucida?

Answer 19

Promotes maturation of the oocyte and follicle.

Serves as barrier that allows sperm of same species in.

Modified ZP prevents additional sperm entry after fertilization

Serves as immunological barrier between mom and baby

Prevents premature implantation of cleaving embryo into the wall of uterine tubes.

Question 20

What is the most common condition associated with spontaneously aborted embryos?

Answer 20

Chromosomal abnormalities

Question 21

What tissue from the implanting embryo directly interfaces with endometrial CT?

Answer 21

Syncytiotrophoblast

Question 22

Identical twinning is made possible by what process of early embryo?

Answer 22

Regulation

Question 23

What is the importance of the inner cell mass of the cleaving embryo?

Answer 23

The embryonic body proper arises from ICM

Question 24

Parental imprinting is a phenomenon that shows certain homologous maternal and paternal chromosomes have different influences on development. Excess paternal influences result in abnormal dev. of what type of tissue at the expense of dev. of the embryo?

Answer 24

Trophoblastic tissues

Question 25

What is the functions of integrins in implantation?

Answer 25

They allow the trophoblast of the embryo to adhere to uterine epithelium

Question 26

What is the cellular origin of syncytiotrophoblast of the implanting embryo?

Answer 26

Cells are derived from the cytotrophoblast and fuse to form this.

Question 27

What is a homeobox?

Answer 27

a highly conserved sequence of 180 nucleotides that codes for 60 aa found i n homeodomain TF proteins.

Question 28

Which of the following is a TF?

a. FGF
b. Pax
c. TGF
d. Notch
e. Wnt

Answer 28

Pax

Works with Sox to affect the lens

Question 29

Where in the cell is RA receptor located?

Answer 29

Nucleus

Question 30

A mutation of what receptor is basal for carcinomas of the skin?

Answer 30

Patched

Question 31

Zinc fingers or helix loop helix arrangements are members of what class of molecules?

Answer 31

Transcription factors

Question 32

Sonic hedgehog is produced in which signaling center?

Answer 32

The notochord, intestinal portals, floor plate of neural tube, zone of polarizing activity in the limb bud