Unit 2: Vascular Physiology

Question 1

What is Capillary Blood Pressure (HP_c)?

Answer 1

Hydrostatic pressure created on the inside of the capillary by the blood.

(Water → OUT of capillary)

Question 2

What is Plasma-Colloid Oncotic Pressure (OP_p)?

Answer 2

Presence of solids

Driving force created by large proteins that cannot pass through capillary wall

(Water → INTO capillary)

Question 3

What is Interstitial Fluid Hydrostatic Pressure (HP_IF)?

Answer 3

The pressure created against the outside of the capillary wall

(Water → INTO capillary)

Question 4

What is Interstitial-Fluid Oncotic Pressure (OP_IF)?

Answer 4

Small amount of proteins that manage to get across capillary

(Water → OUT of capillary)

Question 5

What effect does the net pressure on the atrial side of the capillary have?

Answer 5

Drives water out of capillary

Question 6

What effect does the net pressure on the venous side of the capillary have?

Answer 6

Causes water to be reabsorbed

Question 7

What system picks up excess fluid in the capillaries?

Answer 7

The Lymphatic System

Question 8

What 5 extrinsic factors can influence blood return to the heart?

Answer 8

1. Sympathetic System
2. Skeletal Muscle activity
3. Respiratory Activity
4. Venous Valves
5. Cardiac Suction

Question 9

What is the role of the sympathetic system in influencing blood return to the heart?

Answer 9

Veins are richly innervated by SNS causing vasoconstriction

Question 10

What is the role of skeletal muscle activity in influencing blood return to the heart?

Answer 10

Pumps blood back to the heart

Question 11

What is the role of venous valves in influencing blood return to the heart?

Answer 11

one-way valves allow blood to move in only one direction

Question 12

What is the role of respiratory activity in influencing blood return to the heart?

Answer 12

Pressure in the chest is less than pressure in extremities → difference provides driving force for return

Question 13

What is the role of cardiac suction in influencing blood return to the heart?

Answer 13

Rapid filling of ventricle and opening of A-V valves → suctioning/pulling effect on blood

Question 14

What does Central Venous Pressure (CVP) Measure?

Answer 14

Measured in right atrium → assesses venous pressure

Question 15

What increases Central Venous Pressure (CVP)?

Answer 15

1. serious heart failure: where blood can’t leave right atrium
2. Large blood transfusion

Question 16

What decreases Central Venous Pressure (CVP)?

Answer 16

1. Right atrial contracting with greater force than normal
2. Hemorage: decreased blood return

Question 17

What is Jugular Venous Distension (JVD)?

Answer 17

• Tests right side of heart
• Blood backs up into SVC
• Positive Test = Bilateral distension of veins above level of clavicle with head elevated to 45 degrees

Question 18

What is a Hepatojugular Reflex?

Answer 18

• Tests right side of heart
• Procedure: person supine, push on R upper quadrant for 20-30 sec watch observe jugular pulsation
  
  • Normal will rise a few secs than return to previous levels