bio 5 Flashcards
(23 cards)
what is homeostasis?
it is the regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in reponse to external and internal changes
what is negative feedback?
a mechanism where the body responds to a change by reversing it, bringing the system back towards a normal state or set point
automatic control system
receptor cells
coordination centre
effector
what does homeostasis regulate?
blood glucose levels
water levels
temperature
what does a receptor cell do?
detect changes in the environment (blood glucose concentration/body temperature)
what is a stimulus
a change in the environment
coordination centre
these are regions in the brain, spinal cord, or the pancreas that receive information from the receptors, process it, generates a response
effectors
these are muscles or glands that carry out the response to restore the body to its optimum state
what happens when the blood glucose concentration is low?
the pancreas detects a decrease in blood glucose levels
the pancreas releases glucagon
glucagon travels to the liver
glucagon triggers the liver to break down glycogen (stored glucose) into glucose
the liver releases the glucose into the bloodstream
the increased glucose in the bloodstream raises blood glucose levels back to its normal range
required practical:reaction time
ruler drop test:
1.work with a partner
2.person A holds out their hand with a gap between their thumbs and the first finger
3.person B holds the ruler with the zero at the top of person a thumb
4.Person B drops the ruler without telling Person A and they must catch it
5.the number level with persons A’s thumb is recorded in a suitable table repeat this five times
6.swap places and record another five times
7.you can use the conversion table to help convert your measurements into reaction time or just record the catch distance in centimetres
what hormones are given to women who are having IVF treatment
FSH and LH
what is the cell division that produces sperm and egg cells?
meiosis
why are microscopes needed in IVF
to able to select eggs
to see if the egg has been fertilised
name the target organ for the hormones in IVF
ovaries
Describe how the hormones given to women during IVF treatment interact with other hormones to prepare the body for pregnancy.
FSH and LH cause an increase in progesterone and oestrogen
progesterone and oestrogen maintain uterus lining
uterus lining is prepared for the embryo
two arguments against IVF treatment
stress of operations
success rate is low
multiple births are at risk for the mother
embryos are created but not used
why is the control of body temperature important
to maintain optimum conditions for enzyme condition
explain the role of adrenal glands in decreasing the body’s temperature
release adrenaline to increase heart rate
so more oxygen and glucose to the brain
because oxygen needed for respiration
to move muscles to increase body temperature
how does FSH and then LH help to make a women pregnant
FSH causes eggs to mature
LH causes releases of the egg
so more eggs therefore higher chance of fertilisation
steps of IVF
the woman is giving fertility drugs (like FSH and LH) to stimulate her ovaries
this helps her to produce multiple eggs instead of just one
collection of eggs from the ovary which are fertilised in the laboratory
develop into embryos
embryos inserted into womb
how do hormones travel from one gland to one gland
via blood
give one risk factor for type 2 diabetes
being overweight
describe the sequences of the hormones in the menstrual cycle 5 marks
FSH from the pituitary stimulates an egg to mature
FSH stimulates oestrogen from the ovaries
oestrogen causes the thickening of the uterus lining
oestrogen inhibits FSH bit stimulates LH from the pituitary
the high levels of LH stimulate release the egg
