Introduction to male embryology and spermatogenesis

Question 1

what do supporting cells in males which are derived from the surface epithelium of the testis become and what happens at the same time

Answer 1

sustentacular cells, or Sertoli cells.

At about the same time, PGCs give rise to spermatogonial stem cells

Question 2

what happens to the sex cords in males shortly after puberty

Answer 2

they acquire a lumen and become the seminiferous tubules

Question 3

At regular intervals, cells emerge from this stem cell population to form ____________

Answer 3

typeA spermatogonia and their production marks the initiation of spermatogenesis

Question 4

The last cell division produces type B spermatogonia which ______________

Answer 4

divide to form primary spermatocytes

Question 5

describe formation of spermatids.

Answer 5

Primary spermatocytes then enter a prolonged prophase (22 days) followed by rapid completion of meiosis I and formation of secondary spermatocytes. During the second meiotic division, these cells immediately begin to form haploid spermatids

Question 6

from the time type A cells leave the stem cell population to formation of spermatids why is cytokinesis incomplete

Answer 6

so that successive cell generations are joined by cytoplasmic bridges

Question 7

________________________ remain embedded in deep recesses of Sertoli cells throughout their development.

Answer 7

spermatogonia and spermatids

Question 8

what is the function of the sertoli cells

Answer 8

support and protect the germ cells, participate in their nutrition, and assist in the release of mature spermatozoa

Question 9

how does LH work

Answer 9

it binds to receptors on Leydig cells and stimulates testosterone production, which in turn binds to Sertoli cells to promote spermatogenesis

Question 10

what is the function of FSH

Answer 10

binds to Sertoli cells and stimulates testicular fluid production and synthesis of intracellular androgen receptor proteins.

Question 11

what changes occur during spermiogenesis

Answer 11

1. formation of the acrosome
2. condensation of the nucleus
3. formation of neck, middle piece, and tail
4. shedding of most of the cytoplasm

Question 12

what phagocytize residual bodies

Answer 12

sertoli cells

Question 13

where do spermatozoa go after being fully formed

Answer 13

enters the lumen of seminiferous tubules, pushed towards the epididymis by contractile wall of seminiferous tubules.

Question 14

where do spermatozoa gain full motility

Answer 14

in the epididymis

Question 15

what are he most common chromosomal abnormalities in abortuses?

Answer 15

45, X (turner syndrome), triploidy and trisomy 16

Question 16

what is down syndrome caused by

Answer 16

extra copy of chromosome 21 (trisomy 21)

Question 17

what causes patau syndrome

Answer 17

trisomy 3

Question 18

what causes Klinefelter syndrome

Answer 18

The cells have 47 chromosomes with a sex chromosomal complement of the XXY type and a sex chromatin (Barr) body is found in 80 % of cases

Question 19

what causes Turner’s Syndrome

Answer 19

45, X karyotype

Question 20

what causes cri-du-chat syndrome

Answer 20

caused by partial deletion of short arm of chromosome 5

Question 21

what causes Angelman’s Syndrome

Answer 21

Microdeletion occurs on the long arm of chromosome 15 (15q11-15q13).

Question 22

what causes Prader-Willi Syndrome

Answer 22

micro-deletion occurs on the paternal chromosome

Question 23

what causes DiGeorge Syndrome

Answer 23

deletion in 22q11

Question 24

what is used to assess chromosome number and integrity and what is its requirement

Answer 24

Cytogenetic analysis requiring it in only dividing cells

Question 25

what does FISH (Fluorescence in situ hybridization) use

Answer 25

specific DNA probes to identify ploidy for a few selected chromosomes and for detecting microdeletions bu hybridizing chromosomes

Question 26

what do micro-arrays use

Answer 26

use spots of specific DNA sequences (probes) attached to a solid surface, usually glass or silicon.

Question 27

what can micro-arrays detect

Answer 27

Results can detect single nucleotide polymorphisms, mutations and changes in expression levels