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Muscle Contraction - Term 1 Human Body Notes
Term 1 Human Body Notes
Module
The Human Body (PY4010)
171 Documents
Students shared 171 documents in this course
University
Kingston University
Academic year: 2021/2022
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• The different structural features of the three muscle
types.
Muscles are amazing cells whose singular job is really to shorten (contract)
and then return to their original shape (relax). This process is driven by a rise
in the level of calcium inside the cell.
Skeletal - eg triceps, bicep, gluteus. Attached to bones, locomotion.
Cardiac- a really 'hearty' muscle!
Smooth-controls all involuntary actions eg arteries, guts, bladder or
reproductive organs.
Skeletal muscle cells are very long. They have many nuclei. They have a
distinctive stripy patter as the proteins involved in muscle shortening are
arranged in a very organised pattern. Found in biceps, calves, thighs and
diagram for example.
Cardiac muscle cells are long but way shorter than skeletal muscle. They only
have a single nucleus.
Smooth muscle cells do not have the stripy pattern as the proteins are not
arranged in an organised pattern. Found in arteries, guts, bladder and
reproductive organs.
Contraction is the interaction of actin and myosin. It is fuelled by ATP and
driven by a rise in calcium ions.
T-tubules (transverse tubules) are extensions of the cell membrane that
penetrate into the centre of skeletal and cardiac muscle cells.
The skeletal muscle is made up of groups of bundles (fascicle). These are
made of bundles of cells. These are coated in a substance called Epimysium.
There are 2 types of filaments- thin (mostly actin) and thick (myosin). I band
has only actin. A band has all of the myosin. The space between z lines is
called the sarcomere. H band has just myosin, no actin
M line is an attatchment point for the myosin. Z line is attachment point for
actin.
Actin has an active site for myosin. Under normal conditions, a substance
called tropomyosin is prevent these from meeting.
When the muscle contracts, the myosin head draws the actin
into the centre of the sarcomere. ATP binds to myosin,
causing detachment of myosin from actin. ATP releases
energy, which means the myosin head to detach from the
actin. The cycle then repeats
The different mechanisms by which a rise of calcium is
generated in the different muscle cells.
When a skeletal muscle is stimulated by the release of Ach
by motor nerves, depolarisation occurs. DHP proteins
interact with a calcium release channel (known as RYR) in
sarcoplasmic reticulum. Following stimulus, calcium is
released into the cell.
In cardiac muscle, the activation of the Ca ion channels is
what causes Ca to be released from the SR. Calcium binds to
troponin, which causes it to change shape. This causes
tropomyosin to move to a different position on the actin
filaments. Myosin binding site is now free for the extended
myosin head to bind to.
Sliding filament theory- during contraction, the actin and
myosin filaments slide against each other.
In skeletal/cardiac muscle, calcium binds to troponin, which
causes the removal of a NO mechanism
Smooth muscle- no T tubule system. Rise in calcium through
receptor mediated release from internal calcium store, or
through voltage gated calcium channels. In smooth muscle
cells, calcium binds to calmodulin, which stimulates myosin
light chain kinase (MLCK), which phosphorylates the light
chain of the myosin head. ATP is used to activate the
myosin. Myosin binds to actin.
The different components of the contractile apparatus
including the features of actin and myosin.
• The biochemical mechanisms that link a rise in calcium
with interaction of actin and myosin and how these
differ in the three muscle types.
•
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Muscle Contraction - Term 1 Human Body Notes
Module: The Human Body (PY4010)
171 Documents
Students shared 171 documents in this course
University: Kingston University
Was this document helpful?
•The different structural features of the three muscle
types.
Muscles are amazing cells whose singular job is really to shorten (contract)
and then return to their original shape (relax). This process is driven by a rise
in the level of calcium inside the cell.
Skeletal - eg triceps, bicep, gluteus. Attached to bones, locomotion.
Cardiac- a really 'hearty' muscle!
Smooth-controls all involuntary actions eg arteries, guts, bladder or
reproductive organs.
Skeletal muscle cells are very long. They have many nuclei. They have a
distinctive stripy patter as the proteins involved in muscle shortening are
arranged in a very organised pattern. Found in biceps, calves, thighs and
diagram for example.
Cardiac muscle cells are long but way shorter than skeletal muscle. They only
have a single nucleus.
Smooth muscle cells do not have the stripy pattern as the proteins are not
arranged in an organised pattern. Found in arteries, guts, bladder and
reproductive organs.
Contraction is the interaction of actin and myosin. It is fuelled by ATP and
driven by a rise in calcium ions.
T-tubules (transverse tubules) are extensions of the cell membrane that
penetrate into the centre of skeletal and cardiac muscle cells.
The skeletal muscle is made up of groups of bundles (fascicle). These are
made of bundles of cells. These are coated in a substance called Epimysium.
There are 2 types of filaments- thin (mostly actin) and thick (myosin). I band
has only actin. A band has all of the myosin. The space between z lines is
called the sarcomere. H band has just myosin, no actin
M line is an attatchment point for the myosin. Z line is attachment point for
actin.
Actin has an active site for myosin. Under normal conditions, a substance
called tropomyosin is prevent these from meeting.
When the muscle contracts, the myosin head draws the actin
into the centre of the sarcomere. ATP binds to myosin,
causing detachment of myosin from actin. ATP releases
energy, which means the myosin head to detach from the
actin. The cycle then repeats
The different mechanisms by which a rise of calcium is
