neuromuscular system

Question 1

what is a muscle motor unit

Answer 1

the motor neurone will terminate at several synapses each linked to several muscle fibres
muscle fibres and nervous system which controls contraction and relaxation
motor neurone is stimulated all fibres connected to that neurone are activated at one ‘all or none law’

Question 2

definition of dendrites

Answer 2

high branched processes which extend out from cell body and receive information from sensory organs

Question 3

definition of axon

Answer 3

conduct nerve impulses to other cells

Question 4

definition of myelin sheath

Answer 4

insulated the nerve, helps transfer signals quicker

Question 5

definition of nodes of ranvier

Answer 5

gaps in myelin sheath where the action potential jumps from node to node

Question 6

definition of axon terminal

Answer 6

ends with synaptic end bulb containing neurotransmitter substances

Question 7

how does a motor unit need to be stimulated to enable a muscular contraction

Answer 7

1. the neutron becomes depolarised, firing action potential
2. action potential reaches the neuromuscular junction
3. this causes the neurotransmitter acetylcholine to move to the motor end plate
4. the motor end plate becomes depolarised, resulting in a muscular contraction

Question 8

what is the all or none law

Answer 8

each muscle fibre controlled by a motor unit is enter fully contracted or not contracted at all

Question 9

what is spatial summation

Answer 9

many motor units firing

Question 10

what is wave summation

Answer 10

one motor unit firing continuously

Question 11

what is titanic summation

Answer 11

a continuous muscle contraction

Question 12

what are the 4 stages of sliding filament theory

Answer 12

resting
excitation
contraction
relaxation

Question 13

what happens in the resting phase of the sliding filament theory

Answer 13

the muscle is relaxed, due to lack of ca in the myofibril resulting in a lack of myosin bound to actin

Question 14

what happens in the excitation phase of the sliding filament theory

Answer 14

impulse reaches the neurotransmitter junction, which releases acetylcholine then results in the depolarisation of the motor end plate, releasing ca+ from the sarcoplasmic reticulum. Ca+ bind to toponym altering its shape. results in tropomyosin moving from the active site , allowing myosin filaments to bond to the actin, forming a cross bridge

Question 15

what happens in the contraction phase of the sliding filament theory

Answer 15

breakdown of ATP provides energy requires fro myosin to pull on the actin (power stroke) resulting in the muscle shortening

Question 16

what happens in the relaxation phase of the sliding fialment theory

Answer 16

this takes place when the motor nerve ends and Ca re enters the sarcoplasmic reticulum, meaning that the cross bridges no longer exist

Question 17

is myosin the thick or thin filament

Answer 17

thick

Question 18

is actin the thick or thin filament

Answer 18

thin

Question 19

where does sliding filament theory take place

Answer 19

sarcomere

Question 20

where are the z lines located

Answer 20

end of the sarcomere

Question 21

what is the H zone in the sarcomere

Answer 21

space between the ends of the actin filaments