A blood vessel that takes blood away from the heart is called a/an
Artery
Vein
Capillary
Ventricle
The heart chamber that pumps oxygen depleted blood to the lungs is the
Right atrium
Right ventricle
Left atrium
Left ventricle
The systemic circulation
Begins with oxygen rich blood entering the aorta
Supplies blood to all tissues of the body
Ends with oxygen depleted blood entering the right atrium
All of the above
Cardiac muscle cells are electrically connected via
Desmosomes
Gap junctions
Striations
Motor units
TRUE or FALSE The series of events that create an Action Potential in a neuron are exactly the same as those that create and Action Potential in a cardiac muscle cell
TRUE or FALSE The normally functioning cardiac muscle cell always completely relaxes prior to contracting again due to calcium influx that lengthens the refractory period
TRUE or FALSE All cardiac muscle cells can spontaneously generate action potentials.
In myocardial autorhythmic cells (pacemaker cells), when threshold is reached the action potential fires because
Voltage gated sodium channels open and sodium rushes into the cell
Voltage gated calcium channels open and calcium rushes into the cell
Voltage gated potassium channels open and potassium rushes out of the cell
Increased leaky channels open and there is net sodium influx
In pacemaker cells, decreased permeability to calcium will
Increase heart rate
Decrease heart rate
Have no effect on heart rate
Increase force of muscle contraction
Parasympathetic nervous stimulation onto pacemaker cells results in
Increased heart rate
Decreased heart rate
No change in heart rate
Increased force of muscle contraction
TRUE or FALSE Once pacemaker cells have fired an action potential, this depolarisation spreads throughout the rest of the cardiac muscle cells via the gap junctions
1. In a normally functioning heart the pacemaker cells are in the
Sinoatrial (SA) node
Atrioventricular (AV) node
Autonomic nerves
Purkinje fibres
TRUE or FALSE In a normal cardiac cycle, the ventricles contract first, followed by the atria
In an ECG reading, the T wave represents
Depolarisation of the atria
Depolarisation of the ventricles
Repolarisation of the ventricles
Force of contraction
1. The relaxation phase of the cardiac cycle is called
Diastole
Systole
Depolarisation
Isovolumic ventricular contraction
During the cardiac cycle the phase when the ventricles are contracting and blood is being ejected into the arteries is called
When the atrioventricular valves are open
Blood is flowing from the ventricles into the atria
Blood is flowing from the atria into the ventricles
Blood is being ejected from ventricles into arteries
Blood is being ejected from atria into veins
In order for the semilunar valves to be shut
The pressure in the ventricles must exceed the pressure in the arteries
The pressure in the arteries must exceed the pressure in the ventricles
The atrioventricular valves must also be shut
The atrioventricular valves must also be open
When pressure in the atrium exceeds pressure in the ventricle, this will cause
The AV valve to close
The AV valve to open
The semilunar valve to open
The semilunar valve to close
The volume of blood in the ventricle at the end of diastole is known as
The end diastolic volume (EDV)
The end systolic volume (ESV)
The stroke volume (SV)
The isovolumic volume
TRUE or FALSE During each cardiac cycle, the ventricle ejects the full volume of blood that it contains so there is no blood left in the ventricle at the end of systole
Average stroke volume (SV) of a person at rest is approximately
135 mL
65 mL
70 mL
100 mL
Cardiac Output is a measure of the volume of blood pumped by one ventricle in a given period of time. It is equal to
Heart rate X end diastolic volume (EDV)
Heart rate X stroke volume (SV)
Heart rate X systolic blood pressure
Heart rate X total peripheral resistance
TRUE or FALSE Average resting heart rate is about 70 beats per minute due to tonic input from the sympathetic nervous system that keeps the heart rate lower than that which is set by the pacemaker cells
If force of ventricular contraction is increased, what happens to stroke volume
Decreases
Increases
Stays same
It lowers heart rate
According to the Frank-Starling law, stroke volume (SV) increases as end diastolic volume (EDV) increases due to
Increased sympathetic stimulation of the heart causing increased contraction of ventricles
Increased stretch on myocardial cells due to increased EDV, resulting in increased contraction force
Increased EDV causes increased heart rate and hence increased SV
Venous return decreases with increased EDV so SV must be increased to compensate
What is venous return?
The amount of blood ejected from a ventricle in one cardiac cycle
The amount of blood that is pumped into the veins from the atria in one cardiac cycle
The amount of blood that enters the heart from the veins each cardiac cycle
The amount of blood that enters the systemic circulation each cardiac cycle
Which factors influence venous return?
The skeletal muscle pump
The respiratory pump
Sympathetic innervation of veins
TRUE or FALSE When sympathetic neurons fire onto the heart, both heart rate and force of contraction are increased
