Exam 9: Cardiac Physiology

Random, uncoordinated excitation and contraction of the cardiac cells is known as _________.

PAF is released from the ____________________ lining of vessels.

Indicate the effects of sympathetic and parasympathetic stimulation on the heart using the following answer code: a.caused by sympathetic stimulation b.caused by parasympathetic stimulation c.not brought about by sympathetic or parasympathetic stimulation -Increases the heart rate

Indicate which ion is involved in each event being described by using the following answer code. a.K+ b.Na+ c.Ca₂₊ -Changes in cytosolic _____ concentration bring about changes in the strength of cardiac contraction.

Indicate the effects of sympathetic and parasympathetic stimulation on the heart using the following answer code: a.caused by sympathetic stimulation b.caused by parasympathetic stimulation c.not brought about by sympathetic or parasympathetic stimulation -Decreases the contractility of the atrial muscle

Use the answer code below to complete the following statements. a.stroke volume b.end-diastolic volume c.cardiac output d.heart rate e.end-systolic volume f.sympathetic activity g.stroke volume and heart rate h.end-diastolic volume and end-systolic volume i.end-diastolic volume and sympathetic activity -Heart rate can be increased by increasing _____.

Acetylcholine ____________________ the SA node's permeability to potassium ions; as a result, the length of time between successive T waves ____________________.

Describe the mechanisms involved by which the parasympathetic and sympathetic nervous systems affect cardiac output.Include ACh, NE, regulated K⁺ channels, If channels and T-type Ca²⁺ channels, vagus nerve, cardiac nerves, contractility, stroke volume, and heart rate in your answer.

When the heart is sympathetically stimulated,

An action potential impulse passes through the internodal pathways between the P wave and Q waves on an ECG.

The refractory period in skeletal muscle is ____________________ than the refractory period in cardiac muscle.

Once threshold is reached, the rising phase of the action potential in pacemaker cells is brought about by the opening of ____-type ____ channels.

Select the incorrect statement about rheumatic fever.

Indicate the effects of sympathetic and parasympathetic stimulation on the heart using the following answer code: a.caused by sympathetic stimulation b.caused by parasympathetic stimulation c.not brought about by sympathetic or parasympathetic stimulation -Decreases the rate of depolarization to threshold of the SA node

Which of the following leads to a decrease in ESV?

The membrane potential of cardiac contractile cells at rest is about ____ mV.

An increase in the parasympathetic activity ____________________ the AV-nodal delay.

Indicate which ion is involved in each event being described by using the following answer code. a.K+ b.Na+ c.Ca₂₊ -Explosive increase in membrane permeability to _____ brings about the rapidly rising phase of the action potential in contractile cardiac cells.

Parasympathetic stimulation slows the rate of depolarization of the SA node and thus decreases the heart rate.

The function of the chordae tendineae and papillary muscles is to hold the AV valves open during diastole to ensure complete ventricular filling.