DDA Exam #3 UPDATED Exam Questions
and CORRECT Answers
Chambers through which blood flows from veins to ventricles. Atrial contraction adds to
ventricular filling but is not essential for it. - CORRECT ANSWER - atria
Chambers whose contractions produce the pressures that drive blood through the pulmonary and
systemic vascular systems and back to the heart. - CORRECT ANSWER - Ventricles
Low-resistance tubes conducting blood to the various organs with little loss in pressure. They
also act as pressure reservoirs for maintaining blood flow during ventricular relaxation. -
CORRECT ANSWER - Arteries
Major sites of resistance to flow; responsible for the pattern of blood flow distribution to the
various organs; participate in the regulation of arterial blood pressure. - CORRECT
ANSWER - Arterioles
Major sites of nutrient, metabolic end product, and fluid exchange between blood and tissues. -
CORRECT ANSWER - Capillaries
Sites of nutrient, metabolic end product, and fluid exchange between blood and tissues. -
CORRECT ANSWER - Venules
Low-resistance conduits for blood flow back to the heart. Their capacity for blood is adjusted to
facilitate this flow. - CORRECT ANSWER - Veins
Liquid portion of blood that contains dissolved nutrients, ions, wastes, gases, and other
substances. Its composition equilibrates with that of the interstitial fluid at the capillaries. -
CORRECT ANSWER - Plasma
Includes erythrocytes that function mainly in gas transport, leukocytes that function in immune
defenses, and platelets (cell fragments) for blood clotting. - CORRECT ANSWER - Cells
,What is the normal pathway of blood flow? - CORRECT ANSWER - Blood enters the
heart through two large veins, the
inferior and superior vena cava, emptying oxygen-poor
blood from the body into the right atrium of the heart.
As the atrium contracts, blood flows from your right
atrium into your right ventricle through the open
tricuspid valve.
When the ventricle is full, the tricuspid valve shuts. This
prevents blood from flowing backward into the atria
while the ventricle contracts.
As the ventricle contracts, blood leaves the heart
through the pulmonic valve blood enters into the pulmonary artery and to the lungs
where it is oxygenated.
Note: the oxygen-poor or CO2
containing blood goes through the pulmonary artery to the lungs where CO2 is exchanged for
O2.
Oxygenated blood then leaves the lungs and enters the heart from the pulmonary veins.
What is considered the "natural pacemaker of the heart"
A. AV node
B. SA node
C. Aorta
D. Purkinje fibers - CORRECT ANSWER - B. SA node
Which node is located between the atria and ventricles?
SA or AV node? - CORRECT ANSWER - AV node
,thick bunch of conducting fibers that carry the current to the Purkinje fibers - CORRECT
ANSWER - Bundle of His
specialized conducting fibers composed of electrically excitable
cells; located throughout the ventricular muscle - CORRECT ANSWER - Purkinje Fibers
Describe the cardiac conduction (electrical conduction) through the heart - CORRECT
ANSWER - • The SA node fires an electrical stimulus (or
impulse) across the walls of both left and right
atria causing them to contract
• The impulse arrives at the AV node
• The ventricles fill with blood
• The impulse is directed to follow the bundle of His
• The impulse travels through the apex of the heart
through the bundle branches.
• The Purkinje fibers distribute the impulse across
both ventricles causing ventricular contraction
The sympathetic nervous system (increases or decreases?) heart rate and force of contraction
through the secretion of what neurotransmitter? - CORRECT ANSWER - Increases;
norepinephrine
The parasympathetic nervous system (increases or decreases?) heart rate and force of contraction
through the secretion of what neurotransmitter? - CORRECT ANSWER - Decreases;
acetylcholine
Cardiac action potential is controlled at the cellular level by what ions that are transported in and
out of the cells? - CORRECT ANSWER - Na+, Ca+, K+
, Which ion influences actin and myosin? This controls cardiac cell length and muscle contraction
and is required for contraction to occur.
A. Na+
B. Ca+
C. K+
D. Cl- - CORRECT ANSWER - B. Ca+
Describe phases 0-4 of Ventricular depolarization-repolarization - CORRECT ANSWER -
Phase 0: Voltage-gated sodium
channels rapidly open, rapid
depolarization.
Phase 2: Prolonged "plateau" is
due to the slow
but prolonged opening of
voltage-gated calcium
channels PLUS closure of
potassium channels.
Ventricular depolarization-repolarization
Phase 1: K+ leaves the cell, cell
becomes less positive.
Phase 3: final rapid
repolarization, K+ exits the cell
rapidly
Phase 4: slow depolarization,
K+ enters the cell, Na+ and Ca
2+ exit the cell
ventricular depolarization (impulse spreads to
ventricles, triggering ventricular contraction)
and CORRECT Answers
Chambers through which blood flows from veins to ventricles. Atrial contraction adds to
ventricular filling but is not essential for it. - CORRECT ANSWER - atria
Chambers whose contractions produce the pressures that drive blood through the pulmonary and
systemic vascular systems and back to the heart. - CORRECT ANSWER - Ventricles
Low-resistance tubes conducting blood to the various organs with little loss in pressure. They
also act as pressure reservoirs for maintaining blood flow during ventricular relaxation. -
CORRECT ANSWER - Arteries
Major sites of resistance to flow; responsible for the pattern of blood flow distribution to the
various organs; participate in the regulation of arterial blood pressure. - CORRECT
ANSWER - Arterioles
Major sites of nutrient, metabolic end product, and fluid exchange between blood and tissues. -
CORRECT ANSWER - Capillaries
Sites of nutrient, metabolic end product, and fluid exchange between blood and tissues. -
CORRECT ANSWER - Venules
Low-resistance conduits for blood flow back to the heart. Their capacity for blood is adjusted to
facilitate this flow. - CORRECT ANSWER - Veins
Liquid portion of blood that contains dissolved nutrients, ions, wastes, gases, and other
substances. Its composition equilibrates with that of the interstitial fluid at the capillaries. -
CORRECT ANSWER - Plasma
Includes erythrocytes that function mainly in gas transport, leukocytes that function in immune
defenses, and platelets (cell fragments) for blood clotting. - CORRECT ANSWER - Cells
,What is the normal pathway of blood flow? - CORRECT ANSWER - Blood enters the
heart through two large veins, the
inferior and superior vena cava, emptying oxygen-poor
blood from the body into the right atrium of the heart.
As the atrium contracts, blood flows from your right
atrium into your right ventricle through the open
tricuspid valve.
When the ventricle is full, the tricuspid valve shuts. This
prevents blood from flowing backward into the atria
while the ventricle contracts.
As the ventricle contracts, blood leaves the heart
through the pulmonic valve blood enters into the pulmonary artery and to the lungs
where it is oxygenated.
Note: the oxygen-poor or CO2
containing blood goes through the pulmonary artery to the lungs where CO2 is exchanged for
O2.
Oxygenated blood then leaves the lungs and enters the heart from the pulmonary veins.
What is considered the "natural pacemaker of the heart"
A. AV node
B. SA node
C. Aorta
D. Purkinje fibers - CORRECT ANSWER - B. SA node
Which node is located between the atria and ventricles?
SA or AV node? - CORRECT ANSWER - AV node
,thick bunch of conducting fibers that carry the current to the Purkinje fibers - CORRECT
ANSWER - Bundle of His
specialized conducting fibers composed of electrically excitable
cells; located throughout the ventricular muscle - CORRECT ANSWER - Purkinje Fibers
Describe the cardiac conduction (electrical conduction) through the heart - CORRECT
ANSWER - • The SA node fires an electrical stimulus (or
impulse) across the walls of both left and right
atria causing them to contract
• The impulse arrives at the AV node
• The ventricles fill with blood
• The impulse is directed to follow the bundle of His
• The impulse travels through the apex of the heart
through the bundle branches.
• The Purkinje fibers distribute the impulse across
both ventricles causing ventricular contraction
The sympathetic nervous system (increases or decreases?) heart rate and force of contraction
through the secretion of what neurotransmitter? - CORRECT ANSWER - Increases;
norepinephrine
The parasympathetic nervous system (increases or decreases?) heart rate and force of contraction
through the secretion of what neurotransmitter? - CORRECT ANSWER - Decreases;
acetylcholine
Cardiac action potential is controlled at the cellular level by what ions that are transported in and
out of the cells? - CORRECT ANSWER - Na+, Ca+, K+
, Which ion influences actin and myosin? This controls cardiac cell length and muscle contraction
and is required for contraction to occur.
A. Na+
B. Ca+
C. K+
D. Cl- - CORRECT ANSWER - B. Ca+
Describe phases 0-4 of Ventricular depolarization-repolarization - CORRECT ANSWER -
Phase 0: Voltage-gated sodium
channels rapidly open, rapid
depolarization.
Phase 2: Prolonged "plateau" is
due to the slow
but prolonged opening of
voltage-gated calcium
channels PLUS closure of
potassium channels.
Ventricular depolarization-repolarization
Phase 1: K+ leaves the cell, cell
becomes less positive.
Phase 3: final rapid
repolarization, K+ exits the cell
rapidly
Phase 4: slow depolarization,
K+ enters the cell, Na+ and Ca
2+ exit the cell
ventricular depolarization (impulse spreads to
ventricles, triggering ventricular contraction)
