Reproductive systems Flashcards
(38 cards)
What are the sex chromosomes for mammals and birds?
XY/ZZ for testes and XX/ZW for ovaries
Which hormone causes masculinisation of genitalia in mammals?
androgen release in utero
Which hormone causes feminisation of genitalia in birds?
oestrogen release in ovo
How is sex determination in worms and clown fish different?
- contain both male and female reproductive organs
- in worms it is simultaneous
- in clownfish it is sequential
Describe the location of the internal female reproductive organs
- shares the pelvic cavity with the bladder and rectum
- covered superiorly by the peritoneum
Describe stage 1 of follicle development
- primordial follicles
- primary oocyte, enclosed by single layer flattened follicular/granulosa cells and basal lamina
- primordial follicles are stimulated to form primary follicles
Describe stage 2 of follicle development (uni-layered)
- primary follicle - uni-layered
- oocyte enlarges and follicular/granulosa cells increase in size = cuboidal
- oocyte produces zona pellucida –> glycoproteins, important in binding of spermatozoa
Describe stage 2 of follicle development (multi-layered)
- follicular/granulosa cells increase in number, increase in thickness –> stratified
- zona pellucida assembled
Describe stage 3 of follicle development
- secondary follicle
- spaces develop containing follicular fluid = coalesce to form a cavity
- production of oestrogen by granulosa cells
Describe stage 4 of follicle development
- Graafian (tertiary) follicle
- antrum –> large fluid filled cavity
- surrounded by corona radiata = ‘glowing crown’ , nutrition
What stimulates ovulation?
proteolytic actvity stimulated by gonadotropin (LH) –> oocyte expelled into entrance of uterine tube
What is the corpus luteum and corpus albicans?
corpus luteum = yellow body
- endocrine function follicular cells release –> progesterone and oestrogen
corpus albicans = white body
- cells replaced by collagen scar
List the features of the uterine tube
- intramural
- isthmus
- ampulla
- infundibulum
- ovaries
Describe the 2 types of epithelium in the uterine tubes
- secretory (peg) –> watery secretion for gamete nourishment
- ciliated –> cilia beat rate increases in response to oestrogen
Describe how the shape of the uterus differs amongst animals
simplex - human
bicornuate - pig
bipartite - cow/sheep
duplex - rodent
Describe the layers of the uterine wall
- para/perimetrium –? visceral peritoneum
- myometrium –> interwoven smooth muscle/CT - hormonal response = hypertrophy/hyperplasia
- endometrium –> epithelial layer
List the features of the female external genitalia
- glans clitoris
- vestibule
- mons pubis
- labia majora
- labia minora
- vaginal opening
What is the function of oestrogen?
- essential for ova maturation and release
- establishment of female secondary sexual characteristics
- essential for transport of sperm from vagina to fertilisation site
- contribute to breast development in anticipation of lactation
What is the function of progesterone?
- regulates the development of the endometrium
- important in preparing suitable environment for nourishing a developing embryo/foetus
- contributes to breast’s ability to produce milk
Describe the hormonal processes that take place during female sexual development
- just prior to puberty GnRH pulse generation begins
- luteinizing hormone (LH) and follicle stimulating hormone (FSH) are released from the anterior pituitary
- this is the start of follicular development
- developing follicles release oestrogens
- development of female secondary characteristics
- growth of auxillary hair, libido and pubertal growth spurt due to rise in adrenal androgens
- when sufficient GnRH, LH and FSH are present first period comes
Describe the hormonal changes that take place during the follicular phase
- FSH and LH rise at the beginning of the cycle due to GnRH release
- rising FSH and LH stimulate oestrogen release from the developing follicle
- rising oestrogen levels inhibit FSH but not LH secretion
- inhibin also inhibits FSH
- oestrogen stimulates positive feedback on the follicle causing further oestrogen release, oestrogen levels significantly rise
Describe the hormonal changes that take place during the luteal phase
- ruptured follicle forms the corpus luteum
- corpus luteum produces large amounts of progesterone
- progesterone inhibits LH and FSH release from the anterior pituitary
- after around 10 days the corpus luteum degenerates
- progesterone and oestrogen levels drop
- FSH and LH rise as no longer inhibited
What is the luteal surge?
- high oestrogen levels stimulate the anterior pituitary to produce large amounts of LH
- ovulation occurs due to LH surge
What are the functions of the corpus luteum?
- oestrogens responsible for endometrium thickening
- progesterone responsible for endometrium development and maintenance
- progesterone inhibits LH and FSH secretion
