RAT 6

Question 1

what is meant by mechanical physiology?

Answer 1

the actual processes by which blood fills the cardiac chambers and is pumped out of them

Question 2

what is a cardiac cycle?

Answer 2

sequence of events that take place within the heart from one heartbeat to the next

Question 3

which valves open when the ventricles contract?

Answer 3

aortic valve

Question 4

which valves open during ventricular relaxation?

Answer 4

mitral valve (AV valves)

Question 5

what most likely causes heart sounds?

Answer 5

vibrations of the ventricular and blood vessel walls when the valves shut

Question 6

when does S1 occur?

Answer 6

when the AV valves close (longer, louder)

Question 7

when does S2 occur?

Answer 7

when the SL valves close

Question 8

what are the four phases of the cardiac cycle?

Answer 8

1. ventricular filling phase
2. isovolumetric contraction phase
3. ventricular ejection phase
4. isovolumetric relaxation phase

Question 9

what is EDV?

Answer 9

• end-diastolic volume
• the ventricular volume at the end of ventricular diastole

Question 10

what is ESV?

Answer 10

• end-systolic volume
• volume of blood present in the ventricles at the end of the ventricular ejection phase

Question 11

what is SV?

Answer 11

• stroke volume
• amount of blood pumped in one heartbeat

Question 12

what is a typical value for SV?

Answer 12

70 mL

Question 13

what is blood pressure?

Answer 13

the outward force that the blood exerts on the walls of the blood vessels

Question 14

where is blood pressure the highest?

Answer 14

large systemic arteries

Question 15

what is blood flow?

Answer 15

volume of blood that flows per minute

Question 16

what are two factors that determine blood flow?

Answer 16

• pressure gradient
• resistance

Question 17

how is pressure gradient related to blood flow?

Answer 17

directly proportional

Question 18

how is resistance related to blood flow?

Answer 18

inversely proportional

Question 19

what has the largest influence on the velocity of blood flow?

Answer 19

the cross-sectional area of the blood vessel

Question 20

where is blood flow the fastest?

Answer 20

aorta

Question 21

where is blood flow the slowest?

Answer 21

capillaries

Question 22

where is blood pressure the lowest?

Answer 22

arteries

Question 23

what 3 factors determine blood pressure?

Answer 23

1. peripheral resistance (PR)
2. cardiac output (CO)
3. blood volume and vessel compliance

Question 24

what three factors determine peripheral resistance?

Answer 24

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

Question 25

how does blood vessel radius impact PR?

Answer 25

inversely related; vessel radius increases, resistance decreases

Question 26

how does blood viscosity impact PR?

Answer 26

PR increases by conditions that increase blood viscosity and vice versa

Question 27

how does blood vessel length impact PR?

Answer 27

longer the vessel, the greater the resistance

Question 28

what fourth factor influences PR?

Answer 28

presence of obstructions within the blood vessels that are caused by certain disease states

Question 29

how do changes in CO impact blood pressure?

Answer 29

- increase CO output, Increase blood pressure - decrease CO output, decrease blood pressure

Question 30

the total volume of blood is directly linked to the amount of ___________ in the blood

Answer 30

water

Question 31

how do changes in blood volume impact blood pressure?

Answer 31

blood volume increases, blood pressure increases

Question 32

explain how vessel compliance impacts blood pressure

Answer 32

stretch to accommodate the added fluid when blood volume increases, resulting in only a small rise in pressure

Question 33

which vessels are most compliant?

Answer 33

veins

Question 34

is the right or left ventricle stronger and thicker?

Answer 34

left ventricle

Question 35

does the right or left ventricle pump more blood?

Answer 35

left ventricle

Question 36

does the systemic or pulmonary circuit have more peripheral resistance?

Answer 36

systemic circuit

Question 37

does the systemic or pulmonary circuit have a higher pressure system?

Answer 37

systemic circuit

Question 38

what does the orange line represent?

Answer 38

pressure pulsates

Question 39

what does the black line represent?

Answer 39

mean arterial pressure (MAP) - the average pressure in the arterial circuit

Question 40

why is blood pressure often represented by two numbers?

Answer 40

because it has both contraction and relaxation periods generated by pulsates

Question 41

what is systolic pressure?

Answer 41

blood pressure in the arteries when the ventricles are in systole

Question 42

what is diastolic pressure?

Answer 42

blood pressure in the arteries when the ventricles are in diastole

Question 43

what is the pulse pressure?

Answer 43

difference between the systolic and diastolic pressures

Question 44

in what part of the systemic circuit is there a sharp decrease in pressure? why?

Answer 44

in the arterioles because of the sharp increase in peripheral resistance in the arterioles

Question 45

what instrument is typically used to measure blood pressure?

Answer 45

sphygmomanometer

Question 46

what changes in blood pressure occur in the capillaries? why?

Answer 46

pressure decreases because the reduction in blood volume that takes place in the capillaries

Question 47

what changes in blood pressure occur in the veins? why?

Answer 47

pressure declines even further in veins due to the high compliance of veins and the declining resistance as these vessels merge and become larger

Question 48

what are the four mechanisms that aid in the venous return of blood?

Answer 48

1. venous valves that prevent backward flow in the veins 2. smooth muscle in the walls of veins that may contract under sympathetic NS stimulation to increase the rate of venous return 3. skeletal muscle pumps 4. respiratory pumps

Question 49

what are the branches of the subclavian artery that supply the majority of the arterial blood to the thorax?

Answer 49

anterior and posterior intercostal arteries

Question 50

what organ does the celiac trunk supply?

Answer 50

abdominal organs

Question 51

what organ does the superior mesenteric artery supply?

Answer 51

small intestine

Question 52

what organ does the renal arteries supply?

Answer 52

kidneys

Question 53

what organ do the gonadal arteries supply?

Answer 53

gonads

Question 54

what organ does the inferior mesenteric artery supply?

Answer 54

large intestine

Question 55

what organs do the common hepatic artery supply?

Answer 55

stomach, pancreas, duodenum

Question 56

what organs does the splenic artery supply?

Answer 56

stomach and pancreas

Question 57

what organ does the left gastric artery supply?

Answer 57

stomach

Question 58

what is a pulse?

Answer 58

the pressure changes cause the arteries to expand and recoil with each heartbeat

Question 59

what is a pulse point?

Answer 59

where the pulse can be felt through the skin in the superficial arteries

Question 60

what are the most common pulse points?

Answer 60

- carotid - radial - brachial - femoral - dorsalis pedis - posterior tibial arteries