9.0 reproduction

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  • :

    9.0 REPRODUCTION

    AND

    DEVELOPMENT

  • 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

  • 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

  • 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

  • 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

  • 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

  • Learning outcomes :

    (a) Explain the role of hormone during pregnancy

  • 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)

  • 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

  • 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

  • PARTURITION & HORMONES INVOLVED

    iii. Oxytocin

    - secreted by foetus & mothers 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

  • 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

  • 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

  • ii. delivery of baby

    - The expulsion of the fetus

    - continuous strong

    contractions force foetus

    down and out of the uterus &

    vagina

    - aided by mothers pushing

    - the umbilical cord is then cut

    and clamped

    PARTURITION

    Learning outcomes :

    (b) Explain the role of hormone during parturition / birth process

  • 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

  • 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

  • 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 mothers anterior pituitary to secrete prolactin

    [no lactation during pregnancy since

    prolactin secretion is inhibited]

    Learning outcomes :

    (c) Explain the role of hormone during lactation

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • Learning outcomes :

    (a) Explain the role of hormone during pregnancy

  • 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)

  • 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

  • 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

  • PARTURITION & HORMONES INVOLVED

    iii. Oxytocin

    - secreted by foetus & mothers 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

  • 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

  • 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

  • ii. delivery of baby

    - The expulsion of the fetus

    - continuous strong

    contractions force foetus

    down and out of the uterus &

    vagina

    - aided by mothers pushing

    - the umbilical cord is then cut

    and clamped

    PARTURITION

    Learning outcomes :

    (b) Explain the role of hormone during parturition / birth process

  • 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

  • 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

  • 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 mothers anterior pituitary to secrete prolactin

    [no lactation during pregnancy since

    prolactin secretion is inhibited]

    Learning outcomes :

    (c) Explain the role of hormone during lactation

  • 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

  • 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