Physiology of the Reproductive System Flashcards
Name the components of the male reproductive system.
- Bulbourethral gland
- Prostate gland
- Seminal vesicle
- Ductus deferens
- Epididymis
- Testis
- Scrotum
Where is the seminal fluid located?
- 5% in the bulbourethral glands
- 30% in the prostate gland
- 60% in the seminal vesicles
How much semen does the male reproductive system contain?
2-5ml
How many sperm does the male reproductive system contain?
20-200million sperm per ml of semen
Where are sperm produced?
Seminiferous tubules of the testis
What cells are sperm produced from?
Spermatogonium which produce spermatocytes which undergo meiosis to produce immature spermatids
What cells support and give nutrition to developing gametes in the male?
Sertoli cells
What are the features of the seminiferous tubules?
- 150 µm diameter, 80 cm long
- Total 300-900 m
- Join at rete testis
What is the role of the epididymis?
Sperm storage
What route do sperm take during ejaculation?
- Vas deferens (ductus deferens)
- Seminal vesicles
- Prostate
- Bulbourethral glands
- Urethra
What are the roles of the sertoli cells?
- Form blood-testis barrier (blood-seminiferous tubule barrier)
- Isolate haploid 2ndary spermatocytes, spermatids, spermatozoa from immune system
- Physical movement of developing sperm towards lumen
- Provision of nutrients to sperm
- Removal of wastes from developing sperm
- Removal of excess cytoplasm following cell divisions
- Support for spermiation
Briefly describe the process of sperm production through to ejacualtion
Production 75 days in seminiferous tubules
- Spermatocytogenesis
- Meiosis
- Spermiogenesis
Storage 15 days in epididymis
-Become motile
Sexual intercourse in vagina
- Ejaculation
- Capacitation
What is the counter current heat exchange of the male reproductive system?
- Arterial blood going to the testis enters a dense network of capillaries coming from the testis and epididymis before reaching the spermatic cord
- The arterial blood is cooled by the venous blood
- Helps maintain a constant testicular temperature
What factors affect spermatogenesis?
- Testis temperature
- Endocrine
- Loss of blood-testis barrier
- Immunological reactions
- Environment
- Medication
What endocrine causes can affect spermatogenesis?
- Reduction in gonadotrophins and androgens
- Anabolic steroids
What environmental factors can affect spermatogenesis?
- Occupation e.g. car industry, welders, plastic manufacture, pesticide sprayer
- Radiation
- Smoking, alcohol
What medications can affect spermatogenesis?
- Some anti-hypertensives and anti-depressants
- Chemotherapy
What testis temperature change can affect spermatogenesis?
- Should be 2C below body temperature
- Hyperthermia, mumps, viral and other infections
What are the targets for androgens in males?
- Systemic
- CNS (aggressive behaviour)
- Hypothalamus and anterior pituitary
- Penis (erective, copulatory and ejaculatory effectiveness)
- Striated muscle
- Prostate and seminal vesicles
- Testis (spermatogenesis)
What system effects can androgens have in males?
- Deepening voice
- Male body hair
- Increased sebaceous gland activity
- Protein anabolism
What is the menstrual cycle?
- A regular monthly cycle which occurs in females
- Can be sexually active at any time even if not ovulating
- If no conception occurs then the endometrium is shed as a period
What ae the components of the female ovary?
- Blood vessels
- Stroma
- Follicles (primordial, growing, vesicular, mature grafiaan)
- Corpus lutum
- Corpus albicans
What hormone change occurs shortly before ovulation?
LH surge about 36 hours prior to ovulation
Briefly describe the hormonal changes which occur during a menstrual cycle.
- Cycle usually 28-35 days with bleeding (period) for the first 5-7 days
- LH surge about day 13/14 as ovulation occurs
- FSH has a small surge about day 13/14 when ovulation occurs
- Progesterone levels increase during the luteal phase and fall again as the corpus luteum becomes the corpus albicans
- Oestrogen increases as ovulation takes place
What is the duel role od oestrogen?
- Low oestrogen provides negative feedback
- High oestrogen provides positive feedback
What are the main female reproductive hormones?
- GnRH from hypothalamus
- LH from anterior pituitary
- FSH from anterior pituitary
- Oestradiol from granulosa cells
- Progesterone from corpus luteum
What is the role of GnRH in the female reproductive system?
Stimulate LH and FSH secretion from anterior pituitary
What is the role of LH in the female reproductive system?
Maintain dominant follicle, induce follicular maturation and ovulation, stimulate CL function
What is the role of FSH in the female reproductive system?
Stimulate follicular recruitment and development
What is the role of Oestradiol in the female reproductive system?
Supports the female secondary sexual characteristics and reproductive organs, negative feedback control of LH and GnRH EXCEPT for late follicular phase (positive control of LH surge, stimulates proliferative endometrium, negative control of FSH)
What is the role of Progesterone in the female reproductive system?
Maintenance of secretory endometrium, negative feedback control of HPO
Briefly describe the change in oocytes in a female.
- During foetal development. germline stem cells proliferate generating roughly 7 million oocytes
- At birth, most oocytes degrade so at birth roughly 2 million immature follicles remain
- During puberty, subset of 4-10 immature follicles begin to mature with each menstrual cycle. One follicle ruptures, its oocyte is ovulated and can be fertilised
- During the menopause, too few immature follicles ae left to support monthly ovulation cycle
What are the targets for oestrogens in the female?
- Systemic effects
- CNS
- Anterior pituitary and hypothalamus
- Fat distribution
- Mammary gland
- Bone maturation and turnover
- Cervix, vagina, uterus and fallopian tubes
What systemic effects does oestrogen have in the female?
- Protein metabolism
- Carbohydrate metabolism
- Lipid metabolism
- Water and electrolyte balance
- Blood clotting
What are the female normal hormone ranges for LH(u/l)?
Follicular phase
2-9
Peak
80
Luteal phase
0.5-13
Menopause
64
What are the female normal hormone ranges for FSH (u/l)?
Follicular phase
2-9
Peak
13
Luteal phase
0.5-8
Menopause
134
What are the female normal hormone ranges for Oestradiol (nmol/l)?
Follicular phase
0.08-0.8
Luteal phase
0.08-0.9
Menopause
0.02-0.03
What are the female normal hormone ranges for Progesterone (nmol/l)?
Follicular phase
1-4
Luteal phase
12-70
Menopause
0.06-0.02
