human reproduction Flashcards
sexual reproduction !
process involving fusion of the male & female gametes to form a zygote & production of genetically dissimilar offspring
gametes !
reproductive cells containing haploid number of chromosomes
male : sperm by testes
female : ovum by ovaries
sperm !
head
middle piece
flagellum
smallest cell in body
is mobile
has either X or Y chromosomes
sperm - head !
contains large nucleus containing of one haploid set of chromosomes (23)
contains small amt of cytoplasm
contains an acrosome : contains enzymes for breaking down part of the egg embrace for sperm penetration
sperm - middle piece !
contains numerous mitochondria : provide energy for sperm to swim to egg
- mitochondria : site of aerobic respiration -> release energy
sperm - flagellum / tail !
enables sperm to be motile
- beats to enable sperm to swim towards egg
ovum !
large nucleus containing one haploid set of chromosomes (23)
large amt of cytoplasm
cannot move by itself
only contains X chromosomes
largest cell in body
male reproductive system !
testes (singular : testis) epididymis spermatic cord scrotum seminal vesicles sperm duct prostate gland urethra sphincter muscle penis
testes !
produces sperms & male sex hormones (testerone)
epididymis !
stores inactive sperms from testis before they are released into super duct
spermatic cord !
supplies blood to testis
scrotum
skin sac located outside body : maintain a lower temperature of testis for development of sperms
seminal vesicle !
stores sperms temporally before they are released through rephrase
activating sperms !
seminal vesicles, prostate gland, Cowper’s gland
- secretes sperm containing nutrients & enzymes : nourish sperms + stimulate them into swimming actively
urethra !
transports both urine & semen
sphincter muscle !
prevents urine from exiting the body during ejaculation
prostate gland !
secretes fluid containing nutrients & enzymes to nourish + activate sperms
penis !
erectile organ : becomes erect & had during sexual intercourse —> deposit semen into vagina
excretion : occurs when spongy tissue in penis is filled with blood
sperm duct !
transport sperm to urethra after being released from testis
female reproductive system !
ovary oviduct uterus cervix vagina
ovary !
produces ovum (egg) & female sex hormones (oestrogen, progesterone)
oviduct / fallopian tube !
site of fertilisation
mature eggs are released here
uterus !
site of embryo implantation & foetal development
has elastic muscles : enable contraction during birth to force out the fetus during birth
cervix !
opening : allows menstrual blood to flow out into the vagina
vagina !
location where semen containing sperms is deposited during sexual intercourse
puberty !
stage of human growth & development in which a person’s body becomes capable of reproduction
menstrual cycle !
monthly discharge of broken lining of the uterus wall, dead ovum & blood via the vagina
mensuration - day 1-5
menstruation takes place
broken lining of uterus wall, dead ovum & blood flows out through vagina
menstruation day6-10
ovary : produces oestrogen
- thickens uterine lining
- high concentrations can lead to ovulation (day14)
uterine lining : thickens
blood vessels form inside thick lining
ovulation - day 14
mature ovum released from ovary into oviduct
menstruation - day11-18
fertile period
one of the ovaries : release mature ovum
ovary : produces progesterone, oestrogen decreases for a while
- thickens uterine lining further -> egg can be implanted
- facilitates growth of embryo if egg is fertilised
menstruation - NOTE
egg : survive for 24h
sperm : survive 3-4 days
after this period, rest of the days : infertile
- egg + sperm died
mensturation day19-28
uterine lining : thickest, well supplied with blood vessels (O2, glucose)
mensturation - outcome 1 !
egg : successfully fertilised
uterine lining : continues to thicken until suitable for implantation & growth of embryo
mensuration - outcome 2 !
egg : not fertilised
progesterone : decreases
- no implantation
- thick uterine lining breaks down
primary follicle !
consists of a potential egg cell surrounded by a layer of smaller follicle cells
graafian follicle !
developed from primary follicle
contains a mature egg surrounded by follicle cells & a fluid-filled space
egg : released into oviduct
oestrogen : released into bloodstream -> repair + growth of uterine lining
follicle - ovulation !
Graafian follicle : ruptures + releases egg into oviduct funnel
corpus luteum !
developed from rupture Graafian follicle after ovulation
secretes progesterone & oestrogen : prepare body for pregnancy
if no fertilisation occurs : corpus luteum will persist fr some time -> eventually will break down & start producing hormones -> start of mensturation
fertilisation !
fusion of haploid nucleus of a male gamete (sperm) & haploid nucleus of a female gamete (ovum) to form a diploid zygote
once a sperm enters the egg : membrane of egg changes -> no sperms can enter -> unable to fertilised egg -> dies
implantation !
event where embryo becomes embedded in uterine lining
peristaltic movements in wall of oviduct + cilia lining inner surface of oviduct : sweeps fertilised egg towards uterus
zygote : divides by mitosis -> form embryo
embryo : float freely in uterus for 2 days before implantation
development of placenta !
developed from villi & uterine lining
after implantation : villi grow from embryo into uterine lining
umbilical cord : attaches embryo to placenta
placenta functions !
produces progesterone to maintain condition & thickness of uterine lining throughout pregnancy
space between mother’s blood capillaries & fetus’ blood capillaries -> allows for diffusion of :
- oxygen & food substances (glucose, amino acids) from the mother’s blood into fetus’ blood
- excretory products (urea, carbon dioxide) from the fetus’ blood into the mother’s blood
- antibodies produced by the mother from the mother’s blood to the fetus’ blood
umbilical cord functions !
umbilical vein : transports oxygenated blood & food substances from the placenta to fetus
umbilical arteries : transports deoxygenated blood & metabolic waste products from the fetus to placenta
amniotic sac !
filled with amniotic fluid
amniotic fluid functions !
supports & cushions fetus
protects fetus against physical injury by absorbing shock
allows fetus to move freely during growth -> promote muscle development
lubricates vagina during birth
fetal blood system !
fetal blood capillaries :
- not connected to maternal blood capillaries
- surrounded by maternal blood spaces
- diffusion of dissolved substances occurs across the maternal blood spaces
why is fetal & mother’s blood systems separated ?
mother’s blood pressure : too high for fetus
fetus’ & mother’s blood may be different
- if mixed : maternal antibodies would cause fetus’ blood to agglutinate -> fatal
STI !
disease that is spread that is spread through sexual intercourse
AIDS !
caused by HIV : destroy body’s immune system
not able to produce sufficient antibodies : unable to protect themselves from other infections
symptoms : severe diarrhoea for moths pneumonia choric fever brain infection
modes of transmissions of STI !
unprotected sexual intercoruse with an infected person
passed from infected mother to fetus during pregnancy
sharing of hypodermic needles with contaminated blood of an infected person
blood transfusion with contaminated blood with an infected person
prevention of HIV !
keep to one sex partner
make sure needles used in acupunture, ear piercing, tattooing are sterilised
do not share instruments that can break skin & het contaminated with blood (razors, toothbrushes)
do not abuse drugs : drug addicts share needles
