Muscle contraction Flashcards
what is the relationship between the CNS and Muscular movement?
The CNS (brain and spinal cord) receives sensory information and decides what kind of response is needed.
If the response needed is movement, the CNS…
sends signals along neurons to tell Skeletal muscle to contract.
What is Skeletal muscle?
Skeletal muscle (also called striated, striped or voluntary muscle) is the type of muscle you use to move, e.g the biceps and triceps move the lower arm.
What makes up Skeletal muscle?
Skeletal muscle is made up of large bundles of long cells called muscle fibres.
What is the name of the cell membrane of muscle fibre cells?
Sacrcolemma
Bits of the sarcolemma fold inwards across
the muscle fibre and stick into the sarcoplasm (a muscle cell’s cytoplasm)
When the sarcolemma folds this is called…
transverse tubules (T) tubules.
What are transverse (T) tubules useful for?
Transverse (T) tubules help to help spread electrical impulses throughout the sarcoplasm so they reach all parts of the muscle fibres.
A network of internal membranes called the …
sarcoplasmic reticulum runs through the sarcoplasm.
What does the sarcoplasmic reticulum in relation to muscle contraction?
The sarcoplasmic reticulum stores and release calcium ions that are needed for muscle contraction.
Why do muscle fibres have a lot of mitochondria?
Muscle fibres have a lot of mitochondria to provide the ATP that’s needed for muscle contraction.
muscles cells contain many cells, this is called?
They are multinucleate.
Muscle fibres have lots of long, cylindrical organelles called …
myofibrils.
What makes up myofibrils?
They’re made up of proteins and are highly specialised for contraction.
Myofibrils contain bundles of:
thick and thin myofilaments that move past each other to make the muscle contract.
Thick myofilaments are made of the protein …
myosin
Thin myofilaments are made of the protein …
actin.
If you look at a myofibril under a microscope you’ll see a pattern of:
alternating dark and white bands.
Dark bands contain the …
thick myosin filaments and some overlapping thin actin filaments - these are called A-bands.
Light bands contain…
thin actin filaments only these are called L bands.
A myofibril is made up :
short units called sarcomeres.
The ends of each sarcomere are marked with a…
Z line.
In the middle of each sarcomere is an …
M line.
What is the m line?
The M-line is the middle of the myosin filaments.