Basic Male & Female Reproductive Physiology Flashcards
What is the process of sperm production?
- The spermatocytes found at the basal ends of sertoli cells undergo meiotic division to become sperm.
- As the spermatocytes differentiate into sperm, they move in towards the tubule lumen whilst being continously surrounded by sertoli cells.
- By the time the spermatocytes have reached the luminal surface they have differentiated twice and become spermatids.
- The spermatids eventually turn into sperm and released into the lumen.
What is the hormonal control of sperm production?
GnRH (Hypothalamus)
LH and FSH (Anterior Pituitary)
FSH and LH stimulate the Testes
FSH targets Sertoli cells for spermatogenesis
LH targets Leydig cells to produce testosterone (testosterone has -ve feedback on LH and GnRH production)
What are the factors that affect spermatogenesis?
Testis Temperature - 2 degrees below body temperature
Endocrine - Reduction in gonadotrophins & androgens, anabolic steroids
Loss of blood-testis barrier - Physical damage
Immunological reactions - Auto-immune reaction
Environment - Occupation (car industry, welders, plastics & pesticides), radiation, smoking, alcohol
Medication - Anti-hypertensives & anti-depressants, chemotherapy
What are the major actions of sex steroids in male?
Systemic effects:
- Deepening voice
- Male body hair
- Increased sebaceous gland activity
- Protein anabolism
Central nervous system - aggressive behaviour
Penis - erections, ejaculatory effectiveness
What are the target organs of androgens (male sex steroids)?
- Central nervous system
- Hypothalamus & anterior pituitary
- Penis
- Striated muscles
- Prostate & seminal vesicles
What is the process of oogenesis?
Puberty Oogenesis:
1 - Each primary oocyte divides into a large egg (23 chromosomes) and a tiny first polar body (23 chromosomes)
2- Large egg begins second meiotic division and sister chromatids seperate from each other but still within the same egg
3 - The ovary releases the mature egg in a process called ovulation
4 - If the egg is not fertilized, meiosis is never completed and the egg either disintegrates or passes out of the body
5 - If the egg becomes fertilized the final step of meiosis occurs
6 - Half of the sister chromatids remain in the fertilized egg (zygote) while the other half are released and eventually disintegrate
What are the major actions of the sex steroids in females?
Structural actions of Estrogen:
- Secondary female sex characteristics
- Increase metabolism
- Increase fat store
- Stimulate endometrial growth
- Increase vaginal lubrication
- Increase bone formation/decrease bone resorption
What is the hormonal control of the follicular phase of the menstrual cycle?
Early-Mid Follicular Phase
- Low Estrogen levels exert -ve feedback on GnRH, LH, FSH
Late Follicular Phase & Ovulation
- Estrogen levels rise
- Progesterone levels rise
- Rising estrogen and progesterone cause +ve feedback on Ant Pit and therefore a LH surge
- FSH suppressed by Inhibin
What factors affect oogenesis?
Age
Where is sperm produced in the male body?
Seminiferous tubules of the Testes
What is the function of the epididymis?
Storage of sperm
What are the functions of sertoli cells?
1 - Form blood-testis barrier
2 - Isolate spermatocytes
3 - Allow physical movement of sperm towards lumen
4 - Provide nutrients to sperm
5 - Remove waste products away from sperm
How long does it take to make sperm?
75 days
What is the dual-role of estrogen?
Early follicular phase - Low estrogen levels exert a -ve feedback control on GnRH, FSH, LH production
Mid-late follicular phase - High estrogen levels exert a +ve feedback control on GnRH, FSH, LH production
What is the dominant hormone during the follicular phase?
Estrogen
