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Flashcards in Physiology Deck (188)
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1

The pneumotaxic centre is stimulated when...

a. ventral respiratory neurons fire

b. ventral respiratory neurons stop firing

c. dorsal respiratory neurons fire

c. the pneumotaxic centre is stimualted when dorsal respiratory neurons fire. 

2

The ventral respiratory group neurons...

a. are activated during normal breathing

b. are activated during hyperventilation

c. are activated during apnoea

b. are activated during hyperventilation

3

FEV1/FVC ratio is less than 75% in restrictive lung diseases - true or false?

false as both the FVC and FEV1 both fall, the ratio of remains at a normal level

4

What higher centres in the brain influence respiratory centres?

cerebral cortex, limbic system, hypothalamus

5

A measure of effort that has to go into stretching or distending the lungs

Compliance

6

what is PAO2 at sea level approx?

100mmHg

7

If there is a decrease in blood pressure, the is a(n) _______ in ventilation

increase

8

During inspiration, which neurons are excited?

dorsal respiratory group neurons

9

What is a peak flow meter?

a device which the patient gives a sharp fast blow after maximal inspiration gives an estimate of airway function best of 3

10

Conditions where the Bohr Effect might come into play?

  1. increased PCO2
  2. increased H+
  3. increased temperature
  4. increased 2,3-biphosphoglycerate

11

Three pressures important for ventilation

Atmospheric Intra-alveolar Intra-pleural

12

the proportion of the FVC expired in first second

FEV1/FVC ratio

13

Why is the Bohr Effect useful?

allows oxygen offloading without the need for a drop in PO2

14

According to La Place's law...

smaller alveoli with a smaller radius have a higher tendency to collapse as there is a greater inwardly directed collapsing pressure

15

Afferent discharge from irritated airwasy stimulates what reaction from the medulla...(4)

  1. short intake of breath
  2. closure of larynx
  3. contraction of abdominal muscles 
  4. opening of larynx and expulsion of air at high speed

16

FEV1/FVC ratio is less than 75% in obstructive lung diseases - true or false

true

17

What are the 4 stages of External Respiration?

  1. Ventilation
  2. Gas Exchange between Alveoli and blood Gas
  3. Transport in the blood
  4. Gas Exchange in the tissues

18

What is the difference in oxygen dissociation in myoglobin?

hyperbolic curve as only dissociates at very low PO2

19

What is a pneumothorax?

air in the pleural space

20

The transfer of gases between the body and atmosphere depends upon....

ventilation perfusion

21

Normal CI

2.4-.42L/min/m2

22

At a normal PaCO2 of around 40mmHg, PAO2 =

100mmHg

23

How do we work out the partial pressure of O2 in the atmosphere?

21% of 760mmHg = 160mmHg which is breathed in

24

What is the body's normal response to acute hypoxia?

hyperventilation and increased CO

25

How is the Oxygen dissociation curve affected in HbF?

shifted to the left

26

Other non-respiratory functions of the resp. system (7)

- water loss and heat elimination - enhanced venous return - normal acid-base balance maintenance - speech, singing, vocalisations - defence against inhaled foreign matter - modification and removal of materials passing through - nose as an organ of smell

27

At the lungs, O2 binding Hb ______ the ability of Hb to bind CO2 and H+

Weakens

28

The flat upper portion of the oxygen dissociation curve is important as it means a _______ fall in O2 will not affect oxygen _____ onto _______

moderate, loading, haemoglobin

29

Alveolar ventilation (L) =

(tidal volume - dead space) x resp. rate

30

In systemic arterioles, a decrease in O2 will cause vasodilation to...

promote offloading of oxygen to the tissues