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Flashcards in Respiratory Physiology Deck (14):
1

What is tidal volume?

1. Volume inspired or expired with each breath at rest

2. 500ml males/350ml females

2

What is inspiratory reserve volume?

1. IRV=2.3L

2. Max vol inspired at end of normal tidal insp

3. Inspiratory capacity = TV+IRV

3

What is the expiratory reserve volume (ERV)

1. ERV=750ml

2. Max vol expired at end of normal tidal expirat

4

What is the residual volume?(RV)

1. Volume of air remaining after max expiration

2. Increases with age

3. RV=FRC-ERV

4. 1.2L

5

What is the vital capacity (VC)?

1. Max vol of air exp after max inspiration

2. 4.5L males/3.5L females

3. Decreases with age

4. VC = insp capacity + ERV

6

What is total lung capacity?

1. VC+residual volume

7

What does the oxygen dissociation curve describe?

It describes the relationship between the percentage of saturated haemoglobin and partial pressure of oxygen in the blood. Not affected by the haemoglobin concentration.

8

When the curve shifts to the left what happens?

For a given oxygen tension there is increased saturation of HB with oxygen ie < oxygen delivery to the tissues

9

When the curve shifts to the right what happens?

For a given oxygen tension there is reduced saturation of Hb with oxygen ie enhanced oxygen delivery to the tissues.

10

What causes the curve to shift to the left?

1. HbF: methaemoglobin, carboxyhaemoglobin

2. Low H+ (alkali)

3. Low 2,3-DPG

4. Low temperature

11

What mnemonic helps us to remember things that cause a left shift ( lower O2)?

The L rule! Shifts to L - lowers oxygen delivery caused by:

1. Low H+ alkali

2. Low pCO2

3. Low 2,3-DPG

4. Low temperature

12

What causes the curve to shift to the right?

Shifts to right = raised oxygen delivery

1. Raised H+ acidic

2. Raised pCO2

3. Raised 2,3 - DPG

4. Raised temperature

13

What mnemonic helps to remember what causes shifts to the right?

'CADET, face right!'

  • CO2
  • Acid
  • 2,3 DPG
  • Exercise
  • Temperature

14