Year 11 Flashcards
What is homeostasis?
How the body maintains a constant internal environment, like needing to control levels of water, iron and oxygen.
How does the body keep levels constant?
1) the body has receptors that detect changes
2) sends message to the coordination centre (brain/spinal cord/organ
3) effector (muscle/gland)
4) response
What is a stimulus?
A stimulus is a change in the body’s environment for example a bell ringing, a red light
What are the two parts of the nervous system?
1) the central nervous system (brain and spinal cord)
2) the peripheral nervous system (all branched nerves)
What are the three types of neurone?
1) sensory neurone
2) relay neurone
3) motor neurone
What us an electrical impulse?
A message passed along nerve cells called neurones.
What are reflex actions?
Fast, automatic and protective responses in the body
What are examples of reflex actions?
1) when you touch a very hot object your arm/leg will pull away
2) iris reflex in the eye
What is the gap between two neurones called?
A synapse
What is the endocrine system?
It is a second coordination control system of the body
How does the body react to high blood glucose levels?
1) pancreas detects an increase of blood glucose levels so releases insulin
2) insulin travels in the bloodstream to the liver
3) cells take in more glucose for respiration, the liver takes up excess glucose and stores it as glycogen
4) blood glucose levels are lowered and return to normal homeostatic levels
How does the body react to low levels of blood glucose?
1) pancreas detects a decrease of blood glucose levels so releases glucagon
2) glucagon travels through the bloodstream to the river
3) the glucose is released to the blood for the whole body
4) the glucose levels then rise and return to normal homeostatic levels
What is the role of the follicle stimulating hormone?
1) it causes an egg to mature in an ovary
2) it stimulates the ovaries to release the hormone oestrogen
What is the role of oestrogen in the body?
1) Stimulates the lining of the uterus to grow again after menstruation in preparation for pregnancy
2) Stimulates the pituitary gland to release LH
3) Inhibits the release of FSH so that only one egg matures in the cycle
What is the role of the luteinising hormone in the body?
1) Stimulates the release of a mature egg from the ovary
2) Stimulates the ovaries to release progesterone
3) Inhibits the release of oestrogen
What is the role of progesterone in the body?
1) Maintains the lining if the uterus during second half of the menstrual cycle and during pregnancy
2) Inhibits both FSH and LH
What are the stages of IVF treatment?
1) Giving the mother fertility drugs (FSH and LH) to stimulate the maturation of several eggs
2) The eggs are collected from the mother and fertilised by sperm from the father in the laboratory
3) The fertilised eggs develop into embryos
4) At the stage when they are tiny balls of cells, one or two embryos are inserted into the mothers uterus (womb)
What are the disadvantages of IVF treatment?
- Low success rate or not always successful
- High number of multiple births (can lead to low birth rate or harm to mother)
- Expensive
- Stressful/emotional
- Side effects
What are the economical issues surrounding embryo screening?
- It is very expensive (for the couple)
* Costs the government (and the tax payers) a lot of money
What are the social issues surrounding embryo screening?
- It implies people with genetic problems are “undesirable” which could increase prejudice
- Everyone will want to screen their embryos so they can pick the desirable one
What are ethical issues surrounding embryo screening?
• The rejected embryos are destroyed- they could have developed into humans n
