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50 Cards in this Set
- Front
- Back
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Functions of Circulatory System?
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Transport and Exchange
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Transport and Exchange of...
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Gases (O2, CO2)
Nutrients (sugars, amino acids, fats) Water and Ions Waste Products Vitamins Hormones Immune System and Clotting Factors Heat |
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Closed Circulatory System Components:
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Blood
Blood Vessels Valves Pump (Heart) |
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Principle goal of circulatory system:
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Move blood rapidly between exchange sites and slowly at a exchange sites (lungs and tissues)
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Dual loop system contains:
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4- chambered heart and separate pulmonary and systemic circuits
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Components of blood:
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Plasma
Blood Cells Hematocrit |
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Plasma composed of:
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Water
Dissolved substances Albumin (55%) |
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Blood Cells composed of:
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Erythrocytes (red blood cells) – gas transport (45%)
Leucocytes (white blood cells) – immune functions Platelets – clotting |
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Hematocrit defined as:
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percentage of blood that is cells (45%)
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Erythrocytes (red blood cells):
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No Cell Nucleus – not capable of cell division
Contain the large protein hemoglobin |
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Erythrocytes and no Cell Nucleus means:
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Formed in bone marrow
Stored in bone marrow and in spleen Broken down in spleen and liver (1% per day) |
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Erythrocytes contain the large protein hemoglobin, meaning:
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Contains iron (Fe) and binds O2
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About iron:
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Iron is obtained in the diet
-Iron poor diet results in low hemoglobin, poor oxygen delivery Iron is stored in liver -Bound to protein called ferritin transported in blood bound to another protein transferrin |
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ferritin and transferrin
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Iron is stored in liver
-Bound to protein called ferritin transported in blood bound to another protein transferrin |
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Hemoglobin breakdown:
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Bilirubin and iron
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Regulation of RBC synthesis:
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By kidney hormone erythropoietin
-Kidney cells detect drop in blood O2 levels -More erythropoietin is produced -Erythropoietin stimulates more synthesis and release of RBCs by bone marrow |
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Blood vessels include:
And all composed of: |
Arteries
Arterioles Capillaries Veins and Venules All are lined with endothelial cells -Smooth lining -Permeable barrier for exchange |
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Total blood volume:
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12%- Pulmonary circulation
9%- Heart 11%- Arteries 7%- Arterioles and capillaries 61%- Veins and venules |
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Flow rate (F) of blood is...
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1) directly proportional to Pressure Difference (ΔP)
2) inversely proportional to Resistance (R) (a) friction between blood and blood vessel wall (b) friction within the blood (viscosity) |
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Resistance arises with:
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(a) friction between blood and blood vessel wall
(b) friction within the blood (viscosity) |
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Resistance increases with:
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(1) increased blood viscosity
(2) increased length of blood vessel (3) decreased diameter of the blood vessel |
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Formulas:
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F = ΔP/R
R = (ηL/r4)(8/π) η=viscosity, L=length, r=radius |
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Blood flow is regulated by...
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Changing the radius (diameter) of blood vessels
-Affects distribution of blood to different organs -Affects blood pressure |
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Heart applies pressure to blood during...
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contraction (systole)
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Pressure drops when heart...
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relaxes (diastole)
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Pressure drops throughout circulatory system due to...
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resistance
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Arteries lead blood...
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away from heart
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Arteries carry ___ in systemic circuit
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Oxygenated blood
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Arteries carry ____ in pulmonary circuit
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deoxygenated blood
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Arteries deliver blood...
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rapidly under high pressure
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Arterial walls are...
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Thick and elastic
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Arterial compliance (elasticity) acts as...
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pressure reservoir to ensure blood continues flowing during diastole
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Arterioles (small arteries) contain ___ in their walls which allows them to...
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smooth muscle, greatly change their diameter
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Two functions of arterioles:
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1) distribution of blood to different organs
2) regulation of blood pressure |
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Arteriole smooth muscle is primarily regulated by...
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Vasomotor Fibers from sympathetic nervous system
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Intrinsic Tone:
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At rest, spontaneous medium frequency of action potentials in vasomotor fibers maintains some constriction (medium diameter)
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Intrinsic Tone:
Muscles can ___ when AP's decrease. |
relax further (large diameter)
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Muscles can relax further (large diameter) when AP’s decrease:
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increases blood flow and decreases blood pressure
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Intrinsic Tone:
Muscles can ____ when AP’s increase |
contract further, (small diameter)
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Muscles can contract further, (small diameter) when AP’s increase:
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decreases blood flow and increases blood pressure
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Blood Distribution:
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-During activity blood flow is increased to organs that need it
-Combination of local and central control of arterioles |
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Blood Distribution breakdown by organ:
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Brain- 650 ml/min, 13%
Heart- 215 ml/min, 4% Skeletal muscle- 1030 ml/min, 20% Skin- 430 ml/min, 9% Kidney- 950 ml/min, 20% Abdominal Organs- 1200 ml/min, 24% Other- 525 ml/min, 10% Total- 5000 ml/min, 100% |
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Arteriolar radius effectors:
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Neural, hormonal, local controls- affect smooth muscle, alter arteriole radius
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Neural controls:
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Vasoconstrictors- sympathetic nerves
Vasodialators- neurons that release nitric oxide |
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Hormonal controls:
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Vasoconstrictors- Epinephrine, angiotensin II, vasopressin
Vasodialators- epinephrine, atrial natiuretic hormone |
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Local controls:
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Vasoconstrictors- Internal BP (myogenic response), endothelien-1
Vasodialators- Less oxygen, K+, CO2, H+, osmolarity, andenosine, eicosanoids, brandykinin, substances released during injury, nitric oxide |
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Epinephrine causes some arterioles to relax (___) and others to constrict (___).
How? |
skeletal muscle, most others
Different receptors |
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beta receptors in skeletal muscle
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Binding of epinephrine to beta receptors causes relaxation of arteriole wall
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alpha receptors in most other tissues
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Binding of epinephrine to alpha receptors causes constriction of arteriole wall
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RESULT of epinephrine on arterioles:
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blood is moved into skeletal muscles and away from other tissues
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