Male reproductive processes Flashcards
week 3
structure of speratoza
Compact, streamlined, highly motile
Structure of Oocytes
Nutrient-rich, large, facilitates embryo development
Where is the site of spermatogenesis
lobules with 1-4 seminiferous tubules
what is the pathway of sperm in the testis?
Seminiferous tubules –> through rete testis –> into efferent ducts of epididymis –> spem undergoes maturation
How does sperm mature in the epididymis?
acquire motility and fertilisation ability
stored until ejacultion
What are the cells found within the Seminiferous tubules?
Leydig cells
Sertoli cells
spermatogonia, spermatocyte and spermatid
myoid cells
leydig (interstitial) cells
produces testosterone
Sertoli cells
support spermatogenesis
Spermatogonia, spermatocyte and spermatid
forms the sperm
myoid cells
contract to move sperm through tubules
What is the venous plexus that regulates temperature of the testes?
Pampiniform plexus
Where is the Paminiform plexus located?
wrapped around the testicular artery in the spermatic cord.
How does the pampiniform plexus regulate heat exchange in the testes?
Cools incoming arterial blood before entering via heat exchange with outgoing venous blood.
3 regions of the epididymis
Caput (head)
Corpus (body)
Cauda (tail)
Where is the sperm ejaculated from?
cadua epididymis
Epididymis function
cauda: stroage and sperm ejaculation
sperm maturation
how long can spermatogenesis take?
64-72 days
Steps of spermatogenesis
Spermatogonia undergo mitosis ( Type A replenishes and B daughter cells)
Growth –> prophase I –> enters adluminal compartment = primary spermatocyte
Meiosis I –> secondary spermatocyte
Meiosis II –> early spermatid
Cytodifferentiation –> late spermatid
Maturation –> spermatoza
What is the purpose of mitosis and meiosis in spermatogenesis?
Mitosis = replenish spermatogonia stem cell
Meiosis = produce 4 recombinant haploid
What are the three steps of cytodifferentiation?
Cap phase
acrosomal phase
maturation phase
cap phase
golgi forms acrosomal vesicle, tightly packed DNA
Acrosomal phase
acrosomal vesicle spread ofver nucleus, nucleus and cytoplasm elongate, distal centriole forms flagellum
Maturation phase
mitochondria form midpiece, cytoplasm sheds. Tail matures
Spermiation?
release of differentiated spermatid into the lumen
Why are such a large # of sperm produced?
- chance of fertilisation (significant # are lost during transport in the FRT)
- some sperm degenerate during prolonged storage in the epididymis
- 1/3 developing sperm degenerate by apoptosis
what are the hormones involved in spermatogenesis?
GnRH
LH
FSH
Androgen Binding Protein (ABP+)
Testosterone (T)
Inhibin
Role of LH in spermatogenesis.
stimulates the secretion of Testosterone
Role of FSH in spermatogenesis
supports Sertoli cell function
Role of ABP
sequesters Testosterone to site of spermatogenesis
role of FSH in spermatogenesis
supports Sertoli cell function
role of testosterone
nitiation of spermatogenesis and stimulates pri and sec sex characteristics
role of inhibin in spermatogenesis
regulates spermatogenesis via inhibitingFSH
What does the seminal vesicle secrete?
Secretes fluid containing:
fructose, ascorbic acid, coagulating enzymes and prostaglandins (enhances motility and feralization)
What does the prostate gland secrete?
Milk acidic fluid:
Citrate, enzymes, prostate-specific antigen
What does the Bulbourethral gland secrete?
Thick clear alkaline mucous
Neutarlises traces of acidic urine prior to ejaculation
What is semen?
= mixture of sperm, testicular fluid and accessory gland secretions
What are the functions of semen?
Transport medium
Provides nutrients and chemicals that protect and activate sperm
prostaglandins
stimulate contraction in female tract (facilitates sperm uptake)
relaxin
enhances sperm motility
Clotting factors
- promote semen coagulation
Describe the different spermatogonia in a cell. (1.5 marks)
They become more mature as move closer to the lumen (middle of the cell). The type A daughter cells remain on the outside of the cell so they continue to grow.
Spermatogonium= A and B = pri spermatocyte = secondary spermatocyte = early spermatids = late spermatids = spermatozoa