physiology of reproduction Flashcards
what are leydig cells and where are they
clusters of cells between the seminiferous
tubules and source of testosterone
where are the source of hormones
interstitial cells such as leydig cells
how is the pendulous pouch seperated
median septum
where does meiosis occur in males
seminiferous tubules of males
what are the two types of cells daughter cells produced by spermatogenesis
Type a replenish the pool of spermatogonia
Type b - form mature sperm
how is the blood testis barrier formed
Formed by Sertoli cells and the tight junctions between them
what happens in the epididymis
site of sperm maturation
what is released for male ejaculation
60% seminal vesicle fluid, 30% prostatic & 10% sperm and
trace of bulbourethral fluid
other components of semen
fructose provide energy for sperm motility
– fibrinogen
– clotting enzymes convert fibrinogen to fibrin causing semen to
clot
where do germ cells originate from
yolk sac in the region of the hindgut
how to germ cells migrate
migrate to the genital ridge by amoeboid movement
why is phospholipase c zeta important
oocyte activation
activates egg to release ca
decondensed sperm nucleus into pronucleus
what happens in in vivo fertilisation
egg fertilised in fallopian tube
implantation in uterine cavity
energy for early preimplantation
atp turnover is low
atp/ adp ratio is high
glucose uptake and utilisation is low
role of hcg
essential for early ppregnancy
ensures corpus luteum makes progesterone
repels immune cells- and protects embryo
sex differentiation for men and women
Determined by the SRY GENE
male pathway will be induced if there is anti mullerian hormone and androgens ,
Leydig cells will secrete testosterone
Female pathway is induced to make ovaries etc in the abscence of androgens and amh
what is dihydrotestosterone used for
synthesis and action for development of external genitalia
what happens during infancy
rapid but rapid declerating growth in first 2-3 yrs
determined by nutrit
important determinants of growth
parental phenotypeand genotype
nutrition
Quality and duration of pregnancy
psycho social environment
what is chondrogenesis
growth
where is Human growth hormone produced
somatroph cells in the anterior pituitary gland
what important hormone does puberty require
GnRH
what percentage of girls go into early puberty
80%
what percentage of boys go into early puberty
30% alarming
symptoms of turner syndrome
short stature
recurrent ear infections
webbing of neck
broad chest
Klinefelter syndrome
small testes
reduced sexual hair
tall stature
osteoporosis
what is climacteric menopause
around the time of menopause and the year after
cause of menopause
depletion of primordial follicles
mechanism of menopause
ovaries depleted of follicles
decline of oestrogen production
gradual decline w age
gradual rise of FSH AND LH - lack of negative feedback mechanism
risks of premature menopause
risk of mortality heart disease mood and sexual disorders bone mineral density risk of cognitive dysfunction
symptoms of menopaise
hot flushes
mood swings
irregular cycles
osteoporosis
urogenital signs of menopause
vaginal dryness
painful sex
urethral syndrome
treatments for menopause
HRT- hormone replacement therapy
sedatives
beta blockers
calcium, vit d and calcitonin
what hormone is replaced in HRT
oestrogen or progesterone if the uterus is intact
how is the uterus supported by the pelvic cavity
broad ligaments
round ligaments
cardinal ligaments
what are the fallopian tubes
pathway by which the ovum travels from the ovary to the uterus
function of cervix
connects the uterus with the vagina
basics of ultrasound scans
sound wave that goes in then bounces back
why is ultrasound the preferred imaging method in the UK
CHEAP AND SAFE
What is a transvaginal US used for
to see the endometrium or lining of uterus
And if you’re fat
In what specific cell in the testis do sperm cells mature
sertoli
what is the site of spermatogenesis
Walls of seminiferous tubules
what is the process of ooogenesis
differentiation of an ovum into a cell that can be fertilised
3 steps in oogenesis
Multiplication phase - in utero
Growth phase - primary oocyte to primary follicle
Maturation phase - two cells are formed a cytoplasm cell and polar cell body which is discarded
what is spermatogenesis
cell differentiation process that ensures the production of fertilizing sperm
purpose of blood testes barrier and where it’s formed
Formed between Sertoli cells of thr seminiferous tubules and as such isolate the further developed stages of germ cells from the blood
what is spermiogenesis
remodelling and differentiation into mature spermatozoa
main changes for girls during puberty
breast formation
pubic hair growth
1st period
main changes for boys at puberty
increase in testicle size due to increase in fsh
pubic hair growth
deeper voice
importance of SRY GENE men
men xy- SRY present, SRY protein formed which allows development of the gonads
, leydig cells to testes
thus wolfian duct development
importance of SRY gene WOMEN
not present in women as no Y chromosome
so no SRY protein
bipotential gonads to become ovaries
no wolfian duct
stages in sperm production
spermatogenesis
spermiogenesis
what happens in spermatogenesis
Step 1 - primordial germ cells undergo mitosis to form type a and B cells
Step 2- type B cells will replicate by mitosis to form diploid cells linked by cytoplasm bridges known as primary spermatophores
Step 3- meiosis 1 will produce secondary spermatocytes
Step 4 will produce four haploid cells known as spermatids
Process of spermiogenesis
Golgi body enzymes form the acrosome
Acrosome condenses around the nucleus
centriole elongates to form the tail
Loss of excess cytoplasm
