BIO 269 QUESTIONS AND ANSWERS LATEST UPDATE 100%
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What is Starling's Law?
The greater the filling of the heart, the greater the amount pumped by the heart
Where does the greatest drop in blood pressure occur?
The arterioles because blood needs to slow down before entering the capillaries
Where does most vasoconstriction and vasodilation occur?
In the arterioles
What are the names of the heart's chambers?
Atria and ventricles
Which chambers carry oxygenated blood?
Atria carry oxygenated blood
Which chambers carry deoxygenated blood?
Ventricles carry deoxygenated blood
What are the names of the valves that separate the chambers?
AV Valves (tricuspid and mitral/bicuspid) and Semilunar valves (pulmonary and aortic)
What are the layers of the heart wall from furthest to closest?
Epicardium, myocardium, endocardium
Which layer surrounding the heart is not part of the heart wall?
Pericardium
What is the Coronary Circuit Process?
Starts in the aorta, circles around the heart and dumps blood into the right atrium via the
vena cava (Coronary circuit brings nutrients and O2 to the myocardium) Aorta ->
Coronary Arteries -> Veins -> Right Atrium
What is the general definition of coronary disease?
Disease of blood vessels surrounding the heart
What are the types of coronary disease?
Angina pectoralis and myocardial infarction
What is angina pectoralis?
Disease of coronary arteries; temporary halt in blood delivery
What is myocardial infarction?
Heart attack; non-contractile scar tissue forms due to amitotic myocardium (myocardium
that doesn't undergo mitosis)
What are the steps of the conductive pathway of the heart?
Signal starts at the SA node and spreads down the interatrial and intermodal pathways.
The signal from the interatrial pathway contracts both atria at the same time. The AV
node sends the signal to the Bundle of His which passes it down to the Bundle
Branches which spread out into the Purkinje fibers causing the ventricles to contract
How does heart rate change in response to norepinephrine?
Quickens due to sped up depolarization
How does heart rate change in response to acetylcholine?
Slows due to a slowed depolarization
What do modified muscle cells do?
, Conduct action potentials through the heart
What are pacemaker potentials?
Cells that determine the pace of the heart
What ionic movements cause pacemaker potentials?
Na+ influx, Ca 2+ influx from outside cell and sarcoplasmic reticulum, K+ channel closes
to preserve leaking from cell
Why do action potentials in the ventricles look different than those of the atria?
What are the physiological events that cause them?
Action potentials look different because ventricular muscle has a longer pathway and
thus takes longer to contract because it has more blood to move.
What is the refractory period?
Period of time where the muscle won't react to a 2nd action potential.
What ions cause the refractory period in the heart?
Na+, Ca2+, K+
Why is a long refractory period in cardiac muscle important?
Makes sure cardiac muscle cannot tetanize.
What is the sequence of events for a regular ECG?
P wave (atria depolarization), QRS complex (ventricular depolarization and atrial
repolarization), T wave (ventricular repolarization)
What does an irregular ECG look like?
No P wave, multiple P waves, irregular QRS complex, abnormally tall T waves,
quivering pattern, and a slower heartbeat
What causes an irregular ECG?
Damaged SA node, heart block, fibrillation (heart attack), SA node fires early
What physiology leads to an ECG not displaying P waves?
No atrial depolarization due to a damaged SA node causing the AV node to become the
pacemaker of the heart
What physiology leads to an ECG displaying multiple P waves and irregular QRS
complexes?
Physical blockage in the conductive pathway (between SA and AV nodes); atria
contract twice making the ventricles work harder. Ventricles are blocked from the first
contraction because the P wave keeps firing like normal (called 2nd degree heart block)
What physiology leads to an ECG displaying a quivering pattern?
Atria and ventricles aren't on the same track and the action potentials have a decreased
refractory period
What are the Cardiac Cycle's steps?
Mid-to-late diastole: atria and ventricles are relaxed; ventricles passively filled 80%; AV
valves open, pulmonary and aortic valves closed; SA node discharges; EDV occurs
Ventricular systole: QRS complex occurs after AV node fires; AV valves close,
pulmonary and aortic valves open; isometric pressure build up; ESV occurs; Atrial and
aortic pressure rises; T wave signals end of systole; AV valves open and pulmonary and
aortic valves close
Early diastole: atria fill with blood, AV valves open, but pulmonary and aortic valves are
closed
What causes heart sounds?
Reverberation of blood off AV valves (first sound) and Ventricular walls (second sound)
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What is Starling's Law?
The greater the filling of the heart, the greater the amount pumped by the heart
Where does the greatest drop in blood pressure occur?
The arterioles because blood needs to slow down before entering the capillaries
Where does most vasoconstriction and vasodilation occur?
In the arterioles
What are the names of the heart's chambers?
Atria and ventricles
Which chambers carry oxygenated blood?
Atria carry oxygenated blood
Which chambers carry deoxygenated blood?
Ventricles carry deoxygenated blood
What are the names of the valves that separate the chambers?
AV Valves (tricuspid and mitral/bicuspid) and Semilunar valves (pulmonary and aortic)
What are the layers of the heart wall from furthest to closest?
Epicardium, myocardium, endocardium
Which layer surrounding the heart is not part of the heart wall?
Pericardium
What is the Coronary Circuit Process?
Starts in the aorta, circles around the heart and dumps blood into the right atrium via the
vena cava (Coronary circuit brings nutrients and O2 to the myocardium) Aorta ->
Coronary Arteries -> Veins -> Right Atrium
What is the general definition of coronary disease?
Disease of blood vessels surrounding the heart
What are the types of coronary disease?
Angina pectoralis and myocardial infarction
What is angina pectoralis?
Disease of coronary arteries; temporary halt in blood delivery
What is myocardial infarction?
Heart attack; non-contractile scar tissue forms due to amitotic myocardium (myocardium
that doesn't undergo mitosis)
What are the steps of the conductive pathway of the heart?
Signal starts at the SA node and spreads down the interatrial and intermodal pathways.
The signal from the interatrial pathway contracts both atria at the same time. The AV
node sends the signal to the Bundle of His which passes it down to the Bundle
Branches which spread out into the Purkinje fibers causing the ventricles to contract
How does heart rate change in response to norepinephrine?
Quickens due to sped up depolarization
How does heart rate change in response to acetylcholine?
Slows due to a slowed depolarization
What do modified muscle cells do?
, Conduct action potentials through the heart
What are pacemaker potentials?
Cells that determine the pace of the heart
What ionic movements cause pacemaker potentials?
Na+ influx, Ca 2+ influx from outside cell and sarcoplasmic reticulum, K+ channel closes
to preserve leaking from cell
Why do action potentials in the ventricles look different than those of the atria?
What are the physiological events that cause them?
Action potentials look different because ventricular muscle has a longer pathway and
thus takes longer to contract because it has more blood to move.
What is the refractory period?
Period of time where the muscle won't react to a 2nd action potential.
What ions cause the refractory period in the heart?
Na+, Ca2+, K+
Why is a long refractory period in cardiac muscle important?
Makes sure cardiac muscle cannot tetanize.
What is the sequence of events for a regular ECG?
P wave (atria depolarization), QRS complex (ventricular depolarization and atrial
repolarization), T wave (ventricular repolarization)
What does an irregular ECG look like?
No P wave, multiple P waves, irregular QRS complex, abnormally tall T waves,
quivering pattern, and a slower heartbeat
What causes an irregular ECG?
Damaged SA node, heart block, fibrillation (heart attack), SA node fires early
What physiology leads to an ECG not displaying P waves?
No atrial depolarization due to a damaged SA node causing the AV node to become the
pacemaker of the heart
What physiology leads to an ECG displaying multiple P waves and irregular QRS
complexes?
Physical blockage in the conductive pathway (between SA and AV nodes); atria
contract twice making the ventricles work harder. Ventricles are blocked from the first
contraction because the P wave keeps firing like normal (called 2nd degree heart block)
What physiology leads to an ECG displaying a quivering pattern?
Atria and ventricles aren't on the same track and the action potentials have a decreased
refractory period
What are the Cardiac Cycle's steps?
Mid-to-late diastole: atria and ventricles are relaxed; ventricles passively filled 80%; AV
valves open, pulmonary and aortic valves closed; SA node discharges; EDV occurs
Ventricular systole: QRS complex occurs after AV node fires; AV valves close,
pulmonary and aortic valves open; isometric pressure build up; ESV occurs; Atrial and
aortic pressure rises; T wave signals end of systole; AV valves open and pulmonary and
aortic valves close
Early diastole: atria fill with blood, AV valves open, but pulmonary and aortic valves are
closed
What causes heart sounds?
Reverberation of blood off AV valves (first sound) and Ventricular walls (second sound)
