physiology Flashcards
what is a hormone?
a hormone is a chemical which is produced at one site and has an effect on another site
what happens when a hormone reaches its target tissue?
it brings about a specific effect
where are hormones produced?
hormones are produced in the hypothalamus and the pituitary gland controls the onset of puberty, sperm production and the menstrual cycle
what hormones does the pituitary gland produce?
FSH (follicle simulating hormone) - both males and females
ICSH (interstitial cell simulating hormone) - males
LH (luteinising hormone) - females
what does the hypothalamus do at the beginning of puberty?
at the beginning of puberty the hypothalamus secretes a releaser hormone whose target is the pituitary gland which then secretes hormones
what does the production of hormones from the pituitary gland do?
the release of these hormones triggers the onset sperm production in men and the menstrual cycle in women
what does FSH do at the bloodstream in the testes?
it promotes sperm production in the seminiferous tubules
what does ICSH do when it arrives in the bloodstream at the testes?
it stimulates the interstitial cells to produce the sex hormone testosterone
what does testosterone do?
testosterone stimulates sperm production in the seminiferous tubules and activates the prostate gland and seminal vesicles to produce their secretions
what is the self regulating mechanism of testosterone production?
when the concentration of testosterone increases in the bloodstream it reaches a level where it inhibits the secretion of FSH and ICSH by the pituitary gland which leads to a decrease of testosterone concentration which then triggers the pituitary gland to again make FSH and ICSH
what do the testes produce?
sperm and testosterone
what is sperm formed from and where are they formed?
sperm is formed from germline cells in tiny tubes called seminiferous tubules
what is a sperm duct?
seminiferous tubules unite together to form coiled tubes that link to the sperm duct and sperm leave to the testes through the sperm duct
what is testosterone produced by?
interstitial cells found in the tissues between semiferous tubules and passes directly into the bloodstream
what do seminal vesicles secrete?
seminal vesicles secrete a fluid rich in fructose (to provide energy) and hormonal like compound (to stimulate contractions of the female reproductive tract)
what does the prostate gland secrete?
a thin, lubricating liquid containing enzymes which help to keep the fluid at the optimum viscosity for sperm motility
what is semen?
semen is the collective name for the liquid released by males
what does semen contain?
semen contains sperm from the testes and fluid secretions from the seminal vesicles and prostate gland that maintain the mobility and viability of sperm
what is the female gamete called?
an ova (egg)
what and where are female gametes produced?
female gametes are produced in the ovaries and are produced from germline cells
what do the ovaries contain?
the ovaries contain a mature ova at several stages of production
what are ovums surrounded by?
each ovum is surrounded by. a follicle which protects it and secretes the hormones
what happens to the folicle after ovulation?
after ovulation the follicle develops into a corpus luteum
what is ovulation?
the release of the mature ovum into the oviduct during ovulation
what is. a corpus luteum?
a hormone secreting body that secretes progesterone
function of corpus luteum in gamete production in the ovaries?
the corpus luteum then secretes the hormone progesterone which causes changes in the uterus to make it more suitable for implantation of the blastocyst
what happens to the sperm during intercourse?
during sexual intercourse, the sperm are released into the vagina and move through the cervix, the uterus and into the oviducts where they may meet an ovum
what is fertilisation?
fertilisation is when the nucleus of a sperm fuses with a nucleus of an ovum
where does fertilisation occur?
oviduct
what is a fertilised ovum called?
a zygote
how long does the menstrual cycle last for?
approximately 28 days
what is mensuration indicated by?
by blood flow
what is the first day of menstruation called?
“day 1” of the menstrual cycle
what are the two phases of the menstrual cycle?
follicular phase and luteal phase
which is the first phase of the menstrual cycle
the follicular phase
which phase is the second phase of the menstrual cycle?
the luteal phase
what does FSH do in the follicular phase?
it stimulates development and maturation of a follicle
it stimulates production of oestrogen by the follicle
what does Oestrogen do in the follicular phase?
Oestrogen stimulates rapid growth of the endometrium preparing it for implantation
affects the consistency of cervical mucus making it more easily penetrated by sperm
triggers a surge in the production of LH (around day 14)
what does LH do in the follicular phase?
is the direct cause of ovulation wha
what is the hormone which is present in urine during pregnancy and is the basis of pregnancy tests?
HGC aka Human chorionic gonadotrophin