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Circulatory System Chapter 18,19,20
The myocardium receives its blood supply from the coronary arteries.
Cardiac muscle has more mitochondria and depends less on a continual supply of oxygen than does skeletal muscle.
Anastomoses among coronary arterial branches provide collateral routes for blood delivery to the heart muscle.
If we were able to artificially alter the membrane permeability of pacemaker cells so that sodium influx is more rapid, ________.
threshold is reached more quickly and heart rate would increase
Select the correct statement about cardiac output.
A slow heart rate increases end diastolic volume, stroke volume, and force of contraction
Select the correct statement about the structure of the heart wall.
The myocardium is the layer of the heart that actually contracts.
Compared to skeletal muscle, cardiac muscle ________.
has gap junctions that allow it to act as a functional syncytium
Which of the following chemicals does not help regulate blood pressure?
Which statement best describes arteries?
All carry blood away from the heart.
Damage to the ________ is referred to as heart block.
The P wave of a normal electrocardiogram indicates ________.
To auscultate the aortic semilunar valve, you would place your stethoscope in the ________.
second intercostal space to the right of the sternum
Of the following vessel types, which are responsible for the exchange of gases and nutrients with tissues?
Of the following vessel types, which conduct blood toward the heart, regardless of oxygen content?
Of the following cardiovascular components, which contains the majority of the body's blood volume at any one time?
Systemic veins and venules
Some of the least permeable capillaries are found in the ________, while some of the most permeable capillaries are found in the _________.
brain; bone marrow
Predict the change in peripheral resistance as blood vessel diameter increases.
Peripheral resistance decreases.
Why has pulse pressure disappeared by the time blood reaches capillary beds?
the muscular arterioles do not exhibit elastic rebound
What effect does a long period of skeletal muscle inactivity have on blood flow?
It causes blood pooling and a slowing of blood flow.
What is the major factor controlling stroke volume during resting periods?
Venous return to the heart
Of the following factors affecting blood pressure, which is (are) the most easily regulated?
Vessel diameter and cardiac output