NERVOUS TISSUE Flashcards
what is the nervous system
series of interconnecting neurones that communicate between wach other and organs in the body
what forms do communication come in?
explain what they are.
electrical impulse: travel along length of the neurones as changes in the distribution of charge across the plasma membranes
(potential difference)
chemical neurotransmitters: released by certain neurones onto other effectors
bulbous end
contains neurotransmitters which released when a nerve impulse reaches it
what is a dendrite
receive incoming information branched and numerous allowing many synaptic connections with other neurones
whats a cell body
large volume to accommodate nucleus and organanelles , densly packed with mitchocondria to provide ATP needed to generate a nerve impulses , nissil granuals manufacture proteins
whats an axon
carries outgoing nerve impulses to target cell , long and thin to conduct impulses over a long distance rapidly
what are nodes of ranvier
gaps in the myelin sheaths that allow a nerve impulse to jump from one node to the next speeding up the conduction of a nerve impulse
schwann cells
produce myelin sheath that acts as an electrical insulator for axon
what are axon terminals
highly branched to increase the contract area between a motor neurone and its target cell
what are advantages of nervous system in messages
rapid = impulse travels about 100ms-1
short lived = no lingering effects
localised= specific areas can be targeted to ensure an efficient and effective response is carried out
how do neurones work
neurones have long stretches of cytoplasm called axons
- responsible for carrying nerve impulses
impulses are in the form of changed in the distribution of electrical charge across the axon membrane
- when there is an unequal distribution of charge there is said to be a potential difference
means one area will have more/less positive (or negative) charges than other
- all neurones that are not carrying an impulse along them have a potential difference across plasma membranes all the time
= resting potential
what are nerves made out of
neurones
what do neurones do
carry messages in the form of action potentails
what are sensory neurones
connects sensory receptors to CNS
what are motor neurones
communicates with effectors from CNS
