Chapter 9 Flashcards
What is meant by the cardiac Muscle Works as Syncytium
The cardiac Muscles belonging to certain region ( Ie ventricles/ Atria) Contract as one and fnx as one cell
What are the Advantages of the cardiac muscle functioning as a Syncytium?
Speeds Up conduction
AP travels easily
The division of the muscle of the heart into ___ functional syncytium allows for?
Two. Atrial and ventricular Syncytium.
The atria to contract a short time ahead of ventricular contraction
What separates the each of the syncytium
Fiberous Tissue: The annulus Fibrosis
What other function does the Annulus fibrosis have?
Electrically insulates the nodes of the heart
What allows for quick almost free diffusions of Ions?
Gap Junction
What would happen if the gap junctions shrunk in size?
AP’s travel slower
What’s the arrangement of the heart muscles cells
Interlacing bundles of cardiac muscle fibers arranged spirally around the circumference of the heart.
What is the advantage of the spiral arrangement?
A twisting effect is produced, efficiently pushing blood upwards towards the exit of the major arteries of the heart
*What causes the ventricular cardiac muscle contraction to last longer than skeletal muscles cell contraction?
The presences of a plateau in the AP.
What cause a presences of a plateau in the AP?
the membrane remains depolarized for about 0.2 s, giving a plateau
What happens during each membrane potential Phase?
Ionic Phase leading to AP
phase 0- Fast Na+ channels open then slow Ca++ channels phase 1- K+ channels open phase 2- Ca++ channels open more phase 3- K+ channels open more phase 4- Resting membrane potential
Each cycle is initiated by a ______ generation of an ____ in the ___ ____
Spontaneous
AP
SA Node
Is there a delay in the conduction between the atria and the ventricles. Why or why not?
yes, so that way the atria can contract into the ventricle’s before the ventricles contract:
-> atria pump more blood into the ventricles prior to ejection
The cardiomyocytes re-establish the Na+/K+/Ca2+ gradient during which Period of the cardiac cycle?
Diastole ( Phase of relaxation)
The heart fills with blood during which p0hase of the cardiac cycle
diastole
The period where the heart contracts is?
Systole
What causes the P-wave?
spread of depolarization through the atria, this is followed by atrial contraction
the QRS waves appear as a result of
, electrical depolarization of the ventricles
Ventricular T wave represents
Repolarization of the ventricles:
-> when the ventricle muscle fibers begin to relax
The Pace Maker of the heart is? a. SA node b. AV node c. Purkyngi Fibers d. Hypothalamus e a & b f. a & d
A.
What is reponsible for the electrical activity found at the START of the P-wave
SA nodal fibers send a signal to contract
*Aortic Pressure start ___ after the ____ open during systole
Increasing;
AV valves
Aortic Pressure starts ____ after the end of the ejection phase
Decreasing
