Pharmcacology Flashcards
What are the 3 types of muscle in the body?
Smooth
Skeletal
Cardiac
Is skeletal muscle involved in voluntary or involuntary movement?
Voluntary
Where do the myelinated motor neurones divide into unmyelinated branches?
Near the muscle.
What does each unmyelinated motor neurone branch innervate?
An individual skeletal muscle cell called a muscle fibre.
What is a motor unit?
The neurone and the number of fibres that it innervates
What neurochemical transmitter is mostly involved in skeletal muscle?
Acetylcholine
What is a Schwann cell?
Covers the myelin sheath of an axon and acts as an insulator
How is choline transported into the pre-synaptic cell?
Choline transporter as a symport with Na+.
This means Na+ also comes into the cell.
When the action potential arrives at the terminal this causes depolarisation and what happens?
Voltage-activated Ca++ channels open and allow Ca++ into the cell.
When ACh diffuses into the synaptic cleft which post-synaptic receptors are activated?
Nicotinic ACh
How many subunits make up a nicotinic ACh receptor?
5
How many Na+ in for K+ out?
3 sodium in
2 potassium out
What is an all or nothing action potential?
The action potential must reach the threshold in order for the contraction to take place.
What does the sarcoplasmic reticulum store?
Calcium ions
What happens when the AP propagates over the sarcolemma?
It enters T tubules of the sarcolemma which are close to the SR.
AP causes release of Ca++ from SR which causes contraction due to troponin.
