Physiology Test 2: Cardio Microcirculation

Front 1

What are continuous capillaries and where are they located?

Back 1

1. They have no recognizable intercellular openings
2. The are seen where minimum excess fluid/filtration is desired
3. Places like the BBBarrier, pulmonary and muscular circulations
4. It is important to note that they are not impermeable to gases or small molecules

Front 2

What are fenestrated capillaries and where are they?

Back 2

1. The have a gap that can be opened or closed
2. 15-20 times more permeable than continuous capillaries
3. The are seen where high amounts of filtration occur as in the kidneys

Front 3

What are discotinuous capillaries and where are they found?

Back 3

1. The are ones with large gaps in the endothelial layer
2. These are the siusoids and they have these gaps to allow proteins to enter and exit the circulation
3. The are found in the liver, spleen and bone marrow

Front 4

What are the precapillary sphincters and what do they regulate?

Back 4

1. They are smooth muscle controlling the size and diameter of the openings to the capillary beds and perfusion into tissues
2. It regulates inflow volume and pressure

Front 5

What happens in the microcirculation and where?

Back 5

1. It means the capillary beds where the nutrients are supplied and the removal of waste byproduct occurs.
2. It is composed of arterioles, metarterioles, venules and capillaries

Front 6

What is the effect of arterioles on the circulation?

Back 6

It is the site of the greatest resistance in the circulation.

Front 7

Where are the metarterioles?

Back 7

They are perpendicular branches off of the arterioles. The have a low smooth muscle content and connect to a venule. Multiple capillaries originate from one.

Front 8

What are the two main factors in net fluid movement through the capillaries?

Back 8

1. Hydrostatic pressure inside and outside of the capillaries
2. Oncotic/colloid osmotic pressure inside and outside
3. Normally the osmotic pressure gradient is static and mainly the hydrostatic pressure influences net movement.

Front 9

What fluid forces are at the arterial capillary end?

Back 9

A higher hydrostatic pressure favors filtration, water leaving the beds.

Front 10

What fluid forces are at the venous end?

Back 10

A higher interstitial capillary pressure now favors reabsorption of the water.

Front 11

What is the relationship between pressure signs and forces?

Back 11

1. negative sign will pull water towards an area
2. positive sign will push water away from an area

Front 12

How do you determine the hydrostatic gradient in the capilaries?

Back 12

1. The
(dPh) = (Pc-Pi)
2. Normally it favors filtration
3. The Pi doesn't normally change but the Pc does

Front 13

How do you determine the osmotic pressure gradient?

Back 13

1. (dPpi) = (PIp-PIi)
2. Normally favors capillary retention
3. Albumin accounts for 75% of the osmotic pressure

Front 14

What is the Donnan effect?

Back 14

It is the tendency of negatively charged proteins to attract positive electrolytes and amplify the osmotic effect. The Water will then leave faster.

Front 15

How do you determine net filtration? Where does the most filtration and least occur?

Back 15

Net = (Pc-Pi)-(PIp-PIi)
1. In the kidneys it is almost all filtration to allow electrolyte rebalancing with a secondary collection for the fluid
2. In the lungs there is almost no filtration in order to prevent edema and facilitate O2 diffusion

Front 16

What is Kf and sigma?

Back 16

1. Kf is the filtration coefficient that assigns a relative permeability to fluids
2. sigma is the reflection constant that indicates the relative permeability of proteins

Front 17

What is the average capillary pressure?

Back 17

1. Total outward force = 28.3

Front 18

What happens to the extra fluid filtered from the capillary?

Back 18

Since there is a net filtration from the capillaries the excess fluid is collected by the lymph and returned to the venous circulation

Front 19

What is the flow radius relationship?

Back 19

Flow = 1/r4
It is an inverse relationship that means a small change in radius will change the flow to the fourth power.

Front 20

Name some ways to decrease filtration?

Back 20

1. Decrease capillary pressure
2. Increase interstitial fluid pressure
3. Increase plasma protein content(oncotic)
4. Decrease capillary permeability

Front 21

What is the rate and area of lymphatic drainage?

Back 21

about 80mL/hr from the left side and 20 ml/hr from the right. Lymph drains eventually into the subclavian veins

Front 22

What factors cause edema formation?

Back 22

1. Increase capillary pressure
2. Increased capillary permeability
3. Decreased oncotic pressure
4. Lymphatic obstruction
5. Edema forms in the virtual spaces(joints etc) unless localized by and obstruction

Front 23

What is ascites?

Back 23

It is accumulation of fluid in the peritoneal cavity dues to cirrhosis

Front 24

What do the alpha and beta recpetors do in the circulatory system?

Back 24

1. Autonomically using the alpha and beta 2 receptors. Alpha contracts and beta(be easy) relaxes smooth muscles.

Front 25

What are some other ways to regulate the circulatory system?

Back 25

1. Localized events in the tissues give a level of autonomy and keep the brain from working on it

Front 26

What is the correlation between elastic fibers and stretch?

Back 26

Bad elastic fibers stretch. Good elastic fibers are meant to retain shape with a little flexibility.

Front 27

What do vessels have in their structure?

Back 27

All vessels have endothelium. Arteries, veins, and arterioles all have smooth muscle in them for contraction

Front 28

Where is BP the highest?

Back 28

It is the highest in the aorta.

Front 29

What is the relationship between the circulatory system and BP?

Back 29

The blood pressure is the driving force of systemic circulation. The pressure drops due to resistance. If it drops unexpectedly it could be becauase of an obstruction.

Front 30

What are the targets of blood pressure regulation?

Back 30

1. Amount of fluid loss in the kidneys = diuretic therapy
2. Cardiac output = beta blocking drugs
3. Resistance of the system = ACE inhibitors(vasodialators)
4. Target the distribuition of blood because the venous side has more

Front 31

Mean arterial pressure(MAP) factors

Back 31

1. Blood volume = fluid loss or intake
2. HR and SV = effectiveness of heart as a pump
3. Resistance to blood flow = diameter of the arterioles
4. Relative distribuition of blood = diameter of the veins

Front 32

What causes immediate changes in pressure?

Back 32

1. The contraction of the ventricles
2. The vessel dialtion or constriction
3. Volume changes

Front 33

What is the pulse pressure and what factors affect it?

Back 33

It is the difference between cytosolic and diastolic pressure
2. It corresponds to SV
3. It is influenced by aortic compliance

Front 34

What is the systolic pressure?

Back 34

It is the highest pressure achieved in a systemic artery

Front 35

What is the diastolic pressure?

Back 35

It is the lowest pressure reached in a systemic artery

Front 36

How to calculate the MAP?

Back 36

1. First remember the heart spends 2/3 time in diastole and 1/3 time in systole
2. MAP = (sys - dias/3) + Dias

Front 37

Taking BP

Back 37

1. Inflate cuff till arteries close and no sound is hear
2. Slowly deflate cuff until you hear the kortkoff tapping sound. This is systolic
3. When all the turbulence disappears it is the diastolic pressure

Front 38

What are RAS drugs?

Back 38

These are renin angiotensin drugs and they are ACE inhibitors. They decrease peripheral resistance.