Microcirculation

Question 1

Polycythemia

Answer 1

Abnormal increase in RBC proportion

• Abnormally elevated
• develop HTN

Question 2

Blood viscosity depends on

Answer 2

Fibrinogen
Hematocrit
Vessel radius
Velocity
Temperature

Question 3

Fanhraeus-Lingqvist effect

Answer 3

Viscosity of blood depends on the diameter of the vessel in which its flowing

Question 4

Tube diameters less than 0.3mm

Answer 4

Arterioles/capillaries/venules

-the viscosity of blood decreases

Question 5

Axial streaming

Answer 5

tendency of RBCs to accumulate in the rapidly flowing axial lamina

Question 6

Metarterioles

Answer 6

Provide shunt that bypasses the capillary network

Question 7

Precapillary sphincters

Answer 7

Control local flow within the capillary
-Not innervated but
responsive to local conditions–O2/CO2/pH
Dilation occurs in response to hypoxia

Question 8

Continuous capillaries

Answer 8

Most common

• interendothelial junctions
• absent in brain— keeps BBB tight

Question 9

Fenestrated capillaries

Answer 9

Surround exocrine glands or epithelial membranes such as SI

Question 10

Discontinuous capillaries

Answer 10

Found in liver sinusoids

-Large gaps btwn their endothelial cells

Question 11

Two methods to alter rate a substance is carried to an organ

Answer 11

Change the flow rate through the organ
change the arterial concentration
X=Qx[C]

Question 12

FICK principle

Answer 12

Transport rate IN and OUT of the tissue

Question 13

Four factors that determine the diffusion rate of a substance btwn blood and interstitial fluid

Answer 13

Concentration difference
surface area for exchange
diffusion distance
permeability of the capillary to the diffusing substance