Pressure and Flow in Arteries and Veins

Question 1

How can you measure mean arterial pressure

Answer 1

Auscultation of Korotkoff sounds using sphygmomanometer

Question 2

What are the disadvantage and advantages of using sphygmomanometer

Answer 2

1. Not accurate, discontinuous and needs care

2. Cheap and non-invasive

Question 3

Tapping sound

Answer 3

Systolic

Question 4

Muffled sound

Answer 4

Diastolic

Question 5

Pressure flow in arteries

Answer 5

Elastic arteries act as a pressure reservoir and absorb some of the pressure

Question 6

Pressure wave is affected by (4)

Answer 6

SV
Velocity of ejection
Elasticity of arteries
TPR

Question 7

What is normal arterial pressure

Answer 7

120/80 mmHg

Question 8

What pressure increases with age

Answer 8

Arterial

Question 9

Reduction in elasticity does what to the systole and diastole pressure

Answer 9

Increases systole and decreases diastole

Question 10

What is systemic filling pressure

Answer 10

Blood from the venules and veins filling the right atrium (deoxygenated)

Question 11

Arteries and Arteriole pressure chnage

Answer 11

Small drop 95 to 90 mmHg

Question 12

Arteriole and Capillaries pressure change

Answer 12

Large drop 90 to 40 mmHg

RESISTANCE VESSELS

Question 13

Capillaries to veins

Answer 13

Small pressure change 40 to 20mmHg

Question 14

Pulmonary circulation pressure is ___ of systemic

Answer 14

1/5th

Question 15

What external influences affect flow in veins (5)

Answer 15

Gravity
Skeletal muscle pump
Respiratory pump
Venomotor tone
Systemic filling pressure

Question 16

How does gravity affect the blood flow in veins

Answer 16

Standing upright adds more pressure
Reduces EDV
Reduces preload
Reduces SV- reduces CO
Reduces MAP

Question 17

What is Orthostatic hypotension

Answer 17

When a person’s blood pressure falls when suddenly standing upright

Question 18

What can the height of jugular collapse be used to estimate

Answer 18

CVP (measurement of pressure inside the vena cava)

Question 19

What is jugular vein distention

Answer 19

Increased CVP

Question 20

How does skeletal muscle pump effect the blood flow in the vein

Answer 20

Rhythmic skeletal muscle contractions force blood in the extremities toward the heart

Question 21

What causes varicose veins

Answer 21

Valves of veins fall and allow backflow of blood

Question 22

How does the respiratory pump affect blood flow in veins

Answer 22

When you inhale this creates negative pressure as the diaphragm lowers
Blood is directed to the heart:
Increases EDV, preload and SV

Question 23

How does the venomotor tone effect the blood flow in veins

Answer 23

Increased contractile activity results in rise in tension referred ad venomotor tone

Question 24

The smooth muscle in the wall of the veins contains what receptor

Answer 24

alpha adrenergic (sympathetic)

Question 25

How does the systemic filling pressure affect the blood flow through the vein

Answer 25

Pressure created by ventricles and transmitted through vascular tree to veins

Question 26

What is the anti-clotting mechanism of the endothelium (2)

Answer 26

1. Formation of platelet plug | 2. Formation of fibrin clot

Question 27

What converts fibrinogen to fibrin

Answer 27

Thrombin

Question 28

What is the purpose of the endothelium

Answer 28

Stops blood contacting collagen

Question 29

What does the endothelium produce and what are the functions (2)

Answer 29

``` Prostacyclin and NO- inhibit platelet aggregation Tissue Factor Pathway Inhibitor thrombomodulin Heparin plasminogen activator (t-PA) ```

Question 30

What is the function of Tissue Factor Pathway Inhibitor

Answer 30

Stops thrombin production

Question 31

Function of thrombomodulin

Answer 31

Binds to thrombin and inactivates it

Question 32

Purpose of Heparin

Answer 32

Inactivates thrombin

Question 33

Purpose of plasminogen activator (t-PA)

Answer 33

Digests plasminogen to plasmin and digests clot