Muscle Cell Flashcards
Cardiac output
amount of blood pumped by each ventricle per minute
= HR *SV
Ion channels
Voltage-dependent membrane-imbedded proteins that pass a particular ion, usually selectively, in one direction (dependent on the electrical and chemical gradients) or can be activated by a ligand
Pumps
ATP- dependent and voltage-independent membrane imbedded proteins responsible for the movement of ions against a chemical gradient (and possible an electrical gradient).
Exchanges
voltage -independent & ATP-independent membrane -imbedded proteins that pass usually two different species of ions, uni- or bidirectionally (affected by chemical and electrical gradients.
The 3 states of ion channels (voltage activated)
- reprimed
- activated
- Inactivated- stops passing current, even with maintained depolarisation
Pump function
to maintain required gradients- works against a [] gradient.
Exchanges function
to maintain required gradients - works using a favourable gradient of another ion to more another ions against it’s gradient. Avoids use of ATP.
Cardiac muscle
striated appearance & similar contractile response to skm. electrically excitable
What are the special structure of cardiac muscle
- Desmosome
- Gap junction
- Intercalated discs.
Intercalated discs
Adjacent cardiac cells are interlocked
desmosomes
structures that anchor membranes together
gap junctions
Allow ions to move between cells
functional syncytium
Cardiac muscle cells are electrically coupes & function as a single coordinated unit.
Nernst Potential
Vm(mV)= (RT/F).ln ([K}out/[k]in)
Goldman-Hodgkin-Katz Equation:
Vm (mV) = (RT/F).ln
(PNa[Na+]out + PK[K+]out + PCa[Ca2+]out/
PNa[Na+]in + PK[K+]in + PCa[Ca2+]in)
