Chapter 20: The Heart Flashcards
Located in mediastinum. Average is 70bpm
Heart
Walls of the ______ ventricle or thicker than the _______ side
Left, right
The heart is surrounded by the ________ cavity which is lined by the pericardium.
pericardial
The _______ pericardium covers outer surface of heart.
Visceral pericardium (epicardium)
Middle layer of heart, Cardiac muscle, coronary blood vessels.
Myocardium
Lines inner layer of heart. Endothelium.
Endocardium
Valves that prevent backflow of blood. Separate the atria from the ventricles. Chordae tendinae and papillary muscles.
Atrioventricular Valves
Dense connective tissue. Prevents over stretching of valves. Electrical insulator between atria and ventricles
Fibrous Skeleton
Vessels that branch from ascending aorta. Supply heart muscle with oxygen and nutrients and remove waste products
Coronary Vessels
The right side of the heart is the ______ circuit.
Pulmonary Circuit
The left side of the heart is the ________ circuit.
Systemic Circuit
“Pacemaker cells tell all the other cells what to do. In right atrium
Sinoatrial node (SA node)
On right atrium floor. Relay the contractile stimulus to bundle of His, the bundle branches, Purkinje fibers, and ventricular myocardium
Atrioventricular node (AVnode)
The pulmonary veins carry ______ blood to the ______ atrium.
oxygenated, left
Cardiac veins empty their blood into the __________ atrium.
right atrium
The epicardium is also known as the __________ pericardium.
visceral pericardium
Which part of the conduction system initiates the depolarizing impulse, which spreads throughout the heart?
SA node
What does the ECG wave tracing ?
electrical activity in the heart
What does the QRS complex represent in the ECG wave tracing?
ventricular depolarization
Which part of the intrinsic conduction system delays the impulse briefly before it moves on to the ventricles?
AV node
ear-like extension of the atrium
auricle
The __________ valve prevents backward flow of blood into the left ventricle.
aortic
Action potentials generated by the autorhythmic cells spread to the contractile cells through what structures in the membrane?
gap junctions
One of the changes that occurs in the pacemaker potential (unstable resting membrane potential) in the SA node (an autorhythmic cell) is a decreased efflux of what ion?
potassium
When threshold is reached at the SA node (an autorhythmic cell), what channels open causing further depolarization of the membrane?
fast calcium
Heart rate is controlled by __________ vagus and __________ nerves.
right vagus and sympathetic nerves
During the plateau phase of the cardiac action potential, which ion is entering the cardiac muscle cell?
calcium
Blood is supplied to the myocardium by _______ arteries.
coronary arteries
What’s the order of cardiac excitation?
- SA node
- AV mode
- Bundle of HIS
- Bundle branches
- Purkinje Fibers
The Frank Starling law
The more the heart stretches, the harder it will contract, forcing more blood out.
The foramen ovale in the fetal heart is located in the __________
interatrial septum
Increased pressure in the ventricles would close what valve(s)?
AV valves only
Ventricular systole begins with the closing of the ______ valve.
mitral valve
With each ventricular systole, blood pressure _________
increases
Simulation of the vagus nerve will _______ cardiac output.
decrease
Intrinsic factors influence ______ output.
cardiac
Frank starling regulates _____ volume.
stroke
Stimulation of SNS will ________ stroke volume and heart rate.
increase
Stimulation of the PNS will _______ heart rate by releasing acetylcholine which opens chemically gated ___ channels and allows an efflux of ___.
decrease
K+
Rapid depolarization in cardiac muscle when at threshold, voltage gated ___ channels open and cause an influx.
Na+
The Plateau phase of action potential in cardiac muscle:
When potential reaches +30mV, voltage gated ___ channels close and inactivated until potential drops to -60mV.
Na+ are then pumped out the cell and voltage gated ___ channels are opened.
Loss of Na+ and gain of Ca+ causes potential to remain at 0.
Na+
Ca+
Repolarization period in cardiac muscle:
Slow Ca+ channels close and slow ___ open to cause efflux of ___.
K+
EDV-ESV=___
SV
Preload is the degree of ________ in ventricles during ventricular diastole.
stretching
Afterload is the amount of tension that the ventricles must produce to force open the _________ valve and eject blood.
semilunar
Afterload _______ with increased resistance to blood flow out of ventricle, which _______ stroke volume.
increases
decreases
3 layers of pericardium include visceral (epicardium), parietal, and _______.
fibrous
