Human reproduction 2

zoology

primary oocyte is formed______ and arrested in ___

formed before birth and arrested in diplotene of meiosis 1 till puberty

meiosis 1 in primary oocyte starts before birth

true false

true

secondary oocyte starts meiosis 2 and arrested in_____

arrested in metaphase 2

process of oogenesis

how many oogonia formed before birth and by how many weeks of preganancy

7 million/ couple of million acc to ncert formed before birth

by 20-22 weeks of pregnancy

no more oogonia are formed or added after birth

true false

true

primordial follicle number at birth and in puberty

birth= 2 million per ovary

puberty= 2 lac per ovary

primary follicle number at puberty

and structure

60,000- 80,000 per ovary

single layer of cuboidal follicular cells

primary follicle is present from birth till puberty

true false

false

primordial follicle present from birth till puberty

new theca layer and multilayered follicular cells present in which follicle

secondary follicle

secondary follicle has____ oocyte

primary oocyte in diplotene stage

In tertiary follicle primary oocyte is in which stage

it completes meiosis 1 and forms secondary oocyte in metaphase 2

all layers in tertiary follicle

layers of mature graafian follicle

how secondary oocyte released from granulosa cells

granulosa cells secrete estrogen which is responsible for endometrium proliferation

endometrium proliferation leads to LH surge

this LH surge is responsible for secondary oocyte release

why unequal cell division occur in oogenesis

unequal cell division occurs to retain most of the cytoplasm in female gamete because sperm has very less amount of cytoplasm

ovum is formed only if fertilisation occurs

secondary oocyte formed every month

true false

true

colostrum is rich in ____ except_____

vitamins minerals and fats

except vitamin c and iron

colostrum has antibody

IgA

C

corpus luteum is glandular because it secretes hormones like

lots of progesterone

little estrogen

relaxin hormone at end of pregnancy

inhibin hormone which inhibits fsh

inhibin hormone secreted by

corpus luteum

granulosa cells

sertoli cells

corpus luteum changes into____ if fertilisation does not occur

white, non-glandular corpus albicans

hormone regulation in females after forming fsh and lh

During pregnancy FSH and LH is high

true false

false

fsh and lh low

estrogen and progesterone high

How does LH maintain pregnancy

graafian follicles are formed from

growth of corpus luteum is initiated by

LH

sequence of layers of mammalian egg from outside to inside

corona radiata, zona pellucida, plasma membrane

during oogenesis each diploid cell produces

one functional egg and three polar bodies

how many eggs will be formed from 100 primary oocyte

100 eggs

how many mature eggs are produced by each ovary of a non pregnant woman each year

6

Ovarian events with their reason of occurence

FOL

1. follicular phase- due to increase in FSH

2. ovulatory phase- due to increase in LH

3. luteal phase- due to increase in LH

uterine events with their reason of occurence

MPS

1. menstrual phase- due to decrease in estrogen and progesterone

2. proliferative phase- due to increase in estrogen

3. secretory phase- increase in progesterone

FSH LH is at peak during

ovulation or ovulatory phase

estrogen and progesterone is at peak during

estrogen= ovulatory+ secrotory/luteal phase

progesterone= luteal phase

day of ovulation formula

menstrual cycle-14 days

after menopause

FSH, estrogen and progesterone levels increase or decrease

FSH increase

estrogen and progesterone decrease

corpus luteum secrete

lots of progesterone and little estrogen

egg viability is ___ hours

24-48 hours

or 1-2 days

sperm viability in female reproductive tract is

48-72 hours

upto 5 days

events of male and female gametes from gamete transfer to fertilisation is

1. capacitation-physiological maturation of the sperms so that they become competent to fertilize an oocyte

2. agglutination- sticking of sperms

3. Acrosomal reaction

4. fast and slow block to polyspermy

5. fertilisation

cementing layer between cells of corona radiata is formed by

hyaluronic acid (polysaccharids)

perivitteline space is space between

plasma membrane of 2’ oocyte and zona pellucida

luteal= sceretory= pre-menstrual

learn

which hormone stimulates the buildup of endometrium

estrogen

what is capacitation in terms of sperm

physiological maturation of sperm inside female reproductive tract

capacitation takes ___ hours to make sperms more capable to fertilize ovum

6-7 hours

capacitation has 2 processes namely

1. Ca+ influx= sperm motility increase

2. destablisation of plasma membrane= dissolution of cholestrol and removal of glycoprotein

agglutination is a process which ensures

• that same species gamete fertilise each other

• responsible for reproductive isolation

• species specific

antifertilisin and fertilisin is present on ___ and __ respectively

antifertilisin and fertilisin is chemically ____and ____

sperm, ovum

acidic, glycoprotein

these two chemicals attract each other

what is acrosomal reaction process

1. sperm touches zona pellucida

2. acrosome burst and release sperm lysins

3. secretions of acrosomes help sperm pass through zona pellucida and plasma membrane

sperm lysin enzymes are

1. hyaluronidase= digest hyaluronic acid

2. corona penetrating enzyme= digest corona radiata cells

3. zona lysin= digest zona pellucida cells

what is fast block to polyspermy

temporary

1. when sperm comes in contact with plasma membrane

2. plasma membrane formes a fertilisation cone

3. Na+ influx into 2’ oocyte

4. depolarisation of plasma membrane(inner+, outer-)

what is slow block to polyspermy

permanent. cortical reaction

1. when membrane depolarised

2. induces ser to release Ca+ ions into cytoplasm

3. exocytosis of cortical granulles into perivitteline space

4. zona pellucida become hard and thick so no more sperm can fertilise

entry of sperm in cytoplasm of 2’ oocyte induces

completion of meiosis 2 in sec oocyte arrested in metaphase 2 of meiosis 2

pregnancy begins with

implantation of blastocyst

high level of hcG stimulates the synthesis of

estrogen and progesterone

zygote to blastocyst stages with time taken

1. day1= fertilisation

2. day2 or 30 hours after fertilization= 2 celled

3. day2 or 40 hours after fertilization= 4 celled

4. day 3 or 72 hours after fertilization= 8 celled morula

5. day4= 16 celled morula

6. 32 celled blastocyst at day 5

cleavage division starts when

zygote moves through isthmus into uterus as 2/4/8/16 daughter cell or blastomeres

size of blastomere goes on___

size of embryo____

decreasing

constant

total dna in embryo is increasing

DNA in each blastomere is same

true false

true both

because blastomeres are increasing so total dna increasing

4 points on morula

1. solid mulberry like

2. 8-16 celled embryo

3. formed in fallopian tube 3-4 days after fertilisation

4. zona pellucida intact

3 points blastocyst

1. formed in uterus at day 5 of fertilisation

2. hollow with cavity called blastocoel

3. differentiates into inner cell mass and trophoblast

inner cell mass differentiates to form____

embyro

____ forms foetal part of placenta

trophoblast

hCG hormone function

rescue dying corpus luteum

acts like LH

trophoblast secrete which enzyme and hormone

enzyme for digestion of zona pellucida

hCG hormone

blatula has blatocoel

32 celled stage of embryo is larger than size of fertilised egg

true false

false

32 celled stage is same size as fertilised egg

morula has same amount of cytoplasm and dna as in zyote

true false

false

same cytoplasm more dna

repeat all four lines

implantation occurs on day_____

6-7 days after fertilisation

which hormone is basis for pregnancy test

hCG

if 2 pregnant women has ovarian cyst. one of them has gestation period less than 3 months and other more than 3 months then

less than 3 months abortion is to be done after removing ovaries because progesterone secreted only by corpus luteum of ovary

more than 3 months can continue after removing ovary because progesterone secreted by both corpus luteum and placenta

formation of extra embryonic membranes start from

2nd week