Male Reproductive Systm

Question 0

1st compartment

Answer 0

Basal compartment-> between bassolateral TJ and tunica propria-> spermatogonia reside here-> outside blood testes barrier

Question 1

Serotoli cells

Answer 1

Tight junctions between them create 3 important tubular compartments for sperm production
Create blood-testes barrier

Question 2

2nd compartment

Answer 2

Adlumenal
Intercellular after bassolateral TJ
Inside blood testes barrier
Spermatogenesis
Sertoli cells secrete molecules necessary for sperm development creating a niche
Unidirectional movement of germ cells through tight junctions-> don’t go back into blood stream and create an immune reaction
Protects spermatocytes from pathogens and mutagens

Question 3

3rd compartment

Answer 3

Lumenal
Out in to lumen of seminiferous tubule
Spermatida found on luminal surface of Sertoli cells
Spermatozoa found in lumen of seminiferous tubule

Question 4

Spermatogenesis

Answer 4

Puberty
Spermatogonia stem cells-> mitosis-> one reserve stem cell (dark type A )and one cell for differentiation (pale type A) Spermatogenesis
Pale type A becomes type B
Type B-> maturation-> primary spermatocyte -> replicate DNA -> 4n-> meiosis-> secondary spermatocyte 2n-> meiosis-> Spermatid 1n/haploid
Spermiogensis-> spermatozoa
64 day cycle

Question 5

Spermiogensis 1

Answer 5

Golgi phase
Preacrosomal granules appear in Golgi
fuse to form acrosome vesicle
Near nucleus

Question 6

Spermiogensis 2

Answer 6

Cap phase

Acrosome vesicle changes shape to enclose anterior had of nucleus

Question 7

Spermiogensis 3

Answer 7

Nucleus elongates
Anterior pole has acrosome
Posterior pole has developing flagella 
Microtuble organisation begins 
Cytoplasm migrates to posterior part of cell

Question 8

Spermiogensis 4

Answer 8

Maturation phase
Excess cytoplasm pinched off
Prominent mitochondria in neck region
Axonemal complex of tail produced

Question 9

Production of continuous sperm

Answer 9

Gametic stem cells divide every 16 days
Always a number of stem cells dividing nearby sections of tubule initiate Spermatogenesis with a slight phase advance or retardation-> spermatogenic wave, different times in different regions
Before one daughter cell has matured another has been produced, 3 daughter cells at different stages of differentiation
Coordinated by Sertoli cells

Question 10

Function of Sertoli cells

Answer 10

Germinal:
Protective
Supportive-> nutrients
Phagocytosis
Endocrine:
Leydig cells(LH)-> testosterone-> Sertoli cells-> FSH receptors on Sertoli cells
FSH-> Sertoli-> androgen binding protein inhibit and activin-> carries testosterone in testicular fluid
Inhibin-> inhibits FSH production by negative feedback

Question 11

Erectile physiology flaccid state

Answer 11

Flaccid state:
Sinusoidal smooth muscle contracts
Blood flows internal pudenal-> cavernosal and helicine arteries-> lacunar spaces-> open emissary veins
Low volume, low pressure 
AV anastomoses help shunt

Question 12

Erectile physiology, erectile state

Answer 12

Closure of shunts
Increases blood flow in to helicine arteries
Sinusoid muscle relaxes-> increased blood flow to lacunar spaces
Pressure compresses emissary veins-> decreased venous outflow
High volume high pressure

Question 13

Erectile physiology, nerve supply

Answer 13

CNS-> psychological and tactile stimuli-> internal pudenal
Psychogenic stimuli (visual)-> limbic system 
Neurotransmitters-> dopamine! acetylcholine,VIP, nitric oxide (relaxation of sinusoid muscle) 
Viagra stabilises cyclic guanosine monophosphste