PSL 250 EXAM 5 QUESTIONS WITH VERIFIED ANSWERS LATEST
UPDATE 2026
What is the primary function of the pericardium? - Answers To protect the heart and
prevent overinflation.
What type of tissue primarily composes the pericardium? - Answers Dense irregular
connective tissue and epithelial tissue (makes serous fluid)
What is the role of the serous fluid produced by the pericardium? - Answers To
reduce friction between the heart and surrounding structures.
What are the three layers of the heart wall? - Answers Epicardium, myocardium, and
endocardium.
Epicardium - Answers outer layer of the heart
simple squamous epithelial
Thin layer of adipose connective tissue + blood vessels
Myocardium - Answers cardiac muscle- contract and relax
Endocardium - Answers simple squamous epithelial, connective tissue
What is the primary function of the myocardium? - Answers To contract and relax,
enabling the heart to pump blood.
What is the composition of cardiac myocytes? - Answers Short, branched cells that
can connect to one or more other cardiac myocytes.
Nodal cells - Answers ~ 1% of cells
Autorhythmic ; generate their own electrical activity- action potentials
Little to no contractile activity
cardiac myocytes - Answers ~99% of cells
Short and branched
Can contact one or more other cardiac myocytes
Connected end to end
Intercalated discs
Gap junction-Passage way for electrical activity
Desmosome- proteins that connect one cell to another
What is the function of gap junctions in cardiac myocytes? - Answers To provide a
passageway for electrical activity between cells.
What role do desmosomes play in cardiac tissue? - Answers They connect one
cardiac myocyte to another, providing structural integrity.
, Parasympathetic control of the heart - Answers decreases heart rate and contractility
(ACh)
Sympathetic - Answers increases heart rate and contractility (Norepi/Epi)
electrical conduction system of the heart - Answers Starts in SA node (autorhythmic)
action potentials 60-100 per/min
AV note 40-60 /min
AV bundle aka bundle of his 20-40
Purkinje fibers 20-40
Send A Big Pulse
ectopic beat - Answers Heart rhythm is set by something other than the sinoatrial
node
equations for blood pressure - Answers
Equation for blood flow - Answers change in pressure/ resistance
Blood Flow - Answers
Pressure - Answers force/area
Resistance - Answers a force that opposes the flow of blood
R= nL/r^4
nL=viscosity
Factors - Answers amount of blood and diameter of blood vessel
Compliance - Answers how easily something stretches- change in volume/change in
pressure
cardiac cycle - Answers
diastole - Answers relaxation phase of the heartbeat
systole - Answers Contraction of the heart
Stroke volume - Answers average 70 mL/b (range 50-110mL/b)
b=beat
heart rate - Answers resting 60-80 b/min (max 220-age)
cardiac output - Answers Cardiac Output (L/min) = Heart rate (b/min) x Stroke
Volume (mL/b) ~5L/min at rest
Preload - Answers the stretch of the heart muscle before it contracts (EDV) how
much blood is in the ventricle at the end of diastole
afterload - Answers the pressure the heart must overcome to open the semilunar
valves
Increase afterload will reduce stroke volume
UPDATE 2026
What is the primary function of the pericardium? - Answers To protect the heart and
prevent overinflation.
What type of tissue primarily composes the pericardium? - Answers Dense irregular
connective tissue and epithelial tissue (makes serous fluid)
What is the role of the serous fluid produced by the pericardium? - Answers To
reduce friction between the heart and surrounding structures.
What are the three layers of the heart wall? - Answers Epicardium, myocardium, and
endocardium.
Epicardium - Answers outer layer of the heart
simple squamous epithelial
Thin layer of adipose connective tissue + blood vessels
Myocardium - Answers cardiac muscle- contract and relax
Endocardium - Answers simple squamous epithelial, connective tissue
What is the primary function of the myocardium? - Answers To contract and relax,
enabling the heart to pump blood.
What is the composition of cardiac myocytes? - Answers Short, branched cells that
can connect to one or more other cardiac myocytes.
Nodal cells - Answers ~ 1% of cells
Autorhythmic ; generate their own electrical activity- action potentials
Little to no contractile activity
cardiac myocytes - Answers ~99% of cells
Short and branched
Can contact one or more other cardiac myocytes
Connected end to end
Intercalated discs
Gap junction-Passage way for electrical activity
Desmosome- proteins that connect one cell to another
What is the function of gap junctions in cardiac myocytes? - Answers To provide a
passageway for electrical activity between cells.
What role do desmosomes play in cardiac tissue? - Answers They connect one
cardiac myocyte to another, providing structural integrity.
, Parasympathetic control of the heart - Answers decreases heart rate and contractility
(ACh)
Sympathetic - Answers increases heart rate and contractility (Norepi/Epi)
electrical conduction system of the heart - Answers Starts in SA node (autorhythmic)
action potentials 60-100 per/min
AV note 40-60 /min
AV bundle aka bundle of his 20-40
Purkinje fibers 20-40
Send A Big Pulse
ectopic beat - Answers Heart rhythm is set by something other than the sinoatrial
node
equations for blood pressure - Answers
Equation for blood flow - Answers change in pressure/ resistance
Blood Flow - Answers
Pressure - Answers force/area
Resistance - Answers a force that opposes the flow of blood
R= nL/r^4
nL=viscosity
Factors - Answers amount of blood and diameter of blood vessel
Compliance - Answers how easily something stretches- change in volume/change in
pressure
cardiac cycle - Answers
diastole - Answers relaxation phase of the heartbeat
systole - Answers Contraction of the heart
Stroke volume - Answers average 70 mL/b (range 50-110mL/b)
b=beat
heart rate - Answers resting 60-80 b/min (max 220-age)
cardiac output - Answers Cardiac Output (L/min) = Heart rate (b/min) x Stroke
Volume (mL/b) ~5L/min at rest
Preload - Answers the stretch of the heart muscle before it contracts (EDV) how
much blood is in the ventricle at the end of diastole
afterload - Answers the pressure the heart must overcome to open the semilunar
valves
Increase afterload will reduce stroke volume
