Week 8: The Muscular System Flashcards
What are the three types of muscle?
Skeletal Cardiac Smooth
Are smooth muscles and cardiac muscles voluntary?
No they are involuntary
Are smooth muscles striated?
No
Are cardiac muscle striated?
Yes
What are the functions of skeletal muscle?
Contractions Metabolism Heat generation Amino acid store
What are the properties of skeletal muscle?
Contractility Excitability Extensibility Elasticity
How is skeletal muscle connected to the skeletal?
Via tendons
What is the composition of skeletal muscle?
75% water 20% protein 5% salts and other substances
What are the three types of muscles arcitecture?
Parallel Unipennate Multipennate
How many motor neurons innervate each muscle fibre?
Only one
What is action potential?
The rapid rise and fall of a cells electrical membrane potential
What does action potential provide?
The electrical stimulus for muscle contraction
In order for the muscle to contract what must the level of stimulus cross?
A threshold
What regulate action potential?
The sodium potassium pump
What happens to the muscle contraction if the stimulus doesn’t pass the threshold?
Failure to contract
In the sodium potassium pump what enter and leaves the cell?
Sodium enters Potassium leaves
What happens to the membrane potential after action potential has bee reached?
It decreases during the re-polarisation period and then decreases below resting state during the refractory period
Where in the muscle is calcium released from?
Sarcoplasmic reticulum
Where does the action potential spread?
Down the sarcolemma, reaching transverse tubules (T-tubules)
What happens when calcium is released into the cell?
It binds to troponin on the thin filament therefore enables myosin to bind to actin
At rest, what binds to the myosin head and why?
ATP to release energy that promotes myosin head into an extended, high energy position
What does the extended myosin bind to?
The active site on the actin molecule (called a cross bridge)
When the myosin had bound to the actin molecule what is released and why?
ADP is released to tug the actin towards the centre of the sarcomere
What is needed to break the cross bridge?
A new ATP molecule
