b5 Flashcards
define homeostasis
- maintaining internal conditions of the body
name three things that are controlled by homeostasis
- Temperature
- Water levels
- Blood glucose levels
why is it important that homeostasis takes place?
- so that enzymes and cells can work in stable conditions.
which two parts of the body form the central nervous system (CNS)?
- brain
- spinal cord
what is a stimuli?
- a change in the environment
name the five sense organs
- Touch
- Hear
- See
- Smell
- Lick
where are receptors found?
- in the sense organs
what is a synapse?
- a gap between two nerve cells
state the seven steps of a reflex action
- Stimuli
- Receptor cells
- sensory neurone
- Relay neurone
- Motor neurone
- Effector
- Response
state three reasons why reflex actions are important
- protects from danger
- automatic
- fast
what does the endocrine system consist of?
- it consists of glands
what is a hormone?
- a chemical messenger released in the bloodstream
name the five glands in the body
1.Thyroid
2. Testes
3. Adrenal
4. Ovary
5. Pancreas
which hormones do the five glands produce?
1.Thyroid - thyroxine
2. Testes - testosterone
3. Adrenal - adrenaline
4. Ovary - oestrogen
5. Pancreas - insulin and glucagon
state the difference between type 1 and type 2 diabetes
- in type 1, the pancreas does not release enough insulin, whereas in type 2 the body stops reacting to insulin.
what happens when your blood glucose concentration increases?
- pancreas detects this and releases insulin
- insulin travels in the bloodstream to the body cells
- it triggers them to take in the glucose
- insulin then goes to the muscle and liver cells to store glucose into glycogen.
what happens when your blood glucose concentration decreases?
- pancreas detects this and releases glucagon
- glucagon travels into the blood to the liver and muscle cells
- this triggers cells to turn into glycogen, enabling blood glucose levels to return to normal.
how long is one menstrual cycle?
28 days
what does ovulation mean?
releasing of the egg
which day does a woman ovulate?
day 14
name the four hormones involved in the menstrual cycle
- FSH
- Oestrogen
- LH
- Progesterone
where are the four hormones produced in the menstrual cycle?
- FSH - pituitary glands
- Oestrogen - ovaries
- LH - pituitary glands
- Progesterone - ovaries
what are the roles of the four hormones involved in the menstrual cycle?
- FSH - matures the egg
- Oestrogen - builds the lining of the uterus
- LH - releases the egg (ovulation)
- Progesterone - maintains the lining of the uterus
what is the difference between fertility and infertility?
- fertility means how easy it is for a woman to become pregnant
- infertility means how difficult it is for a woman to become pregnant
how does the fertility drug helps women get pregnant?
- FSH and LH are given to a woman
- this causes a woman to ovulate more than usual
- this increases chances of becoming pregnant
explain the four steps of in-vitro fertilisation (IVF)
1.fertilisation takes place outside the body
2. the mother is treated with FSH and LH, causing several eggs to mature
3. the eggs and sperm is collected and fertilised with each other.
4. once the embryos are tiny balls, they are inserted into the woman’s uterus.
state the advantages and disadvantages of IVF
advantages =
- gives the woman a chance to have a baby
- works where other fertility treatments might fail
- you can use a donated egg or sperm
disadvantages =
- success rate is not high
- it can be expensive
- emotionally stressful for mother and father
- multiple embryos destroyed (unethical)
what is meant by contraception?
- preventative way from pregnancy taking place.
name the six ways of contraception
- pill
- implant/patch/injection
- IUD
- spermicide
- condom/diaphragm
- natural
how do the six ways of contraception prevent pregnancy and what are the pros and cons?
- pill = stops egg from maturing = very effective, headaches
- implant/patch/injection = patch lasts for one week/implant lasts for three years = highly effective, doesn’t protect against STD
- IUD = stops fertilised egg from implanting in the uterus = more convenient than pill, doesn’t protect against STD
- spermicide = a chemical that disables or kills the sperm = not as effective
- condom/diaphragm = protects against STD/has to be used with spermicide = no side-effects, not protected against STD
- natural = by not having sexual intercourse
how are hormones carried around in the body?
- in the bloodstream
