unit 2 – the continuation of life
Post on 19-Mar-2016
35 Views
Preview:
DESCRIPTION
TRANSCRIPT
UNIT 2 – THE UNIT 2 – THE CONTINUATION OF LIFECONTINUATION OF LIFE
Chapter 15 – Sex Organs & Chapter 15 – Sex Organs & Hormonal ControlHormonal Control
TestesTestes Site of sperm & testosterone productionSite of sperm & testosterone production SpermSperm made in the made in the seminferous tubulesseminferous tubules
(connected to sperm duct)(connected to sperm duct) TestosteroneTestosterone produced by produced by insterstitialinsterstitial
cellscells Sperm need energy & a liquid medium Sperm need energy & a liquid medium
(semen) to move(semen) to move Seminal vesiclesSeminal vesicles secrete liquid: secrete liquid: - - FructoseFructose - for energy- for energy - - ProstaglandinsProstaglandins - stimulate female contractions- stimulate female contractions Prostate glandProstate gland – secretes enzymes – secretes enzymes - maintains - maintains semensemen viscosity viscosity The seminal vesicles & prostate are The seminal vesicles & prostate are
accessory glandsaccessory glands
OvariesOvaries Site of egg productionSite of egg production Eggs contained in Eggs contained in
Graafian follicleGraafian follicle - secretes - secretes oestrogenoestrogen After ovulation, follicle After ovulation, follicle
develops into develops into corpus corpus luteumluteum
- secretes - secretes progesteroneprogesterone
Hormonal ControlHormonal Control Hormones – chemical messengersHormones – chemical messengers Secreted by endocrine glands into Secreted by endocrine glands into
bloodstreambloodstream Specific responses from target Specific responses from target
tissuestissues Pituitary:Pituitary: Secretes gonadotrophic hormonesSecretes gonadotrophic hormones e.g e.g FSH (follicle stimulating FSH (follicle stimulating
hormone), hormone), ICSH (Interstitial cell stimulating ICSH (Interstitial cell stimulating
hormone)hormone) LH (lutenising hormone)LH (lutenising hormone)
Influence of hormones - Influence of hormones - malesmales
FSH promotes sperm FSH promotes sperm productionproduction
ICSH (LH) stimulates ICSH (LH) stimulates testosterone productiontestosterone production
Testosterone:Testosterone: Stimulates sperm production Stimulates sperm production Also activates prostate & Also activates prostate &
seminal vesiclesseminal vesicles Testosterone self-regulatesTestosterone self-regulates - high conc. inhibits FSH & - high conc. inhibits FSH &
ICSH secretionICSH secretion - low conc. FSH & ICSH - low conc. FSH & ICSH
secreted againsecreted again - this is negative feedback- this is negative feedback
ICSH
Influence of hormones - Influence of hormones - ovariesovaries
FSH FSH stimulates stimulates Graafian Graafian follicle follicle development development
- & oestrogen - & oestrogen secretionsecretion
LH triggers LH triggers ovulationovulation
LH stimulates LH stimulates progesterone progesterone secretionsecretion
Influence of hormones – Influence of hormones – uterus/pituitaryuterus/pituitary
Oestrogen:Oestrogen: Stimulates proliferation of Stimulates proliferation of
uterus lining (endometrium)uterus lining (endometrium) Stimulates LH secretion by Stimulates LH secretion by
pituitarypituitary Progesterone:Progesterone: Promotes endometrium Promotes endometrium
thickeningthickening Inhibits FSH & LH secretionInhibits FSH & LH secretion
Menstrual CycleMenstrual Cycle Continuous cycle – 28 days Continuous cycle – 28 days
longlong Follicular PhaseFollicular Phase FSH stimulates Graafian FSH stimulates Graafian
folliclefollicle Endometrium proliferated ( Endometrium proliferated (
by Oestrogen production)by Oestrogen production) Day 14 – LH production Day 14 – LH production
surgesurge Graafian follicle ruptured Graafian follicle ruptured Egg into oviduct – 3 to 4 Egg into oviduct – 3 to 4
days for fertilisationdays for fertilisation
Menstrual CycleMenstrual Cycle Luteal Phase:Luteal Phase: Graafian follicle into corpus Graafian follicle into corpus
luteumluteum Progesterone rise = endometrial Progesterone rise = endometrial
developmentdevelopment Pituitary inhibited (-ve feedback) Pituitary inhibited (-ve feedback)
– FSH/LH levels drop (no more – FSH/LH levels drop (no more ovulation)ovulation)
Day 22 – corpus luteum Day 22 – corpus luteum degeneratesdegenerates
Progesterone & oestrogen levels Progesterone & oestrogen levels dropdrop
Day 28 – endometrium lost = Day 28 – endometrium lost = menstruationmenstruation
Menstrual CycleMenstrual Cycle
FertilisationFertilisation If fertilised – egg secretes If fertilised – egg secretes
HCG (similar to LH)HCG (similar to LH) Corpus Luteum maintainedCorpus Luteum maintained Progesterone secreted Progesterone secreted
continuously – endometrium continuously – endometrium thickenedthickened
Menstruation preventedMenstruation prevented - at 6 weeks placenta controls - at 6 weeks placenta controls
progesterone productionprogesterone production Pregnancy tests detect HCG Pregnancy tests detect HCG
in urinein urine
Role of cervixRole of cervix Cervix cells secrete mucus Cervix cells secrete mucus
– lubrication of the vagina– lubrication of the vagina Oestrogen stimulates Oestrogen stimulates
watery mucus secretionwatery mucus secretion – – easier sperm penetrationeasier sperm penetration Sperm directed by Sperm directed by
molecules in mucusmolecules in mucus Prostaglandins assist in Prostaglandins assist in
muscular contractionsmuscular contractions High levels of progesterone High levels of progesterone
thickens mucus thickens mucus – – protects fertilised egg protects fertilised egg
from infectionfrom infection
FertilityFertility In males – FSH/ICSH at a In males – FSH/ICSH at a
constant levelconstant level Constant production of Constant production of
testosterone & spermtestosterone & sperm Men are Men are continuously continuously
fertilefertile In females – hormone levels In females – hormone levels
alter greatlyalter greatly Cyclical fertility – Cyclical fertility – (3-4 (3-4
days after ovulation)days after ovulation) Signs – temp increase Signs – temp increase
(0.5(0.5ooC) & watery mucusC) & watery mucus
top related