Neurones and resting potential Flashcards
describe
-type of transmission
-route of transmission
-speed of response
-location of response
-duration of response
in nervous communication
-electrical transmission
-via nervous system
-fast
-muscles and glands
-short-lasting
what is the stimulus response pathway for nerve impulses
stimulus->
sensory receptor->
sensory neurone->
CNS= brain and spinal chord, and relay neurones->
motor neurone->
effector
what are the 3 types of neurones and their function
sensory neurone= transmit impulses from receptors towards the central nervous system
relay neurones= located inside CNS transmit impulses between sensory and motor neurones
motor neurones= transmit impulses from the CNS to effectors-muscles or glands-
draw and label the structure of a sensory neurone
- skin containing cell receptor cells
- dendron carrying impulse towards cell body
- myelin sheeth, schwann cells and nodes of ranvier
- cell body
- axon carrying impulse away from cell body
. dendrites connecting to relay neurone
7.axon terminal/ synaptic endings
draw and label the structure of a relay neurone
cell body with a short axon and dendrites
-no myelin sheeth
-axon terminal
draw and label the structure of a motor neurone
- cell body and dendrites
2.axon
3.myelin sheeth, schwann cells and nodes and ranvier
4.synaptic endings/ motor end plates/ neuromuscular junction/ axon terminal
5.muscle cells
explain the functions of each neurone part
axon= long process carries impulses away from the cell body, often over long distances
-cell surface membrane= gated ion channels controlling movement of Na+, K+ Ca++, sodium potassium pumps to actively transport ions = lots of mitochondria
-cell body= nucleus, many mitochondria and ribosomes
-dendrites= small processes connecting to other neurones carrying nerve impuluses towards body cell
-schwann cells= wrap around the axon creating a fatty insulating layer of myelin
-myelin sheath= insulates so prevents ion movement resulting in increase speed of conduction as impulse jumps
-nodes of ranvier= short gaps between schwann cells occur ebery 1-3mm, non myelinated
explain the difference between the structures of sensory, motor and relay neurones
-myelin sheath only on sensory and motor
-sensory has a cell body in the middle
-no dendron on motor and relay
compare the features of myelinated and non-myelinated neurones
myelinated:
-location= one third of peripheral nuerones in vertebrates
-speed of transmission of nerve impulse/action potential= 100-120ms-1
distance that nerve impulses are carried= long distances, from sensory receptors to CNS then to effectors
non-myelinated;
-location= 2/3 of peripheral neurones and all neurones in CNS
-speed of transmission of nerve impulse/action potential=2-20ms-1
distance that nerve impulses are carried= short distances, neurones are shorter and coordinate activities such as breathing and action of digestive system
describe the axon when neurones are at rest/ resting potential
-neurones aren’t transmitting an action potential
-outside of axon membrane is positively charged relative to the interior of the cell which is negative
-cell membrane is polarised= potential difference across the membrane is about -SIXTY-70 mV
describe and explain how the resting potential is established and how it is maintained in a sensory neurone
- sodium-potassium actively pumps 3 sodium ions out of axon and 2 potassium ions in
- potassium ions passively leak out/diffuse out of axon via potassium ion channels
- membrane is less permeable to sodium so fewer sodium ions diffuse back in
- voltage-gated sodium ion gates are closed
what are the 2 mechanisms involved during resting potential
-active transport by sodium/potassium pump
-facilitated diffusion of potassium ions via potassium ion channel proteins
