Microcirculation topic physio

Question 1

What is microcirculation

Answer 1

Refers to the capillaries and nearby lymphatics

Question 2

What is microcirulation the site of

Answer 2

• Gas exchange
  -Nutrient + waste exchange

Question 3

What is osmosis driven by

Answer 3

Starling forces

Question 4

What is the starling equation + explaim each component

Answer 4

Jv= Kf [Pc-Pi) -(c-i)]

Jv = Fluid movement

Kf = Hydraulic conductance (capillary permeability)

Pc = Capillary hydrostatic pressure → pushes fluid OUT

Pi = Interstitial hydrostatic pressure → pushes fluid IN

πc = Capillary oncotic pressure → pulls fluid INTO capillary

πi = Interstitial oncotic pressure → pulls fluid OUT

Question 5

In relation to the starling equation
What does:
-Kf(permeability) increase with + where is it high and low
-

Answer 5

1.Capillary imjury, burns, toxins
High- Glomerular capillaries + Low in Cerebral capillaries

Question 6

In relation to the starling equation what is
-Pc( capillary hydrostatic pressure) determined by

Answer 6

• Arterial + venous pressure

Question 7

In relation to the starlings equation what does
πc( capillary oncotic pressure) depend on

Answer 7

• Plasma protein concentration
• if PPC decreases then the COP decreases

Question 8

In relation to the starling eqation when does
πi (interstitial oncotic pressure) increase

Answer 8

• Increases if protein leaks into interstitium

Question 9

What does lymphatic system return

Answer 9

Excess interstitial fluid
escaped proteins

Question 10

What are the causes of edema in relation to starlings ewuation

Answer 10

↑ Pc (venous obstruction, heart failure)

↓ πc (low plasma protein)

↑ Kf (burns, inflammation)

Blocked lymphatics:

Cancer surgery

Radiation

Filariasis

Immobility

Question 11

Name 3 local special mechanims that control blood flow

Answer 11

• Autoregulation
  -Actove hyperemia
  -Reactive hyperemia

Question 12

Name 5 organ specific circulations that control blood flow
1.What is that controle by
2.What is it controlled by

Answer 12

• Coronary circulation- local hypoxia + adenosine
  -cerebral circulation- CO2/H+
  -Pulmonary circulation
  -Renal corculation
  -Skeletal muscle

Question 13

What is temperature regulation controlled by

Answer 13

• Anterior hypothalamus

Question 14

What causes fever

Answer 14

Pyrogens

Question 15

Explain how fever occurs starting from Pyrogen

Answer 15

1.Pyrogen enters body + causes WBC to release IL-1

2.IL-1 acts on Anterior hypothalmus + causes it to release more prostaglandins

3. Prostaglandins raise the temperature set point
   4.Now fever occurs

Question 16

Name 3 temperature disorders and breifly explain

Answer 16

Heat exhastion:
- Excess sweating
Heat stroke:
- Failure of heat dissipation

Malignant hyperthermia : triggered by inhalational asethetics