Cardiac Cycle
This node delays the electrical impulse to allow the ventricles time to fill with blood.
What is the AV (atrioventricular) node?
This variable represents the amount of blood ejected from one ventricle during a single heartbeat.
What is stroke volume?
MAP can rise if either of these two factors increase.
What is cardiac output and total peripheral resistance?
These receptors detect changes in blood pressure and are located in the carotid sinus and aortic arch.
What are baroreceptors?
In this type of solution, water moves into the cell, causing it to swell.
What is a hypotonic solution?
The vagus nerve slows heart rate, while this system increases heart rate.
What is sympathetic nervous system?
If venous constriction occurs due to sympathetic stimulation, this variable increases, which then increases preload.
What is venous return?
These small blood vessels contribute most to total peripheral resistance because they contain large amounts of smooth muscle and can significantly change diameter.
What are arterioles?
This adrenergic receptor, when bound by norepinephrine, causes vasoconstriction of most systemic arterioles.
What is an α receptor?
This ion has the greatest influence on the resting membrane potential because the membrane is most permeable to it at rest.
What is potassium (K⁺)?
During ventricular contraction, these valves open once ventricular pressure exceeds arterial pressure, allowing blood to enter the pulmonary trunk and aorta.
What are semilunar valves?
This pump helps move blood back to the heart during exercise.
What is the skeletal muscle pump?
This property of blood vessels opposes blood flow and is influenced by vessel diameter, length, and blood viscosity.
What is resistance?
If blood pressure suddenly rises, this immediate response occurs through the baroreceptor reflex.
What is increase in parasympathetic activity and decrease sympathetic activity to heart?
Unlike skeletal muscle, cardiac muscle cells are electrically connected by these structures, allowing depolarization to spread rapidly from cell to cell
What are gap junctions?
This electrical event corresponds with ventricular contraction and masks atrial repolarization on an ECG.
What is the QRS complex?
An increase in this variable makes it harder for the ventricle to eject blood and may decrease stroke volume if the heart cannot compensate.
What is afterload?
This property of large arteries allows them to stretch when the heart ejects blood and then recoil to help maintain continuous blood flow during diastole.
What is elastic recoil?
This type of vessel returns excess interstitial fluid to the bloodstream, helping maintain blood volume.
What is a lymphatic vessel?
In smooth muscle, contraction can occur even without troponin because calcium binds to this regulatory protein to activate myosin light-chain kinase.
What is calmodulin?
The rapid depolarization phase of a pacemaker action potential is caused by the influx of this ion.
What is calcium (Ca²⁺)?
If afterload increases significantly and the heart cannot compensate, this will happen to stroke volume and cardiac output.
What is stroke volume decreases and CO may decrease?
During exercise, cardiac output increases significantly but MAP only increases slightly because of this change in skeletal muscle blood vessels.
What is vasodilation of arterioles in skeletal muscle?
When a hemorrhage causes a sudden drop in blood pressure, baroreceptors trigger these cardiovascular responses to restore blood pressure.
What is increased heart rate and vasoconstriction?
During short bursts of high-intensity exercise when oxygen delivery is insufficient, skeletal muscle relies on this metabolic pathway to rapidly generate ATP, producing lactate as a byproduct.
What is glycolysis?