Ch 18 quiz
hemmorhage with a large loss of blood causes...
a lowering of blood pressure due to change in cardiac output
which of the following is a chronotropic agent that decreases heart rate
acetylcholine
the ___ carry blood away from the heart
arteries
what hormone is released to decrease blood pressure
atrial natriuretic peptide (ANP)
what occurs at the area labeled D on the graph
av valve opens
which wave on the electrocardiogram ECG represents ventricular depolarization
QRS
what occurs at B on the graph
semilunar valve closes
the right and left atria depolarize and contract following the arrival of the action potential from the
sinoatrial SA node
the volume of blood ejected from each ventricle during a contraction is called the
stroke volume
cardiac output is increased by
sympathetic stimulation
Archie has a resting heart rate of 145 bpm this condition is called
tachycardia
what occurs at the circle labeled 4 on graph
isovolumetric vetricular contraction
if the SA node is not functioning an ECG will show
no p waves with a HR between 40-60 bpm
thick projections of muscle in the ventricles that anchor chordae tendineae are called
papillary muscles
what occurs at the circle labeled 5 on the graph
peak systolic pressure
what is found between the visceral pericardium and the parietal pericardium
pericardial fluid
hypertension increases ____ causing stroke volume to ____
preload;increase
which of the following vessels carry oxygenated blood
pulmonary vein
the left ventricular wall of the heart is thicker than the right in order too
pump blood with great force
calculate the cardiac output of a patient with a heart rate of 100 bpm and a stroke volume of 75 mL
750 ml/mm
determine the mean atrial pressure (MAP) given systolic pressure of 130 mm Hg and diastolic pressure of 70 mm Hg
90 mm Hg
which valve is situated between the left atrium and left ventricle
bicuspid valve (mitral)
An increase in the rate of action potentials from baroreceptors will trigger a reflex to
both decrease heart rate and decrease pressure
the long plateau phase of the cardiac muscle action potential is due to
calcium influx as those channels remaining open
normal heart sounds are caused by which of the following events
closure of the heart valves
which of the following stimuli is detected by a chemoreceptor
decreased blood oxygen concentration
the aorta receives the full force of blood exiting the heart during ventricular systole. which of the following statements best describes the adaptive anatomy of the aorta
elastic fibers are extensive in the tunica media of the aorta and dampen the pulse pressure generated by the heart
Compared to skeletal muscle, cardiac muscle ________.
has gap junctions that allow it to act as a functional syncytium
The frank-starling law states that if other factors are constant, a _______
higher stroke volume will produce a higher end diastolic volume
What ion movement changes the membrane potential in a contractile cell from negative to positive?
influx of sodium ions