Cardia muscles and contraction Flashcards
What are the 2 types of cardiac muscle cells?
- cells that don’t contract but control and coordinate the heartbeat in the conducting sysem
2) Contractile cells (pacemakers) Produce contractions that propel blood; found in myocardium
How do cardica muscle cells compare to skeletal muscle cells. (The 6 features(
1) Smaller and have single nucleus per fiber
2) Branch and join neighboring cells through intercalated disks
3) Gap junctions and desmosomes at intercalated discs
4) T-tubules are larger and branch
5) Sarcoplasmic reticulum is smaller
6) Mitochondria occupy one-third of cell volume
Intercalated disks have what 2 interesting features
desmosomes and gap junctions
What are desmosomes and where are they found?
areas where cells are strongly attached,
Found between epithelial cells of the skin.
Why does the heart need desmosomes
Heart needs desmosomes due
To their chemical activity. It allows the heart to produce more powerful contractions. When a region of the heart
Contracts, all parts of the heart contracts contributing to a more powerful contraction.
What is the role of gap junctions in the heart
allow for communication between the cells. Cells are able to coordinate their activity. Form channels
That join 2 cells together, allows cytosol to move from cell to cell. In the heart, gap junctions allow for contraction
The spiral arrangement of ventricular contraction allows for
ventricular contraction to squeeze the blood upward from the apex
Intercalated disks allow_____-that transfer force from cell to cell, and gap junctions that allow electrical signal to pass rapidly from cell to cell
intercalated disks
What stimulates contractile cells to contract
the conducting system
What of the conducting system distribute the stimulus to the contractile cells of the heart
Purkinje fibers
excitable cells and can conduct action potentials
cardiac muscle cells
Cardiac muscle cells action potentials trigger release of
calcium and subsequent contraction of cardiac muscle cells
How does AP in muscles cells cause contraction?
by allowing for the release of calcium from the SR.
