9.0 reproduction
DESCRIPTION
biology matriculationTRANSCRIPT
![Page 1: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/1.jpg)
:
9.0 REPRODUCTION
AND
DEVELOPMENT
![Page 2: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/2.jpg)
9.1 Asexual reproduction in plants and animals
9.2 Sexual reproduction in flowering plants
9.3 Human reproductive system
9.4 Fertilization and foetal development
9.5 Roles of hormones
9.0 REPRODUCTION AND DEVELOPMENT
![Page 3: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/3.jpg)
9.5 Roles of hormones
a) Explain the role of hormones during pregnancy
i. progesterone
ii. estrogen
iii. human chorionic gonadotrophin (hCG)
b) Explain the role of hormones during parturition /
birth process
i. progesterone
ii. estrogen
iii. oxytocin
iv. prostaglandin
c) Explain the role of hormones during lactation
i. oxytocin
ii. prolactin
![Page 4: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/4.jpg)
Learning outcomes :
(a) Explain the role of hormone during pregnancy
1st trimester
i. Progesterone
- initiates increased mucus in cervix (forming a protective plug)
- stimulates growth of the maternal portion of placenta
- maintains the thickness of endometrium
- prevents ovulation & menstrual cycle
- stimulates breasts enlargement
ii. Estrogen
• important for development of uterus, foetus & mammary glands
PREGNANCY & HORMONES INVOLVED
![Page 5: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/5.jpg)
iii. hCG (human chorionic gonadotropin)
• The chorion secretes hCG
• Function: stimulate the corpus luteum to continue to secrete progesterone and estrogen
• hCG level is so high & some is excreted in urine
Learning outcomes :
(a) Explain the role of hormone during pregnancy
1st trimester
![Page 6: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/6.jpg)
Learning outcomes :
(a) Explain the role of hormone during pregnancy
1st trimester
iv. hCS (human chorionic somatotropin )
• Starting at week 5, the placenta secretes hCS which stimulates:
– secretion of estrogens & progesterone by corpus luteum
– entry of amino acids into cells of embryo (for protein synthesis)
– development of mammary glands
– glucose & lipid metabolisms in the mother
![Page 7: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/7.jpg)
Learning outcomes :
(a) Explain the role of hormone during pregnancy
![Page 8: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/8.jpg)
2nd trimester
Learning outcomes :
(a) Explain the role of hormone during pregnancy
• hCG secrete by the placenta declines
• Corpus luteum degenerates, progesterone decrease
• Placenta takes over from corpus luteum by secreting progesterone & estrogen, (maintain pregnancy)
![Page 9: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/9.jpg)
Learning outcomes :
(a) Explain the role of hormone during pregnancy
3rd trimester
• Level of estrogen & progesterone increase during pregnancy prevent from miscarriage
• And induce the birth
process
![Page 10: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/10.jpg)
PARTURITION & HORMONES INVOLVED
During pregnancy, progesterone & estrogens are
secreted by placenta
i. Progesterone
High level of progesterone prevents contractions of
uterus (prevents birth of immature baby)
ii. Estrogen
- Estrogens reach highest level during last weeks
of pregnancy
- This triggers formation of oxytocin receptors on
uterus
Learning outcomes :
(b) Explain the role of hormone during parturition / birth process
![Page 11: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/11.jpg)
PARTURITION & HORMONES INVOLVED
iii. Oxytocin
- secreted by foetus & mother’s posterior pituitary
- stimulates contractions of uterus
- stimulates placenta to secrete prostaglandins
iv. Prostaglandins
- Enhance contractions of uterus
- The contractions stimulate release of more oxytocin &
prostaglandins by positive feedback
- Contractions become stronger & more frequent
- that push the baby
Learning outcomes :
(b) Explain the role of hormone during parturition / birth process
![Page 12: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/12.jpg)
![Page 13: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/13.jpg)
• Parturition (birth process)
occurs as a result of the strong,
rhythmic contractions (labour)
• Induced and regulated by
estrogen, oxytocin, and
prostaglandins.
• 3 stages of parturition:
i. dilation of cervix
ii. delivery of baby
iii. delivery of placenta
PARTURITION
Learning outcomes :
(b) Explain the role of hormone during parturition / birth process
![Page 14: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/14.jpg)
i. dilation of cervix
- opening up & thinning of
cervix
- ending with complete
dilation
- amnion ruptures releasing
amniotic fluid, which flows
out through the vagina.
- contractions get stronger
PARTURITION
Learning outcomes :
(b) Explain the role of hormone during parturition / birth process
![Page 15: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/15.jpg)
ii. delivery of baby
- The expulsion of the fetus
- continuous strong
contractions force foetus
down and out of the uterus &
vagina
- aided by mother’s pushing
- the umbilical cord is then cut
and clamped
PARTURITION
Learning outcomes :
(b) Explain the role of hormone during parturition / birth process
![Page 16: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/16.jpg)
iii. delivery of placenta
- The expulsion of the
placenta
- continuing contraction
expel the placenta &
associated membranes
(the afterbirth)
PARTURITION
Learning outcomes :
(b) Explain the role of hormone during parturition / birth process
![Page 17: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/17.jpg)
LACTATION & HORMONES INVOLVED
• ‘Milk production that occurs in the mammary glands’
• An aspect of postnatal care
• The breasts contain mammary glands
• Alveoli of mammary glands will produce milk, that is secreted into mammary ducts which open at the nipple
Learning outcomes :
(c) Explain the role of hormone during lactation
![Page 18: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/18.jpg)
LACTATION & HORMONES INVOLVED
• During pregnancy, progesterone stimulates development of mammary alveoli
• Estrogens stimulate development of mammary ducts
• When placenta is discharged after birth, levels of estrogens & progesterone decrease
• This allows mother’s anterior pituitary
to secrete prolactin
[no lactation during pregnancy since
prolactin secretion is inhibited]
Learning outcomes :
(c) Explain the role of hormone during lactation
![Page 19: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/19.jpg)
LACTATION & HORMONES INVOLVED
• Prolactin stimulates mammary
alveoli to produce milk (~ 2
days after birth)
• Mammary secretion for first
few days is the colostrum
(thick, yellowish fluid with high
protein content & rich in
maternal antibodies)
• Oxytocin stimulates
contraction of smooth muscles
surrounding mammary glands,
thus controlling release of milk
Learning outcomes :
(c) Explain the role of hormone during lactation
![Page 20: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/20.jpg)
• Nerve impulse will be sent
to the hypothalamus & sent
impulse to posterior
pituitary to release oxytocin
• Fx (oxytocin): Contraction
of the smooth muscle of
alveoli & force milk through
the duct & out of the nipple
• The anterior pituitary responds by releasing prolactin
• Fx (prolactin): Stimulate the production of milk
After birth, milk production is stimulated
by the sucking infant
Learning outcomes :
(c) Explain the role of hormone during lactation
![Page 21: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/21.jpg)
9.1 Asexual reproduction in plants and animals
9.2 Sexual reproduction in flowering plants
9.3 Human reproductive system
9.4 Fertilization and foetal development
9.5 Roles of hormones
9.0 REPRODUCTION AND DEVELOPMENT
![Page 22: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/22.jpg)
9.5 Roles of hormones
a) Explain the role of hormones during pregnancy
i. progesterone
ii. estrogen
iii. human chorionic gonadotrophin (hCG)
b) Explain the role of hormones during parturition /
birth process
i. progesterone
ii. estrogen
iii. oxytocin
iv. prostaglandin
c) Explain the role of hormones during lactation
i. oxytocin
ii. prolactin
![Page 23: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/23.jpg)
Learning outcomes :
(a) Explain the role of hormone during pregnancy
1st trimester
i. Progesterone
- initiates increased mucus in cervix (forming a protective plug)
- stimulates growth of the maternal portion of placenta
- maintains the thickness of endometrium
- prevents ovulation & menstrual cycle
- stimulates breasts enlargement
ii. Estrogen
• important for development of uterus, foetus & mammary glands
PREGNANCY & HORMONES INVOLVED
![Page 24: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/24.jpg)
iii. hCG (human chorionic gonadotropin)
• The chorion secretes hCG
• Function: stimulate the corpus luteum to continue to secrete progesterone and estrogen
• hCG level is so high & some is excreted in urine
Learning outcomes :
(a) Explain the role of hormone during pregnancy
1st trimester
![Page 25: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/25.jpg)
Learning outcomes :
(a) Explain the role of hormone during pregnancy
1st trimester
iv. hCS (human chorionic somatotropin )
• Starting at week 5, the placenta secretes hCS which stimulates:
– secretion of estrogens & progesterone by corpus luteum
– entry of amino acids into cells of embryo (for protein synthesis)
– development of mammary glands
– glucose & lipid metabolisms in the mother
![Page 26: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/26.jpg)
Learning outcomes :
(a) Explain the role of hormone during pregnancy
![Page 27: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/27.jpg)
2nd trimester
Learning outcomes :
(a) Explain the role of hormone during pregnancy
• hCG secrete by the placenta declines
• Corpus luteum degenerates, progesterone decrease
• Placenta takes over from corpus luteum by secreting progesterone & estrogen, (maintain pregnancy)
![Page 28: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/28.jpg)
Learning outcomes :
(a) Explain the role of hormone during pregnancy
3rd trimester
• Level of estrogen & progesterone increase during pregnancy prevent from miscarriage
• And induce the birth
process
![Page 29: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/29.jpg)
PARTURITION & HORMONES INVOLVED
During pregnancy, progesterone & estrogens are
secreted by placenta
i. Progesterone
High level of progesterone prevents contractions of
uterus (prevents birth of immature baby)
ii. Estrogen
- Estrogens reach highest level during last weeks
of pregnancy
- This triggers formation of oxytocin receptors on
uterus
Learning outcomes :
(b) Explain the role of hormone during parturition / birth process
![Page 30: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/30.jpg)
PARTURITION & HORMONES INVOLVED
iii. Oxytocin
- secreted by foetus & mother’s posterior pituitary
- stimulates contractions of uterus
- stimulates placenta to secrete prostaglandins
iv. Prostaglandins
- Enhance contractions of uterus
- The contractions stimulate release of more oxytocin &
prostaglandins by positive feedback
- Contractions become stronger & more frequent
- that push the baby
Learning outcomes :
(b) Explain the role of hormone during parturition / birth process
![Page 31: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/31.jpg)
![Page 32: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/32.jpg)
• Parturition (birth process)
occurs as a result of the strong,
rhythmic contractions (labour)
• Induced and regulated by
estrogen, oxytocin, and
prostaglandins.
• 3 stages of parturition:
i. dilation of cervix
ii. delivery of baby
iii. delivery of placenta
PARTURITION
Learning outcomes :
(b) Explain the role of hormone during parturition / birth process
![Page 33: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/33.jpg)
i. dilation of cervix
- opening up & thinning of
cervix
- ending with complete
dilation
- amnion ruptures releasing
amniotic fluid, which flows
out through the vagina.
- contractions get stronger
PARTURITION
Learning outcomes :
(b) Explain the role of hormone during parturition / birth process
![Page 34: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/34.jpg)
ii. delivery of baby
- The expulsion of the fetus
- continuous strong
contractions force foetus
down and out of the uterus &
vagina
- aided by mother’s pushing
- the umbilical cord is then cut
and clamped
PARTURITION
Learning outcomes :
(b) Explain the role of hormone during parturition / birth process
![Page 35: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/35.jpg)
iii. delivery of placenta
- The expulsion of the
placenta
- continuing contraction
expel the placenta &
associated membranes
(the afterbirth)
PARTURITION
Learning outcomes :
(b) Explain the role of hormone during parturition / birth process
![Page 36: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/36.jpg)
LACTATION & HORMONES INVOLVED
• ‘Milk production that occurs in the mammary glands’
• An aspect of postnatal care
• The breasts contain mammary glands
• Alveoli of mammary glands will produce milk, that is secreted into mammary ducts which open at the nipple
Learning outcomes :
(c) Explain the role of hormone during lactation
![Page 37: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/37.jpg)
LACTATION & HORMONES INVOLVED
• During pregnancy, progesterone stimulates development of mammary alveoli
• Estrogens stimulate development of mammary ducts
• When placenta is discharged after birth, levels of estrogens & progesterone decrease
• This allows mother’s anterior pituitary
to secrete prolactin
[no lactation during pregnancy since
prolactin secretion is inhibited]
Learning outcomes :
(c) Explain the role of hormone during lactation
![Page 38: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/38.jpg)
LACTATION & HORMONES INVOLVED
• Prolactin stimulates mammary
alveoli to produce milk (~ 2
days after birth)
• Mammary secretion for first
few days is the colostrum
(thick, yellowish fluid with high
protein content & rich in
maternal antibodies)
• Oxytocin stimulates
contraction of smooth muscles
surrounding mammary glands,
thus controlling release of milk
Learning outcomes :
(c) Explain the role of hormone during lactation
![Page 39: 9.0 Reproduction](https://reader030.vdocuments.net/reader030/viewer/2022020211/577c7e141a28abe054a08282/html5/thumbnails/39.jpg)
• Nerve impulse will be sent
to the hypothalamus & sent
impulse to posterior
pituitary to release oxytocin
• Fx (oxytocin): Contraction
of the smooth muscle of
alveoli & force milk through
the duct & out of the nipple
• The anterior pituitary responds by releasing prolactin
• Fx (prolactin): Stimulate the production of milk
After birth, milk production is stimulated
by the sucking infant
Learning outcomes :
(c) Explain the role of hormone during lactation