muscle anatomy Flashcards
Parts of a muscles zooming out and in
1) tendon attaching to muscle
2)Epimysium (layer around entire muscle)
3) muscle belly contains bundles/groups of singular muscle fibers
Perimysium: The perimysium is a connective tissue layer that surrounds and separates these
4) Singular muscle fiber contains groups of
fascicles and provides blood flow.
5) Endomysium: Each individual muscle fiber, or muscle cell, is surrounded by a layer of connective tissue, contains nerves and blood vessels
6) Endomysium is the layer that surrounds every individual muscle cell contains
7) A muscle fiber contains bundles of myofibrils or the contractile units of a
muscle
which zone has actin-thin filaments?
I band
Which zone has myosin thick filaments?
M and H Zones
which zone contains both actin and myosin filaments?
The A zone or the outer
How does muscle contraction affect
the z and m lines?
1) Z discs are at the ends of sarcomeres. They move closer together or shorten when the crossbridge forms/ overlap
2) The M line is the middles of the sarcomere where no movement occurs it just contains thick filaments
How does muscle contraction affect
the H zone, A and I bands?
1) The H zone is where actin disappears. H zones become narrower.
2) A zones are were overlap occurs of myosin overlaps with actin but does not change length
3) I bands become shorter when the fiber contracts
on an xray picture of this what distinguishes actin and myosin?
1) white lines show actin
2) dark lines show myosin
During crossbridge or overlap what can the color’s indicate?
When crossover occurs the black spaces decrease as the muscle contracts. less crossover more white which reveals muscles is relaxed or very little force
Actin-myosin crossbridge process. Define the process
1.Action potential travels down t-tubule stimulating the SERCA pump which then vomits calcium into cytosol of cell
2. The calcium binds to troponin which has a direct effect transformational change in the tropomyosin complex which Results in an open space or site on the actin filament
3. The myosin head can now attach to open site or binds to it.
4. The powerstroke requires ATP and ATPase to contious this process. Shortening of sarcomere occurs
5.ADP and Phosphate Release: After the power stroke, ADP and inorganic phosphate (Pi) are released from the myosin head.
6)New ATP Binding: ATP binds to the myosin head, causing the cross-bridge to detach from actin.
7.Myosin Head Reset: The energy from the hydrolysis of ATP into adenosine diphosphate (ADP) and inorganic phosphate (Pi) resets the myosin head into a high-energy position.
8.Cycle Continues: The cycle of cross-bridge formation, power stroke, and detachment continues as long as calcium ions are available, and ATP is present. This repetitive process leads to the shortening of the sarcomeres, which, in turn, results in muscle contraction.
Calcium Removal: When the nerve impulse stops, the calcium ions are actively transported back into the sarcoplasmic reticulum. As calcium levels decrease, troponin-tropomyosin complexes return to their blocking position on the actin filaments.
9.Relaxation: Without calcium ions, myosin heads can no longer bind to actin, and the muscle relaxes. The sarcomeres return to their resting length.
label diagram
label unit
what are the 3 processes within a muscle that uses energy?
1) SERCA pump release and absorption of calcium
2) active transport of ions in and out of muscle cells
3)crossbridge cycling
