(02) p1-20

Question 1

systolic pressure = highest pressure

diastolic pressure = lowest

left ventricle contracts to systolic pressure (the peak)

then it goes way down - so blood from atrium can get in

aortic valve prevents blood in aotra from going backwards

(dashed line is mean pressure)

systolic = 120 mmHg (in arteries)

diastolic = 80 mmHg (in arteries)

go from pulsatile flow to on by the type you reach capillaries due muscular walls

notice pulmonary capillaries do have some pulsatile flow (cause there aren’t so many muscles in them to dampen out flow)

pulmonary resistance is much lower than systemic resistance

Question 2

(What would happen if the heart suddenly stops pumpkins)

1. what would happen to aortic pressure?
2. to venous?
3. what would happen eventually?
4. when there is an equilbrium of pressure from the arterial side to the venous side - what do you call that?

Answer 2

1. decrease
2. increase
3. reach equilibrium - flow will stop
4. mean circulatory filling pressure

Question 3

(Mean Circulatory pressure)

1. what is this?
2. what is the pressure?

3-4. function of what two things?

5. is this directly measured in clinical practice?

Answer 3

1. pressure in vascular system at equilibrium
2. 7 mmHg
3. blood volume
4. distensibility of vasculature (level of vascular resistance)
5. obviously not

Question 4

(case example)

1. ascites - free fluid in abdomen

Answer 4

1. white abdomen due to ascites
2. heart looks pretty good
3. no fluid in chest
4. he had a massive tumor growing in right atrium

(then go on to next question)

Question 5

so why is he showing left heart signs?

the left cardiac output has to equal the right cardiac output!!

Question 6

as the cross sectional area increases the velocity decreases

Answer 6

this also applies to small vessels

APPLIES WHEN FLOW IS CONSTANT!

Question 7

same concept as previous slide

Question 8

(Blood)

(Hematocrit or packed cell volume (PCV))

1. What is normal in dog?
2. determines what?

(don’t focus too much on learning comopnents in picture - get a general idea…)

Answer 8

1. 37-55%
2. blood O2 carrying capacity

Question 9

(Blood)

(oxygenated hemoglobin)

1. What combines with hemoglobin in RBC?

(Reduced hemoglobin)

2. O2 status?
3. When do we see visible cyanosis ( blue or purple coloration of the skin or mucous membranes due to the tissues near the skin surface being low on oxygen)?

Answer 9

1. O2
2. O2 has been released “desaturated”
3. when there is at least 5g desaturated Hgb

Question 10

(Properties of Blood)

(Viscosity)

1. what is it?
2. What is the major determinant of viscosity?
3. How does increase in viscosity affect blood flow?

Answer 10

1. internal fluid resistance of a substance
2. RBC’s (as hematocrit increases viscosity goes way up)
3. more difficult blood flow - more resistance

Question 11

(Erythrocytosis vs. Anemia)

(Erythrocytosis (polycythemia))

1. abnormally high what?
2. increases what?
3. also increases what?

(Anemia)

1. abnormally low PCV (RBC mass)
2. how about here?

Answer 11

1. PCV (RBC mass)
2. more oxygen carrying capacity
3. viscosicty –> increased cardiac workload
4. opposite of above - will need to increase CO to compensate

(normal PCV - best balance)

Question 12

(Pressure Across Systemic Circulaiton)

(pressure drop across systemic circulation)

pefursion p = mean arterial pressure - mean right atrial pressure

Question 13

(Resistance)

1. what is it?
2. what is the equation?
3. Can resistance be measured directly? calculated from what?

Answer 13

1. the impediment to blood flow in a vessel
2. R = change in P/Q or (perfusion P/Q)
3. no, BP and flow

(she won’t ask us about units)

Question 14

1. resistance increases fastest where?
2. where does wall/lumen ratio increase the fastest?
3. Therefore arterioles are considered what?

(Changes in the degree of constriction or relaxation of arterioles can affect the entire CV system)

1-3. what three things?

Answer 14

1. arterioles
2. arterioles
3. control valves to the microcirculation
4. blood pressure
5. flow distribution
6. cardiac workload

(if you start running - vessels to leg skeletal muscles will dilate - to splachnic will constrict)