unit 6 Flashcards
what are the changes in the environment detected by
receptors
what are changes in the environment called
stimuli
what do endocrine glands do
secrete hormones
what are responses with the endocrine system like
-secretion of hormones
-slow
-long lasting
-widespread
what can the nervous system be divided into
-the central nervous system
-the peripheral nervous system
what can the peripheral nervous system be divided into
the automatic and voluntary nervous system s
what does the central nervous system involve
the brain and spinal chords
what does the peripheral nervous system involve
sensory and motor neurones
what are sensory neurones
- posses receptors stimulated by specific stimulus
-an impulse is transmitted along this sensory neurone
-to the cns
what does a motor neurone do
transmits an impulse to the effector either a muscle or a gland
what do relay neurones do
act as a link between motor and sensory neurone
-found in CNS
-also called intermediate or coordinator neurones
what does the axon do
conducts nerve impulses
what does the myelin sheath do
- consists of lipid
-surrounds axon
-formed by Schwann cells
-provides electrical insulation
what does synaptic knobs do
provides communication with other neurones and effectors
what are reflexes
rapid and automatic response to a stimulus
describe the reflex arc of a reflex
-receptors detect stimulus and transmit impulse along sensory neurone
-sensory neurone synapses with a relay neurone, passes impulse to motor neurone
-motor neurone to effector
how is the nervous system different to the endocrine system
- involved brain and spinal chord
- rapid , short live and localised responses.
what are advantages of reflexes
- automatic and rapid responses
-prevents damage to tissues
-increases escape chance from predators
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what are the 2 simple responses maintaining organisms in a favourable environment
-taxes
-kineses
describe taxes
singular simple response
-direction of the movement of organism is determined by the direction of stimulus
-negative and positive phototaxis e.g a plant towards light for photosynthesis
-chemo taxis
- movement towards and away from a high concentration of substance
eg. bacteria away from toxins and towards food source
describe kenesis
response where organism doesn’t move towards stimulus
-changes the speed of an organism
-the rate it changes direction
