lecture 7: chapter 16

Question 1

what does the term microcirculation refer to

Answer 1

functions of the capillaries and the neighbouring lymphatic vessels

Question 2

what percentage of blood is present in the capillaries at any given time

Answer 2

5%

Question 3

TRUE or false; since there is only 5% of blood in circulation in capillaries it is not important

Answer 3

false, it is important for all gaseous exchanges

Question 4

what is good about having 3-10 billion capillaries

Answer 4

there is a larger surface area which allows them to perform the function of solute and fluid exchange
=a lot of places to move places around

Question 5

what are the 4 functions of the microcirculation

Answer 5

Ensures constant plasma and interstitial fluid communication

Accelerates distribution of nutrients, and hormones, and dissolves gases through tissues

Transports insoluble lipids and tissue proteins that cannot cross capillary walls

Flushes bacterial toxins and chemicals to immune system tissues

Question 6

what is the capillary bed/plexus

Answer 6

it connects 1 arteriole to 1 venule

Question 7

are vascular anastomoses more common in veins or arteries?

Answer 7

veins

Question 8

what do arterial anastomoses provide

Answer 8

alternate pathways (collateral channels) for blood to reach a body region

Question 9

explain how arterial anastomoses provide alternate channels

Answer 9

If one branch is blocked, the collateral channel can supply the area with adequate blood supply

Question 10

what is an example of arteriovenous anastomoses

Answer 10

thorough fare channels

Question 11

where are vascular anastomose common

Answer 11

joints, in skin, abdominal organs, brain, heart

Question 12

what is the trajectory of blood in microcirculation

Answer 12

arteriole
meta arteriole
capillaries
venules

Question 13

what is the composition of arterioles

Answer 13

one mono layer or endothelial cells and 1 layer of smooth muscle

Question 14

what is the composition of meta arteriole

Answer 14

one mono layer of endothelial cells with occasional smooth muscle

Question 15

what is the composition of capillaries

Answer 15

1 layer of endothelial with no smooth muscle cells at all

Question 16

what is the composition of venules

Answer 16

1 mono layer of endothelial and some smooth muscle

Question 17

where is the pre capillary sphincter

Answer 17

present at the junction where the capillaries arises from the meta arteriole

Question 18

what to sphincters respond to

Answer 18

local metabolytes

nerological signals

Question 19

what is the function of the sphincters

Answer 19

regulate flow direction into true capillaries or through channels

guard the entrance to each capillary

Question 20

what allows blood flow to be changed by sphincters

Answer 20

vasomotion-contraction and relation cycle of capillary sphincters

Question 21

what causes the blood flow in capillary beds to constantly change routes

Answer 21

sphincters

Question 22

what is blood flow regulated by and what does that mean

Answer 22

regulated by vasomotor nerves and local chemical condition, so it can either bypass or blood the capillaries

Question 23

true or false: blood always floods and flows through the enter capillary bed

Answer 23

no, it can be redirected dependant on tissue needs

Question 24

what are the 3 types of capillaries

Answer 24

continuous
fenestrated
sinusoidal

Question 25

where are continuous capillaries usually found

Answer 25

in skin and muscles

Question 26

true or false: continuous capillaries are not efficient at moving substances in and out because the endothelial cells are so close together

Answer 26

true

Question 27

what is characteristic of endothelial cells in continuous capillaries

Answer 27

the endothelial cells are so close so they provide an uninterrupted lining

Question 28

what are adjacent cells held together with

Answer 28

tight junctions

Question 29

what allows the passage of fluids in continuous capillaries

Answer 29

intercellular clefts

Question 30

where is an example of continuous capillaries of the brain and why its used there

Answer 30

in the brain there are tight junctions completely around the endothelium constitute the blood-brain barrier to make a protective against toxins

Question 31

where are fenestrated capillaries found

Answer 31

where there is active capillary absorptions or filtrate formation occurs (ex: small intestine, endocrine glands, kidneys

Question 32

explain the endothelium in fenestrate capillaries

Answer 32

riddled with pores (fenestrations)

Question 33

which type of capillaries have the greatest permeability to solutes and fluids

Answer 33

fenestrate capillaires

Question 34

true or false: since fenestrated capillaries have pores they don't have intercellular clefts

Answer 34

false, they do have

Question 35

what are sinusoid (discontinuous) capillaries

Answer 35

highly modified, leaky, fenestrated capillaries with large lumens

Question 36

where are sinusoid (discontinuous) capillaries

Answer 36

found in the liver, bone marrow, lymphoid tissue and some endocrine organs

Question 37

which capillaries have the biggest pores

Answer 37

discontinuous

Question 38

what is the function of discontinuous capillaries

Answer 38

allow large molecules (proteins and blood cells) to pass between the blood and surrounding tissues

Question 39

true or false: has blood passes from continuous to discontinuous is becomes more sluggish/less laminar

Answer 39

true

Question 40

what are capillaries composed of

Answer 40

unicellular layer of endothelial cells surrounded by basement membrane

Question 41

how does solute and water move across capillary wall

Answer 41

intercellular cleft (space between cells) or by plasmalemma vesicles.

Question 42

what is the diameter of capillaries

Answer 42

4-9 microns

Question 43

what is the main passage of substances through capillary to tissue

Answer 43

through clefts

Question 44

what are the smallest blood vessels

Answer 44

capillaries (allow only 1 single RBC to pass at a time)

Question 45

what is the width of capillary intercellular slit pores?

Answer 45

6-7 nanometers

Question 46

what does the The permeability of the capillary pores for different substances varies according to

Answer 46

their molecular diameters.

Question 47

true or false and why: The capillaries in different tissues have no differences in their permeabilities

Answer 47

The capillaries in different tissues have extreme differences in their permeabilities because of fenestrations

Question 48

give an example of how different tissues have different permeability

Answer 48

liver takes large molecules so their capillaries will have a higher fenestration

Question 49

how do water, ions, and small molecules (glucose) get diffuse

Answer 49

diffuse between adjacent endothelial cells | or through fenestrated capillaries

Question 50

how do some ions like NA+, K+ ca2+ and Cl- diffuse through

Answer 50

though channels in cell membranes

Question 51

how do large, water soluble compounds pass through/diffuse

Answer 51

pass through fenestrated capillaries (and occasionally through endothelial cells)

Question 52

how do lipids and lipid soluble materials (o2 and co2) diffuse through

Answer 52

through endothelial cell membranes

Question 53

how to plasma proteins diffuse through

Answer 53

cross endothelial lining in sinusoids (really large pores)

Question 54

the larger the side the harder/easier to permeate

Answer 54

harder to permeate

Question 55

true or false: since hemoglobin and albumin have the same molecular weight, they have the same permeability

Answer 55

false, albumin has a harder time permeating

Question 56

why is albumin harder to permeate than hemoglobin?

Answer 56

Gibbs Donnan effect | albumin have a greater osmotic force

Question 57

explain why albumin has a greater osmotic force

Answer 57

albumin has a negative charge (attracts sodium ions) albumin binds a small number of chloride ions (attracts more sodium ions)

Question 58

explain why albumin has a hard time permeating

Answer 58

because of its greater osmotic force is pulls liquid towards it

Question 59

Most important means by which substances are transferred between plasma and interstitial fluid is by what

Answer 59

diffusion

Question 60

since salt has a high osmotic force what does that do for diffusion

Answer 60

it attracts fluid in the capillary (pulls water out)

Question 61

what is the space between cells called

Answer 61

interstitium

Question 62

what is the fluid in the interstitium called

Answer 62

interstitial fluid

Question 63

what is the consistency of interstitial fluid

Answer 63

gel

Question 64

what are the two major types of solid structures in the interstitium called

Answer 64

collagen fibers and proteoglycan filaments (coiled molecules composed of hyaluronic acid)

Question 65

true or false: there is very little free fluid under normal conditions in interstitium

Answer 65

true

Question 66

the collagen bundle fibers in the interstitium provide what

Answer 66

structure

Question 67

explain the capillary exchange at the arterial end of the capillary

Answer 67

fluid moves OUT of the capillary | into the itnersticial fluid

Question 68

explain capillary exchange at the venous end of capillary

Answer 68

fluid moves INTO capilary | OUT OF THE INTERSTICUAL FLUID

Question 69

what are the 2 hydrostatic forces

Answer 69

capillary hydrostatic pressure | interstitial fluid hydrostatic pressure

Question 70

where is capillary hydrostatic pressure higher and why

Answer 70

higher at the arteriolar end than venule | *because of ressitance)

Question 71

where does capillary hydrostatic pressure force fluid

Answer 71

forces fluid outward through the capillary membrane pushes fluid from cap to interstitium

Question 72

Normally interstitial fluid hydrostatic pressure is negative or positive

Answer 72

negative

Question 73

what is the negative pressure in the interstitual fluid hydrostrate pressure caused by

Answer 73

pumping action of lymphatics the fluid is constantly drained and leaking out of interstitium which helps push more fluid in

Question 74

where does interstitial fluid hydrostatic pressure force fluid

Answer 74

usually pushes fluid from cap to interstitium (except for when pressure is positive)

Question 75

when interstitial fluid pressure is positive what happens

Answer 75

it opposes filtration

Question 76

capillary hydrostatic pressure is good for absorption or filtration

Answer 76

filtration

Question 77

interstitial fluid hydrostatic pressure is good for filtration or absorption

Answer 77

reabsorption (when pos)

Question 78

what are the osmotic forces

Answer 78

plasma colloid osmotic pressure interstitial fluid osmotic pressure

Question 79

what is another name for plasma colloid osmotic pressure

Answer 79

plasma oncotic pressure

Question 80

what is the major determinants of oncotic pressure

Answer 80

plasma proteins

Question 81

what is the most abundant plasma protein and what does it generate

Answer 81

albumin, generates 70% of oncotic pressure

Question 82

plasma colloid osmotic pressure/plasma oncotic pressure tends to cause what

Answer 82

IN AWARD (INTO CAPILLARY) MOVEMENT OF FLUID

Question 83

WHAT IS another name for interstitial fluid osmotic pressure

Answer 83

interstitial fluid oncotic pressure

Question 84

what is interstitial fluid osmotic pressure caused by

Answer 84

small amount of plasma proteins that leak into the interstitial space

Question 85

interstitial fluid osmotic pressure tends to cause inward or outward movement of fluid

Answer 85

outward movement

Question 86

plasma colloid osmotic pressure opposes what and what does that cause

Answer 86

opposes filtration, causing osmosis of water inward through the membrane

Question 87

interstitial fluid colloid pressure promotes what and why

Answer 87

promotes filtration by causing osmosis of fluid outward through membrane

Question 88

what is filtration

Answer 88

The sum of the hydrostatic and osmotic forces favours the net movement of water from the capillary to the interstitial space

Question 89

what is reabsorption

Answer 89

The sum of the hydrostatic and osmotic forces favors the net movement of water from the interstitial space to the capillary

Question 90

what is the filtration rate

Answer 90

the net filtration pressure (NFP) multiplied by the coefficent filtration

Question 91

what is the NNFP format

Answer 91

NFP= PC - Pic - Pip + Piif

Question 92

what is the filtration coefficent

Answer 92

Kf | product of surfeace area times the hydraulic conductiveity of memberan

Question 93

know the determinants of net fluid movement across capillaries

Answer 93

diagram of capillary and 4 pressures

Question 94

what is the starling equilibrium

Answer 94

The Starling equation describes the net flow of fluid across a semipermeable membrane. It describes the balance between capillary pressure, interstitial pressure, and osmotic pressure.

Question 95

what is the normal capillary hydrostatic pressure

Answer 95

approx 17 mmHg

Question 96

what is the normal interstitial fluid pressure in most tissues

Answer 96

-3

Question 97

what type of organs have positive interstitial pressures

Answer 97

encapsulated organs

Question 98

what is the negative interstitial fluid pressure caused by

Answer 98

pumping of lymphatic system

Question 99

what is colloid osmotic pressure caused by

Answer 99

large proteins

Question 100

what increases the colloid osmotic effect of proteins

Answer 100

presence of negative ions on proteins (Gibbs Donnan)

Question 101

what is the reflection coefficient of capillaries

Answer 101

it quantitates the amount of protein that is reflected away from capillary membrane

Question 102

what does a reflection coefficient of 1 mean

Answer 102

all proteins are reflected and none pass through pores

Question 103

what does a reflection coefficient of 0 mean

Answer 103

it is permeable to all proteins

Question 104

true or false: physiologically you can never have a coefficient of 1 or 0

Answer 104

true

Question 105

go over the 3 slides about forces causing filtration, reabsorption etc

Question 106

what is the net filtration pressure and what does that cause

Answer 106

0.3 mmHG which causes a net filtration rate of 2 ml/min for the entire body (this means we are constantly moving more fluid from capillary to interstitium than opposite)

Question 107

even though there is a net outward force (moving fluid from cap to interstitium) do the vessels swell

Answer 107

no because of the draining from lymphatic systems

Question 108

where is the transition point

Answer 108

it is a point between filtration and reabsorption where there is equilibrium

Question 109

is the transition point closer to venous end or arterial end

Answer 109

closer to venous

Question 110

true or false: capillaries filter more than they reabsorb

Answer 110

true

Question 111

is the transition point always the same? give example

Answer 111

no it changes depending on the needs of the tissue (whether they need more filtration or reabsorption) ex: in skeletal we need a lot of filtration so it will, be closed to venous side

Question 112

during filtration, are we only moving fluid?

Answer 112

no also moving oxygen, glucose etc

Question 113

during reabsorption are we only moving fluid?

Answer 113

no also waste products