chapter 14- Exam 2

Question 1

what does the circulatory system do

Answer 1

Transporting nutrients to the tissues

Transporting waste products away from the tissues

Transporting hormones

Question 2

what are the arterial walls like and what do they do

Answer 2

they have strong walls and transport blood under high pressure

Question 3

what are the arterioles wall like and what do they do

Answer 3

have muscular walls that can completely relax/dilate altering blood flow in each tissue in response to its needs

Question 4

what controls blood into the capillaries

Answer 4

arterioles

Question 5

what do the capillaires do

Answer 5

exchange fluid, nutrients, electrolytes, hormones, and other substances between the blood and the interstitial fluid

Question 6

what are the capillary walls like and what do they do

Answer 6

walls are very thin with numerous minute capillary pores permeable to water and other small molecular substances

Question 7

what are the venules

Answer 7

venules receive blood from capillaries and gradually become progressively larger veins to transport blood back to the heart and serve as a major reservoir of blood

Question 8

what is the venous systems walls like

Answer 8

Because the pressure in the venous system is very low, the venous walls are thin, but muscular enough to contract or expand and act as a controllable reservoir

Question 9

what happens to the volume of blood in a closed system

Answer 9

the fixed volume of blood in various areas change with demand

Question 10

what percent of the entire blood volume is in the systemic circulation

Answer 10

84%

Question 11

how does the 84% of the blood volume in the systemic circulation get divided up

Answer 11

64- in veins
13 in arteres
7 -systemic arterioles + caps
7 in the heart 
9 in pulmonary circulation

Question 12

what have a larger cross sectional area

veins or arteries

Answer 12

veins

Question 13

what are the cross sectional areas of the systemic system

Answer 13

Aorta	= 2.5
Small Arterioles = 20
Arterioles =40
Capillaries=	2500	
Venules	=250
Small Veins	=80
Venae Cavae =8

Question 14

what is hemodynamics

Answer 14

the physical factors that govern blood flow

Question 15

what is similar to Ohms law in electricity

Answer 15

flow of fluid is proportional to the drive force (pressure) through a resistance

Question 16

what is velocity of BF

Answer 16

is the speed at which blood flows in the circulation (mm/sec)

Question 17

what happens to the velocity with the fixed volume of blood

Answer 17

Velocity of blood flow is inversely proportional to the vascular cross-sectional area

Question 18

what is the equation of the velocity of blood flow

Answer 18

velocity or BF= BF/ cross sectional area

Question 19

what are the units of flow

Answer 19

cm^3/ min

**1 ml = 1 cm^3

Question 20

what are the units of velocity

Answer 20

cm/ min

Question 21

what are the units of cross secitonal area

Answer 21

cm^2

Question 22

at rest with a relatively constant flow what are the velocity

Answer 22

Aorta 33cm/sec
> Arterioles
> Small veins
> Capillaries 0.3 cm/sec

Question 23

what is flow equal too

Answer 23

velocity x Area

Question 24

how do you keep flow constant

Answer 24

as area decreases ( means velocity increases )

Question 25

what is pressure equal

Answer 25

force/ area

Question 26

where is high pressure found

Answer 26

in the arterial tree

Question 27

where is low pressure

Answer 27

in the venous side of the circulation

Question 28

what happens with large pressures in the arteriolar capillary jx

Answer 28

it willldrop across

Question 29

how is blood flow controlled to tissues

Answer 29

blood flow is controlled in relation to tissue needs

Question 30

how is Q controlled to tissues

Answer 30

Q is mainly controlled by local tissue flow

Question 31

how is arterial pressure control to tissue

Answer 31

arterial pressure is controlled independent of either local blood flow control or Q control

Question 32

when tissue is active what will happen to blood flow

Answer 32

it can increase as much as 20 to 30 times the resting level

Question 33

how can Q increase

Answer 33

the heart cant increase Q greater than 4 to 7 time resting level -- 5 L/min at rest to 35 L/min in high level athletes So not possible to increase blood flow everywhere in the body.

Question 34

what do the microvessel do

Answer 34

they continuously monitor tissue needs, dilating or constricting, to control local blood flow precisely to that level required for the tissue activity.

Question 35

what are some other things that help the vessels in controlling blood flow

Answer 35

Central nervous system and hormones provide additional help in controlling tissue blood flow.

Question 36

how is Q controlled

Answer 36

mainly controlled by the sum of all local tissue flow ---For example: Exercise → ↑ VR → ↑ Cardiac Output ---CO increases to meet the increasing needs of increasing metabolic tissue

Question 37

how is arterial pressure controlled

Answer 37

this is controlled independent of either local blood flow control or cardiac output control

Question 38

go to slide 17

Answer 38

read about the arterial pressure and how the body handled it

Question 39

what does Q =

Answer 39

change in Pressure over resistance

Question 40

what is flow

Answer 40

through a blood vessel is determined by Q 1. the pressure difference between the two ends of the vessels ( arterial - venous ) 2 resistance of the vessel

Question 41

what is blood flow

Answer 41

quantity of blood that passes a given point in the circulation in a given period of time

Question 42

what is unit of blood flow

Answer 42

usually expressed as milliliters (ml) or Liters (L) per minute

Question 43

what is Q

Answer 43

Overall flow in the circulation of an adult ~5 liters/min

Question 44

what is laminar flow

Answer 44

Blood usually flows in streamline fashion with each layer of blood remaining the same distance from the wall, this type of flow is called laminar flow

Question 45

what happens with laminar flow occurs

Answer 45

the velocity of blood in the center of the vessel is greater than (2x greater) that toward the outer edge creating a parabolic profile

Question 46

what are some causes of turbulent blood flow

Answer 46

- High velocities - Sharp turns in the circulation - Rough surfaces in the circulation - Rapid narrowing of blood vessels

Question 47

what will you hear with laminar flow

Answer 47

is it silent

Question 48

what will you hear with turbulent flow

Answer 48

it tends to cause vascular murmurs

Question 49

why are murmurs important

Answer 49

they help with diagnosing vessel stenosis, vessel shunt, and cardiac valvular lesions

Question 50

what is reynolds number

Answer 50

a dimensionless quantity used to predict flow patterns

Question 51

what is the reynolds number equation

Answer 51

ssel diameter D x mean velocity v x density ρ divided by viscosity η

Question 52

when does turbulence occur

Answer 52

- With a large diameter and rapid flow - High Velocity - Sudden change in vessel diameter

Question 53

what is blood pressure

Answer 53

Blood pressure is the force exerted by the blood against any unit area of vessel wall

Question 54

what is resistnace

Answer 54

Resistance is the impediment to blood flow in a vessel Δ P = mmHg Q ml/min *** read bottom of slide 29 and 32

Question 55

what is conductances

Answer 55

Conductance is a measure of the blood flow through a vessel for a given pressure difference ***its ml/min per mmHg

Question 56

what is conductance sensitive to

Answer 56

change in diameter of vessels == The conductance of a vessel increases in proportion to the fourth power of the radius

Question 57

what is poiseuillie law

Answer 57

look at slide 35 for equaiton