Exam 3 Flashcards
Regulation of heart rate by changing the rate of depolarization of the sinoatrial node is often referred to as:
a. chronotropy
b. inotropy
c. both of the above
d. none of the above
a. chronotropy
The seal between the cells of a continuous capillary is not usually complete, leaving areas of unjoined membrane that allow fluids and small molecules to pass from the blood to the interstitial fluid. These areas are known as:
a. fenestrations
b. tight junctions
c. intercellular clefts
d. sinusoids
c. intercellular clefts
In the cardiac cycle, the ventricle fills mostly as a result of:
a. passive blood flow from the atrium
b. forces of suction from ventricular expansion
c. ventricular contraction
d. high ventricular pressure
a. passive blood flow from the atrium
Cardiac pacemaker cells have an unstable resting membrane potential as the result of an unusual _______________ current
a. magnesium
b. sodium
c. chloride
d. calcium
b. sodium
Electrical signals move through the heart in a particular order. Which order is correct?
a. SA node; internodal pathway; AV node; bundle of his; purkinje fibers
b. AV node; SA node; internodeal pathway; bundle of his; purkinje fibers
c. SA node; AV node; internodeal pathway; purkinje fibers; bundle of his
d. bundle of his; purkinje fibers; internodal pathways; AV node; SA node
a. SA node; internodeal pathway; AV node; bundle of his; purkinje fibers
Norepinephrine has the following effect on pacemaker cells:
a. increased sodium influx
b. increased potassium influx
c. increased ATPase activity
d. decreased calcium influx
a. increased sodium influx
The __________ and _________ valves of the heart have no chordae tendinae attached to them.
a. aortic semilunar; pulmonary semilunar
b. aortic semilunar; left atrioventricular
c. pulmonary semilunar; right atrioventricular
d. left atrioventricular; right atrioventricular
a. aortic semilunar; pulmonary semilunar
Small muscle masses attached to the chordae tendinae are the :
a. trabeculae carnae
b. pectinate muscles
c. papillary muscles
d. venae cavae
c. papillary muscles
Isovolumemetric contraction:
a. refers to the short period during ventricular systole when the ventricles are completely closed chambers
b. refers to the short period during ventricular astole when the pressure in the ventricles decreases drastically
c. refers to the short period during ventricular systole when the pressure in the ventricles decreases drastically
d. both a and b
e. both a and c
e. both a and c
By both ________ the EDV and _________ the ESV, the stroke volume can at times be increased to about double normal ( that is: double the normal stroke volume value):
a. decreasing; increasing
b. decreasing; decreasing
c. increasing; decreasing
d. increasing; increasing
c. increasing; decreasing
What type of capillary is normally found in the intestine?
a. continuous
b. fenestrated
c. sinusoidal
d. none of the above
a. continuous
____________ venous return, such as might result from blood loss ___________ EDV and SV.
a. high; increases
b. low; decreases
c. high; decreases
d. low; increases
b. low; decreases
Examples of the conducting pathways include:
a. atrioventricular bundle
b. internodal pathway
c. purkinje fibers
d. both b and c
e. both a and c
d. both b and c
Cardiac output is equal to heart rate times:
a. blood pressure
b. heart diameter
c. heart length
d. stroke volume
d. stroke volume
How do cardiac muscle cells communicate with one another?
a. neurotransmitters
b. gap junctions
c. synapses
d. tight junctions
b. gap junctions
Conducting pathways:
a. contract
b. do not contract
c. undergo rhythmic depolarizations
d. both a and c
e. both b and c
e. both b and c
The P wave of a normal EKG indicates:
a. ventricular repolarization
b. atrial repolarization
c. ventricular depolarization
d. atrial depolarization
d. atrial depolarization
The rising phase ( = depolarization) of a contractile cardiac muscle cell action potential is caused by a __________ influx
a. potassium
b. sodium
c. chloride
d. calcium
b. sodium
Which tunic of a blood vessel contains an endothelium?
a. tunica intima
b. tunica media
c. tunica externa
d. all of the above
a. tunica intima
__________ capillaries are the most porous of all capillaries.
a. continuous
b. fenestrated
c. sinusoidal
d. all of the above
c. sinusoidal
The rising phase (= depolarization) of a cardiac pacemaker action potential is caused by a ________ influx
a. potassium
b. sodium
c. chloride
d. calcium
d. calcium
The end-diastolic volume is:
a. the maximum volume of blood in the ventricle
b. the maximum volume of blood in the atrium
c. the minimum volume of blood in the ventricle
d. the minimum volume of blood in the atrium
a. the maximum volume of blood in the ventricle
Select the correct statement about the structure of the heart wall.
a. the heart chambers are lined by endomerium
b. the heart chambers are lined by endomysium
c. the heart chambers are lined by epicardium
d. the myocardium is the layer of the heart that actually contracts
d. the myocardium is the layer of the heart that actually contracts
(T or F) Epinephrine is a negative inotropic agent
a. true
b. false
b. false
(T or F) Increases in heart rate are termed bradycardia
a. true
b. false
b. false
(T or F) The dicrotic notch refers to the brief rise in pressure caused by the closure of the atrioventricular (AV) valve during ventricular systole
a. true
b. false
b. false
In the cardiac cycle, when the AV valve is open and the semilunar valve is closed, this is most likely ventricular systole
a. true
b. false
b. false
(T or F)When a cardiac muscle cell is stretched, the strength of its contraction increases
a. true
b. false
a. true
(T or F) The plateau phase in the action potential of contractile cardiac muscle cells is due to the influx of sodium ions
a. true
b. false
b. false
(T or F) Acetylcholine decreases heart rate by binding to adrenergic receptors on the pacemaker cells of the heart
a. true
b. false
b. false
(T or F) Stroke volume is defined as the volume of blood pumped out by one ventricle with each beat
a. true
b. false
b. false
(T or F) An EKG is a recording of the action potentials of the pacemaker cells only
a. true
b. false
b. false
(T or F) Cardiac output is defined as the volume of blood pumped out by one ventricle with each beat
a. true
b. false
b. false
(T or F) The mitral valve has chordae tendonae but the tricuspid valve does not
a. true
b. false
b. false
(T or F) Only muscular arteries contain smooth muscle cell layer in their wall
a. true
b. false
b. false
(T or F) Stimulation of the parasympathetic nervous system increases the strength of contraction of cardiac muscle cells
a. true
b. false
b. false
(T or F) The increased pressure as a result of the contraction of skeletal muscles forces the venous valves (in the lower limbs) farthest from the heart to open and the venous valves (in the lower limbs) closest to the heart to close, pushing blood toward the heart
a. true
b. false
b. false
(T or F) During inhalation, the thoracic pressure drops, and this respiratory pump helps draw blood into the veins of the thoracic cavity
a. true
b. false
a. true
(T or F) The elastic nature of the aorta helps to maintain stable blood pressure during ventricular systole
a. true
b. false
b. false
(T or F) Small molecules such as water and ions can move across the capillary wall via a paracellular pathway, through the pores between the cells of the capillary wall
a. true
b. false
a. true
