B10 the human nervous system Flashcards
what is homeostasis
the regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external changes
what does homeostasis control in the human body
temperature
water levels
blood glucose concentration
what are the 2 types of responses a control system may involve
chemical
nervous
what are the control systems
effectors
coordination centers
receptors
what do control systems do
they recognize when there is a change from optimal conditions then they send a signal to reverse the change
what are receptors
they detect change (stimuli)
what are coordination centres
brain and spinal cord
interpret the change detected by the receptors and decide what needs to be done
what are the effectors
muscles or gland which carry out the change to bring back to optimum levels
what is the nervous system
sends very fast and precise electrical impulses through nerves to respond to things very quickly
what is the endocrine system
releases hormones into the blood stream they only effect certain cells that have the right receptors
what are the differences between the nervous system and the endocrine system
endocrine system is slower longer lasting and more generalised
describe the process of the nervous system
information from receptors pass along cells to the CNS
CNS coordinates the response of effectors which may be muscles contracting or glands secreting
hormones
describe reflex actions
automatic and rapid
they do not involve the conscious part of the brain
what is a synapse
gaps between neurons
when an electrical impulse reaches a synapse a chemical is released that diffuses across the gap
describe what happens in a reflex arc
pain stimulus is detected by receptor
impulses from receptor pass along a sensory neuron to CNS
an impulse then passes through a relay neuron
a motor neuron carries an impulse to the effector
effector responds
