52 Questions
What is the focus of the first topic in this course?
Cardiovascular physiology
What does the electrical axis of the heart represent?
Direction of electrical activity flow in the heart
What function do endogenous pacemaker cells serve in the heart?
Maintenance of heart rhythm
What is the purpose of an ECG (electrocardiogram) in diagnosing heart conditions?
Assessing electrical activity of the heart
Which part of the cardiovascular system is responsible for producing the familiar heartbeat pattern on an ECG?
Conductile cells
How many major topics does this course cover?
Four
What is the function of the right ventricle?
Pumping blood to the lungs
Which septa separates the two ventricles of the heart?
Interventricular septum
What is the function of the left ventricle?
Pumping oxygenated blood to the systemic circulation
Why does the right ventricle not need to pump with as much force compared to the left ventricle?
It faces less resistance in the pulmonary circuit
Where is the electrical activity that causes the heart muscle to depolarize and contract generated?
Sinoatrial (SA) node
What is the function of the internodal pathways in the heart's conduction system?
Carrying waves of depolarisation throughout the atria
What prevents electrical activity in the heart from simply going anywhere and ensures that it must go through a specific point?
Atrioventricular (AV) node
What is the role of Purkinje fibers in the heart's conduction system?
Originating at the bottom of the heart and conducting electrical activity upward into the contractile muscle
How are cells within the heart electrically coupled?
By protein fibers called desmosomes and gap junctions
What is the purpose of gap junctions in cardiac muscle cells?
Allowing direct transfer of electrical current between cells without neurotransmitter involvement
Why is stretching and enlargement of cardiac muscle cells undesirable?
It can ultimately lead to heart failure due to impaired contraction
What is the equation for cardiac output?
CO = HR x SV
What is the main function of cardiovascular regulatory systems?
To prevent blood pressure from falling too low
Which factor primarily affects blood pressure within the circulatory system?
Peripheral resistance
What is the primary function of the atrioventricular valve?
To prevent blood backflow
What is the role of spirometry in respiratory physiology?
Measure lung capacity
What is the main topic of the next lecture after discussing respiratory physiology?
Regulation of cardiac output
What does alveolar ventilation look at in respiratory physiology?
Gas exchange site
What are the primary components of the digestive system?
Stomach and intestines
What is the main function of the accessory organs in the digestive system?
Facilitate gut function
What is the role of renal physiology in the body?
Regulate kidney function
What are the components involved in ventilation-perfusion matching?
Volume of air and volume of blood
What does blood-gas transport in respiratory physiology refer to?
Transporting oxygen and CO2 in red blood cells
What causes the large upswing in depolarization during the third phase of the cardiac action potential?
Opening of L-type calcium channels
What leads to the repolarization in the fourth phase of the cardiac action potential?
Opening of voltage-dependent potassium channels and closing of calcium channels
What is the role of calcium channels in the plateau phase (phase 2) of the cardiac action potential?
They open to allow a massive amount of calcium through
What happens in phase 3 of the cardiac action potential?
Delayed-rectifying potassium channels open and calcium channels close
What causes the large upswing in depolarization in the pacemaker potential?
Opening of voltage-gated sodium channels
What brings about repolarization in the pacemaker potential?
Opening of voltage-dependent potassium channels and closing of calcium channels
What is the role of calcium channels in the pacemaker potential?
They open to allow a massive amount of calcium through
What happens in phase 1 of the cardiac action potential?
Inward-rectifying potassium channels close and calcium channels open
How long is the cardiac action potential?
250 to 300 milliseconds
What is the resting potential for contractile muscle cells during the cardiac action potential?
-90mV
What leads to the initial depolarization during phase 0 of the cardiac action potential?
Opening of voltage-gated sodium channels
What is responsible for preventing the atria from contracting while the ventricles are contracting?
The slight increase in resistance caused by the AV node
What percentage of blood flow under resting conditions does the contraction of the atria account for?
10%
What is the endogenous pacemaker of the heart?
SA node
What term is used to describe an area functioning as a pacemaker that is not the SA node?
Ectopic pacemaker
What happens if the SA node fails as the pacemaker of the heart?
The AV node takes over as pacemaker
What do modern pacemakers sense and stimulate as needed?
Heart rate
What is never at rest in the pacemaker cells of the heart?
'Funny' channels
What drives the depolarization in the first phase of the pacemaker potential?
Increase in sodium permeability and reduction of potassium permeability
What channels begin to open just short of the threshold level in order to trigger an action potential in the second phase of the pacemaker potential?
'T-type' calcium channels
Which ions are involved in driving the rest of the depolarization in cardiac pacemaker cells?
Calcium and potassium
What is implanted in the chest with two leads going into the heart through the vena cava in a modern pacemaker?
A computerized pacemaker
What does an early implantable pacemaker stimulate the heart with?
Set rates of wall electricity
Test your knowledge of the cardiovascular system anatomy with this quiz. Explore the structure and function of the heart's chambers and how blood moves through them.
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