Exam 4 lecture 23

Question 1

Arteries and veins

Answer 1

-Endothelium
-Smooth muscle (Arteries have more)
-Veins have valves
-In arteries, smooth muscle can change how much blood goes where

Question 2

Vasoconstriction

Answer 2

Blood flow goes down

Question 3

Vasodilation

Answer 3

Blood flow goes up

Question 4

Hydrostatic pressure gradients

Answer 4

Arterial: 60-80 mmHg
Capillary: 20-30 mmHg
Veins: 5-10 mmHg

-Higher at systole than diastole

Question 5

Resistance

Answer 5

-Opposition to flow
-Resistance up, flow down
-Arteries and arterioles

Sources: Length of vasculature, viscosity of fluid, Radius of vasculature (biggest role)

Question 6

Length of vasculature

Answer 6

-Longer blood vessel, higher resistance
-Small effect

Length * 2 = Resistance * 2 = Blood flow / 2

Question 7

Viscosity of fluid

Answer 7

-Thickness
-Hematocrit: % of blood volume occupied by RBC, normal 36-50%

Vol RBC / Vol total

-Hct down, resistance down, blood flow up

Question 8

components of blood

Answer 8

45% cellular components:
-Mostly RBC
- 1% WBC
-Platelets

55% plasma
-Water (Solvent)
-Ions (PH buffering)
-Plasma proteins
-Substances transported by blood

Question 9

Changes in blood vessel diameter

Answer 9

-Significantly alters peripheral resistance

R alpha 1/r^4
-Says if radius is doubled, flow goes up by 1/16

r *2 =down R * 16 = flow * 16

Question 10

Blood flow to organs

Answer 10

-Not equal
-Can be changed
-Regulated by ANS
-Determined by diameter of arteriole supporting each organ