Cardiovascular System - Vascular Function and Hemodynamics

Question 1

two closed systems of conduits

Answer 1

1. pulmonary vessels

2. systemic vessels

Question 2

main classes of blood vessels (3)

Answer 2

1. arteries
2. capillaries
3. veins

Question 3

where do arteries carry blood?

Answer 3

away from heart

Question 4

what do capillaries do?

Answer 4

connect arteries with veins

Question 5

where do veins carry blood?

Answer 5

to the heart

Question 6

classification of arteries

Answer 6

1. aorta
2. arteries
3. arterioles

Question 7

aorta

Answer 7

largest artery of systemic circulation

Question 8

arteries

Answer 8

medium and small arteries branching off aorta

Question 9

arterioles

Answer 9

smallest branches of arteries

Question 10

structure of systemic arteries (3 main layers)

Answer 10

1. tunica intima
2. tunica media
3. tunica externa

Question 11

tunica intima

Answer 11

epithelium, basement membrane, and elastic fibers

Question 12

tunica media

Answer 12

smooth muscle

Question 13

tunica externa

Answer 13

connective, elastic, and collagenous fibers

Question 14

function of aorta and its branches

Answer 14

• elastic vessels
• receive blood directly from heart (oxygenated)
• blood volume is under high pressure (stressed volume)

Question 15

function of arterioles

Answer 15

• resistance vessels (extensive development of smooth muscle)
• site of highest resistance to blood flow
• regulate blood flow and pressure
• innervated by sympathetic adrenergic nerve fibers

Question 16

structure of capillaries

Answer 16

• smallest and most numerous blood vessels

- thin-walled structures lined with a single layer of endothelial cells surrounded by a basal lamina

Question 17

function of capillaries/ perfusion

Answer 17

• nutrients, gases, water, and solute are exchanged
• not all capillaries are perfused with blood at all times
• selective perfusion of capillary beds depending on the metabolic needs of the tissues

Question 18

internal respiration (capillary bed)

Answer 18

• gas exchange between blood and tissues

Question 19

exchange vessels in capillary bed (3)

Answer 19

terminal arterioles, capillaries, and venules

Question 20

classification of veins (3)

Answer 20

1. venules
2. small and medium veins
3. vena cava (superior and inferior)

Question 21

structure of veins

Answer 21

• thin-walled

- same three layers as arteries (smooth muscle, elastic muscle, and connective tissues)

Question 22

function of veins (systemic circulation)

Answer 22

• carry blood toward the heart (deoxygenated)
• large capacitance (hold >60% of total blood volume)
• blood volume under low pressure (unstressed volume)

Question 23

vessels in pulmonary circulation

Answer 23

1. arteries
2. capillaries
3. veins

Question 24

veins in pulmonary circulation

Answer 24

• transport oxygenated blood from the lungs to the left atrium of the heart
  (2 pulmonary veins for each lung)

Question 25

capillaries in pulmonary circulation

Answer 25

- gases, water, and solute exchanged between the blood and the alveolar gas - external respiration (gas exchange between blood and air)

Question 26

arteries in pulmonary circulation

Answer 26

- carry deoxygenated blood from right ventricle to the lungs | - lower pressure and vascular resistance

Question 27

stroke volume (SV)

Answer 27

amount of blood pumped from a ventricle each time the ventricle contracts

Question 28

cardiac output (CO)

Answer 28

- volume of blood pumped by a ventricle in 1 minute | - CO = SV * heart beats per minute

Question 29

circuit through the cardiovascular system

Answer 29

1. oxygenated blood fills left ventricle 2. blood is ejected from left ventricle to aorta 3. cardiac output is distributed among various organs 4. blood flow from the organs is collected in the veins 5. venous return to the right atrium 6. mixed venous blood fills the right ventricle 7. blood is ejected from the right ventricle into the pulmonary artery 8. blood flow from the lungs is returned to the heart via the pulmonary veins

Question 30

main functions of the vascular system (4)

Answer 30

1. transforms pulsatile output of the heart to a more continuous flow (arteries) 2. distributes the CO to the tissue based on tissue needs (arterioles) 3. exchanges materials with the tissues (capillaries) 4. provides a volume reservoir (veins)

Question 31

physical principles of blood flow

Answer 31

1. steady-state flow 2. elasticity of vessels 3. velocity in vessels 4. steady-state flow in tubes

Question 32

blood flow through a blood vessel is determined by:

Answer 32

1. pressure difference between the two ends of the vessels | 2. resistance of the vessel to blood flow

Question 33

compliance (elasticity) in veins vs arteries

Answer 33

compliance of veins is much greater than compliance of arteries

Question 34

capacitance definition | / old vs young arteries

Answer 34

- ability to distend, hold a volume of blood at a given pressure - old arteries must have higher pressure than young arteries to hold same volume

Question 35

branching of systemic circulatory system | highest to lowest velocity of vessels

Answer 35

aorta --> capillaries --> vena cava

Question 36

assumptions for poiseuille's flow (6)

Answer 36

1. fluid is Newtonian 2. flow is laminar 3. no "slippage" at walls 4. tube is cylindrical with circular cross section, // walls 5. walls of tube are rigid 6. tube is long compared to the entrance length

Question 37

entrance effects in establishing poiseuille's flow

Answer 37

"plug flow" to laminar flow! | slowly reaches a parabolic velocity profile

Question 38

arterial pulse pressure

Answer 38

- ejection of blood into the arterial tree cause the arterial pressure pulse - pulse depends on stroke volume and arterial compliance

Question 39

relationship between pulse pressure and stroke volume

Answer 39

- larger SV causes larger pulse pressure | - same stroke volume at higher Pa causes larger pulse pressure

Question 40

effect of compliance on pulse pressure

Answer 40

same stroke volume at lower compliance causes a larger pulse pressure

Question 41

pressures in the systemic circulation (4)

Answer 41

1. diastolic pressure 2. systolic pressure 3. pulse pressure 4. mean pressure

Question 42

diastolic pressure in systemic circulation

Answer 42

- lowest arterial pressure measured during a cardiac cycle | - pressure in artery during ventricular relaxation when no blood is being ejected from the LV

Question 43

systolic pressure in systemic circulation

Answer 43

- highest arterial pressure measured during a cardiac cycle | - pressure in the artery after blood has been ejected from the LV during systole

Question 44

pulse pressure

Answer 44

difference between systolic and diastolic pressures

Question 45

mean pressure

Answer 45

average pressure in a complete cardiac cycle

Question 46

estimation of blood pressure by sphygmomanometry

Answer 46

- fast decline in cuff pressure may miss the first Korotkoff sound - 1st Korotkoff sound is where cuff pressure is just lower than systolic pressure - disappearance of Korotkoff sound represents point where cuff pressure just lower than diastolic pressure

Question 47

pressure in systemic circulation | highest to lowest

Answer 47

1. left ventricle --> aorta --> arteries --> arterioles --> capillaries --> venules --> veins --> vena cava --> right atrium

Question 48

pressure in pulmonary circulation (highest to lowest)

Answer 48

right ventricle --> pulmonary artery --> arteries --> arterioles --> capillaries --> venules --> pulmonary veins --> left atrium