Cardiovascular Additional

Question 1

the sequence of intrinsic conduction system elements

Answer 1

SA node, internodal pathways, AV node, AV bundle, bundle branches, Purkinje fibers

Question 2

chordate tendineae

Answer 2

string-like bands attached to AV valves pulling downward and preventing them to be pushed into the atria when the heart is pumping blood

Question 3

two types of cells in the heart

Answer 3

autorhythmic (pacemaker) cells in SA node and contractile everywhere else

Question 4

autorhytmic cells do not have

Answer 4

steady resting membrane potential

Question 5

contractile cells do not have

Answer 5

threshold

Question 6

processes in autorhytmic cells

Answer 6

1) pacemaker period – F-type channels, both Na+ and K+ come in;
2) depolarization –T-type, fast Ca2+ channels, Ca2+ come in;
3) repolarization –K+ channels; K+ come out;

Question 7

processes in contractile cells

Answer 7

1) AP comes from autorhytmic cells
2) rapid depolarization– fast Na+ channels open, Na+ comes in
3) plateau – fast K+ channels open and K+ comes out while slow L-type Ca2+ channels open and Ca2+ comes in
4) repolarization –Ca2+ close, slow K+ open and K+ comes out