reproduction Flashcards
(12 cards)
functions of reproductive organs
the formation, storage and transport of gametes
production of life
hormones
endocrine system in reproduction
The pituitary galnd releases LH and FSH
LH and FSH releases are crontrolled by GnRH released by the hypothalamus
LH and FSH have various functions controlled by negative feedback from sex hormones made in the ovary (secrete oestrogen and progesterone controling the menstrual cycle and pregnancy) and testes ( testosterone controls the development of male sexual characteristics and sperm production)
Gametogenesis
gamete formation
germ cells, meiosis and maturation
primary sex organs and secondary sexual characteristics and accessory organs in males
primary sex organs make haploid gametes and produce sex hormone
accessory sexual organs include the structures used to carry gametes, bring about fertilization and protect the zygote.
secondary sexual characters - pubic hair lower voice
testes which is important for spermatogenesis to occur as the temperature is slightly lower outside the body
accessory sex glands- seminal vesicles- fructose, prostaglandin providing 60% of semen volume
prostate- secrete alkaline fluid and citric acid providing clotting enzymes and PSA
bulbourethral gland- mucus
mostly made of seminiferous tubules produce 100 million spermatozoa a day
walls of tubules have primitive germ cells which mature and move to lumen
leydig or interstitial cells ate found in between the tubules and their main fuction is to produce testosterone by LH
sertoli cells are support cells in the tubules and make regulators for spermatogenesis
spermatogensis
primitive germ cells next to the basal lamina mature into primary spermatocytes
primary spermatocytes undergo meiosis dividing into secondary spermatocytes and then spermatids which contain 23 chromosomes
continue their mobility through the epididymis
female reproductive system
primary- ovaries which produce the ova and sex hormones
accessory organs- fallopian or uterine tubes, uterus, vagina and vulva
ovaries- small organs located on each side of the uterus, they produce haploid ova and secrete sex hormones
- the ovaries contain a man number of follicles they were formed in foetal life
- primary oocyte is sourounded by follicular cells
oestrogen controls the develpoment of secondary sexual characters which include- finer body hair, wider pelvis
progesterone is for
stimulating uterine changes during the menstrual, affecting the breast tissue develpoment
oogensis
several follicles enlarge and one becomes the dominat follicle and a cavity forms around the follicle
the granulosa cells and theca interna make oestrogen
the follicle ruptures releasing the ovum, ovulation
secondary oocyte immediately beigins the second meiotic division stopping at metaphase and is only completed once sperm enters the egg
fallopian tubes
-extends fro the uterus to the ovaries
- possess cilia and the beating of cilia helps the ovum to move in the tube which catch the egg as it leaves the ovary during ovulation
uterus
thick muscular sac at the front of the pelvic cavity
contraction of the smooth muscle wall in the uterus is what pushes the baby out
vagina and vulva
muscular tube leading from the vaginal orifice to the uterus
vulva are the external organs
fertilization
1) chemoattraction of the sperm to the ovum by substances produced by the ovum
2) adherence to the zona pellucida, a gel- like membranous structure surrounding the ovum
3) penetration of the zona pellucida and the acrosome reaction (with the help of ca2+ ions)
4) adherence of the sperm head to the cell membrane of the ovum, the breakdown of the area of fusion and release of the sperm nucleus into the cytoplasm of the ovum
inside the ovum the sperm nucleus swells and bothe the sperm and ovum nuclei are now pronuclei
chromosomes move to the centre and miotic spindles form and is made into a diploid zygote
implantation
endometrial cells at point of contact thicken known as decidua
trophoblast cells invade decidua and relase enzymes causing bastocyst to bore into deeper tissues utilizing the breakdown products
