Exercise Physiology - Cardiovascular: Vasculature

• AACVV
• Ateries direct blood from heart;
• Ateries branch to form multiple Arterioles;
• Eacch arterioles gives rise to 2 - 5 Capillaries;
• Several capillaries join together to form a Venule;
• A number of venules form a single, larger Vein

This walled, large-diameter vessels that carry blood away from the heart

The largest artery which directly receives blood from the left ventricle;

Because of their proximity to the heart, blood pressure is highest in the arteries

Branches of the artery which are smaller and which demonstrate a lower blood pressure than arteries

Very small in diameter and have thin walls allowing the exchange of nutrients and gases with tissue

Begin the return of blood to the heart

Low-pressure, large diameter vessels that return blood to the heart

Satisfy the demand of active tissue for blood, both to provide nutrients and oxygen, and to remove metabolic by-products and carbon dioxide

• Located at regular intervals throughout the vasculature;
• Ensure unidirectional blood-flow through this network and allow for circulation of blood within the entire body

• Providing direction for the delivery of blood;
• Regulating flow rates that are appropriate for the needs of the tissue;
• The greater the metabolic activity, the greater the flow rate of blood to specific activities

• Process the tissue goes through to ensure increase demand for blood in the exercising muscles is met;
• Happens through relaxation of the smooth muscle layered around the walls of the arterioles

• The reduction of blood flow to other tissue, especially the viscera, so the blood needs of the working muscles can be satisfied;
• Happens through contraction of the smooth muscle layered around the walls of the arterioles

The force exerted by the blood on the walls of the vessel as it flows through the vessel

Because the heart pumps in a pulsatile, rather than in a contant fashion

• Most pronounced: Arteries, where blood exits the heart
• Least pronounced: Venules and veins, furthest away from the heart

• The resistance imposed by the vessel to it's flow as blood is pumped from the heart;
• Negatively effects SV

• Amount of blood in the ventricle immediately before contraction;
• Positively effects SV

• 1) The greater the compliance, the more easily the walls of the vessel can be stretched to accomodate the surge of blood during system, allowing for greater SV;
• 2) Healthy blood vessels show high compliance, decreasing afterload
• 3) Atherosclerosis decreases arterial compliance and increases blood pressure

• Pressure exerted on arterial walls during systolic (contraction) of left ventricle;
• Used to estimate contractile force generated by the heart

• Healthy: 120 mm Hg
• Hypertension: Above 140 mm Hg

• Pressure exerted on arterial walls during diastolic (resting) phase of cardiac cycle;
• Value reflects the health of vasculature

• Healthy: 80 mm HG
• Hypertension: Above 90 mm GH

• Difference between SBP and DBP;
• Healthy person: 120 (SBP) - 80 (DBP) = 40 mm Hg (PP)

• Average pressure exerted throughout the entire cardiac cycle, which reflects the average force of driving blood into the tissue;
• MAP = DPB (80) + 1/3 (SBP (120) - DBP (80)) = about 93 mm HG in healthy person

• Correlate of myocardial oxygen uptake and hence the workload of the left ventricle;
• RPP = SBP * HR
• At rest RPP = 120 (SBP) * 72 (HR) = 8640

• 1) Redistribute blood flow to meet increased demand of working muscles
• 2) Overall vasodilation to accomodates the rise in cardiac output, enabling exercise-induced increase in pumping capacity of the heart

• Movement of blood away from visceral organs to skeletal muscles through vasoconstriction of arterioles w/in viscera and vasodilation of arterioles w/in muscles;
• During rest, only 20% of cardiac output is directed towards muscles;
• During exercise 85% of cardiac output is directed towards muscles

• Elevates SBP;
• Increases up to 200 mm Hg during maximal rhythmic exercise (running);
• Maintains at 140 - 160 mm Hg during sub-maximal exercise;
• Exercise should stop if SBP significantly drops

• Remains steady or decreases slightly;
• Exercise should stop if DBP significantly hikes

• 1) Under resting conditions and sub-maximal exercise, trained individuals display reduced DBP, SBP and MAP
• 2) Exercise is more effective only among those who are mildy hypertensive
• 3) Max SBP is higher on well-conditioned people, and DBP and MAP are lower

• 1) Improves ability of vascular system to redistribute blood flow at start of exercise so that "shunting" of blood to working muscles occurs quicker
• 2) Improved capillarity with the muscles leading to increased mitochondrial density and enhanced capacity to extract oxygen from blood delivered to it

• Elicits higher SBP and DBP than during more conventional exercise due to smaller muscle mass involved and greater resistance to blood flow that occurs with these exercises;
• Should be considered when making exercise recommendations, especially in those with cardiovascular problems

Forceful contractions of myofibers impede blood flow through the muscles, elevating blood pressure

• During isometric (no movement) contractions (ex. planks, wall squats);
• Can raise SBP up to 450 mm Hg;
• Should be considered when making exercise recommendations, especially in those with cardiovascular problems