Biology Hl Reproductive Notes

Topics: Meiosis, Reproductive system, Pregnancy Pages: 11 (2046 words) Published: February 24, 2013

Male sperm fuses with female egg.
If tdf (a gene) is present, then the embryo develops testes and produces testosterone.

Female Reproductive system

• Female baby develops if tdf is not present.
• Tdf – a gene located on Y chromosome; if girl, then two X chromosomes, hence no Tdf. • Female hormones: progesterone and estrogen
( both secreted by mother’s ovaries and placenta which allow female genetilia to develop.

Parts of the female reproductive system:

Oviduct/Fallopian tube – site of fertilization
Ovary – produce and release ova and female sex hormones
Uterus – receives and nurtures embryo during development.
Cervix – contains glands that secret hormones during sexual arousal// holds fetus in uterus. Vagina – receives penis/ semen during intercourse/ allows menstrual flow outside the body/ birth canal for fetus. Labia – protect vaginal and urethral openings


Menstrual Cycle

Oocyte: egg // Follicle: fluid filled sac containing the oocyte. 1. Follicular Phase: a group of follicles are stimulated to grow. 2. As follicles grow endometriym thickens.
3. The most developed follicle breaks open and releases an egg into the fallopian tube. 4. Luteal Phase: The other follicles degenerate and the main one becomes a corpus luteum. 5. If fertilization does not occur, corpus luteum breaks down and thickening of endometrium breaks too and sheds during menstruation.

* 36 day period – one complete menstrual

Hormones in the female reproductive system:

( Anterior Pituitary hormones: FSH and LH in the membranes of follicle cells

• Development of oocyte in the follicle
• Thickening of follicle wall
• Secretion of follicular fluid
• Secretion of estrogens by follicle wall
• Completion of meiosis in the oocyte
• Partial digestion of follicle wall to allow it to open (ovulation) • Growth of the corpus luteum which secretes estrogens and progesterone

( Ovarian hormones: absorbed by female cells to influence gene expression and development of embryo into a female.

• produced by ovaries of:
o follicle cells
▪ during 1st half of menstrual cycle
o corpus luteum
▪ during 2nd half of menstrual cycle
▪ throughout pregnancy
• promotes secondary sexual characteristics:
o breast development
o pubic hair
o fatty deposits developing rounder hips
o female behavior pattern
• inhibits milk production by mammary glands
• increases thickness of endometrium of uterus
• inhibits FSH production in anterior pituitary
• at very high levels, stimulates LH & FSH production in anterior pituitary Progesterone:
• produced by corpus luteum
o during 2nd half of menstrual cycle
o throughout pregnancy
• inhibits milk production by mammary glands
• increases/maintains thickness of endometrium of uterus • inhibits FSH production in anterior pituitary
• inhibits LH production in anterior pituitary
IVF – in vitro fertilization
• IVF is fertilization outside body / "in glass"
• Down-regulation: drug stops normal menstrual cycle
• Superovulation: FSH injections into female stimulate more than one follicle to mature • Follicle maturation: HCG matures the follicles
• Egg Collection: secondary oocytes harvested from follicles at ovulation, via suction into syringe • Semen Collection: sperm donated from male
• Semen Processing: washing of sperm
• Insemination: sperm mixed with eggs in petri dish, or injected directly into egg • Embryo Selection: development to blastocyst stage in petri dish • Embryo transfer: up to 4 embryos placed in uterus

• if implantation is successful, one or more embryos will develop • pregnancy test is done to see if implantation / pregnancy has...
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