# Shared Flashcard Set

## Details

Circulation and Hemodynamics
N/A
45
Physiology
01/11/2012

Term
 What are the boundaries of the high pressure side of the vascular system?
Definition
 Contracting left ventricle to systemic capillaries
Term
 What are the boundaries of the low pressure side of the vascular system?
Definition
 Systemic capilaries to the left ventricle
Term
 How is flow (Q) calculated?
Definition
 Area * Velocity
Term
 What has the highest total cross sectional area in the vascular system?
Definition
 Capillaries
Term
 The principle stating "an increase in the velocity of horizontal fluid flow will result in a decrease in the lateral pressure" is known as what?
Definition
 Bernoulli effect
Term
 In the vascular system, kinetic energy manifests as what?
Definition
 Velocity
Term
 In the vascular system, potential energy is maintained as what?
Definition
 Pressure
Term
 Total pressure is equal to what?
Definition
 Lateral pressure + dynamic pressure
Term
 How can a reduction of lateral pressure occur?
Definition
 Increased velocity of flow converts potential energy into kinetic energy, decreasing lateral pressure
Term
 What does Ohm's law show concerning pressure??
Definition
 Change in pressure = Flow * Resistance
Term
 What are the two types of pressure that should be considered regarding hemodynamics?
Definition
 Driving pressure and hydrostatic pressure
Term
 The pressure difference between two points along the axis of a blood vessel is known as what?
Definition
 Driving pressure
Term
 What causes hydrostatic pressure?
Definition
 Gravity
Term
 What position increases hydrostatic pressure?
Definition
 Upright position
Term
 Blood flowing smoothly along the tubes with the fastest flow being in the center of the blood vessel describes what?
Definition
 Laminar flow
Term
 Irregular and random flow resulting in a loss of kinetic energy and velocity of blood flow describes what?
Definition
 Turbulent flow
Term
 Is the Reynolds number high or low in laminar and turbulent flow?
Definition
 Low in laminar, high in turbulent
Term
 How do you calculate the Reynolds number?
Definition
 Re = (density * diameter * velocity)/(viscocity)
Term
 Is cardiovascular flow mostly laminar or turbulent?
Definition
 Laminar
Term
 What common audible vibration does turbulent flow often produce?
Definition
 Murmurs
Term
 How do you calculate resistance?
Definition
 Change in pressure/Flow
Term
 What are the 3 factors that can alter resistance according to Poieulle's relation?
Definition
Term
 What are the assumptions of Poieulle's relation?
Definition
 Flow is laminar, velocity of fluid layer at wall is zero, tube is straight, rigid, w/constant radius, fluid is incompressible, viscosity of fluid is constant, flow is steady
Term
 Viscocity is defined as what?
Definition
 Ratio of shear stress to shear rate
Term
 What equation derives viscocity?
Definition
 Viscocity = (Force/Area)/(Velocity/Depth)
Term
 What effect does anemia have on viscocity?
Definition
 Decreased RBC and hematocrit reduces viscocity
Term
 What effect does polycythemia have on viscocity?
Definition
 Increased RBC and hematocrit increases viscocity
Term
 What ist he relationship between resistance and conductance?
Definition
 Conductance = 1/Resistance
Term
 How do you measure total conductance in parallel vessels?
Definition
 Equals the sum of the conductance in each parallel vessel
Term
 The total quantity of blood that can be stored in a given part of the circulation for each mmHg in pressure is known as what?
Definition
 Compliance
Term
 How is compliance measured?
Definition
 Increase in volume/increase in pressure
Term
 How do the compliance of veins compare to that of arteries
Definition
 24x greater
Term
 What effect does decreasedc ompliance have on the heart?
Definition
 Increases cardiac work
Term
 Compliance decreases with age usually as a result of what?
Definition
 Arteriosclerosis, increased vessel rigidity
Term
 Arterial blood pressure are reflective of what factors of arteries close to the heart?
Definition
 THeir elasticity and the amount of blood ofreced into them at any time
Term
 What pattern do changes in blood pressure follow in elastic arteries near the heart?
Definition
 Pulsatile (rises and falls)
Term
 How does aortic compliace allow for steady flow?
Definition
 Arterial walls are stretched during ventricular systole, storing a substantial fraction of the stroke volume. The recoil of the arterial walls allows for continuous capillary flow, even during diastole
Term
 Pulse pressure is defined as what?
Definition
 The difference between systolic and diastolic pressure
Term
 Pressure in the right atrium is called what?
Definition
 Central venous pressure
Term
 Why is pressure in the right atrium considered central venous pressure?
Definition
 All systemic veins flow into the right atrium
Term
 What regulates central venous pressure?
Definition
 Ability of right heart to pump blood to lungs and tendency for blood to flow from periphery to right atrium
Term
 What factors can increase central venous pressure?
Definition
 Increased blood volume, increased venous tone (constriction), decreased arterial tone (dilation)
Term
 Large veins have low resistance until they enter what?
Definition
 Thoracic cavity
Term