EXAM 2 - Reproduction Flashcards
What are Gametes
Sex cells: Sperm and ova
Sex organs (gonads)
Testes and Ovaries
3 x accessory reproductive organs
Ducts
Glands
External genitalia
Anatomy: PENIS (Location, Structure, Function)
Location: External
Structure: Richly supplied with nerve endings
FUNCTION:
- urination
- release of semen
Anatomy: SCROTUM (Location, Structure, Function)
Location: External
Structure: Encloses 2 x testes and epididymis
FUNCTION:
- maintains testes at a suitable temp for sperm production
Anatomy: TESTES (Location, Structure, Function)
Location: Internal / inside scrotum
Structure:
Function:
- produce sperm
- produce / secrete testosterone
- Seminiferous tubules in Testes = where meiosis occurs
Anatomy: Epididymis (Location, Structure, Function)
Location: Internal / inside scrotum
Structure:
Function:
- stores maturing sperm, until sperm released into vas deferens for ejaculation
- if not, then until sperm are disintegrated / reabsorbed
Anatomy: VAS DEFERENS (Location, Structure, Function)
Location: Internal
FUNCTION:
- Carries sperm FROM epididymis TO ejaculatory duct
Anatomy: SEMINAL VESICLES(Location, Structure, Function)
(Fluid producing glands)
Location: internal, next to bladder
FUNCTION:
- Secretes fluid to nourish sperm
- fluid also helps stimulate muscle contractions in female
Anatomy: PROSTATE GLAND (Location, Structure, Function)
(Fluid producing glands)
LOCATION: internal, under bladder
FUNCTION:
- secretes fluid to nourish sperm
- AND (fluid) initiates movement of sperm
Anatomy: COWPER’S (BULBOURETHRAL) GLANDS (Location, Structure, Function)
(Fluid producing glands)
LOCATION: internal, inferior to prostate
FUNCTION:
- secretes fluid that neutralizes the acidity of any urine in urethra prior to the passage of semen
Spermatogenesis
DEFINITION: Production of Sperm in seminiferous tubules (in testes)
Diploid chromosomal number (2n) = Two sets (23 pairs) of chromosomes
GAMETES: Haploid chromosomal number: (n) - only 1 x set of 23
Spermatogenesis
DEFINITION: Production of Sperm in seminiferous tubules (in testes)
Diploid chromosomal number (2n) = Two sets (23 pairs) of chromosomes
GAMETES: Haploid chromosomal number: (n) - only 1 x set of 23
Meiosis v. Mitosis
Meosis:
- Involves 2 x consecutive cell divisions (so 4 daughter cells instead of 2)
-BUT only 1 x round of DNA replication
Functions of Meiosis:
- # of chromosomes cut in half (23 instead of 46)
- to introduce genetic diversity
The Hypothalamic-Pituitary-Gonadal (HPG) Axis
- Hypothalamus releases GnRH
- This causes anterior pituitary to release FSH + LH
3a) FSH = causes sperm to be produced (follicle stimulating hormone)
3b) LH = causes testosterone to be produced (Lutenizing Hormone)
4) NEGATIVE FEEDBACK = Inhibin released & testosterone levels stop spermatogenesis when sperm count is high
Anatomy: OVARY (location, structure, function)
- Produces and stores eggs
- Produces estrogen and progesterone
Anatomy: FIMBRAE (location, structure, function)
Have cilia that sweep egg into the oviduct/fallopian tubes
Anatomy: UTERINE TUBE (location, structure, function)
aka fallopian tubes
- conducts the egg into the uterus
- site of fertilisation
Anatomy: UTERUS (location, structure, function)
muscular chamber where the embryo develops
Anatomy: CERVIX (location, structure, function)
Opening of uterus/neck of vagina
- NEARLY closes off outer end of uterus
- Supports developing embryo during pregnancy
Anatomy: VAGINA (location, structure, function)
Receptable for semen,; birth canal
Oogenesis
Production of female gametes (eggs)
Oogenesis v. Spermatogenesis
- NUMBER OF FUNCTIONAL GAMETES DIFFER:
- Oogensis: 1 viable ovum
- unequal divisions = ensures oocyte has nutirnets to survive 6-7 day journey to uterus
- Spermatogenesis: 4 viable sperm - ERROR Rates:
- Oogenesis: 20%
- Spermatogenesis: 3-4%
Ovarian Cycle (2 x phases)
Follicular phase (days 1-14)
Luteal phase (days 15-28)
Follicular phase = period of vesicular follicle growth (growth of egg)
Luteal phase = period of corpus luteum activity
OVULATION (release of egg) = mid cycle
Follicular phase: time can sometimes vary (not always 14 days)
Luteal phase: always 14 days
Regulation of Ovarian Cycle**
BEFORE puberty: small amount of estrogen (from ovaries) INHIBITS hypothalamic release of GnRH
- (if leptin levels are adequate), hypothalamus becomes less estrogen-sensitive and releases GnRH. (step 1 of the males one)
- This causes the anterior pituitary to release FSH and LH (step 2 of males one)
- POSITIVE FEEDBACK: Events continue until an adult cyclic pattern is achieved, and menarche occurs
Menstrual Cycle (3 x phases)
- Menstrual Phase (day 1-5)
- Proliferative Phase (day 6-14)
- Secretory Phase (day 15-28)
Menstrual Cycle: Menstrual Phase
- Days 1-5
- Uterine lining is shed
- Ovarian hormones at their lowest
- END OF PHASE: Ovarian follicles start to produce more estrogen
Menstrual Cycle: Proliferative Phase
- Days 6-14
- Functional layer of endometrium is rebuilt
- Estrogen levels rise / peak end of cycle
- FSH & LH peaks end of cycle
- Progesterone starts to rise
