B5-Homoeostasis and response Flashcards
What is homoeostasis
Maintaining a stable internal environment
What does negative feedback do and what examples
Negative feedback counteracts changes – if something gets too high or too low your body is negative feedback to be back to normal
Glucose regulation, Body temperature, water levels
How does the central nervous system coordinate a response
Stimulus – receptor – sensory neurone – central nervous system – motor neurone – Effecter-Response
What is a synapse
The connection between two neurons
What is the reflex arc
Stimulus – receptor – sensory neurone – Relay neuron – motoneuron – affecter
This Important because The automatic and rapid response which doesn’t involve the conscious part of the brain prevents injury
Where are there: pituitary gland, Thyroid,ovaries, adrenal gland, testes, pancreas
The pituitary gland: brain thyroid: Neck Ovaries: been ovaries Adrenal gland: near the pancreas Pancras: pancreas Testes: testes
What is the endocrine system
The composition of glands which Secrete chemicals called hormones directly into the bloodstream
What is the difference between a nerve and a hormone
Nerves are very fast, act for a very short time, Act on a very precise
area
Hormones are slow, act for a long time, act in a more general way
The control of Blood glucose concentration
Its bloody Glucose levels are too high the pancreas produces the hormone insulin which causes glucose to move from the blood into the cells –E.g. the liver where is change to glycogen For storage
When there is not Enough glucose in the blood the pancreas releases glucagon which stimulates the release of glucose from the liver which raises blood glucose levels
She’s done for negative feedback
What is type one diabetes
Where the pancreas produces little or no insulin meaning that the person has no control over their blood glucose levels
Treated with insulin injections
What is Type 2 diabetes
And when the body cells no longer respond to insulin produced by the pancreas
What is FSH, Where is it made and what does it stimulate
Causes the egg to mature
There pituitary gland
Stimulates oestrogen
What is oestrogen, Where is it made and what does it inhibit/stimulate
Causes the lining of the uterus to grow
Ovaries
Stimulates LH and inhibits FSH
Where is LH made and what does it do
Pituitary land
Stimulates the release of the egg
Where is progesterone made, What does it do and what does it inhibit
Ovaries
It maintains the lining of the uterus during the second half of the cycle – when progesterone levels for the lining breaks down
It inhibits the release of LH and FSH
What is the order of the hormones in the menstrual cycle
FSH – causes egg to mature
*Stimulates the ovaries to produce oestrogen
Oestrogen – causes lining of uterus to grow
*Stimulates LH and inhibits FSH
LH-Stimulates the release of an egg
Progesterone – maintains the lining of the uterus during the second half the cycle and when levels of progesterone falls The lining breaks down
*Inhibits the release of FSH and LH
What are the hormonal ways of controlling fertility
– oestrogen/progesterone
– the pill – contains oestrogen and progesterone
– the Contraceptive patch – contains oestrogen and progesterone (it’s stuck into the skin and last week)
– the contraceptive injection(Contains progesterone and lasts around 2 to 3 months
– IUD-A T shape device that is inserted into the uterus to kill sperm and prevent implantation of a fertilised egg (contains progesterone)
Barrier methods of contraception
Condom
– die for again – a shallow plastic cup that fits in the cervix (it’s a barrier and also contain spermicide which kills sperm)
– spermicide can be used alone
What are those drastic ways of avoiding pregnancy
– Sterilisation
– avoiding intercourse
How do you fertility drugs work
They contain FSH which cause more eggs to mature in ovary and also triggers oestrogen production – LH is then given to stimulate the release of the egg
*Can always work/could cause multiple births
How does IVF work
It involves collecting multiple eggs from the woman’s ovaries and fertilising them in a Lab With a male sperm –Some of the fertilised eggs Are then planted into the woman’s uterus and others are frozen for later use
Disadvantages of IVF
They can cause multiple births, it’s expensive and the success rate is low, it can be stressful and upsetting
Why are people against IVF
It often results in a news embryos are destroyed, people think it’s unethical because each and we have potential human life – the genetic testing of embryos before implantation also raises ethical issues about some people think it could lead to the selection of preferred characteristics
What is adrenaline
Hormonal which is released in response to stressful and scary situations – your brain detects the fear of stress and says nervous impulses to the adrenal glands which respond by secreting Adrenaline
This gets your body ready for “fight or flight “by triggering mechanisms increase supply of oxygen and glucose to the cells in the brain muscles
