Micrcirculation and Intro to Edema Flashcards
1
Q
The blood remains in the capillaries for only (blank) seconds
A
1 to 3 seconds
2
Q
Because the same volume of blood must flow through each segment of the circulation each minute, the velocity of blood flow is inversely proportional to (blank).
A
vascular cross-sectional area.
3
Q
Blood flow through the capillaries is regulated by contractions and relaxation of the (blank)
A
arterioles and the precapillary sphincters.
4
Q
Contraction and relaxation of arterioles and precapillary sphincters is controlled by (blank).
A
local condtions of the tissues (concentrations of O2 and nutrients, end products of metabolism, H+, etc)
5
Q
arterioles give rise to (blank) which give rise to capillaries.
A
metarterioles
6
Q
Arteries, arterioles, and small venules have a lot of (blank)
A
smooth muscle
7
Q
There are scattered (blank) in the metarterioles, and the opening of the capillaries are guarded by muscular
A
smooth muscle cells
precapillary sphincters
8
Q
most (blank) substances diffuse through capillary membrane along the intercellular cellular clefts.
A
water-soluble
9
Q
Vesicle formation and diffusion of lipid-soluble molecules through the (blank) are other pathways for exchange.
A
endothelial cell
10
Q
The wall of a true capillary is composed of a unicellular layer of (blank) and is surrounded by a (blank) on the outside.
A
endothelial cells, basement membrane
11
Q
True capillaries do not have (blank)
A
smooth muscle
12
Q
What is the total thickness of a capillary wall?
A
.5 micrometers
13
Q
(blank) between the endothelial cells allow passage of water-soluble substances.
A
clefts(pores)
14
Q
What are the three types of capillaries?
A
fenestrated, sinusoidal, continuous
15
Q
Capillaries in different parts of the body have different degrees of (blank)
A
leakiness
16
Q
What is the most common form of capillary?
A
continous
17
Q
Where do you find fenestrated capillaries?
A
pancreas, exocrine glands, kidney, intestine
18
Q
Where do you find sinusoidal capillaries?
A
liver, spleen, bone marrow
19
Q
Which type of capillary has a basememnt mebrane, intercellular junction and coated pits and uses vesicles?
A
continuous
20
Q
As the blood flows along the lumen in the (BLANK) , tremendous numbers of water molecules and dissolved particles diffuse back and forth through the capillary wall.
A
capillary
21
Q
What are the four different types of exchange across the capillary wall?
A
diffusion, bulk flow, vesicles, active transport
22
Q
What molecules utilize diffusion in capillaries?
A
02, CO2, lipid-soluble substances, steroid hormones, anesthetics
23
Q
What molecules utilize bulk flow in capillaries?
A
H20, electrolytes, glucose, amino acids, (small molecules)
24
Q
What molecules utilize vesicles in capillaries?
A
macromolecules i.e large water-soluble substances and some proteins
25
What molecules utilize active transport in capillaries?
ions, small molecules
26
By far, the most important means by which substances are transferred between the plasma and interstitial fluid is by (blank)
diffusion
27
(blank) is the movement of a molecule from high concentration to a low concentration
diffusion
28
Transfer of substances between the cells and the systemic capillary blood is in response to (blank)
diffusion gradients
29
Changes in pressure gradient (either hydrostatic or colloid osmotic) across a capillary alters (blank)
bulk flow
30
Glucose is typically transported across capillary wall via bulk flow but sometimes is transported how?
active transport
31
Bulk flow of water and dissolved substances out of the capillary through endothelial pores is in response to a (blank) gradient.
hydrostatic pressure
32
Hydrostatic pressure inside the capillary is always (blank) than the pressure of the interstitial fluid surrounding the capillary.
greater
33
local changes in vascular resistance that may not alter systemic blood pressure produe local changes in (blank)
capillary blood pressure
34
The most important factor found thusfar to affect the degree of opening and closing of the metarterioles and precapillary sphincters is the concentration of (blank).
oxygen in the tissues
35
What happens during arteriolar constriction to the capillaries?
reduction in hydrostatic pressure in capillaries, so reabsoprtive forces will exceed filtration forces and net reabsorption of interstitial fluid in the the vascular bed will occur.
36
What happens during arteriolar dialation to the capillaires?
hydrostatic pressure will increase in capillaries and so you will get net flow out of the capillaries into the tissue
37
(blank) pressure depends on the concentration of plasma proteins
colloid osmotic pressure
38
(blank) generate an osmotic pressure because water but not large protein molecules, crosses the capillary wall. Thus, water is drawn into the blood to dilute the protein.
blood proteins
39
Osmotic pressure is bring water (blank) and hydrostatic is bringing water (blank)
in
| out
40
Large proteins such as (blank) are present in blood but not in the spaces around the cells in the body (interstitial space).
albumin
41
(blanK) are osmotic particles that produce an osmotic pressure.
blood proteins
42
The osmotic (oncotic) pressure generated by the blood proteins is opposed by the capillary blood (blank).
(hydrostatic) pressure
43
what kind of flow does hydrostatic pressure and osmotic pressure participate in?
bulk flow
44
Over the length of a typical capillary in the body, the blood pressure (blanks) to what numbers?
declines from 35 to 15 mm Hg due to resistance of the capillaries
45
The osmotic pressure due to blood proteins is app. (blank) .
25 mm Hg
46
Assuming osmotic pressure remains constant along the length of the capillary, blood pressure at the (blank) end of the capillary is greater than the osmotic pressure, while at the venous end it is less.
arterial end
47
At the arterial end of the capillary, the balance between the blood pressure and osmotic pressure favors the movement of water (blank) of the capillary; at the venous end it favors movement of water (blank) the capillary.
out
| into
48
What are the two exceptions to the classical principle that arterial ends of capillairs typically have water going out and the venule end of water moving in?
kidney and lung
49
In the kidney what is the net movement of water?
continuous filtration (water moves out of capillary)
50
In the lung what is the net movement of water?
Continuous reabsorption (water into capillary)
51
What is the starling equation?
fluid movement=hydraulic conductance X [(capilliary hydrostatic pressure-capillary oncotic pressure) -(intersitial hydrostatic pressure-intersitial oncotic pressure)]
52
What does the starling equation explain?
how hydrostatic and oncotic pressure deteremines fluid movement (net driving force)
53
(blank) cause movement of water across the capillary wall.
hydrostatic and osmotic
54
When you see the word oncotic what do you think?
| the word hydrostatic?
into
| out of
55
Increased blood volume is one way to "correct" (blank) pressure
low arterial blood pressure
56
Increase in capillary blood pressure increases (blank)
filtration
57
decrease in capillary blood pressure increases (blank)
reabsorption
58
filtration is the same thing as (blank).
| Reabsorption is the same thing as (blank).
water out of capillary
| water into the capillary
59
(blank) through its effect on capillary blood pressure alters transcapillary water movement.
vascular resistance
60
Can systemic arterial blood pressure change transcapillary water movement?
yes
61
If everything else is unchanged, an increase in systemic arterial or venous pressures will increase (blank) and decrease reabsorption because of the increase in capillary blood pressure.
capillary filtration
62
If everything else is unchanged, a decrease in systemic arterial or venous pressure will increase (blank) and decrease capillary filtration.
reabsorption
63
if you have increased venous or arterial pressure is directly proportional to what?
capillary pressure
64
High capillary pressure means increased (blank)
filtration
65
Low capillary pressure means increased (blank)
reabsorption
66
You will get filtration when your (blank) is greater than zero,
You will get reabsorption when your (blank) is less than zero.
fluid movement.
67
```
What will these cause:
Arteriolar dilation
Venous constriction
Increased venous pressure
Heart failure
Extracellular volume expansion
Standing
```
Increased capillary hydrostatic pressure
68
```
What will these cause:
Hypoalbuminemia
Severe liver disease
Nephrotic syndrome
Protein malnutrition
```
decreased capillary oncotic pressure
69
What will these cause:
| Burn, Trauma, Sepsis, Allergic reactions, Inflammation
Increased hydraulic conductance
70
Why do african children have swollen bellies
You need to have salt and protein in your blood to hold fluid in the blood vessels. With low protein levels (low oncotic pressure), the blood can't hold fluid in the vessels and so it leaks out as edema. This collects in the abdomen as ascities
71
reabsorption plus lymph flow equals what?
filtration
72
Where does the fluid lost in filtration go?
into lymph flow
73
The (blank) represents a second circulation, parallel to the blood vasculature,
lymphatic vasculature
74
In most vascularized tissues, the (blank) is critical to both hydrostatic and homeostatic maintenance
lymphatic system
75
The (blank) accounts for the clearance of interstitial fluid (ISF) with its constituent proteins and other solutes not absorbed across postcapillary venules.
lymph circulation
76
(blank) are the “safety valve” that normally balances out any net differences between the oncotic and hydrostatic pressure.
Lymphatic vessels
77
The lymphatic capillaries are extremely thin-walled, freely permeable to (blank) (large gaps), and they readily admit water through junctions that may act as one-way flap vales.
proteins and small particles
78
Lympathic capillaries are held open by radiating (blank) anchored to the surrounding fibrous matrix
fibrils
79
The walls of collecting lympathics have (blank)
smooth muscle cells
80
Lymph is propelled back to the general circulation in a manner reminiscent of the muscular pump for (blank) .
venous return
81
What is the fundamental process that removes excess water and plasma proteins from the interstitial spaces?
contraction-relaxation cycle of lymph bulbs
82
Lymphatic pressures along the lymphatic vasculature are generated by (blank) .
lymphatic vessel contraction and organ movements
83
What are the factors affecting lympathic return?
Peristaltic contractions
One way valves
Movement of skeletal muscles
Respiratory diaphragm (decreases intrapleural pressures)
84
Under normal conditions, tissue pressure is slightly (blank)
negative
85
An increase in interstitial water volume can cause interstitial pressure to be (blank).
positive
86
If the interstitial tissue volume exceeds the 'safe range' what will happen?
high hydrostatic pressure will exist and edema will be present
87
Dehydration of intersitial tissue can cause very (blank) hydrostatic pressure.
negative
88
would lympathic obstruction cause edema?
yes
89
Does the lymphatic system support interstitial solute and fluid clearance from the brain?
yes
90
There is a (blank) between the systemic circulation and the brain circulation
barrier
91
Most water-soluble substances diffuse through the capillary membrane along the (blank).
intercellular clefts
92
The movement of large molecules and highly charged ions from the blood into the brain and spinal cord is severely (blank).
restricted
93
Brain capillaries are not (blank) and have reduced transcytosis.
leaky
94
Brain capillaries are not leaky and have reduced (blank)
transcytosis
95
Endothelial cells in the brain sit on a (blank) basal lamina.
thick!
96
Brain capillaries have what differences to nonbrain capillaries?
brain capillaries have astrocytic endfoot processes and tight junctions and reduced transcytosis
97
For most substances, ease of passage is determined largely by (blank)(solid points).
lipid solubility
98
Certain molecules needed for brain metabolism, cross the barrier more readily than their lipid solubility alone would suggest. Such compounds (d-glucose, L-DOPA, phenylalanine) , why?
because of specialized transport systems that help out
99
What is the chemical property that has the greatest effect on a sbstances capacity to pierce the blood brain barrier?
lipid solubility
100
The greater the lipid solubility the (blank) it passes across the BBB.
easier i.e high extraction
101
A complex system of (blank) enables the brain capillaries to control movement into and out of the tissues.
transporters
102
Some transporters merely facilitate osmotic diffusion while others are “active” mechanisms requiring a source of (blank)
energy
103
(blank) consists of enzymatic steps by which compounds are modified in the endothelium and rendered unable to enter the brain.
“Metabolic” BBB
104
What is an example of a molecule that undergoes metabolic BBB and this is controlled by the brain barrier?
L-dopa
105
The (blank) tends to break down in areas of infection or injury. It is important in the treatment of what disease?
BBB
| parkinsons
106
The BBB can be temporarily disrupted by sudden marked increases in (blank) or by IV injection of hypertonic fluids.
blood pressure
107
In the development of (blank), new blood vessels, no tight junctions, the lack of a barrier helps in identifying the location of tumors.
tumors
