Knowledge check 3 (Cardiovascular System pt 1)
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54 Terms
What are the effects of aerobic training on hemoglobin?
Hemoglobin levels increase.
What happens to blood volume with aerobic training?
Blood volume increases.
How does aerobic training affect the oxygen cost of breathing?
It decreases the oxygen cost of breathing.
How does aerobic training affect lactate threshold (LT)?
It increases lactate threshold.
How does aerobic training affect maximal ventilation (VE)?
It increases maximal ventilation.
What is the indirect method of measuring blood pressure?
The auscultation method using a sphygmomanometer and cuff.
What is systolic blood pressure (SBP)?
The pressure exerted against the aorta during ventricular contraction.
What is diastolic blood pressure (DBP)?
The pressure associated with blood flowing through the peripheral circulation.
What happens to systolic blood pressure during exercise?
It increases.
Why does systolic blood pressure increase during exercise?
Heart rate and the amount of blood being circulated increase.
What happens to diastolic blood pressure during exercise?
It stays the same or decreases.
Why does diastolic blood pressure stay the same or decrease during exercise?
Peripheral vasodilation decreases resistance to blood flow.
What is peripheral resistance?
The resistance blood encounters as it flows through blood vessels.
What three factors influence peripheral resistance?
Vessel cross-sectional area, vessel length, and blood viscosity.
How does vasodilation affect peripheral resistance?
It decreases resistance.
How does vasoconstriction affect peripheral resistance?
It increases resistance.
What is the relationship between cross-sectional area and blood flow velocity?
They have an inverse relationship.
Why is blood flow velocity low in capillaries?
Their large total cross-sectional area allows time for oxygen extraction.
What does MAP stand for?
Mean Arterial Pressure.
What does MAP represent?
The general average pressure in the vascular system.
Why is MAP closer to diastolic blood pressure?
The cardiac cycle spends approximately 2/3 in diastole and 1/3 in systole.
What is the formula for MAP?
MAP = DBP + 1/3(SBP - DBP).
What is microcirculation?
Blood flow through capillary beds where gas exchange occurs.
What happens during gas exchange in capillaries?
Oxygen moves into tissues and carbon dioxide enters the blood.
What is internal respiration?
Gas exchange between blood and body tissues.
What are precapillary sphincters?
Small bands of smooth muscle that regulate blood flow into capillaries.
What happens to precapillary sphincters during exercise?
They relax, allowing more capillaries to open.
What causes precapillary sphincters to relax during exercise?
Increased local blood pressure and local metabolites.
What is the purpose of increased capillary blood flow during exercise?
To increase the available area for oxygen and carbon dioxide exchange.
What initiates the electrical impulse of a heartbeat?
Spontaneous depolarization of the SA node.
What is the SA node?
The heart's natural pacemaker.
What is the pathway of electrical conduction through the heart?
SA node → AV node → Bundle of His → right and left bundle branches → Purkinje fibers.
What is the function of the AV node?
It briefly delays the electrical impulse to allow ventricular filling.
What do Purkinje fibers do?
Distribute electrical impulses throughout the ventricular myocardium.
What does an ECG or EKG record?
The electrical activity of the heart.
What does the P-wave represent?
Depolarization of the atria.
What does the QRS complex represent?
Depolarization of the ventricles.
What does the T-wave represent?
Repolarization of the ventricles.
What does the PR segment represent?
The pause at the AV junction before ventricular activation.
What does the ST segment represent?
The period when the ventricles are depolarized; changes can indicate cardiac injury or ischemia.
What is central command?
The motor cortex's control and modulation of cardiovascular activity during exercise.
What is the sympathetic nervous system's effect on heart rate?
It increases heart rate through catecholamine release.
What is a chronotropic effect?
An effect that changes heart rate; positive chronotropic effects increase it.
What is an inotropic effect?
An effect that changes heart contractility; positive inotropic effects increase contraction strength.
What neurotransmitter does the parasympathetic nervous system release?
Acetylcholine (ACh).
Which cranial nerve mediates parasympathetic control of the heart?
Cranial nerve X, the vagus nerve.
What is bradycardia?
A slowing of heart rate.
How does parasympathetic activation affect the SA node?
It decreases its rate of discharge, slowing heart rate.
What peripheral receptors provide cardiovascular input?
Chemoreceptors, mechanoreceptors, and baroreceptors.
What is venous return?
The amount of blood returned to the heart.
What four mechanisms help regulate venous return?
One-way valves, skeletal muscle pumps, respiratory pumps, and smooth muscle bands.
What is the skeletal muscle pump?
Muscle contractions help push blood through veins toward the heart.
What is the respiratory pump?
Breathing-related pressure changes help move blood toward the heart.
Why are one-way valves important for venous return?
They prevent blood from flowing backward.