topic 5 - Homeostasis and response Flashcards
what does the cererbal cortex control
Consciousness , intelligence , memory and language , also senses - hearing and vision
this is the larger part of brain on the side
What does the cerebellum control
Balance and muscle co-ordination
this is at the back , bottom of the brain
what does the medulla do
controls unconscious activities such as breathing and the beating of the heart
at the very bottom near neck , in the brain stem
what does the hypothalamus do
regulates body temperature and sends signals to the pituitary gland which is under it . its in the middle of the brain
What are the ways to study the brain
Study people with brain damage eg if someone got hurt at a part of their brain and now they cant move their leg
Electrically stimulate parts of the brain and see the reaction
Scanning brain - CT scan using X rays to see where the damage is or mri scan to see brain activity
why is it hard to study the brain
The brain is delicate and complex , open to trauma or damage , the brain is very complex - difficult to fix with drugs and medication , mental health problems , infection
What is the role of FSH and LH and where are they produced
Both produced in Pituitary glands
FSH - matures egg and stimulates Oestrogen secretion
LH - for ovulation and inhibits FSH
What is the role of Oestrogen and progesterone and where are they produced
Ovaries
Oestrogen - stimulates growth of uterus lining , stimulates LH secretion + inhibits FSH
Progesterone - maintains uterus lining, breaks down without; inhibits LH/FSH
Menstrual cycle
- Uterus lining breaks down for first 4 days
- Uterus lining rebuilds for 10 days
- Egg develops and is released (day 14)
- Wall is maintained (breaks down on day 28 if no fertilised egg is present)
Fertility control methods
Oestrogen, at high levels, inhibits FSH
· Progesterone produces thick mucus – prevents conception
· Oestrogen + Progesterone pill causes nausea
· Progesterone pill causes fewer side effects
· Barrier methods prevent STIs
· Sterilisation, natural family planning, abstinence
· IVF: FSH + LH given to woman; eggs collected and fertilised; implanted back into uterus – may lead to multiple births/harsh side effects: nausea, vomiting
Plant hormones - Growth
Auxins - Inhibits growth in roots but stimulates growth in shoots
phototropism = growth response to light Geo/gravitropism = gravity
auxin is always on bottom or on shaded side since light breaks down auxin , more growth on the right causes it to curve towards the left
Plant hormones commercially
Auxin - to grow plants such as plant cuttings by rooting powders , as weed killers - since too much can disrupt their growth process by overstimulating them this can kill the plant. , for promoting growth in tissue culture.
Ethene: stimulates ripening of fruit via cell division and stimulates an enzyme for ripening - control ripening of fruit during storage and transport.
Gibberellins - end seed dormancy ,promote flowering ,increase fruit size.
seed dormancy in certain months - so needed
seedless fruit variants grow smaller than seeded plants
