HUMAN REPRODUCTION Flashcards
humans are oviparous or viviparous?
viviparous(give birth to young ones)
what are the steps of reproduction?
- gametogenesis
- insemination
3.fertilization
4.implantation
5.gestation
6.parturition
what is insemination?
transfer of male gamete into female reproductive tract
what is implantation?
attachment of blastocyst to uterine wall
what is gestation?
period of embryonic development
what is parturition?
delivery of the fully developed foetus
parts of male reproductive system?
- main reproductive part
- ductal system
- accessory glands
- external genitalia(penis)
dimensions of testes?
length:4-5cm
width:2-3cm
location of testes?
during embryonic development, in abdominal cavity.
before birth, it descends into scrotum
what is monorchidism and cryptorchidism?
monorchidism: failure of descend of one testis
cryptorchidism: failure of descend of both testes
what is castration?
removal of testes.
in choir boys in european countries, so that their voice remains high pitched.in bulls to make them less aggressive for the use in farming
why are testes located in scrotum?
because temperature of scrotum is 2-2.5 degree celsius less than normal body temperature. this low temperature is required for spermatogenesis.
what are the coverings of testes?
- TUNICA VAGINALIS(parietal and visceral)
2.TUNICA ALBUGINEA - TUNICA VASCULOSA
how many testicular compartments/testicular lobes are present in one testis?
tunica albuginea divides each testis into 250 testicular compartments.
no. of seminiferous tubules in each testicular compartment?
2-3
what is the pathway of sperm?
seminiferous tubule->tubuli recti->rete testis->vasa efferentia->epidydimis->vas deferens
abdominal cavity is attached to scrotum through?
inguinal canal
what passes through the inguinal canal?
spermatic cord(blood vessels, nerves, lymphatics)
fibres which attach to the wall of scrotum are called?
gubernaculum/mesorchium
epithelium of epidydimis?
pseudostratified epithilium with steriocilia
(microvilli)
highly coiled
releases factors for maturity of sperms
parts of epidydimis?
- caput
- corpus
3.cauda
vas deferens loops around? swollen terminal part of vas deferens is called?
urinary bladder, ampulla
what is ejaculatory duct?
vas deferens and seminal vesicle ducts form ejaculatory duct which opens finally into the urethra.
what is erection organ? what controls erection?
penis. erection is controlled by autonomic nervous system, increase in blood supply and vasodilation takes place.
what is the terminal part of penis called?
glans penis.
what is foreskin?
the lose fold of skin which covers the penis
seminal vesicle:
paired or unpaired?
location?
seminal fluids?
secretions?
paired gland
behind urinary bladder
constitutes 60-70% seminal fluids
transparent jelly like secretion(fructose and prostaglandins)
function of fructose and prostaglandins secreted by seminal vesicle?
fructose- provides energy to sperm
prostaglandins- smooth muscle contractors(cause smooth muscle contraction of uterine wall to assist motility of sperm)
prostate gland:
paired or unpaired?
location?
seminal fluids?
secretions?
unpaired
prostate part of urethra, at the base of urinary bladder
secretions give milky appearance to semen
constitutes 20-30% seminal fluids
Ca2+ : help in motility of sperm
profibrinolysin: lyse the clot of semen in female genital tract
bulbourethral gland:
paired or unpaired?
location?
secretion?
paired
base of penis
mucus(provides lubrication)
what is semen?
SPERM(from seminiferous tubule)+SEMINAL VESICLE(from seminal vesicle, prostate gland and bulbourethral gland)
what is the pH of semen and why?
7.2-7.7
the alkaline pH counteracts the adverse effects of urine.
quantity of semen per ejaculation?
sperm count per ejaculation?
2-2.5 ml/ejaculation
200-300 million/ejaculation
what is the condition of sperm required for a male to be fertile?
60% of the sperms should have normal shape and size. out this, 40% should have vigorous motility
cells of testicular compartments?
1.sertoli cells/nurse cells/sustentacular cells
2.leydig/interstitial cells
3.immuno competant cells
what are the functions of sertoli cells?
- provide nourishment to sperms
2.phagocytosis of dead and remains of sperms - release anti-mullerin factor
4.produce inhibin(to regulate spermatogenesis)
5.blood-testis barrier
6.produce ABP(androgen binding protein )
what are the functions of leydig cells?
- secretion of TESTOSTERONE.(a. spermatogenesis
b. development of secondary sexual characters)
what are the functions of immuno competant cells?
kill/destroy foreign antigen or virus particle
what is spermatogenesis?
it is the formation of haploid spermatids from diploid male germ cell(spermatozoa)
when does spermatogenesis start and end?
starts at puberty and continues throughout life although declining at old age
steps in spermatogenesis?
spermatogonia(2n)—–>primary
[growth]
spermatocyte(2n)—–>secondary
[meiosis-1] spermatocyte(n)
—–>spermatids(n)—> spermatozoa(n)
[meiosis-2] [spermiogenesis]
what is spermiogenesis?
transformation of spermatids into spermatozoa.
sperm head gets attached to sertoli cells
what is spermiation?
release of sperm into the lumen of seminiferous tubule
which gonadotropins does the anterior pituitary secrete?
- FSH(follicle stimulating hormone)
- LH(leutinising hormone)/ICSH(interstitial cell stimulatory hormone)
action of FSH in regulation of spermatogenesis?
it acts on sertoli cells.1. inhibin2. spermiogenesis
action of LH/ICSH in spermatogenesis?
acts on leydig cells.
|
androgen
|
spermatogenesis
spermatid v/s spermatozoa?
SPERMATID: heavier
has cell organelles like E.R., golgi body
non-motile
SPERMATOZOA: lighter
compact nucleus
less cytoplasm
golgi body forms acrosome
less cytoplasm
parts of sperm?
- head region
- neck
- middle piece
- tail
what is head region of sperm?
head is conical in shape. it has enlarged nucleus
what is acrosome?
the tip of the head of sperm is made up of ACROSOME which has enzymes like hyluronidase
explain neck region of sperm.
proximal centriole: helps in division of zygote
distal centriole: formation of axial filaments
explain middle piece of sperm.
it comprises of large no. of mitochondria which are spirally arranged.
the mitochondria provide energy for sperm motility
how many mitochondria are there in 1 sperm?
approx. 25
what are clumped mitochondria called?
nebenkern
what type of movement does human sperm show?
flagellar movement
what type of movement does sperm of ascaris show?
amoeboid movement(non-flagellated)
dimensions and shape of ovaries?
2-4cm
almond shape
what are the parts of ovary?
1.germinal epithelium(simple cuboidal)
2.tunica albuginea
3.ovarian stroma[a.peripheral cortex(follicular growth) b. inner medulla(nerves, blood vessels, lymphatics)]
what are the parts of female reproductive system?
- ovary
- fallopian tube
- uterus(has cervix)
- vagina
what is the shape of uterus?
inverted pear shape
what are the parts of uterus?
- fundus(upper dome shaped)
- cornua(the corners where oviducts attach to uterus)
- corpus/body(middle part)
what are the walls of uterus?
- perimetrium
- myometrium
- endometrium
explain perimetrium and myometrium.
PERIMETRIUM: outermost
protection
MYOMETRIUM: middle layer
smooth muscles
responsible for uterine contractions
explain endometrium.
innermost layer
glandular
highly vascular
during menstrual cycle it undergoes cyclic changes
how is cervix connected to uterus and vagina?
uterus-inner opening
vagina-outer opening
what are the dimensions of fallopian tube?
10-12cm
what are the parts of fallopian tube?
- infundibulum(funnel shaped)
2.ampulla(wider part, site of fertilisation)
3.isthmus(last part, narrower lumen)
what are fimbriae?
they are finger like projections of infundibulum which collect the ovum after ovulation. fimbriae form an opening called OSTIUM
dimensions of vagina and what type of structure it is?
8-12cm
fibromuscular
what is hymen?
the vaginal orifice is partially covered by a membrane called hymen.
is hymen an indicator of virginity?
NO,
hymen can be torn during 1st intercourse but it can also be torn due to vigorous exercise, horse riding, injury etc.
parts of external genitalia/vulva?
- mons pubis
- labia majora
3.labia minora - clitoris
- para urethral glands/skenes gland
- bartholins gland
what is mons pubis, labia majora and labia minora?
MONS PUBIS: fatty tissue covered by skin and hair
LABIA MAJORA: fleshy folds which surround vaginal orifice
LABIA MINORA: fold of tissue
what is clitoris?
it is a tiny finger-like projection present at the anterior junction of labia minora
what are the secretions of para urethral glands and bartholins gland?
SKENES GLAND: alkaline secretions
BARTHOLINS GLAND: mucus
are mammary glands paired or unpaired?
location?
development?
-paired
-in front of major pectoralis muscle in thorax region
-at puberty, due to release of progesterone and estrogen
mammary glands are modified?
sweat glands
each mammary gland comprises of how many lobes?
15-20 lobes
what is inside each lobe in mammary glands?
no. of lobules
what are alveoli in mammary glands?
grape-like cluster of milk secreting glands.
structure of mammary glands after alveoli?
mammary tubules->mammary ducts->mammary ampullae->lactiferous duct
contents of human milk?
- fats
- protein(cassein)
3.vitamins - minerals
what is human milk deficient in?
- poor Fe content
- low vit.C content
what is colustrum?
1st 3 days of milk after parturition.
what does colustrum contain?
immunoglobulin IgA
what is the milk producing hormone?
prolactin
what is the milk ejecting hormone?
oxytocin
what is oogenesis?
formation of ova/ovum from gamete mother cell (oogonia)
when does oogenesis start?
during embryonic stage
how many oogonia are formed in each fetal ovary?
couple of millions(2-20 lacs)
more oogonia are formed after birth. true or false?
FALSE
what is primary oocyte?
oogonia undergoes meiosis-1 and gets arrested at prophase-1, is called primary oocyte.
what is primary follicle?
each primary oocyte gets surrounded by a layer of granulosa cells forming primary follicle
how many follicles are left in each ovary after the degeneration of many follicles during the phase from birth to puberty?
60,000-80,000 primary follicles remain in each ovary
what is secondary follicle?
the primary follicle gets surrounded by more layers of granulosa cells and a new theca layer is formed. the is the secondary follicle
features of tertiary follicle.
secondary follicle transforms into tertiary follicle
primary oocyte converts into secondary oocyte
presence of antrum
theca is organised into inner theca interna and outer theca externa
when is secondary oocyte formed?
formed in tertiary follicle.
primary oocyte grows in size and complete 1st meiotic division to form secondary oocyte
what type of division is the 1st meiosis? what are the products?
unequal division
large haploid secondary oocyte + tiny 1st polar body(n)
does secondary oocyte undergo meiosis-2?
secondary oocyte undergoes meiosis-2 and gets arrested at metaphase-2
what happens if sperm enters the secondary oocyte arrested at metaphase-2?
mmeiosi-2 is completed and then fertilisation occurs
what happens if sperm does not enter the secondary oocyte arrested at metaphase-2?
the secondary oocyte arrested at metaphase-2 is released out of the body during menstrual cycle
products of meiosis-2?
ovum/ova(n) and 2nd polar body
what is follicular atresia?
the degeneration of follicles between the phase of birth and puberty
what does the tertiary follicle convert into?
graafian follicle
what is zona pellucida?
secondary oocyte forms a layer surrounding it in the tertiary follicle known as zona pellucida
what is antrum?
fluid filled cavity present in tertiary follicle
features of graafian follicle.
mature follicle
enlarged antrum
what is ovulation?
the release of secondary oocyte(ova) by the rupture of graafian follicle
what is corpus luteum? features.
after ovulation, the reamains of graafian follicle gets degenerated into corpus luteum.
yellow coloured
glandular
what is corpus albicans?
corpus luteum further degenerates into corpus albicans.
white colored
what is menstrual cycle?
the reproductive cycle in female primates(monkeys, apes, humans). the cycle of events from one menstruation till the next.
what is the duration of menstrual cycle?
28/29 days
what are the approx. no. of follicles maturing in a female’s lifetime?
450-500 follicles
what are the phases of menstrual cycle?
- MENSTRUAL/BLEEDING PHASE
- PROLIFERATIVE/FOLLICULAR PHASE
- SECRETORY/LUTEAL PHASE
what is the duration of menstrual/bleeding phase?
3-5 days
what happens in the bleeding phase?
due to regress/degeneration of corpus luteum, progesterone levels decrease, endometrium ruptures, sheds off and bleeding takes place
how much blood is released in the bleeding/menstrual phase?
50-100 ml
what happens to gonadotropins in the proliferative phase?
gradual increase in gonadotropins(FSH, LH).
they stimulate follicular growth and secretion of estrogen from developing follicles
why is the 2nd phase of menstrual cycle known as the follicular phase?
since follicular growth takes place in this phase in ovary
why is the 2nd phase of menstrual cycle known as the proliferative phase?
because endometrium regenerates due to proliferation
which cells release estrogen in follicular phase causing peak of estrogen hormone?
granulosa cells
when is the peak in FSH, LH in menstrual cycle?
mid cycle(14th day)
what is LH surge?
rapid release of LH leading to its max. levels during mid cycle
what is the effect of LH surge?
induces rupture of graafian follicle.
release of ova(OVULATION)
what are the pre-ovulatory hormones?
FSH
LH
ESTROGEN
what is formed in the secretory/luteal phase?
corpus luteum
what are the secretions of corpus luteum?
mainly progesterone
small amount of estrogen
what is the main pregnancy hormone? and its function?
PROGESTERONE
maintaining the endometrium lining
what happens if fertilisation does not take place?
corpus luteum gets degenerated
progesterone levels fall
endometrium lining ruptures
begining of new menstrual cycle
luteal phase lasts for?
14 days
