Physiology: Male and Female Flashcards
What are the components of female reproductive physiology?
- HPO axis
- Ovarian cycle
- Menstrual cycle
- Hormones
What is GnRH?
Gonadotrophin releasing hormone
What are the female gonadotrophins?
- FSH (follicle stimulating hormone)
- LH (luteinising hormone)
What steroid hormones are involved in the female reproductive system
- Oestrogen (Oestroadiol, oestrone, oestriol)
- Progesterone
- Testosterone
What is the Hypothalamo-pituitary-ovarian axis?
- Hypothalamus releases GnRH which acts on pituitary gland
- Pituitary gland release FSH and LH which act on the ovaries
- Ovaries release ova , progesterone and oestrogen
What are the 2 functions of the ovary?
Production of eggs and production of steroid hormones
What type of feedback does oestrogen have on the anterior pituitary and hypothalamus?
- Negative for most of the cycle
- Positive (day 12-14) in response to LH surge
How is a new cycle started?
FSH and LH initiate the growth of new ovarian follicles, beginning a new cycle
What is the follicular phase of the ovarian cycle concerned with?
Follicular growth
-The development of a single follicle for egg release
What is the luteal phase of the ovarian cycle concerned with?
Maturation of the corpus luteum
What does the corpus luteum produce?
Progesterone
What effect does progesterone have on the uterus?
Causes pregnancy changes to occur such as thickening of the wall of the uterus
What are the phases of the menstrual cycle?
- Menstrual phase (0-4)
- Proliferative phase (4-14)
- Secretory phase (14-26)
- Premenstrual phase(26-28)
When in the menstrual cycle do hormones level drop?
Around day 26 if no pregnancy is detected
What are the stages of oogenesis?
- Oogonium forms primary oocyte
- Undergoes 1st meiotic division to form secondary oocyte and polar body
- Secondary oocyte undergoes 2nd meiotic division to form ovum and polar body
- Ovum becomes mature egg cell
What are oogonium?
Stem cells in the ovary
What happens to oogonium?
They undergo mitotic division to produce primary oocytes which is completed at or shortly after birth.
At what stage is meiosis arrested?
It starts but is arrested in the prophase
What happens to the primary oocytes during the ovarian cycle?
- Group of primary oocytes are hormone responsive in each cycle of which one grows to complete first meiotic division and release a haploid secondary oocyte at ovulation.
- The extra genetic material is released as the first polar body
When do secondary oocytes under go the second meiotic division?
When they are fertilised by a sperm to form the mature ovum and second polar body
How does age affect female fertility?
- Most fertile at birth
- Fertility steadily declines until 37 (end of fertility)
- Irregular cycles occur until the menopause (average age 51)
What are the components of male reproductive physiology?
- Testis
- Sperm production
- Sperm travel pathway
- Hormones
What are the male reproductive hormones?
- GnRH (hypothalamus)
- Gonadotrophins: FSH and LH (pituitary)
- Testosterone (testis)
What is the site of sperm production?
Seminiferous tubules
What produces sperm?
Germ cells (spermatognia)
What do the sertoli cells do?
- Support sperm producing cell
- Produce inhibin
What produces testosterone?
Interistitial cells of Leydig in the testis
What hormone controls the Leydig cells?
LH
What hormone controls the spermatogonia in the ST?
FSH
What does FSH activity lead to?
Spermatogenesis
What does LH activity lead to?
Release of testosterone
What does testosterone do?
- Responsible for secondary male sex characteristics
- Acts on seroli cells
Describe the travel of sperm?
- Sperm produced in the testis
- Aggregate in the epididymis
- Travel through vas deferens
- Semen (from seminal vesicles and prostate) mixes in with sperm
- Sperm and semen travel through the urethra and are ejaculated out the penis
What is the lifespan of spermatozoa?
- Produced from puberty throughout life
- About 30 million produced per day
- 60-75 days for sperm production
- 10-14 days for transport to epididymis
- 20-100 million released per millilitre of ejaculate
What factors affect oogenesis/spermatogenesis?
Problem with the hormonal control (genetic, tumours, medications, functional)
Problem at the site of production(genetic, cancer treatment induced, surgery, trauma, infections
What are the higher control centres involved in the reproductive function of the gonads?
Hypothalamus and pituitary through the production of GnRH and FSH and LH
What do FSH and LH signal in the female?
Follicular development, maturation and ovum release as a part of ovarian cycle and menstrual cycle is coordinated in preparation for a pregnancy each cycle.
What role do FSH and LH play in the male?
Control continuous sperm and testosterone production from the testicles .
Where does fertilisation of the egg take place?
Fallopian tube
What must be true of the sperm travel pathway for ejaculation to occur?
Must be intact and functioning
What is the main factor affecting female fertility?
Increasing age
Describe spermatogenesis?
- Spermatogonium undergoes mitosis to produce primary spermatocyte
- Primary spermatocyte undergoes 1st meiotic division to produce 2 secondary spermatocytes
- They undergo the 2nd meiotic division to produce 4 spermatids
- They undergo spermiogenesis to become mature sperm cells
