nervous system

Question 1

functions of nervous system

Answer 1

sensory- sensory input
intergrative- analyses & interprets sensory input
motor- motor output

Question 2

sensory input

Answer 2

general
nociceptors- pain
mechanoreceptors:
tactile- touch, pressure, vibration
baroreceptors- blood pressure
proprioceptors- body position
sensory receptors eyes, ears, mouth & nose

Question 3

motor output

Answer 3

activates muscle & glands

Question 4

Central nervous system

Answer 4

brain & spinal cord

control centre performs integration

Question 5

peripheral nervous system

Answer 5

sensory receptors and cranial spinal and peripheral nerves that link all parts of body to CNS

Question 6

2 functional systems [ANS and SNS]

Answer 6

somatic motor output from CNS to skeletal muscle
somatic= voluntary & involuntary movements
autonomic motor output from CNS to glands, cardiac & smooth muscle
controls involuntary

Question 7

2 functional division [sympathetic & parasympathetic]

Answer 7

symph= fight/ flight
increase heart rate, respiratory airflow, blood flow
parasympathetic= rest & digest
stimulates digestive system, urination & defecation
contract pupils decrease heart rate & respiratory airflow

Question 8

neurons

Answer 8

stimulate electrical signals called graded and action potentials to conduct sensory and motor info
require oxygen and glucose
unable to divide and replace themselves

Question 9

structural component of Neuron

Answer 9

dendrites- receptive region convert info into graded potential
cell body- receives info from other neutrons & converts to graded potential
axon- conducting region= generates & conducts action potentials to convey info from initial segment to axon terminal
covered by myelin sheath which increase speed
nodes of ranvier
axon terminals- release neurotransmitter to transmit info to another neuron, muscle, gland

Question 10

neuron cell bodies in clusters

Answer 10

nuclei (nucleus) CNS

ganglia (ganglion) PNS

Question 11

neruon axons bundled

Answer 11

tracts CNS

nerves PNS

Question 12

functional classifications

Answer 12

sensory neuron- conduct sensory input (unipolar)
interneurons- conduct info within CNS (multipolar)
motor neuron- conduct motor output away from CNS (multipolar)
lower motor neurone conduct somatic motor output
preganglionic & postganglionic neurons conduct autonomic motor output

Question 13

chem gated channels

Answer 13

open to chem stimulus

located in dendrites and cell body

Question 14

mechanically gated channels

Answer 14

open to mech stimulus

located in dendrites

Question 15

voltage gated channels

Answer 15

open and close to voltage changes

located ini axon and axon terminals

Question 16

depolarisation

Answer 16

membrane potential is less negative
stimulus opens NA gated channels
ICF gains +ve ions= less negative

Question 17

hyperpolarisation

Answer 17

membrane potential becomes more negative
stimulus opens K gated channels
efflux of K ions out of ICF
ICF looses +ve ions= more negative

Question 18

graded potentials

Answer 18

small changes in MP
when a stimulus opens chem gated or mechanically gated channels
short distance signals

Question 19

initiate an action potential

Answer 19

graded potential travel to initial segment & depolarises to -55mV (threshold)
stimulating voltage gated channels to open

Question 20

action potential

Answer 20

long distance

self propagating= triggers itself

Question 21

1. depolarisation

Answer 21

at threshold voltage gated Na channels open Na diffuse into ICF shifts to +30mV

Question 22

2. repolarisation

Answer 22

at +30mV voltage gated Na channels close and voltage gated K channels open
K ions diffuse out of ICF returning MP to resting state

Question 23

3. hyperpolarisation

Answer 23

as MP approaches -70mV voltage gated K channels slowly close K ions continue to flow = ICF more negative
shifts to -90mV

Question 24

both voltage channels close

Answer 24

the movement of K and Na ions leak through leakage channels and ATPase pumps to restore RMP

Question 25

continuous conduction

Answer 25

unmyelinated axons action potentials generated at voltage gated channels of axon less 2 m/s

Question 26

saltatory conduction

Answer 26

myelinated axons action potentials are generated at nodes of ranvier more 100m/s

Question 27

information transfer

Answer 27

1. action potential arrives & depolarise at axon terminal 2. depolarisation stimulates voltage gated Ca channels to open and Ca enters axon terminals 3. Ca entry triggers synaptic vesicle to release stored neurotransmitter 4. neurotransmitter diffuses across synapse and binds to chemically gated channels 5. influx of NA ions to ICF=PM depolarises excitatory postsynaptic potential produced 6. EPSP travels & depolarises initial segment to threshold action potential generated = info transmitted

Question 28

termination of synaptic transmission

Answer 28

diffuses away degraded by enzymes in synapse reuptake