Making egg and sperm Flashcards
metaphase diff between mei and mit
mit : single chromosomes line up along the equator
mei : first bivalents line up, then the single chromosomes line up
female reproductive system
ovaries suspended by ligaments in the peritoneal cavity
fimbriae : extneded part of the fallopian tube and directs the ovum(egg/oocyte) into fallopium tube
uterus –> cervix –> vagine –> vulva
fimbriae
finger like projections of the fallopian tube and captures the oocytes/eggs/ovum from the ovaries to the fallopian tube
covered by cilia which sweeps the ooctyes up the oviduct into the uterus
oocytes
eggs/ ovum
fallopian tube
oviduct or also called uterine tubef
where does fertilisation generally occue
near the top third part of the fallopian tube where sperm and egg fertilise
male reproductive system
testis located IN the scrotum
epididymus is located within the scrotum and attached to the posterior side of testicles.
sperm produced in testis, matured in the epididymus and then released in vas deferens during ejaculation. and then passes into the uretha
scrotum
regulates the temperature of the testis
testis
where sperm is produced, site of spermatogenesis
ovaries
eggs are produced, site of oogenesis
epididymus
is where sperm completes maturation after they’re producted in the testes
vas deferens
about 45cm, where sperm ejaculates, helps sperm by peristaltic movement, propels sperm
joins up with the seminal vesicle, just before it enters the prostate gland
uretha
males are 12cm, and women’s are 2-3 cm which is why women are more likely bladder infections e.g UTI
seminal vesicles
also called seminal glands that secretes a thick alklaine fluid that includes
prostaglandin
—> stimulate mobiloty of the sperm
fructose
–> nutrient resource for the sperm
clotting agents
—> coagulates semen before ejaculation
(temporary clotting process, prevents sperm from dehydrating)
prostate gland function
prostatic fluid contains citric acid
–> stimulates ATP production in sperm
proteolytic enzymes
–> eventually breakdown clotting agents in semen to keep sperm to continue to swim
bulbourethral (cowper’s) glands
(3rd)
mucous
–> protects the sperm from the acidic environment (urine) by lubricating the urethra and when leaving penis
alklaine fluid : neutralise urethra and also the vagina
semen sites composition
60% seminal vesicle
30% prostate
5% testes
5% bulbourethral glands
spermatogenesis
seminiferous tubules (located within testes)
spermatagonia
–mitosis–>
primary spermatocyte
– meiosis –>
secondary spermatocyte (haploid)
–meiosis 2 –> spermatids
–differentiation
–> sperm cells (spermatoza)
spermatids need to mature (into the epididymis)
seminiferous tubules
seminiferous tubules are in the testes: 2 types of cells
–> germ cells : develop into spermocytes (–>undergo mitosis and meiosis and differeintiate to make sperm) e.g. spermatogonia
–> sertoli cells : nourish/nurse developing germ cells
sperm cell structure
head : nucleus + acrosome (enzymes to penetrate the egg/oocyte)
mitochrondia : product ATP to power the tail
oogenesis
oogonia ( first step)
–> primordial follicle (oocyte + surrounding granulosa cells)
at puberty, start meiosis and stop at prophase 1
= some primordial follicles start to differentiate primary follicles = layer of granulosa cells thickens and primary oocyte gets bigger = zone pellucida forms around the primary oocyte (important for fertilisation and prevent for more than one sperm penetrating)
–> primary follicles develops into a secondary follicle during the menstrual cycle = an outer layer called theca is formed and granulosa cells start to secrete a fluid to form a cavity within the follicle
–> before ovulation, secondary follicles will develop into a graafiene follicle (still a primary oocyte so still stuck in prophase 1
–> they complete meiosis one and form a secondary oocyte (haploid) and completes meiosis 2 if fertilised
secondary oocyte is released and the structure that remains inthe ovaries is called the corpus luteam
corpus luteam
important in regulatin the progesterone
(thickening uterus wall and nourishes of the embryo and can regulate the menstrual cycle
continues secreting progesterone whiel the placenta is developing which is called the first trimester of gestation (3 months) and then slowly degenerate but degenerates much quickly if no fertilisation
hormones in male before puberty
hypothalamus and anterior pituitary before puberty are immature
interstitiual cells are the ones that are around the seminiferous tubules = they secrete testosterone
testosterone has an inhibitory effect on the hypothalamus and anterior pituitary
hormones in female before puberty
ovaries secrete oestrogen and progesterone, inhibitory effect on hypothalamus and anterior pituuitary gland
hormones in male during puberty
during puberty, hypothalamus and anterior pitruaty no longer inhibited:
hypothalamus releases the gonadotropin releasing hormones (GnRH)
–> stimulates the secretion of luteinising hormone (LH) and follicle stimulating homrone (FSH) in the anterioir pituitary gland
these hormones stimulate the interstitual cells (which secretes testosterone) and sertoli cells (mainly feed the developing germ/sperm cells) to mature
male characteristics develop
hormones in female during pubert
hypothalamus and anterior pituitary mature, no longer inhibited, serete GnRH and stimulate the production of LH and FSH
LH : regulates ovulation, thats when the secondary oocyte is released
FSH : takes oocyte from primary oocyte to secondary oocyte
female characteristics develop
