1.3.2 Cardiac Myocyte Flashcards
What is the thick black squiggly line in this image of a cardiac myocyte?
Intercalated disc
What are each of the arrows pointing to in this image?
Top arrows - Purkinje fibers
Bottom arrow - cardiac muscle cells
What is this an image of?
Cross section of purkinje fibers - Note the heavy connective tissue layer surrounding this bundle
What can be noted about each of these images of mitochondria?
Three cells at various times after anoxia. Control (A); medium (B) and heavy C. Note the condensation of the chromatin in B and C. Also note the mitochondrial swelling and damage, particularly in C.
What is this an image of?
High power images of Purkinje Fibers
What is this process of atheroma formation?
In this image of a dog heart what are being stained black?
Purkinje fibers
Memorize Robbins Table 12-5
Describe the process of EC coupling of an action potential
The action potential travels down the T-tubule triggering the opening of the voltage gated calcium channels. The influx of calcium triggers the release of calcium from the Ryanodine channels in the sarcoplasmic reticulum. The calcium binds to the troponin complex allowing myosin to bind to actin. The muscle contracts to produce force. The calcium is pumped out of the cell by sodium-calcium exchangers, and also is pumbed into the SR via calcium ATPase. The graph shows the relationship between the action potential (AP), increase in calcium [Ca]I and muscle force (Contraction).
Describe all the parts of this image
What are the prominent features of cardiac myocytes?
Striations, centrally placed nuclei, branched cells, and intercalated discs
What is this an image of?
A SEM image of a single isolated cardiac myocyte
What do each of the letters in this image of an intercalated disk represent?
D=Desmosome; FA=Fascia Adherens; SR=Sarcoplasmic Reticulum; G=Glycogen granules; T=T-tubules; N=Nexus (Gap junctions); M=Mitochondria.
Increased calcium release will result in what with muscles?
It will result in increased cell shortening
What do each of these images correspond to?
What it the protein Titin?
It provides the elastic tensile strength of the muscle. Connects myosin to the Z disc
Below is what Dr. Werle said:
Titan is a large structural protein that contains a number of subunit domains as illustrated in section A. These domains contain ribbons that lay on top of each other. With physical stress the protein will stretch, and as it does so the ribbons will start to move. If a single water molecule enters into the space between the ribbons, then the subunit will immediately expand. This is seen in the cartoon in section B. An atomic force microscope was utilized to pick up a single titan molecule. As the titan molecule is stretched the length will increase. If one of the subunits expands then the length of the titan molecule will increase dramatically. This is also show in the graph in C. As the titan is stretched there is a change in length (x axis; extension). When the titan is fully extended it will resist the change in length and tension will increase (Y axis). When a subunit is expanded by a water molecule then the length of titan will increase readily without much force.
The arrow pointing to the mitochondria in this image is showing an example of what?
This is showing reprofusion injury. Overall the cell looks good but that one mitochondria got messed up
What bloodflow restored to this cell in adequate time?
In this cell, the restoration of blood flow was too late, and the cell is dying. The mitochondria are breaking up, and the chromatin is condensing.
Where on this image are the intercalated discs and striations?
Just point at them
What is this an image of?
Cardiac myocytes stained with H&E
