Lecture 10 Flashcards
Systemic Systolic and Diastolic Pressure
120/80 mmHg
Pulmonary Systolic and Diastolic Pressure
25/8 mmHg
Capillaries
Exchange between blood and extracellular fluid
Relationship between velocity of blood flow and vascular cross sectional area
Velocity of blood flow is inversely proportional to vascular cross sectional area
Functional Principles of the Circulatory System
Rate of blood flow to each tissue of the body is almost always precisely controlled in relation to the tissue need
The cardiac output is controlled mainly by the sum of all the local tissue flows
Arterial pressure regulation is generally independent of either local blood flow control or cardiac output control
Factors that determine blood flow
Pressure gradient and resistance
Pressure Gradient
Pressure difference between the two ends of a vessel
Resistance
Impediment to blood flow through the vessel
Relationship between flow and pressure and flow and resistance
Flow is directly proportional to pressure and inversely proportional to resistance
Laminar Flow
Flow of blood in layers; each layer maintains the same distance from the vessel wall and each layer slips easily past surrounding layers
Turbulent Flow
Flow is non layered and produces more resistance than laminar flow; creates murmurs
Blood Pressure
Force exerted by the blood against any unit area of the vessel wall; can be measured with a mercury manometer or with electronic transducers
Resistance
Impediment of blood flow in a vessel
Conductance
Measure of blood flow through a vessel for a given pressure difference; exact reciprocal of resistance
Viscosity
Measure of the fluid’s internal resistance, primarily determined by the hematocrit; greater viscosity means greater resistance
