Male reproduction Flashcards
What hormone is released from the testes?
Testosterone
How does testosterone affect hormone release from the hypothalamus and pituitary?
It inhibits hormone production
Describe the release of GnRH in males?
GnRH is released from GnRH neurones in the hypothalamus
In males GnRH levels are quite constant and aren’t controlled by pulsatility
Where do the gonads develop in males?
Posterior abdominal wall before descending into the scrotum
What structure guides the gonads through the layers of the abdominal wall?
Gubernaculum
What structure does the gubernaculum form after decent in males?
Testicular ligament (Spermatic cord)
What structure passes alongside the gonads to reduce friction?
Vaginal process (Processus vaginalis)
What structure is formed by the gubernaculum after decent in females?
Round ligament of the uterus
What structure is formed by the movement of the sub-cutaneous tissue from the abdominal cavity upon testicular descent?
Dartos muscle
What structure is formed by the movement of the external oblique muscle from the abdominal cavity upon testicular descent?
External spermatic fascia
What structure is formed by the movement of the internal oblique from the abdominal cavity upon testicular descent?
Cremaster muscle
What structure is formed by the movement of the fascia of the deep muscle from the abdominal cavity upon testicular descent?
Cremasteric fascia
What structure is formed by the movement of the peritoneum from the abdominal cavity upon testicular descent?
Vestige of vaginal process
What is the function of the dartos muscle?
This contracts to wrinkle the skin of the scrotum to decrease heat loss, functioning in temperature regulation
What is the function of the cremaster muscle?
Contracts to raise the test closer to the body to decrease heat loss, functioning in temperature regulation
What are the main structures within the teste?
- Seminiferous tubules
- Rete testis
- Epididymis
- Vas deferens
Describe the movement of sperm in the testes
Produced in the seminiferous tubules
Collected by the rete testis
Passes into the epididymis which becomes the vas deferens
Passes through the spermatic cord, past the seminal and prostatic glands, before moving through the penis as the urethra
What are the 2 regions of the seminiferous region?
Extra-tubular compartment (Interstitial and intravascular compartment)
Intra-tubular compartment (Basal and adluminal compartment)
What is the function of the blood testes barrier?
This separates mature sperm from immature and immune cells
Why is the blood-testes barrier needed?
Mature sperm from the immature cells
This is because stem cells that form sperm cells are only produced after birth, so there is no foetal sensitisation by the immune system
The blood-testes barrier therefore prevents immune destruction of the spermatogenic stem cells
What is contained within the intra-tubular compartment of the seminiferous region?
Germ cells
What cells form the blood-testes barrier?
Tight junctions between sertoli cells
What structure in the testes requires lower temperature?
Sertoli cells
How does the blood-testes barrier allow structures in and out between the blood and testes?
The blood testes barrier can form and reform allowing required cells through (Potential target for male contraceptive)
How long does spermatogenesis take?
70 days
How many spermatozoa are produced every heartbeat?
Around 1,000
When does spermatogenesis begin?
During puberty
What cells in the testes produce testosterone?
Leydig cells
What hormone stimulates testosterone release from Leydig cells?
LH
What hormones stimulate spermatogenesis?
Testosterone
FSH
What are some of the functions of testosterone?
- Spermatogenesis
- Enlargement of the male sex organs
- Secondary sexual characteristics
- Anabolism
- Maintaining integrity of blood-testicular barrier
- Release of mature sperm from sertoli cells by influencing peritubular myoid cells
- Decreased release of GnRH and LH
How do sertoli cells affect hormone release?
Sertoli cells secrete androgen binding globulin (ABG) and inhibin
Inhibin decreases the release of LH and FSH
What are some factors that regulate a sperms ability to enter the cervical mucus?
- Thickness of mucus (Hydration of cervical mucus under hormonal control)
- Motility of sperm
- Interaction with reactive oxygen species (Produced by leukocytes that have infiltrated the cervical mucus)
- Interaction with mucins
