Heart Flashcards
Physiology section
When the action potential becomes positive
Depolarization
Period of slow repolarization called
Plateau phase
When the action potential becomes normal
Repolarization
lasts about as long as the plateau phase of the action potential in cardiac muscle
Refractory period
The conduction system of the heart includes:
SA nodes, AV nodes, AV bundles, Bundle branches and Purkinje fibers
Function as the heart’s pacemaker
Sinoatrial node
Located in the lower portion of the atrium
Atrioventricular node
Pass to the apex of the heart and extend to the heart muscles
Purkinje fibers
If the SA node unable to function, another area such as the AV node, becomes the pacemaker. The resulting heart rate is much slower than normal and the result is called
Ectopic beat
Reduces the output of the heart to only a few millimeters of BPM when it occurs in the ventricle
Fibrillation
They apply a strong electrical shock to the chest region
Defibrillation
The record of these electrical event is an
Electrocardiogram
ECG consist of 3 waves which are?
P,QRS and T wave`
Depolarization of the atrial myocardium
P wave
from depolarization of ventricles
QRS wave
Represents the repolarization of the ventricles
T wave
The atria contracts and begin to relax
PQ interval
Represents the length of time required for ventricular depolarization and repolarization
QT interval
Repetitive pumping process that begins with the onset of cardiac muscle
Cardiac cycle
Contraction of two atria
Atrial systole
Contraction of two ventricle
Ventricular systole
Relaxation of two atria
Atrial diastole
Relaxation of two ventricle
Ventricular diastole
The first heart sound can be represented by the syllable
Lubb
second heart sound can be represented by the syllable
Dubb
If heart valve does not close completely it is called as?
Incompetent valve
Results of faulty valves
murmurs
The volume of blood pumped by either ventricle of the heart each minute
Cardiac output
Volume of blood pumped per ventricle each time heart contracts
Stroke volume
Results from the heart’s normal functional characteristics and does not depend on either neural or hormonal regulation
Intrinsic regulation
Involves both neural and hormonal control
Extrinsic regulation
The degree to which the ventricular walls are stretched at the end of the diastole
Preload
Relationship between preload and stroke volume is called
Starling’s law of the heart
Refers to the pressure against which the ventricles must pump blood
Afterload
Is a mechanism of the nervous system that plays an important role in regulating heart function
Baroreceptor reflex
Stretched receptors that monitor blood pressure in the aorta in the wall of the internal carotid arteries which carry blood to the brain
Baroreceptors
Medula oblongata is _
cardioregulatory center