Unit 3 - Vascular Physiology

Question 1

what unit is blood pressure measured in?

Answer 1

mm Hg (millimeters of mercury)

Question 2

What unit is blood flow measured in?

Answer 2

ml / min

Question 3

perfusion

Answer 3

rate of blood flow per given mass of tissue

= mm/min/g

Question 4

How are blood flow & blood pressure related?

Answer 4

Flow is directly proportional to Pressure

Question 5

peripheral resistance

Answer 5

a measure of the amount of friction blood encounters as it passes through vessels

Question 6

F = change in P/Resistance
F = change in P/R

Answer 6

If R increases - F decreases

Question 7

What’s the relationship between resistance & vessel radius?

Answer 7

A 2X increase in radius decreases resistance by 16X

R = 1/r4 (to the 4th power)

Question 8

Resistance to blood flow depends on 3 factors:

Answer 8

CONSTANT FACTORS:

1. vessel length
2. blood viscosity

DYNAMIC FACTOR:
3. vessel radius

Question 9

Velocity of Flow

Answer 9

• total volume flow divided by the cross-sectional area of the vascular bed.
• expressed at distance/time (cm/min)

V = F/A
V = velocity, cm/min
F = flow rate, ml/min
A = cross-sectional area, cm2 (squared)

Question 10

How veins/arteries organized?

Answer 10

Arteries > arterioles > capillaries > venules > veins

Question 11

How is arterial blood pressure measured?

Answer 11

systolic / diastolic

normal is 120/80 mmHg

Question 12

sphygmomanometer

Answer 12

measures blood pressure

Question 13

mean arterial pressure (MAP)

Answer 13

average pressure driving blood forward into the tissues thru out the cardiac cycle

MAP = diastolic pressure + 1/3 pulse pressure

Question 14

pulse pressure is determined how?

Answer 14

systolic pressure - (minus) diastolic pressure

usually 12- 80 = 40

Question 15

What are the 2 primary determinants for blood pressure?

Answer 15

cardiac output (SV & HR)
total peripheral resistance (TPR)

Question 16

Three main factors that influence TPR (total peripheral resistance)

Answer 16

1. vessel radius
2. vessel length
3. blood viscosity

Question 17

Factors determining Blood Pressure

Answer 17

1. Intrinsic: auto regulation / local control / short-term
2. Extrinsic:
   
   • Neural control - short term
     * Hormonal control - long term

Question 18

What would cause INTRINSIC regulation to kick in?

Answer 18

Organ working hard

• decreased O2
• increased CO2 - lead to increased acid
• increased K+
• increased osmolarity
• adenosine release (from using up ATP)
• prostaglandin release (local chemical messengers)
• histamine ( causes relaxation of smooth muscle)
• NO Endothelin (if not present, smooth muscles will not relax)

Question 19

What’s formula to determine Net Filtration Pressure?

Answer 19

{hydrostatic capillary pressure + interstitial fluid osmotic pressure} - {capillary osmotic pressure + interstitial hydrostatic pressure}

Question 20

Name 2 hormones that act as vasoconstrictors.

Answer 20

1. epinephrine

2. vasopressin / antidiuretic hormone (ADH)