Electrical Activity of the Heart Flashcards
What can act as a large calcium store?
Sarcoplasmic reticulum
What does calcium bind to?
Troponin
Explain why cardiac muscle can act as a functional syncytium?
Cardiac muscle can function like one massive cell despite being composed of many different cells
State 3 ways in which cells are linked together.
- Desmosomes
- Intercalated discs
- Gap junctions
Desmosomes provide what type of connection?
Physical connection
Gap junctions provide what type of connection?
Electrical connection
_____ muscle can exhibit tetanus while there is no tetanus in _____ muscle
Skeletal
Cardiac
Compare the length of the action potential of cardiac muscle with that of skeletal muscle.
Cardiac - 250 ms (longer because more calcium is released)
Skeletal - 2 ms (shorter)
State why cardiac muscle cannot exhibit tetanic contraction.
Cardiac muscle has a long refractory period (ensures heart fully relaxes and prevents tetanic contraction)
Why do you not want tetanic muscle contraction in your heart?
It would mean your heart would beat once and there would not be another one causing ASYSTOLE (cardiac arrest).
What forms the intercalated discs?
Desmosomes and gap junctions
Calcium saturation troponin
LATER
What do cells which have unstable resting membrane potentials act as?
Pacemaker cells (these produce the electrical impulses that cause your heart to beat)
Graph of non - pacemaker vs pacemaker potential:
INSERT HERE
What is responsible for the resting membrane potential of non-pacemaker action potentials?
The permeability of potassium ions (PK+)