NEURO

Question 1

SALTATORY CONDUCTION

Answer 1

FAST DUE TO MYELINATION
up to 40m/sec
Schwann cells form PNS; oligodendrocytes form CNS
nodes of ranvier

Question 2

WAYS TO ADJUST MUSCLE FORCE

Answer 2

Adjusting how much each fibre contracts - more AP = more force/tension
increasing the number of muscle fibres contracting - using motor unit etc

Question 3

HOW DO MUSCLE FIBRES RELAX

Answer 3

motor neuron ceases AP

removal of Ca2+ from sarcoplasmic reticulum

Question 4

HOW DOES THE MYOSIN BINDING SITE BECOME EXPOSED

Answer 4

Binding on Ca2+ onto troponin [on thin filament] causes the movement of tropomyosin.
this exposes binding site

Question 5

STEPS OF SYNAPTIC TRANSMISSION

Answer 5

AP depolarises synaptic terminal
Ca+ channels open and enter, interacting with synaptic vesicles
neurotransmitter released into cleft and into the post-synaptic membrane receptors, which can let ions through [positive or negative]

positive charged could cause ap

Question 6

STEPS OF MUSCLE CONTRACTION

Answer 6

myosin binding site must be exposed.
1. myosin head splits into ADP + P
2. head attaches to actin molecule at binding site
3. power stroke - slides thin over thick
4. myosin detaches form actin

this continues for as long as there is Ca and ATP

Question 7

CONTINUOUS CONDUCTION

Answer 7

UNMYELINATION
up to 2m/sec
propagates like a slow fuse