spermatogenesis

Question 1

in order to have a constant production of spermatozoids, males must have adequate secretion of GnRH, what hypothalamic center is the only active in males?

Answer 1

tonic center

Question 2

IN seminiferous tubules at the interstitial compartment we can observe what cells that express what type of receptor to synthesize this specific hormone?

Answer 2

leydig cells express LH receptors an synthesize Testosterone

Question 3

At the adluminal compartment what cells are observed and they express what receptors resulting in the synthesis of what hormone?

Answer 3

Sertoli cells express FSH receptors ad synthesize estradiol

Question 4

Spermiation

Answer 4

once formed the release of spermatozoids from Sertoli cells into the lumen of the seminiferous tubule

Question 5

Cycle of the Seminiferous tubules

Answer 5

period of time required for a group of cells in a section of seminiferous tubule to pass through all of the stages

Question 6

Spermiogenesis

Answer 6

morphological conversion of round spermatid into spermatozoa

Question 7

spermatogenesis

Answer 7

cellular mechanisms that provide continuous supply of male gametes

Question 8

During this phase of the Spermiogenesis the Acrosome forms a distinct cap over nucleus, the remaining Golgi apparatus move away from nucleus and and a primitive flagellum forms from distal centriole

Answer 8

the Cap phase

Question 9

what is the precursor of hormones such as progesterone, estradiol and testosterone?

Answer 9

Cholesterol

Question 10

During this phase of the Spermiogenesis the Manchette migrates towards tail and the mitochondria cluster on the neck of the flagellum

Answer 10

The Maturation phase

Question 11

During this phase of the spermiogenesis the Acrosome continues to spread and develop around the nucleus, the nucleus elongates and the Machete forms- microtubules, postnuclear cap

Answer 11

the Acrosomal phase

Question 12

During the initial phase of the Spermiogenesis the Glogi apparatus packages enzymes that eventually will become the acrosome, also initial arrangement of cellular organelles

Answer 12

The Golgi phase

Question 13

how many meiotic divisions are necessary to reduce a haploid spermatid?

Answer 13

2

Question 14

how long does it take for a spermatogonia cell to become spermatozoid in bulls?

Answer 14

60-61 days

Question 15

what is the normal spermatozoid motility in a semen collection to consider the sample optimal?

Answer 15

at least 60%

Question 16

what is the physiological function of dihydrotestosterone in males?

Answer 16

various embryological structures develop, regulates along with prostate function, aids in increasing Sertoli cell, spermatogonial and spermatocyte populations

Question 17

the presence of a small amount of cytoplasm in the ejaculated spermatozoid is due to

Answer 17

over use of the male, epididymal issues, lack of transportation time in epididymis and disease

Question 18

in what organ the spermatozoids mature ad become futile and motile

Answer 18

epididymis

Question 19

what hormone causes apoptosis of the surge center in males

Answer 19

testosterone transformation to Estrogen

Question 20

where does spermatogenesis occur?

Answer 20

Sertoli cells –> seminiferous tubules

Question 21

when does spermatogenesis occur?

Answer 21

before puberty

Question 22

spermatogenesis phases;

Answer 22

proliferation phase , meiotic phase, differentiation phase

Question 23

Proliferation phase

Answer 23

mitotic division of spermatogonia. Stem cell renewal

Question 24

meiotic phase

Answer 24

genetic diversity

Question 25

differentiation phase

Answer 25

“Spermiogenesis”- differentiation of the spermatozoids, structural changes

Question 26

what changes do spermatids go through during differentiation

Answer 26

nucleus is high condensed, acrosome is formed, cell becomes motile, formation of the flagellum, mitochondrial helix

Question 27

spermatozoa=

Answer 27

head + tail

Question 28

head=

Answer 28

nucleus + acrosome + postnuclear cap

Question 29

tail

Answer 29

middle piece + principal piece + terminal piece

Question 30

what happens if there is a disruption of spermatogenesis cycle

Answer 30

can lead to short-to-long term stoppage in sperm production

ex: fever, stress, toxins, heat stress

Question 31

how long does it take for a spermatogonia cell to become spermatozoid in rat?

Answer 31

approximately 54 days

Question 32

how long does it take for a spermatogonia cell to become spermatozoid in man?

Answer 32

75-80 days

Question 33

factors that affect reproductive efficiency in males

Answer 33

environment, Nutrition, sexual maturation of the animal, diseases, management of the animal, genetics

Question 34

there is a positive correlation between what assessing scrotal circumference

Answer 34

positive correlation between scrotal circumference and testicular weight, number of sperm in testes and number of sperm in epididymis

Question 35

different ways of semen collection

Answer 35

electric stimulation, manual collection, teaser, artificial vagina

Question 36

ways to extract semen in bulls and stallions?

Answer 36

electro-ejaculator, teaser, artificial vagina

Question 37

what do you look at when doing a semen analysis

Answer 37

volume of ejaculate, color and consistency of the ejaculate, concentration of semen, progressive motility, semen morphology, semen viability

Question 38

endogenous factors that affect sperm motility?

Answer 38

age, sperm maturation, energy stores, surface and surface-active agents (antibodies, detergents, etc.)

Question 39

exogenous factors that affect sperm motility

Answer 39

biophysical and physiological factors, suspending fluids, stimulation- inhibition (prostaglandins, environmental pollutants, hormonal treatments)

Question 40

how to tell semen viability

Answer 40

cells that stain dark are no viable as the stain can enter the damaged cell, cells that are therefore not stained are viable. Cells that are not moving are motile = not viable, cells that re moving = viable

Question 41

normal rate of motility in bulls

Answer 41

60% motility

Question 42

aging in the testes is associated

Answer 42

decline in the number of leydig and sertoli
thickening of the basement membrane of the seminiferous tubules
arrested divisions of germ cells