neuronal communication

Question 1

name 4 types of sensory receptors

Answer 1

mechanoreceptors- pressure
chemoreceptors- chemicals
thermoreceptors- heat
photoreceptors- light

Question 2

explain the movement of sodium within pacinian corpuscles

Answer 2

1- in resting state- stretch mediated channels in neurone membrane too narrow to allow sodium ions through
2- corpuscle changes shape when pressure is applied- membrane surrounding neurone stretches
3- when membrane stretches, Na+ channels widen so it can diffuse into neurone
4-increase is Na+ ions changes potential of membrane so it become depolarised (electrically charged) resulting in generator potential
5-generator potential creates action potential transmitted along neurones to CNS

Question 3

name the structural components of synapses

Answer 3

synaptic cleft- separates axons - dendrites
presynaptic neurone
postsynaptic neurone
synaptic knob- end of presynaptic neurone
synaptic vesicles- contain neurotransmitter
neurotransmitter receptors

Question 4

name + describe the 2 types of neurotransmitter

Answer 4

inhibitory

• result in hyper polarisation of postsynaptic neurone
• prevent action potential being triggered

excitatory

• cause depolarisation of postsynaptic neurone
• if threshold reached then action potential is triggered

Question 5

what is spatial summation

Answer 5

multiple presynaptic neurones connect to one postsynaptic neurone
each releases nt which build up in synapse and triggers action potential

Question 6

what is temporal summation

Answer 6

single presynaptic neurone release nt several times over short period
builds up until it triggers action potential

Question 7

name structures of the brain and their functions

Answer 7

cerebrum= voluntary actions
cerebellum= unconscious actions
medulla oblongata= autonomic control
hypothalamous= produces hormones and regulates temp + water balance
pituitary gland= stores + releases hormones

Question 8

name and describe types of muscle

Answer 8

skeletal
-movement
cardiac
-found in heart
-myogenic
involuntary/ smooth
walls of blood vessels and organs

Question 9

describe the structure and function of muscle fibres

Answer 9

bundle of muscle fibres enclosed in membrane called sarcomella
contain multiple, long nuclei
many muscle cells fused together
share cytoplasm called sarcoplasm
lots of mitochondria provide ATP for contraction

Question 10

name the 2 types of microfibrils

Answer 10

actin (thin)

myosin (thick)

Question 11

define z-line and h-zone

Answer 11

z-line= distance between myosin filaments
h-zone= distance between actin filaments