Homeostasis-mocks revision
homeostasis
the maintenance of a constant internal environment in the body.
effector
muscles or glands which respond to change
receptor
detects change
co-ordination centre
recieves/processes information
what is in a control system
receptor, co-ordination centre and effector
what order is a reflex arc
stimulus, receptor, sensory neurone, relay neurone, motor neurone, effector
explain the synapse (3points)
1. a junction between two neurones
2. electrical impulses traveling down neurones are converted into a chemical message accross the synapse
3. crosses the gag through diffusion
define hormone
a chemical substance, produced by a gland and carried in the bloodstream, which alters the activity of specific target organs
role of thyroid
controls metabolic rate (the amount of energy expended in a set amount of time) of the body
produces thyroxine which controls the speed at which oxygen and food products react to release energy for the body to use
role of pancreas
controly glucose levels in the blood using glucagon (to convert glycogen into glucose) and insulin (to convert glucose into glycogen)
role of ovaries
controls development of female secondar sexual characteristics
involved in the mentrual cycle
role of testes
controls development of male secondary sexual characteristics
involved in sperm production
name the glands in the endocrine system (6points)
pituitary (brain), Thyroid (neck), Pancreas (middle, below adrenal), adrenal (middle, above pancreas also theres two), ovaries and testes
role of adrenal
prepares body for stressful situations
role of pituitary (4points)
1. growth in children
2. stimualtes thyroid
3. stimulates ovaries in women
4. stimulates testes in men
what hormone is produced when blood glucose levels are low and what does it do
glucagon-converts glycogen stored in muscles back to glucose
what hormone is released when blood glucose levels are too high, and what does it do
insulin-converts glucose to glycogen in tissue cells where it will be stored
what is glucose
a sugar used in respiration
what is glycogen
a storage carbohydrate found in the liver and muscles
Type 1 diabetes (2points)
1. develops before 20 (around 12)
2. pancreas stops making insulin
Type 2 diabetes (3points)
1. develops after 40
2. reduced amounts of insulin of the body stops responding normally to insulin
3. caused by diet and lifestyle
how to treat type one diabetes
insulin injection, diet contol and exercise
how to treat type two diabetes
medication, diet control and exercise
define primary sexual characteristics
ones people are born with (ovaries, testes)
define secondary sexual characteristics
ones developed in pudertt (oestrogen, testosterone)
Day one of the menstrual cycle
uterus lining is shed
day 7 of the menstrual cycle
uterus lining thinckens, new egg is maturing in ovaries
Day 14 in the menstrual cycle
ovulation, uterus lining is max thick and egg is released into the oviduct
day 21 in the menstrual cycle
egg is passed into the uterus
Why and when is Follicle Stimulating Hormone (FSH) produced
matures the egg and stimulates ovaries to produce oestrogen, at the start of menstruation
What does oestrogen do and why
thickens uterus lining, stops FSH and starts LH, after mensturation but before ovulation
what does Luteinising Hormone (LH) do and when is it produced
releases the egg on day 14
what does progesterone do and when is it produced
maintains pregnancy and uterus lining and stops FSH and LH after ovulation
what does birth control contain
oestrogen and/or progesterone
two forms of infertility treatments
hormone therapy and in vitro fertilisation
steps of IVF (6points)
1. FSH is administered in levels higher than naturally occur to over-stimulate the ovaries
2.the eggs are removed with an aspirating needle guided by an ultrasound
3. a sample of semen is collected
4. the eggs are left with the sperm in a petri dish for 24hours
5. the embryos are screened for genetic suitability
6. 3 days after fertilisation the embryos are implanted in the uterus
what makes up the central nervous system (CNS)
brain and spine
process of a signal crossing the synapse (4points)
1. and electrical impulse travels down neurone 1
2. neurotransmitters are released at the end of the neurone
3. neurotransmitters diffuse accross the gap and bind with receptor molecules on the membrane of neurone 2
4. neurone 2 is stimulated to transmit the electrical pulse
what is a neurotransmitter
a chemical transmitter molecule that crosses the synapse
define diffusion
the movement of a substance from an area of high concentration to an area of lower concentration
where is ADH produced, where does it target and what does it do
1. from pituitary gland
2. targets kidneys
3. contols blood water content
where is adernaline produced, where does it target and what does it do
1. from the adrenal glands
2. multiple targets (respiratory and circulatory systems)
3. prepares body for fight or flight