Module 8 ML-1 Flashcards
Atrium
-top chambers of the heart, they are small in size and there is a left and a right
Ventricles
-bottom chambers of the heart, they are large and there is a left and a right
Myocardium
cardiac muscle cells
Are there striations in cardiac muscle?
Yes, they come from the regular arrangement of the myofilamemnts
True or false; cardiac cells are branched on the ends
True
What provides the mechanical and electrical connections between cardiac muscle cells
intercalated disks
What provides the structural support
Desmosomes and intercalated disks
The cardiac muscle is what?
A functional syncytium
Why is the resting membrane potential very negative at -89
Lots of potassium leak channels
What are the 4 steps of an AP in cardiac muscle
- current enters from neighboring cells through gap junctions
- rapid opening of voltage gated sodium channels are responisble for the rapid depolarization phase
- Plateu occurs
- slow opening of voltage gated potassium channels are responsible for the repolarization phase
What causes the plateu during the repolarization
due to slow but prolonged opening of voltage gated calcium channels; L type channels
L type channles are the same as what?
DHPRs and act as functional calcium channels
Prolonged refractory period prevents what in cardiac muslce
tetanus
Why can you not summate force in cardiac?
this allows time for the ventricles to relax and fill with blood prior to the next heartbeat
What muscle types contain myosin thick filaments and actin thin filaments
Sk, Sm, Card
