36 Questions
What is the function of the atria in the heart?
Collect blood and push it into lower chambers
Where is the base of the heart located?
Superior and medial to the apex
Which vessel attaches at the base of the heart?
Aorta
Where is the epicardium located in relation to the myocardium?
Most superficial layer
Which vessels are responsible for carrying deoxygenated blood to the lungs?
Pulmonary artery
What is the main purpose of the pericardial cavity?
Produce lubricating fluid
What is the function of Ca++ channels at 0mV in repolarization?
Close
If the endocrine control was absent, how many times per minute would the AV node fire?
40 - 60
What is the purpose of Ca++ binding to troponin during muscle contraction?
Allow the myosin and actin cross bridge
What would be the heart rate range if the Purkinje fibers were firing at 15 - 20 times per minute?
15 - 20 BPM
What would happen if the Ca++ channels remained open during repolarization?
Premature contractions would occur
During which phase of the cardiac cycle does the P wave represent the depolarization of the atria?
Atrial systole phase
What is the main function of an artificial pacemaker in the context of heart function?
To ensure effective heart contractions
Which of the following is characteristic of the T wave in the cardiac cycle?
Repolarization of ventricles
In which phase of the cardiac cycle is the blood pushed out by the ventricles known as end diastolic volume (EDV) or preload?
Ventricular systole phase
Which of the following statements correctly describes the role of myoglobin in heart cells?
Myoglobin stores oxygen in muscle cells
During which phase of the cardiac cycle do semilunar valves close and atrioventricular valves are also closed?
Ventricular diastole phase
What is the percentage range for normal ejection fraction?
50% - 70%
Which heart sound is associated with blood being pushed into a stiff or hypertrophic ventricle?
S4
What does an increased level of thyroid hormone do to heart rate and contractility?
Increases heart rate and contractility
Which neurotransmitter is released during parasympathetic stimulation of the heart?
Acetylcholine
What does caffeine and nicotine do to heart rate?
Increase
Which reflex involves pressure and stretch leading to increased parasympathetic stimulation of the heart?
Baroreceptor reflex
What can cause a decrease in heart rate?
Hypoxia
'S7' is referred to when both which sounds are present at the same time?
'S3' and 'S4'
'Cardiac reserve' is defined as the difference between which two values?
'Max CO' and 'resting CO'
What is the function of the endothelium in the heart?
Act as a barrier between the blood and heart muscle
Which type of valve separates the atria from the ventricles in the heart?
Atrioventricular valve
Where does the right ventricle receive deoxygenated blood from?
Right atrium
What is the function of the moderator band in the heart?
Muscles for cardiac conduction
What is the primary function of coronary circulation in the heart?
Provide oxygenated blood to cardiac muscle
What feature allows ions to travel between adjacent cardiac muscle cells?
Gap junctions
Which structure in the heart slows down impulses and forces contraction of the atrioventricular septum?
Atrioventricular node
What happens to Na+ channels in cardiac conductive cells during spontaneous depolarization?
They open slowly to create depolarization
What is the main characteristic of cardiac contractile cells during repolarization?
A plateau phase at +30mV
What initiates an electrical potential at a fixed rate in cardiac muscle cells?
Myocardial conducting cells
Learn about the cardiac conduction system and excitation-contraction coupling in the heart. Explore topics such as the role of calcium ions, refractory periods, SA node firing rate, and the function of different components in the conduction system.
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