B10 Homeostasis/nervous system Flashcards
what do enzymes need in order to work?
very stable conditions
what is homeostasis?
the regulation of internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external changes
what is homeostasis used for in humans?
to keep the blood glucose level, temperature and water levels constant
what does homeostasis consist of?
automatic control systems that make sure the internal conditions of the body stay constant
what do automatic control systems involve?
the nervous systems or hormones
what do receptor cells do?
detect changes to the environment
this could be the internal or external environment
what is a stimulus?
a change to the environment
what is a coordination centre?
it receives and processes the information from the receptor cells
what is the job of an effector?
carry out the response (restore the optimum level/condition)
what is an effector?
a muscle or gland
what is the central nervous system (CNS)?
the brain and spinal cord
what is the peripheral nervous system?
the nerves running to and from the CNS
what are the parts of a reflex arc?
receptor
sensory neurone
CNS
relay neurone (in the CNS)
motor neurone
effector
response
what is a synapse?
a junction between two neurones
how do synapses work?
when an electrical impulse reaches the synapse, a chemical is released
this diffuses over the gap (synapse) between the two neurones and triggers an electrical impulse to be sent down the next neurone
what do reflexes do?
help protect from danger as they are very rapid
what is a reflex action?
an automatic and rapid response to a stimulus
what is the independent variable in the reaction time practical?
the person being tested
what is the dependent variable in the reaction time investigation?
reaction time
what are some control variables in the reaction time investigation?
starting distance between the thumb and the first finger should be kept constant
always measure from the top of the thumb
conditions in the room
what are some other possible independent variables for the reaction time investigation?
the effect of practice (a person catches the ruler a large number of times and look to see if the reaction time changes depending on the number of tries)
the hand catching the ruler
if chemicals have an effect on reaction time
what does the brain control?
complex behaviours