Testes/Spermatogenesis/Male Endocrinology

Question 1

List some basic components of the male reproductive system

Answer 1

• testis
• excurrent duct system
• spermatic cord
• accessory sex glands
• penis + muscles
• scrotum

Question 2

In the boar, describe the location of the epididymis in relation to the body

Answer 2

It is closer to the body

Question 3

What feature in the dog’s penis allows for intromission without an erection?

Answer 3

Os penis

Question 4

List two species where the scrotum is described as perineal

Answer 4

• toms
• boars

Question 5

What is the function of the spermatic cord?

Answer 5

Connections, heat exchange, cremaster muscle loc

Question 6

List the contents of the spermatic cord

Answer 6

• Cremaster
• Pampiniform plexus
• Testicular a
• Ductus deferens
• Parietal/Visceral Vaginal tunic

Question 7

Describe the pampiniform plexus

Answer 7

Highly convoluted Testicular a and vein network wrap around the artery to exchange heat

Question 8

How is arterial blood in the testes cooled?

Answer 8

Heat transfer to testicular a and evaporative cooling due to contact with skin

Question 9

List some species with abdominal testes

Answer 9

• elephants
• birds
• bats
• dolphins

Question 10

How is pulse pressure eliminated in the testes?

Answer 10

Long, convoluted, high elasticity brings pressure down to ~10 mmHg

Question 11

Describe how testosterone is higher in the testes

Answer 11

Testosterone stays in the testes due to an exchange from v to a (concentratio gradient) and thus gets recirculated

Question 12

Which striated muscle supports the testes?

Answer 12

Cremaster

Question 13

T/F the cremaster can sustain contractions

Answer 13

false

Question 14

What does the cremaster promote?

Answer 14

Pumping through Pampiniform plexus - venous return (for temp control)

Question 15

List the 4 layers of the scrotum

Answer 15

• skin
• tunica dartos
• scrotal fascia
• parietal tunic

Question 16

Why is cooling obligatory in the testes?

Answer 16

for normal spermatogenesis

Question 17

At what scrotal temp is tachypnea induced?

Answer 17

> 36 C

Question 18

What is the smooth muscle that contracts in response to cold scrotal temperature?

Answer 18

Tunica dartos

Question 19

Describe how the artificial cryptorchid can increase a higher rate of growth and leaner carcass

Answer 19

Testosterone is maintained

Question 20

The testicular capsule is made of ?

Answer 20

Visceral vaginal tunic and Tunica albuginea

Question 21

What is the tubular compartment in the testes?

Answer 21

Parenchyma

Question 22

The central dense CT that prevents the collapse of the ducts is the ________________

Answer 22

Mediastinum

Question 23

What are the ducts that transport sperm from periphery to mediastinum of each lobule called?

Answer 23

Seminiferous tubules

Question 24

The seminiferous tubules empty into the what in the mediastinum?

Answer 24

Rete tubules

Question 25

Which cells in the seminiferous tubules contract to move fluid from Sertoli cells around spermatozoa?

Answer 25

Peritubular cells

Question 26

What are the cells that have LH receptors that produce testosterone?

Answer 26

Leydig cells

Question 27

What is the pathway via which T is produced?

Answer 27

Progesterone pathway

Question 28

The governors of spermatogenesis are the _______________ cells

Answer 28

Sertoli

Question 29

What type of junctions can you find in the Sertoli cells?

Answer 29

Tight junctions

Question 30

Sertoli cells convert T into ?

Answer 30

E2 or DHT

Question 31

What limits access to the adluminal compartment of the testes?

Answer 31

Blood testis barrier

Question 32

Why is the blood testis barrier crucial?

Answer 32

To avoid immune response to germ cells during meiosis

Question 33

Where does the final maturation of spermatozoa occur and they are stored?

Answer 33

Excurrent duct system (epididymis)

Question 34

How are spermatozoa transported in the epididymis?

Answer 34

smooth muscle contractions

Question 35

Describe the movement of the cytoplasmic droplet as it is transported?

Answer 35

It moves down as it moves from head to tail of epididymis

Question 36

Sexual activity will increase transit time in which part/s of the epididymis?

Answer 36

Tail

Question 37

T/F Transit time in the epididymal head and body is constant

Answer 37

True

Question 38

What is the total count of Extragonadal reserves?

Answer 38

Epididymis + ductus deferens + ampulla

Question 39

Describe LH secretion in males and how it relates to the release of testosterone

Answer 39

LH secretion is episodic (every 2-6 hours) and testosterone is secreted soon after each LH episode

Question 40

T/F males have a surge center

Answer 40

false

Question 41

Around how long is the LH secretion?

Answer 41

30 - 75 min

Question 42

Testosterone is secreted for around __________ mins

Answer 42

20-60

Question 43

Why is it important for testosterone to be secreted in a pulsatile pattern?

Answer 43

To maintain high T in testes, low in blood (doesnt downregulate GnRH/LH)

Question 44

What would happen if no T pulses or long LH is happening?

Answer 44

Negative feedback: no GnRH, no LH and no T = no spermaogenesis

Question 45

In the proliferation phase, which cell divisions are happening?

Answer 45

Mitotic

Question 46

How many spermatogonia can arise from an A1 in the proliferation phase?

Answer 46

32

Question 47

In the meiotic phase, how many haploid spermatids can arise from a B spermatogonium?

Answer 47

256

Question 48

Spermiogenesis would mean the spermatids are?

Answer 48

in differentiation (head, flagella, midpiece)

Question 49

Differentiation includes which phases?

Answer 49

- Golgi - Cap - Acrosomal - Maturation

Question 50

Which specific structure of the spermatid gives rise to its motility?

Answer 50

The microtubules

Question 51

What would happen if you administered testosterone every day to a dog?

Answer 51

No spermatogenesis would occur