Veterinary Physiology Circulatory System, Lymphatics, Blood Pressure, Vascular Smooth Muscle

Front 1

What does Fick's Law state about diffusion of small, water-soluable substances across a capillary wall?

Back 1

The law states that the rate (ease) and direction of diffusion depends on both the permeability and the concentration gradient.

Front 2

What is an A-V Shunt?

Back 2

An ateriovenous anastomoses, which is a vessel that runs from an arteriole to a venule, bypassing the capillary bed.

Front 3

Name 3 reasons that capillaries are good exchange vessels

Back 3

1. Capillary walls are very thin at only one cell thickness
2. Capillary walls are porous
3. Blood flow is relatively slow (because there are millions of them)

Front 4

According to the Starling Hypothesis, the exchange of water and solutes between capillaries and the interstitial tissue space rely on the balance of what factors?

Back 4

1. Capillary hydrostatic pressure
2. Interstitial hydrostatic pressure
3. Capillary oncotic pressure
4. Interstitial oncotic pressure
5. the capillary permeability

Front 5

What is oncotic pressure?

Back 5

The osmotic pressure due to the presence of colloids (non-diffusable substances) in solution.

Front 6

Define filtration

Back 6

When fluid leaves the capillary because the net net hydrostatic pressure is greater than the net oncotic pressure

Front 7

Define reabsorption

Back 7

When fluids enters the capillary because the net hydrostatic pressure is lower than the net oncotic pressure.

Front 8

What is the purpose of the lymphatic system?

Back 8

To recapture fluid and plasma proteins that have leaked from vessels into the interstitial space, in order to filter them and return back into the blood circulation via a vein.

Front 9

Define edema

Back 9

the accumulation of excess fluid in the interstitial spaces. This is due to a shift in one of the factors of Starling's hypothesis.

Front 10

Name three mechanisms that cause edema

Back 10

1. a hydrostatic pressure gradient
2. a colloid-osmotic pressure gradient
3. increased capillary permeability

Front 11

Name a cause of increased capillary permeability based edema

Back 11

histamine release (allergic reaction)

Front 12

Name a cause of increased hydrostatic pressure edema

Back 12

pulmonary edema from left-sided heart failure, systemic edema from right-sided heart failure

Front 13

Name a cause of decreased oncotic pressure edema

Back 13

hypo-proteinemia associated with malnutrition, severe burns,

Front 14

Name some alternative reasons for edema

Back 14

lymphatic obstruction or atresia (narrowing), immobilization, increased endothelial permeability to proteins

Front 15

High Altitude Pulmonary Edema

Back 15

Not completely understood:
Lower atmospheric pressure with reduced oxygen concentration. Pulmonary arteriole vasoconstriction occurs, with increased capillary permeability. The edema that accumulates is very proteinaceous.

Front 16

systolic pressure (SP)

Back 16

the peak (highest) arterial pressure in the cardiac cycle

Front 17

diastolic pressure (DP)

Back 17

the lowest arterial pressure in the cardiac cycle

Front 18

Mean Arterial Blood Pressure (MABP) calculation

Back 18

DP + 1/3(SP - DP)

Front 19

dicrotic notch

Back 19

in the recording of the arterial pressure, indicates the closure of the aortic valve and the end of ventricular systole

Front 20

pulse pressure (PP)

Back 20

the difference between systolic and diastolic pressures
SP - DP

Front 21

Blood pressure reporting (manual)

Back 21

is written SP/DP such as 120/90

Front 22

Physical attributes of systolic pressure

Back 22

the blood flow into the arteries during systolic contraction is higher than the flow out of the arteries (into the arterioles), which causes an increase in arterial volume and pressure.

Front 23

Physical attributes of diastolic pressure

Back 23

the result of aortic/arterial vessel wall recoil.
During diastole, the elastic recoil of the arterial walls provides the driving force to propel blood out the arteries

Front 24

What happens when the aorta is stiff or has reduced elasticity?

Back 24

during systole the aorta does not expand at all, so the systolic pressure is increased (same volume in a smaller space).
during diastole, there is less recoil in the aorta, so the diastolic pressure is reduced.

Front 25

What are general cardio/circulatory factors that will affect blood pressure?

Back 25

stroke volume, heart rate, total peripheral resistance, compliance of the blood vessels