CHAPTER 18 quiz
Compared to skeletal muscle, cardiac muscle ________. Question 16 options: has gap junctions that allow it to act as a functional syncytium has more nuclei per cell lacks striations cells are larger than skeletal muscle cells
A
Damage to the ________ is referred to as heart block. A) AV node B) SA node C) AV valves D) AV bundle
A
Select the correct statement about the structure of the heart wall. Question 15 options: The myocardium is the layer of the heart that actually contracts. Connective tissue in the heart wall aids in the conduction of the action potential. The fibrous skeleton forms the bulk of the heart. The heart chambers are lined by the endomysium.
A
The source of blood carried to capillaries in the myocardium would be the ________. Question 7 options: coronary arteries fossa ovalis coronary sinus coronary veins
A
The tricuspid valve is closed ________. Question 14 options: when the ventricle is in systole while the ventricle is in diastole while the atrium is contracting by the movement of blood from atrium to ventricle
A
Commotio cordis is heart failure due to a ________. Question 20 options: mild electrical shock to the heart itself relatively mild blow to the chest that occurs during a vulnerable interval (2 ms) when the heart is repolarizing severe electrical shock to the body loss of blood from an artery
B
If we were able to artificially alter the membrane permeability of pacemaker cells so that sodium influx is more rapid, ________. Question 19 options: potassium channels compensate and no change in heart rate would occur threshold is reached more quickly and heart rate would increase tetanic contraction would occur due to the short absolute refractory period of cardiac muscle heart rate would decrease, but blood pressure would rise due to the excess sodium present
B
Small muscle masses attached to the chordae tendineae are the ________. Question 4 options: venae cavae papillary muscles pectinate muscles trabeculae carneae
B
The time of day most hazardous for heart attacks is ________. Question 18 options: evening morning noontime during sleep
B
Which vessel of the heart receives blood during right ventricular systole? Question 13 options: aorta pulmonary trunk pulmonary veins venae cavae
B
During the period of ventricular filling ________. Question 17 options: the atria remain in diastole it is represented by the P wave on the ECG blood flows passively through the atria and the open AV valves into the ventricles pressure in the heart is at its peak
C
Foramen ovale ________. Question 12 options: is a connection between the pulmonary trunk and the aorta in the fetus is a condition in which the heart valves do not completely close connects the two atria in the fetal heart is a shallow depression in the interventricular septum
C
If the length of the absolute refractory period in cardiac muscle cells was the same as it is for skeletal muscle cells ________. Question 9 options: contractions would last as long as the refractory period it would be less than 1-2 ms tetanic contractions might occur, which would stop the heart's pumping action it would be much longer before cardiac cells could respond to a second stimulation
C
If the vagal nerves to the heart were cut, the result would be that ________. Question 11 options: the heart would stop, since the vagal nerves trigger the heart to contract the AV node would become the pacemaker of the heart the heart rate would increase by about 25 beats per minute parasympathetic stimulation would increase, causing a decrease in heart rate
C
The P wave of a normal electrocardiogram indicates ________. Question 3 options: ventricular repolarization ventricular depolarization atrial repolarization atrial depolarization
C
The fact that the left ventricle of the heart is thicker than the right ventricle reveals that it ________. Question 8 options: expands the thoracic cage pumps a greater volume of blood pumps blood against a greater resistance sends blood through a smaller valve
C
The term for pain associated with deficient blood delivery to the heart that may be caused by the transient spasm of coronary arteries is ________. Question 5 options: ischemia pericarditis angina pectoris myocardial infarct
C
To auscultate the aortic semilunar valve, you would place your stethoscope in the ________. Question 6 options: fifth right intercostal space second intercostal space to the left of the sternum second intercostal space to the right of the sternum fifth intercostal space inferior to the left nipple
C
Which of the events below does not occur when the semilunar valves are open? Question 1 options: A.Ventricles are in systole. B. Blood enters pulmonary arteries and the aorta. C. Ventricles are in diastole. D. AV valves are closed.
C
Norepinephrine acts on the heart by ________. Question 10 options: blocking the action of calcium decreasing heart contractility causing a decrease in stroke volume causing threshold to be reached more quickly
D
