Reproductive System Flashcards
define reproduction
process of formation of individuals by sexual and asexual means, which can repeat the process in their own turn
primary reproductive parts
gonads- testes and ovaries which produce gametes
accessory reproductive parts
structures, ducts, glands which help in transfer and meeting of gametes leading to fertilisation
location of testes
oval organs, contained in a thin-walled sac of skin called scrotum
in embryonic stage- within abdomen
high temp effect on sperms
high temperature inside body does not permit maturation of sperms
structure of testis
encased in a capsule which is internally divided into 250 lobules
each lobule contains
- seminiferous tubules: sperms produced here, called spermatogenesis
- interstitial cells: packing tissues between the coils of seminiferous tubules. AKA Leydig cells, producing testosterone
location of epididymis
fitting like a cap on the upper pole of the testis
function of epididymis
stores the sperms for some days during which they mature and become motile
location of vas deferens
arises from epididymis from each testis, travels upward into abdomen passing through inguinal canal
cause of hernia
due to pressure in abdomen, intestine bulges into the scrotum through inguinal canal
accessory glands of male reproductive system
- seminal vesicles
- prostate gland
- bulbo-urethral/ cowper’s gland
location of seminal vesicles
lobulated glands located between posterior surface of urinary bladder and rectum
function of seminal vesicles
produces a secretion which serves as a medium of transportation for the sperms (called semen)
by addition of semen, sperms become more active
location of prostate gland
bilobed structure which surrounds the urethra close to its origin from the bladder
function of prostate gland
pours alkaline secretion into semen that neutralises acid in vagina
location of cowper’s glands
two small ovoid glands which open into the urethra just before it enters the penis
function of cowper’s gland
lubricant
location of penis
in front of the scrotum, cylindrical in shape, serves for passing out both semen and urine
location and function of ovaries
small ovoid bodies
their peripheral part produces ova
define follicle
a maturing egg is contained in a cellular sac called follicle. as the egg grows larger, the follicle enlarges and is filled with a fluid, and is now called graafian follicle
define oogenesis
the process in which ova-producing cells give rise to mature ovum
define ovulations
process of rupture of the graafian follicle releasing the egg
define corpus luteum
the remnants of the follicle persists for some time to convert it into a yellow mass, which secretes 2 hormones
hormones secreted by follicle
- oestrogen (prior to ovulation)
- progesterone
uterus
hollow pear-shaped muscular organ
situated in the pelvic cavity between urinary bladder and rectum
vagina
muscular tube starting from lower end of the uterus upto the outside
receives male penis
vulva
external female genitalia
sides have fleshy folds, called labia minora, hidden by larger hair folds, labia majora
define puberty
period during which immature reproductive system of boys and girls matures and becomes capable of reproducing
define menarche
onset of menstruation in a young female at 13 years
define menopause
permanent stoppage of menstruation in females at the age of 45 years
menstrual phase
- blood is discharged
- bleeding due to shedding and rupturing of blood vessels that make up the thickened innermost lining of uterus (endometrium)
- ovary begins to form a new egg in a follicle
- 3-5 days
follicular phase
- 5-12 days
- oestrogen increases
- hormone acts on uterus and causes lining to become thicker and more blood vessels
- prep for uterus to receive fertilized egg and assist in early implantation of embryo
ovulatory phase
- 13th or 14th day
- follicle ruptures and releases egg down towards oviduct
- two hormones produced, FSH and LH, promote maturation and release of ovum
luteal days
- day 15-28
- uterus line thickens
- emptied follicle turns into hormone-producing body called corpus luteum
define fertilization
the fusion of male gamete and female gamete to form a zygote
acrosome of sperm
at the top of the head of sperm
secretes hyaluronidase which facilitates entry of sperm into egg by dissolving wall of ovum
nucleus of sperm
contains genetic material (22+X or 22+Y)
combines with nucleus of egg containing 22+X chromosomes, restoring original 23 pairs
mitochondria of sperm
provides ATP energy for sperm to swim
define blastocyst
the zygote starts dividing into 2, 4, 8, 16 cells and so on. by the time it reaches the uterus, it has formed a small hollow ball of numerous cells
define implantation
the blastocyst it forms a pit in endometrial lining and gets fixed in it in a week’s time after ovulation
define embryo
a growing egg after fertilisation until main parts of the body and the internal organs have started to take shape
define foetus
when embryo starts having the look of a baby
define pregnancy
state of carrying the unborn young one inside the body
extraembryonic membranes surrounding blastocyst
amnion
chorion
allantois
placenta
amnion
sac which develops around the embryo even before the formation of allantois
a fluid AKA amniotic fluid fills space between amnion and embryo
functions of amniotic fluid
- protects embryo from jerks and mechanical shocks
- keeps even pressure around embryo
- allows foetus some restricted movement
- prevents sticking of foetus to amnion
placenta
disc-like structure attached to uterine wall
cord containing blood vessels connects placenta with foetus, called umbilical cord
functions of placenta
- diffusion of nourishment from mother’s blood to growing foetus
- disposal of wastes from blood of foetus to mother
how does placenta act as endocrine gland
produces progesterone and oestrogen
define gestation
full term of development of the embryo in the uterus is called gestation .
lasts for 280 days
define parturition
act of expelling full term foetus from mother’s uterus at the end of gestation
fraternal/ diovular/ dizygotic twins
produced from two eggs
BB, GG, BG possible
identical twins
single fertilised egg splits into two
only BB or GG
causes of triplets
- one single zygote, splitting into two, and one split part again splitting into two
- two eggs, one zygote produces identical twins by splitting and another normal baby
causes of quadruplets
- two pairs of identical twins from two eggs
- other combinations of identical and fraternal twins
