80 Questions
During the cardiac cycle, which phase involves ventricular relaxation?
Diastole
What percentage of extracellular calcium enters the cell through slow calcium channels?
10-20%
What is the function of the sarcoplasmic reticulum in muscle cells?
Store calcium
Which part of the heart's intrinsic conduction system is responsible for initiating the heartbeat?
SA node
What event marks the beginning of ventricular contraction in the cardiac cycle?
Conduction through AV node and AV bundle
Which part of the heart's extrinsic innervation system is associated with speeding up heart rate?
Cardioaccelerator center
What is the function of the myocardium?
Contractile function
Which structure in the heart is responsible for the spontaneous depolarization?
Pacemaker cells
Where is the fibrous pericardium located?
Around the heart muscle
What is the main function of the serous pericardium?
Reduction of friction during heartbeats
Which artery supplies blood to the anterior part of the heart?
Anterior interventricular artery
What characterizes cardiac myocytes?
Presence of intercalated discs
Which factor affects stroke volume by influencing the length of muscle fibers?
Preload
What effect does increased contractility have on stroke volume?
Increases it
Which neurotransmitter, through parasympathetic control, increases K+ channels permeability and decreases Ca2+ permeability?
Acetylcholine
Which receptors are activated by catecholamines (NE & Epi) to increase Na+ and Ca2+ permeability?
β1-adrenergic receptors
Which structures form after the endocardial tubes during embryology of the heart?
Sinus venosus, atrium, ventricle, bulbus cordis
Which condition results from congestive heart failure?
Dilated cardiomyopathy
What adaptation in the fetal heart allows blood to bypass the non-functional lungs?
Ductus Arteriosus
Which heart rate condition involves an abnormally fast heart rate?
Tachycardia
During the cardiac cycle, ventricular contraction follows ventricular repolarization.
False
About 10-20% of extracellular calcium enters the cell through fast sodium channels.
False
The SA node is responsible for initiating the heartbeat in the heart's intrinsic conduction system.
True
The Cardioaccelerator center is associated with slowing down heart rate.
False
The U wave is a common wave observed in a normal EKG.
False
Ventricular ejection occurs during the systole phase of the cardiac cycle.
True
The fibrous pericardium is located within the mediastinum.
False
The myocardium is the innermost layer of the heart.
False
Angina pectoris is a condition caused by a complete blockage of a coronary artery.
False
The great cardiac vein drains into the coronary sinus.
False
Cardiac myocytes are characterized by their smooth appearance without striations.
False
Coronary circulation is responsible for delivering deoxygenated blood to the heart muscle.
False
The Frank-Starling Law of the heart states that as the preload increases, the stroke volume decreases.
False
Decreased contractility can lead to an increase in stroke volume.
False
Parasympathetic control of heart rate involves an increase in K+ channels permeability and a decrease in Ca2+ permeability.
True
Sympathetic control of heart rate involves activation of β1-adrenergic receptors, leading to decreased permeability to Na+ and Ca2+.
False
The foramen ovale is a fetal adaptation that allows blood to bypass the liver.
False
Congestive Heart Failure is characterized by the heart's inability to pump enough blood to meet the body's needs.
True
Coronary atherosclerosis is a condition characterized by low blood pressure.
False
Dilated cardiomyopathy is a disorder where the heart's main pumping chamber becomes stiff and unable to fill properly.
False
What triggers the release of calcium from the sarcoplasmic reticulum in muscle cells?
Extracellular calcium
Which part of the cardiac cycle follows ventricular repolarization?
Ventricular Contraction
What is the function of the Cardioaccelerator center in the extrinsic innervation of the heart?
Speeding up heart rate
What characterizes autorhythmic cells in the heart's intrinsic conduction system?
Unstable resting potential
Which part of the heart's intrinsic conduction system is responsible for initiating the heartbeat?
SA node
What is the role of the sarcoplasmic reticulum in muscle cells?
Stores calcium
Describe the characteristics of cardiac myocytes.
- Branched, 2. Striated, 3. Intercalated discs
What is the function of the serous pericardium?
The function of the serous pericardium is to reduce friction between the heart and surrounding structures.
Explain the physiological role of pacemaker cells in the heart.
Pacemaker cells in the heart spontaneously depolarize, establishing the heart's rhythm without neural input.
What are the two layers of the serous pericardium?
The two layers of the serous pericardium are the parietal layer and the visceral layer.
Describe the blood flow in the coronary circulation system.
The coronary circulation system includes the left and right coronary arteries, cardiac veins, and the coronary sinus.
What is the function of the fibrous pericardium?
The fibrous pericardium provides structural support and protection to the heart.
Explain the role of the Frank-Starling Law of the heart in regulating stroke volume.
The Frank-Starling Law states that as the preload (end-diastolic volume) increases, the stroke volume increases as well.
What are the two major components of the cardiac output formula and how do they interrelate?
Cardiac Output (CO) is the product of Heart Rate (HR) and Stroke Volume (SV). They work together to determine the volume of blood pumped by the heart per minute.
How does increased contractility affect stroke volume?
Increased contractility leads to an increase in stroke volume.
Describe the adaptations in the fetal heart that allow blood to bypass the non-functional lungs.
The adaptations include the Foramen Ovale and the Ductus Arteriosus.
What is the primary neurotransmitter involved in parasympathetic control of heart rate and how does it affect ion permeability?
Acetylcholine is the primary neurotransmitter. It increases K+ channels permeability and decreases Ca2+ permeability.
Explain the role of the Cardioaccelerator center in regulating heart rate.
The Cardioaccelerator center is associated with increasing heart rate rather than slowing it down.
What is the main characteristic of Dilated Cardiomyopathy?
Dilated Cardiomyopathy is characterized by the heart's main pumping chamber becoming stiff and unable to fill properly.
How does coronary atherosclerosis impact heart function?
Coronary atherosclerosis can lead to multiple myocardial infarctions and reduce cardiac output.
Sarcoplasmic reticulum stores ______
calcium
Extracellular calcium triggers the release of calcium from the ______
SR
About 1% of the cardiac fibers are ______
autorhythmic
Isovolumetric ventricular relaxation occurs during the __________ of the Cardiac Cycle
diastole
During the cardiac cycle, ventricular contraction follows ventricular ______
repolarization
The difference between End Diastolic Volume and End Systolic Volume is the _________ Volume
stroke
Factors affecting Stroke Volume include the length of muscle fibers and __________
preload
The SA node is responsible for initiating the heartbeat in the heart's intrinsic ______ system
conduction
The Cardioaccelerator center is associated with ______ up heart rate
speeding
Increased contractility leads to __________ stroke volume
increased
Parasympathetic Control of heart rate involves the release of __________
acetylcholine
Sympathetic Control of heart rate involves activation of β1- adrenergic receptors and the release of __________
catecholamines
The 4 chambers of the heart (Sinus venosus, Atrium, Ventricle, Bulbis cordis) form during __________ of heart development
embryology
Congestive Heart Failure can be caused by multiple myocardial infarctions and __________ cardiomyopathy
dilated
The left coronary artery branches into the anterior interventricular artery and the ______________ artery
circumflex
Coronary veins drain into the _____________
coronary sinus
Cardiac myocytes are characterized by being ____________ and striated
branched
Pacemaker cells in the heart are known for their ____________ depolarization
spontaneous
Dilated cardiomyopathy is a disorder where the heart's main pumping chamber becomes stiff and unable to ____________ properly
fill
Angina pectoris is a condition characterized by chest pain due to reduced blood flow to the ____________
heart
Test your knowledge on the general information, pump systems, location, structure, chambers, valves, chordae tendineae, and papillary muscles of the heart. This quiz covers topics related to the cardiovascular system discussed in Chapter 18 of cardiovascular physiology.
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