Term
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Definition
| the blood delivered locally to the capillaries of the specific tissue (p. 781). Dependent of the number of blood vessels in a tissue, local regulation of flow and total blood flow. Measured in ml / minute. |
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Term
| Degree of vascularization |
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Definition
| the extent of blood distribution within a tissue. How many blood vessels are present determines the potential of blood delivery. Metabolically active tissues have a high blood supply. |
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Term
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Definition
| formation of new blood vessels in tissues that require them. e.g.: this may increase in response to aerobic training. Regression (or return to previous state) can occur when blood vessel demand diminishes (e.g.: aerobic training turns to a sedentary lifestyle). |
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Term
| Local, Short-Term Regulation |
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Definition
| a response to changes in metabolic activity of tissues. The stimulus for local regulation is changing concentrations of chemicals together called vasoactive chemicals |
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Term
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Definition
dilate arterioles and precapillary sphincters causing an increase in blood flow into a capillary bed.
--receive a signal to change
--increase blood flow if needed--provides oxygen & takes away heat, provides nutrients
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Term
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Definition
constrict arterioles and precapillary sphincters causing a decrease in blood flow into a capillary bed.
--signals that they don't need anything so send blood elsewhere
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Term
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Definition
--tissue does it on its own w/o nervous system
--the ability of individual vascular beds to control local blood flow in response to changing metabolic needs. Blood flow in most tissues increases in proportion to the metabolic demand of the tissue.
--causes immediate and localized homeostatic adjustments. |
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Term
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Definition
--too little oxygen or nutrients, will increase blood flow
Ex: histamine and nitric oxide
1- decrease in oxygen levels
-2- Decreased nutrient levels
3- Increased CO2, H+, K+, lactic acid levels
-4- Vasodilation paracrines (chemical substances that have an effect on tissues close to where the substance is released)
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Term
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Definition
Response to decrease in metabolism with the following changes in chemical concentration; drives blood to where it's needed
-1- Increased oxygen levels
-2- Increased nutrient levels
-3- decrease in CO2, H+, K+, lactic acid levels
-4- Vasoconstrictor paracrines
i. Endothelins: substances released by damaged endothelial cells that line blood vessels; a local constrictor that doesn't involve nervous system
ii. Prostaglandins
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Term
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Definition
| the amount of blood transported throughout the entire cardiovascular system in a given period of time. Total blood flow = cardiac output measured in L/min. If cardiac output increases, then total blood flow increases and more blood is available to body tissues. If cardiac output decreases, then total blood decreases and less blood is available to body tissues. Factors that regulate total blood flow affect the activity of the heart, tone of blood vessels and volume of blood. |
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Term
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Definition
| A force exerted against a fluid is hydrostatic pressure. In a pressure gradient, hydrostatic pressure will push a liquid from areas of high pressure to areas of low pressure. |
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Term
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Definition
| Within the systemic circulation: the pressure difference between the beginning of the aorta to the entrance into the right atrium. Blood pressure is the force per unit area exerted on the wall of a blood vessel by its contained blood. (units are millimeters of mercury – mmHg). The blood pressure gradient is the driving force that propels blood through the vessels. |
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Term
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Definition
the peak blood pressure measured when the artery is maximally stretched during ventricular systole.
--ventricles are at the their max contraction, producing the highest pressure
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Term
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Definition
the minimum blood pressure measured when the artery is recoiled during ventricular diastole.
--minimum pressure exerted against the wall
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Term
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Definition
the difference between systolic pressure and diastolic pressure; indicates the force of contraction by the ventricle. The size of the pulse pressure is a measure of the elasticity and recoil of arteries. Healthy arteries expand and recoil easily. If the arteries were not elastic or lost recoil, then it would be harder for the heart to pump blood.
--indication of the health of an individual
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Term
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Definition
the rhythmic throbbing sensation associated with pulse pressure.
--speed of heart rate
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Term
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Definition
Although arterial pressure fluctuates, a single value is used to represent conditions within the body.
(MAP) = diastolic pressure + 1/3 (pulse pressure)
--average force exerted against walls of vessels
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Term
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Definition
sufficient for exchange of materials between blood and surrounding tissues, but low enough to prevent capillary damage.
--pressure gradient within capillaries
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Term
| Capillary blood pressure in the systemic circulation |
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Definition
| pressure within capillary beds (range of 35 Hg mm on arterial end – 16mm Hg on venous end) |
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Term
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Definition
--Pressure b/t capillary bed & back to heart
--this determines venous return
--not pulsatile |
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Term
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Definition
--the movement of blood from the capillaries back to the heart via the veins
--determined by venous pressure |
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Term
| Venous pressure gradient in systemic circulation |
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Definition
| 16mmHg in smallest veins – almost 0 mmHg at entrance of right atrium |
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Term
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Definition
| assist movement of venous blood in the limbs. As skeletal muscles contract, veins are squeezed to propel blood toward the heart, and valves prevent blood backflow. Inactivity can result in dilated veins in the limbs. |
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Term
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Definition
| assists the movement of blood within the thoracic cavity. |
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Term
| Venous pressure in systemic circulation |
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Definition
| 16 mm Hg to almost 0 mmHg at the distal end of the vena cava. |
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Term
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Definition
| the amount of friction the blood experiences as it travels through the blood vessels. The resistance of the cardiovascular system opposes movement of blood flow. |
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Term
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Definition
| the resistance in blood vessels. |
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Term
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Definition
--causes of vascular resistance
--thick fluid has a lot of stuff dissolved in it, making it thicker and more resistant to flow
The resistance of a fluid to its flow. The greater the viscosity (or thickness of the fluid), the greater the resistance. An increase in formed elements or large proteins will increase viscosity and therefore increase resistance. |
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Term
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Definition
| Increasing the length of a blood vessel increases friction; decreasing the length decreases friction. What is easier to move fluid through-- a drinking straw or a water hose if both have the same diameter? On a day-to-day basis, vessel length remains constant and this component of vascular resistance remains constant. |
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Term
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Definition
| the smaller the vessel diameter, the greater the resistance; the larger the vessel diameter, the less friction. |
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Term
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Definition
| the difference in flow rate within a conduit or tube. Fluid moves faster in the center of a tube and slows down its movement at the edge or near the wall. If the diameter of a blood vessel decreases, more blood is near the edge and movement of blood slows down. If the diameter of a blood vessel increases, less blood is near the edge of the vessel and movement of blood increases. |
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Term
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Definition
--The volume of blood moving through a given area in a given time expressed in L/min
--factors that affect this: blood pressure gradients and resistance
--has a direct relationship to the pressure gradient and an indirect relationship to resistance |
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Term
| Neural Regulation of Blood Pressure |
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Definition
| Blood pressure must be adequate to overcome resistance and provide perfusion of all tissues. But not be too high as to cause damage to the blood vessels. It is important that cardiovascular regulation occurs in an appropriate time, in an appropriate location and so as to maintain perfusion to essential organs. |
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Term
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Definition
| located in the medulla oblongata. This complex integrates information and nerve responses for the regulation of blood pressure. |
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Term
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Definition
| autonomic regulation of heart activity (and cardiac output) |
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Term
| Cardioacceleratory center |
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Definition
Sympathetic. Nerves to SA node increase heart rate and nerves to myocardium increase contractility. The result is an overall increase in cardiac output.
--excitatory--output & pressure go up |
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Term
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Definition
Parasympathetic. Nerves to SA and AV nodes decrease heart rate with the result of a decrease in cardiac output.
--inhibitory--output & pressure go down, HR decreases
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Term
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Definition
| autonomic regulation of blood vessels tone (and resistance) |
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Term
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Definition
| smooth muscle with α receptors contracts in response to sympathetic stimulation resulting vasoconstriction. Most blood vessels in the body have α receptors. |
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Term
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Definition
| smooth muscle with β receptors relaxes in response to epinephrine resulting in vasodilation. Smooth muscle in blood vessels with β receptors is located in skeletal muscle and the heart. |
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Term
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Definition
| reflexes respond to changes in blood pressure; they are specialized nerve receptors that monitor the degree of stretch in the walls of blood vessels. They consist of nerve endings within blood vessels located in the aortic sinus (expanded region within the ascending aorta – important in regulating systemic blood pressure) and the carotid sinus (expanded region near the base of the internal carotid arteries-important in monitoring blood pressure changes in the head and neck). |
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Term
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Definition
respond to stretch of the artery wall, not directly to pressure. Information from the baroreceptors is relayed to the cardiovascular center in the medulla oblongata.
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Term
| Hormonal Regulation of Blood Pressure |
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Definition
hormones provide for short and long-term regulation of cardiovascular performance. They typically regulate blood pressure by changing resistance or blood volume.
--provides profusion to essential organs beyond local control; vital organs always trump local--based on survival needs
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Term
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Definition
the rate of blood flow transported per unit time.
Velocity of blood flow is dependent on the total cross-sectional area of that part of the circulation. You do not consider just one vessel in an area, but all of them. Velocity = 1 / total cross section area.
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Term
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Definition
| --have a small cross-sectional area--resulting in a fast velocity |
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Term
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Definition
| --have a large cross-sectional aread--resulting in a slow velocity |
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Term
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Definition
| have a small cross sectional area--resulting in a fast velocity |
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Term
| Sympathetic Response during heavy exercise |
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Definition
--Blood flow to heart increases (up to 3 fold)
--skeletal muscle increases (up to 11 fold)
--to the skin (up to 5 fold)
--faster and stronger heart beat
--blood reservoirs w/i veings are moving toward arteries |
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