MMED2931 Lecture Notes - Lecture 8: Skeletal Muscle, Brainstem, Mechanoreceptor
4 Jun 2018
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Cardiovascular system Lecture 3: Control of blood flow and blood pressure
Learning objectives:
1. Define blood flow, blood pressure, and resistance
2. Describe the relationship between blood flow, blood pressure, and resistance
3. Describe the local and central control of blood flow
4. Explain how the body monitors and regulates blood pressure
Definitions:
- Blood flow: V of blood flowing through a vessel, organ, or entire circulation in a
given period of time
- Blood pressure: F per unit area exerted on the wall of a blood vessel by blood
- Resistance: the opposition to flow
Relationship between flow, pressure, and resistance:
- When fluid is pumped through a closed system, its flow is determined by the P
gradient (P = P1 – P2) and by the resistance (R) to that flow
- Flow = P/R
-
Resistance: opposition to flow caused by friction between blood/blood vessel
walls
- Affected by radius of vessel, length of vessel, viscosity of blood
- Desried y Poiseuilles Law
o
Blood flow through the organs of the body:
- Most tissues and organs receive oxygenated blood via arteries and
return deoxygenated blood to circulation via veins
- Parallel arrangement of major vascular beds prevents flow in one
organ from significantly affecting blood flow in other organs
- Factors affecting blood flow in organs: its function, weight, & current
metabolic state
o Organs have the ability to regulate their own blood flow
o Blood flow through organs determined
mostly by Resistance within the organ
because arterial venous P normally
maintained within narrow range
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Document Summary
Cardiovascular system lecture 3: control of blood flow and blood pressure. Learning objectives: define blood flow, blood pressure, and resistance, describe the relationship between blood flow, blood pressure, and resistance, describe the local and central control of blood flow, explain how the body monitors and regulates blood pressure. V of blood flowing through a vessel, organ, or entire circulation in a given period of time. F per unit area exerted on the wall of a blood vessel by blood. When fluid is pumped through a closed system, its flow is determined by the p gradient ( p = p1 p2) and by the resistance (r) to that flow. Resistance: opposition to flow caused by friction between blood/blood vessel walls. Affected by radius of vessel, length of vessel, viscosity of blood. Blood flow through the organs of the body: Most tissues and organs receive oxygenated blood via arteries and return deoxygenated blood to circulation via veins.
