Flashcards in exam 1 review Deck (86)
where does apex point?
towards the left hip
which layer of the heart wall consumes the most energy?
what causes the plateau portion of the action potential in contractile cardiac muscle cells?
an influx of calcium ions
where does the stimulus for the heart's rhythmic contractions come from?
a pacemaker potential
which structure is responsible for setting the hearts pace?
why is the SA node the pacemaker?
it depolarizes the fastest
what would happen if the AV node became the pacemaker?
the rhythm would be slower
which heart abnormality has no P waves on an otherwise normal ECG?
what does input to the heart from the cardioinhibitory center primarily affect?
the SA node and AV node
what causes the lub sound?
closing of AV valves
what causes the dub sound?
closing of Semilunar valves
which blood vessel components is most critical in regulating systemic blood pressure?
the ability to recognize and bind to a specific antigen
what contains the majority of the body's blood volume at any one time?
systemic veins and venules
why has pulse pressure disappeared by the time blood reaches the 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 slowing of blood flow
the major factor controlling stroke volume during resting periods?
venous return to the heart
what do baroreceptors detect changes in?
stretch in arterial walls
hormone that will help lower blood pressure
atrial natriuretic peptide
why is vasodilation prominent in the skin when a person increases physical activity?
heat is dissipated across the skin from the blood to help cool the body
primary mechanism driving filtration in capillary beds?
hydrostatic pressure within the capillaries
what creates capillary colloid osmotic pressure?
nondiffusible plasma proteins
a severe allergic reaction
where does blood from the digestive organs empty into before going through the liver?
hepatic portal vein
major vessel delivering deoxygenated blood to the lungs
which vessel receives blood drainage from the liver and returns it to the heart?
inferior vena cava
what portion of the hemoglobin does oxygen bind to?
what does an elevated neutrophil count indicate?
an acute bacterial infection
antihistamine counters the actions of which white blood cells?