Spermatogenesis

Question 1

Where are sperm made and stored?

Answer 1

→ In the testes

→ stored in the epididymis

Question 2

What contracts during ejaculation?

Answer 2

→ The vas deferens

Question 3

Where do the sperm travel to after the vas deferens?

Answer 3

→ Seminal vesicle which contribute seminal fluid

→ move to the prostate which also contribute secretions

Question 4

Where does the vas deferens meet the urethra?

Answer 4

→ In the prostatic gland

Question 5

What is responsible for erections?

Answer 5

→ Hydrostatic pressure

Question 6

Where are the testes located?

Answer 6

→ in the scrotum outside the body cavity

Question 7

Why are the testes located outside the body?

Answer 7

→ Optimum temperature for sperm production

→ overheating reduces sperm count

Question 8

What is the normal volume of the testes and how is this measured?

Answer 8

→ 15-25ml

→ orchidometer

Question 9

What do the tubules lead to?

Answer 9

→ Rete on one side

Question 10

What does the rete lead to?

Answer 10

→ Epididymis and vas deferens

Question 11

What is 90% of the testis made up of?

Answer 11

→ seminiferous tubules

Question 12

Where is the site of spermatogenesis?

Answer 12

→ Seminiferous tubules

Question 13

How long does it take for sperm to go from the basal side to the lumen?

Answer 13

→ 74 days

Question 14

What are sertoli cells held together by?

Answer 14

→ Tight junctions

→form Adluminal compartment

Question 15

What are tight junctions for?

Answer 15

→ preventing an immune response against sperm cells

→filled with blood and lymphatic vessels, Leydig cells(secrete androgens) and interstitial fluid.

Question 16

What are the walls of the seminiferous tubules made of?

Answer 16

tall columnar endothelial cells Sertoli cells.

Question 17

Summarise spermatogenesis in 3 steps

Answer 17

→ mitotic proliferation of spermatogonia
→ Meiosis and development of spermatocytes

→ spermiogenesis , elongation, loss of cytoplasm and movement of cellular content

Question 18

What do spermatids remain connected by and why?

Answer 18

→ A cytoplasmic bridge

→ they form a syncytium allowing synchronous development

Question 19

What are the 2 differences between oogonia and spermatogonia?

Answer 19

→ Cannot make more oocytes by mitosis
→ sperm can divide mitotically

→ limited supply of eggs

Question 20

What do Leydig cells do?

Answer 20

→ LH binds

→ Convert cholesterol into testosterone

Question 21

What receptors do Sertoli cells have?

Answer 21

→ FSH

Question 22

What is the function of Leydig and Sertoli cells?

Answer 22

→ Leydig cells make testosterone

→ Sertoli cells make ABP which makes testosterone more soluble so it can be concentrated in the lumen

Question 23

What happens if you take anabolic steroids?

Answer 23

→ Decrease in LH and FSH

→ Testicular atrophy occurs

Question 24

What happens during an erection?

Answer 24

→ Vasodilation of the corpus cavernosum

→ Partial constriction of the venous return

Question 25

Describe the formation of spermatozoa

Answer 25

→ The sperm start as spermatogonia which are diploid → they replicate by mitosis and form 2 types of cell → type A and type B → type A is used as the template and replicates again → type B moves into the adluminal compartment and becomes a primary spermatocyte → the primary spermatocyte undergoes meiosis I and become secondary spermatocyted → 2ndary spermatocytes divide to form 4 daughter cells (meiosis II) → these are spermatids

Question 26

How often do new cycles of spermatogenesis occur?

Answer 26

→ every 16 days

Question 27

What does the autonomic nervous system do during an erection?

Answer 27

→ Coordinated smooth muscle contraction of the vas deferens, glands and urethra

Question 28

What does the parasympathetic system do during an erection?

Answer 28

→ controls erections

Question 29

What does the sympathetic system do during an erection?

Answer 29

→ Controls the movment of sperm into the epididymis, vas deferens and penile urethra →adrenergic fibres release NA to contract epididymis

Question 30

What does the somatic nervous system do during an erection?

Answer 30

→ Expulsion of glandular secretions and evacuation of the urethra

Question 31

How many sperm are produced per day?

Answer 31

→ 300 million

Question 32

What is the normal ejaculate volume?

Answer 32

→ 1.5-6mL

Question 33

What does seminal fluid consist of?

Answer 33

→ Secretions from seminal vesicles → prostate → bulbo-urethral gland and epidydimal fluid

Question 34

What is is the function of the bulbo urethral gland?

Answer 34

→ produces a clear viscous secretion high in salt | → pre-ejaculate

Question 35

What is the function of pre-ejaculate?

Answer 35

→ The fluid lubricates the urethra for the spermatozoa to pass through which neutralizes traces of acidic urine →Prevents damage of sperm due to friction of speed

Question 36

What do seminal vesicle secretions contain?

Answer 36

→ Proteins → enzymes → fructose → mucus → vitamin C → prostaglandins

Question 37

What is the function of the seminal vesicle secretions?

Answer 37

→ provide an energy source | → high pH protects again acidic environment in the vagina

Question 38

What is the function of the prostate?

Answer 38

→ Secretes white fluid roughly 30% of seminal fluid

Question 39

What is the function of the prostatic secretions?

Answer 39

→ High zinc concentration which is anti bacterial | → prostatic acid, phosphatase and prostate specific antigen which are involved in liquefaction

Question 40

What should the normal morphology % be?

Answer 40

→ more than 4% normal

Question 41

What does a spermatozoa's head contain?

Answer 41

→ Acrosome

Question 42

What is the acrosome reaction?

Answer 42

→ The head 'explodes' and enzymes are released which make the sperm bury into the zona pellucida of the egg

Question 43

What do sperm need to undergo for them to be functional?

Answer 43

→ Capacitation

Question 44

When does capacitation need to occur?

Answer 44

→ 4-18 hours of being released

Question 45

What is the mitochondrial sheath for?

Answer 45

→ Swimming

Question 46

What does the axoneme consist of and where is it ?

Answer 46

→ 9 pairs of tubules with a pair down the center | → tail

Question 47

Which part of the ejaculate is sperm rich?

Answer 47

→Initial portion | →99.9% lost before reaching ampulla of the uterine tube.

Question 48

What is liquefaction?

Answer 48

Normal semen comes out thick during ejaculation- deposited near cervix  →Liquefaction time measures how long it takes before it becomes liquid. J → Proteases from prostate mediates it

Question 49

What is the role of the axoneme?

Answer 49

→Use ATPP from mitochondria to slide against each other →generates the propulsive force for sperm cell movement

Question 50

How does viagra help with erection problems?

Answer 50

→inhibits phosphodiesterase which breaks down cGMP →cGMP dilates corpus carvenosa