Shared Flashcard Set

Details

Physiology- Cardiophysiology
Circulatory System (T Pierce)
38
Medical
Post-Graduate
01/12/2009

Additional Medical Flashcards

 


 

Cards

Term
Functions of circulation
Definition
  • delivery of nutrients and oxygen
  • remove wastes
  • temperature regulation
  • buffer body fluid
  • immune defense
  • hormone transport
  • antioxidant defense
Term
Mechanism of circulation throughout body
Definition

diffusion

convection

Term
compare the flows and pressures of the right and left sides of heart
Definition
the blood flow through each side is the same, but the pressure generated is five times stronger on the left side of the heart
Term

Method of arrangement of organ's specific vascular bed

Definition

vascular beds arranged in parallel, and this allows for better control depending on the needs of each organ (ex: if GI needs more blood or less blood, it can adjust)

Term
system of arrangement of bv's in systemic and pulmonary circuits
Definition

bv's arranged in circuits

Term
compare the mean length of various components of circulatory system
Definition

large arteries have the highest mean length

capillaries have the smallest mean legnth

large veins go back to having high mean length

Term
compare the cross sectional areas of the various components of the circulatory system
Definition

smallest in large arteries

largest in capillaries

small again in large veins

Term
equation for velocity
Definition
velocity = flow/cross sectional area
Term
equations for cardiac output
Definition

CO= HR x SR

CO= MAP/Total peripheral resistance

Term
Compare MAP in each component of the circulatory system as well as pulsation pressures
Definition
  • largest at aorta
  • greatest decrease btw small arteries and arterioles (major pt of regulation)
  • lowest at the veins
  • pulsations of large arteries can be higher than in the aorta
Term
what causes the pulsation pressures
Definition

due to pumping action of heart

Term
Where in the circulatory system would one find the greatest volume of blood?
Definition
veins/venules
Term
Functional/structure of aorta and large arteries
Definition
  • function- pressure storers
  • structure
    • high elastin content, allowing for capacity to store pressure and elastic recoil
    • thick walls cause low compliance
Term
Structure/function of small arteries and arterioles
Definition
  • function- resistance vessels
  • structure
    • walls with circular smooth muscle
    • innervated
    • exhibit stock pilling
Term
Pressure ranges in small arteries and arterioles
Definition

small arteries- 60-90 mmHg

arterioles- 40-60 mmHg

Term
Structure and function of capillaries
Definition
  • function- exchange vessels
  • structure
    • tiny with thin walls
      • walls made of single layer of endothelial cells
    • in normal conditions, 25% are open
    • regulation via pre capillary sphincters that respond to local or circulating vasoactive factors
    • fenestrations whose size determine hydraulic conductivity
Term
Structure and function of veins
Definition
  • function- volume storarge
  • structure
    • thin walls (high compliance)
    • little elastin or smooth muscle (low pressure)
Term
equation for compliance
Definition
Compliance = change in volume/change in pressure
Term

Define stressed volume

Definition
volume at which compliance of a vein starts to abruptly decrease
Term
Role of age in compliance
Definition
compliance decreases with age, leading to an increase in blood pressure
Term
equation for flow
Definition
Q = change in pressure/resistance
Term
Where in the circulatory system do we see the largest drop in pressure why?
Definition
arterioles, because it is the most "resistant" segment
Term
Equation for Poiseuille's law. derive Resistance equation from this?
Definition

Q = (ΠΔPr^4)/8ηL

R =ηL/r^4

Term
Factors that could alter Poiseuille's law
Definition
  • vessels are stretchable
  • vessels are leaky
  • viscosity is not constant
  • flow is not laminar
Term
Describe what is ment by critical closing pressure.  Effect of constriction and dilation?
Definition

minimal pressure for blood flow to occur

constriction will increase critical pressure

dilation will decrease critical pressure

Term
Role of critical closing pressure in CV shock
Definition
  • not enough P in vascular bed
  • bv's compress via adrenergic stimulation in an attempt to increase critical pressure
Term
What can affect viscocity?
Definition

hematocrit (increase leads to increase viscocity)

radius (decrease leads to decrease viscocity)

velocity (decrase lead to increase viscocity)

Term
Major hemodynamic properties of blood
Definition

nonlinear viscocity

high protein concentration in plasma

axial streaming of large particle

ability to coagulate

Term
Explain the axial streamlining of RBC's
Definition
RBC's tend to accumulate in the center of the blood vessel, so measurements in hematocrit in various parts of body can vary
Term

Two types of blood flow

Definition

laminar

turbulent

Term
Clinical situations where you can see turbulent flow
Definition

anemia

stenosis of valve

constriction of artery

pressure cuff

Term
Characteristics of laminar flow
Definition
  • streamlined
  • outer most layer moves slowest while center moves fastest
Term
Describe turbulent flow
Definition
  • relationships between flow and pressure no longer linear
  • rate of flow exxceed critical velocity
  • caused by passing over sharp turn, rough surface
Term

Equation of reynolds ratio

Definition
R = (DσV)/η
Term
Equation for Laplace's law
Definition

T = Ptrr/μ

 

Term
Effect of aortic aneurysm on laplace's law
Definition
radius increase, leads to decrease in wall thickness, then leadin to increase in tension
Term
How does laplace's theorem explain the wall thickness of a capillary?
Definition
the capillary has a very small radius, so it needs only a thin wall to maintain pressure
Term

Explain Fahreaeus Lindquist effect

Definition
viscosity is smaller in smaller blood vessels (decrease radius)
Supporting users have an ad free experience!