Test 2- Colombo - Male Repro

Question 1

The sperm cell is what?

Answer 1

Haploid flagellated cell with a head and a tail. Head delivers DNA, tail does the locomotion.

Question 2

The head of the sperm contains genetic info and the _____________.

Answer 2

Acrosome

Question 3

The acrosome is a vehicle full of enzymes which can break down what, and it is called what?

Answer 3

The outer layer of the ovum

Acrosome rxn

Question 4

What are the centrioles in a sperm cell formed from?

Answer 4

A complex of microtubules. The centriole is delivered to the ovum w/ genetic material to form a centrosome and are involved int he initial zygotic divisions.

Question 5

What is the axoneme?

Answer 5

The cytoskeletal component of the flagella formed from microtubules (made of tubulin)

*This is the engine room of the sperm. It is packed with MITOCHONDRIA. Max velocity: 1-4mm/min.

Question 6

What is on the cell membrane of sperm that give it a sense of direction and what is this called?

Answer 6

Chemotactic sensors

Gradient sensing

Question 7

Spermatogenesis begins around what age?

Answer 7

13

Question 8

What starts the process of spermatogenesis?

Answer 8

LH and FSH released from the Ant Pit. This continues thruout life.

Question 9

Where are sperm produced?

Answer 9

In the testes, packed with could seminiferous tubules. These tubules are lined with spermatogonia.

Question 10

What are spermatogonia?

Answer 10

Germinal epithelial cells

Question 11

What surrounds the spermatogonia?

Answer 11

Large Sertoli cells

Question 12

What do Sertoli cells do?

Answer 12

They act like nurses to the developing sperm. They supply nutrients, moving the differentiating cells, and FORMING THE BLOOD-TESTIS BARRIER (Sertoli Cell Barrier).

Question 13

Why is the Sertoli Cell Barrier important?

Answer 13

If blood saw sperm, it would attack auto-immunly. Due to this, the testes are said to be immunologically privileged.

Question 14

What do the Leydig cells do?

Answer 14

Produce testosterone

Question 15

What tells the Leydig cells to produce testosterone?

Answer 15

LH - This initiates puberty and spermatogenesis

Question 16

Tell me the pathway of cells in spermatogenesis.

Answer 16

Spermatogonia (D)> Primary Spermatocyte (D) {This is the mitotic division}> 2 Secondary Spermatocytes (Each are [H]){This is the first meiotic division}> 4 Spermatids (H){This is the second meiotic division}> 4 Sperm cells (H) {Tails added. No division}

Question 17

How does the sperm cell get to the seminiferous tubule?

Once there, is the sperm cell motile?

Answer 17

The tail is added to the spermatid. The tail then decouples from the Sertoli cell. The sperm cell enters into the seminiferous tubule.

It is NOT motile.

Question 18

How is spermatogenesis hormonally controlled?

Answer 18

GnRH stims Ant Pit to release LH, FSH, and GH.

LH stims Leydig cells to make testosterone. Testosterone then drives spermatogenesis division.

FSH stims Sertoli cells. Estrogens formed from testosterone regulate spermatogenesis.

GH does a basic total regulation of testes metabolism.

This process is inhibited by inhibin. Inhibin is produced by Sertoli cells. This negatively feedbacks in excess FSH secretion

Question 19

How does a sperm cell get from the seminiferous tubules to the ductus (vas) deferens?

Answer 19

Seminiferous tubules>tubulus rectus>rete testis>epididymis>ductus deferens

Question 20

What does the rete testis do?

Answer 20

It is a net-like structure that delivers maturing sperm to epididymis AND reabsorbs some tubular fluid. This concentrates the sperm cells.

Question 21

How many mature sperm are produced per day, and how long are they typically stored in ductus?

Answer 21

120 Million

About a month

Question 22

What does a vasectomy do?

Answer 22

Obstructs ductus. Prevents sperm from entering into semen.

Question 23

Why do the testes hang down from the body?

Answer 23

Spermatogenesis is most efficient at just below body temp.

Question 24

What do the seminal vesicles release, what do those secretions do, and how much of a percentage of semen is their secretion?

Answer 24

Fructose - Fuel for sperm motility

Prostaglandins - Thins cervical mucus, possibly causes propulsion inwards

Fibrinogen - This can be cleaved to form a clot later on.

60-70%

Question 25

What are the seminal vesicles lined with?

Answer 25

Secretory epithelium - it secretes mucus

Question 26

What secretions does the prostate add to the semen, what do those secretions do, and how much of the semen is it?

Answer 26

Clotting enzymes - causes semen to clot slightly - “keeping it in place”

Profibrinolysin - helps to breakdown the clot that semen forms

Alkaloids - sperm do better at a more neutral pH. Optimal pH - around 6.5

25-30%

Question 27

What do the bulbourethral glands do?

What percentage of ejaculate do they contribute to?

Answer 27

Produce a mucus-like secretion that forms the pre-ejaculate and lubricates and cleanses the urethra.

*This secretion can contain sperm from prior ejaculations, but more importantly, this fluid can transmit infectious agents in the pre-ejaculate.

1%

Question 28

The finished product of semen is what pH?

Answer 28

7.5

Question 29

What does the semen do around the cervix?

Answer 29

Forms a weak clot that gradually degrades after about 20 minutes

Question 30

How long can sperm survive in utero?

Answer 30

2-3 days

Question 31

What is sperm capacitation?

Answer 31

Semen contains a number of mobility inhibition factors to keep the sperm in “stasis” and once in the vagina, the inhibition factors are “capacitated” or washed away. Once this occurs, sperm becomes fully motile.

The cell membrane around the acrosome weakens, allowing easier rupture

Ca2+ permeability increases which causes more vigorous motion in the flagella

Question 32

What three things cause vasodilation of the penis?

Answer 32

Ach, NO, and vasoactive transmitters

Question 33

T/F - STDs can be transmitted in the ejaculate.

Answer 33

True