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What are the 5 types of vessels that make up the vascular system and how are they connected
- 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
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What is an artery?
This walled, large-diameter vessels that carry blood away from the heart
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What is the aorta?
The largest artery which directly receives blood from the left ventricle;
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What is blood pressure the highest and why?
Because of their proximity to the heart, blood pressure is highest in the arteries
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What are arterioles?
Branches of the artery which are smaller and which demonstrate a lower blood pressure than arteries
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What are capillaries?
Very small in diameter and have thin walls allowing the exchange of nutrients and gases with tissue
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What are venules?
Begin the return of blood to the heart
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What are veins?
Low-pressure, large diameter vessels that return blood to the heart
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What is the main function of the vascular system?
Satisfy the demand of active tissue for blood, both to provide nutrients and oxygen, and to remove metabolic by-products and carbon dioxide
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What are one-way valves and where are they located?
- Located at regular intervals throughout the vasculature;
- Ensure unidirectional blood-flow through this network and allow for circulation of blood within the entire body
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What does proper function of the vascular system entail?
- 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
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What is vasodilation of the arterioles? How does it happen?
- 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
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What is vasoconstriction? How does it happen?
- 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
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What is blood pressure?
The force exerted by the blood on the walls of the vessel as it flows through the vessel
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Why does blood pressure oscillate?
Because the heart pumps in a pulsatile, rather than in a contant fashion
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Where is the heart's degree of pulsatility most pronounced and least pronounced and why?
- Most pronounced: Arteries, where blood exits the heart
- Least pronounced: Venules and veins, furthest away from the heart
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What is afterload and how does it effect SV?
- The resistance imposed by the vessel to it's flow as blood is pumped from the heart;
- Negatively effects SV
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What is preload and how does it affect SV?
- Amount of blood in the ventricle immediately before contraction;
- Positively effects SV
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What are key components to the compliance of a vessel as it relates to afterload?
- 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
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What is Systolic Blood Pressure (SBP) and what is it used for?
- Pressure exerted on arterial walls during systolic (contraction) of left ventricle;
- Used to estimate contractile force generated by the heart
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What should SBP be for healthy people? What SBP indicates hypertension?
- Healthy: 120 mm Hg
- Hypertension: Above 140 mm Hg
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What is Diastolic Blood Pressure (DBP) and what is it used for?
- Pressure exerted on arterial walls during diastolic (resting) phase of cardiac cycle;
- Value reflects the health of vasculature
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What should DBP be for healthy people? What DBP indicates hypertension?
- Healthy: 80 mm HG
- Hypertension: Above 90 mm GH
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What is Pressure Pulse (PP) and what should PP be in healthy person?
- Difference between SBP and DBP;
- Healthy person: 120 (SBP) - 80 (DBP) = 40 mm Hg (PP)
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What is Mean Arterial Pressure (MAP)? What is the formula for MAP?
- 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
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What is Rate-Pressure Product (RPP) or double product? What is the formula for RPP?
- Correlate of myocardial oxygen uptake and hence the workload of the left ventricle;
- RPP = SBP * HR
- At rest RPP = 120 (SBP) * 72 (HR) = 8640
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Describe the 2 major modifications the vascular system undergoes during exercise to increase the oxygen delivery to active tissues
- 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
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What is shunting and how does it effect the distribution of blood?
- 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
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How is SBP affected by cardiac output during exercise?
- 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
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How is DBP effected by cardiac output during exercise?
- Remains steady or decreases slightly;
- Exercise should stop if DBP significantly hikes
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What benefits does prolonged exercies have on the vascular system?
- 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
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How does endurance training improve vascular system?
- 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
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What effects does rhythmic upper body endurance exercies have of SBP and DBP and why should the trainer keep this in mind?
- 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
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What effect does resistance training have on blood flow?
Forceful contractions of myofibers impede blood flow through the muscles, elevating blood pressure
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When is increased blood pressure during resistance training most pronounced? Why should the trainer keep this in mind?
- 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
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