Skeletal muscle structure and function Flashcards
What is the muscle fibre enveloped by?
a sheath of connective tissue
What is the smallest unit of a myofibril?
Sarcomere
What are the actin molecules attached to?
They are attached to nebulin which ensures uniformity in length
What is the function of the t-tubules?
They run alongside the z discs of the muscle fibre, action potentials are conducted alongside them
What causes the calcium release from the sarcoplasmic reticulum?
depolarisation of the t-tubules
What is the function of tropomyosin?
Blocks the binding site of the myosin
What are some functions of skeletal muscle?
Move the body, Support and Protection and controls body posture
How does muscle contraction occur?
ATP binds to a myosin head
It then becomes hydrolysed to ATP + P which provides energy for the power stroke
After the powerstroke, both ADP + P are released
another ATP molecule binds breaking the actin/myosin bond
What is the effect of calcium binding to troponin?
Calcium binding to troponib moves the tropomysosin out of the way of the myosin binding sites
How does Rigor Mortis occur?
ATP production ceases after death
so when calcium leaks into the cytosol and causes binding of the myosin heads there is no ATP to break the bond
What is nebulin?
an actin-binding protein that helps ensure uniformity and length
Where is calcium released from?
Sarcoplasmic reticulum
What happens to the calcium after the muscle contraction?
Ion pumps in the sarcoplasmic reticulum pump the calcium from the cytosol back into the sarcoplasmic reticulum
What is hypocalcaemia in ruminants called?
paresis
What is hypocalcaemia in dogs called?
tetany
