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Year 1 - Respiratory (DP) > Physiology > Flashcards

Flashcards in Physiology Deck (57):
0

How do the lungs adhere to the thoracic wall?

Intrapleural fluid cohesiveness
Negative intracellular pressure

1

What happens during inspiration?

Diaphragm contracts and flattens
External intercostals contact and increase ant-post diameter
Ribs moved up and out
Increased in lung size reduces intra-alveolar pressure
Air enters down pressure gradient

2

Why do the lungs and chest wall recoil?

Due to elasticity

3

What is the role of surfactant?

Reduces alveolar surface tension to prevent collapse

4

What cells produce surfactant?

Type ii alveoli

5

What causes respiratory distress of the newborn?

Preterm births result in babies with lack of surfactant so high surface tension

6

What is the theory behind alveolar interdependence?

If an alveoli starts to collapse...
- Stretches surrounding alveoli
- They recoil -> Expansive
- Re-opens closed alveoli

7

What is the tidal volume?

Volume entering/leaving lungs in a single breath (~500ml)

8

What is the inspiratory reserve volume?

Extra air that can be expired over resting TV (~3000ml)

9

What is the inspiratory capacity?

Max volume of air inspired at the end of quiet expiration (~3500ml)
IC = IRV + TV

10

What is the expiratory reserve volume?

Extra air that can be expired after quiet expiration (~1000ml)

11

What is the residual volume?

Minimum lung volume after max expiration (~1200ml)

12

What is the functional residual capacity?

Volume of air in lungs after normal quiet expiration (~2200ml)
FRC = ERV + RV

13

What is the vital capacity?

Max volume of air that can be exhaled following max inspiration (~4500ml)

14

What is the total lung capacity?

TLC = VC + RV

15

If pulmonary compliance decreases, what effects will be noted?

Increased inflation work
Shortness of breath
Restrictive pattern

16

What can cause decreased Po compliance?

Po fibrosis/oedema
Lung collapse
Pneumonia
No surfactant

17

What occurs in emphysema?

Increased compliance
Elastic recoil lost
Increased exhalatory work

18

Which is greater and why, alveolar or pulmonary ventilation?

Pulmonary
Anatomical dead space

19

Is it better to increase tidal volume or RR to increase ventilation?

TV

20

What factors affect gas exchange in alveoli?

Partial pressure gradient of gasses
Diffusion coefficient for gasses
SA
Membrane thickness

21

What would a big gradient between PAO2 and PaO2 suggest?

Right-left shunt in the heart

22

Beginning at the trachea, describe the respiratory "tree"

Trachea
Bronchi
Bronchioles
Terminal bronchioles
Respiratory bronchioles
Alveolar ducts
Alveolar sacs

23

What causes a right shift in the Hb saturation curve?

Increased PCO2
Lower pH
Increased temperature
Increased 2,3-Bisphosphogylcerate

24

Where is myoglobin found?

In skeletal and cardiac muscle

25

When myoglobin is present in the blood what does this indicate?

Muscle damage

26

How is carbon dioxide transported in the blood?

Solution (10%)
Bicarbonate (60%)
Carbamino compounds (30%)

27

What is the equation for bicarbonate formation?

CO2 + H2O H2CO3 H+ + HCO3-

28

What enzyme catalyses the production of carbonic acid?

Carbonic anhydrase

29

What are the driving forces behind bicarbonate formation?

Venous [Cl-] > Arterial [Cl-]
Arterial [HCO3-] > Venous [HCO3-]

30

Which respiratory group neurones result in inspiration?

Dorsal

31

What results in passive expiration (neuronal)?

The dorsal resp. group stops firing

32

What neuronal controls result in active expiration?

Increased dorsal firing results in ventral firing

33

Where are the dorsal and ventral respiratory groups located?

In the medulla

34

What is the role of the pneumotaxic centre?

Terminates inspiration
Stimulated when dorsal group fires

35

What happens if the pneumotaxic centre is inhibited?

Prolonged inspiratory gasps - apneusis

36

What is the role of the apneustic centre?

Excites dorsal area
Inhibits pneumotaxic area
Prolongs inspiration

37

Where are the pneumotaxic and apneustic areas located?

In the pons

38

What structures stimulate the respiratory centres in the brain?

Higher brain centres
Stretch receptors
Juxtapulmonary receptors
Joint receptors
Baroreceptors

39

What is the Hering-Breuer Reflex?

A stretch response inhibiting inspiration and preventing hyperinflation

40

What factors increase ventilation?

Body movement
Adrenaline
Increased body temp

41

What are some symptoms of altitude sickness?

Headache
Fatigue
Nausea
Tachycardia
Dizziness
SoB
Unconsciousness

42

What are the chronic adaptions to high altitude hypoxia?

Polycythaemia
Increased 2,3-Bisphosphoglycerate production
Increased number of capillaries
Increased mitochondria

43

A 67 year old man who smokes since his teens has got COPD. What is his FEV1/FVC:
- 90%
- 4%
- 80%
- 60%
- 20%

60%

44

Which of the followings is correct in a patient with emphysema? Select ONE BEST OPTION
A. Gas exchange is unaffected
B. The work of breathing is decreased
C. The pulmonary compliance is increased
D. The total lung volume is decreased
E. The FEV1/FVC ratio is increased

Pulmonary compliance is increased

45

Which of the followings is correct in a patient with COPD? Select ONE BEST OPTION
A. Inspiration will be more difficult than expiration
B. Dynamic airway compression is likely to occur during active expiration
C. The presence of emphysema will help alleviate dynamic airway compression
D. Oxygen saturation should be maintained near 100% if the patient is retaining CO2
E. Dynamic airway compression is likely to occur during inspiration

Dynamic airway compression is more likely to occur during active expiration

46

From the list below select the ONE MOST RELEVANT option which describes the mechanisms involved in the causation of shortness of breath in this patient
A 21‐year‐old woman sees her GP about intermittent breathlessness. She often feels breathless when she’s in a crowded room. When she feels breathless, she also notices numbness and tingling around her mouth. A full blood count requested by the GP showed haemoglobin of 10.5 grams/dl.
A. Increased work of breathing due to reversible airways obstruction
B. Increased central and autonomic arousal
C. Reduced oxygen carrying capacity of the blood
D. Stimulation of peripheral chemoreceptors
E. Reduced surface area for gas exchange

Increased central and autonomic arousal

47

Q5) From the list below select the ONE MOST RELEVANT option which describes the mechanisms involved in the causation of shortness of breath in this patient
A 52‐year‐old man complains of gradually increasing shortness of breath on exertion and a dry cough. He has smoked 10 cigarettes a day since he was 14. On examination of his chest there are dry crackles at both bases.
A. Reduced pulmonary compliance and impaired gas diffusion
B. Increased work of breathing caused by reversible airway obstruction
C. Increased alveolar surface tension
D. Fixed airway obstruction and decreased surface area for gas exchange
E. Metabolic acidosis

Reduced pulmonary compliance and impaired gas diffusion

48

In a patient with pulmonary fibrosis, the FEV1/FVC% is likely to be Select ONE OPTION
A. 35% B. 40% C. 80% D. 60% E. 20%

80%

49

Q7) From the list below select the ONE MOST RELEVANT option which describes the mechanisms involved in the causation of shortness of breath in this patient
A 72‐year‐old woman has had two myocardial infarctions in the past, and a recent echocardiogram has shown moderately impaired left ventricular function. She complains to her GP of shortness of breath, which is worse at night.
A. Increased alveolar surface tension
B. Increased work of breathing due to reversible airways obstruction
C. Reduced oxygen carrying capacity of the blood
D. Reduced pulmonary compliance and impaired gas diffusion
E. Stimulation of central chemoreceptors

Reduced pulmonary compliance and impair gas diffusion

50

Q8) From the list below select the ONE CORRECT ANSWER
A previously fit 22 old man has been unwell for 2 days. He presents with cough productive of greenish septum, fever, and shortness of breath. His PO2 is 8.2 kPa. What is his saturation likely to be?
- 98%
- 90%
- 82%
- 75%
- 60%

90%

51

Q9) A 52‐year‐old man with shortness of breath on exertion was diagnosed with diffuse pulmonary fibrosis. His arterial blood gas results under resting conditions showed a PO2 of 10.2 kPa, %saturation of 97%, and PCO2of 4.9 kPa. His haemoglobin is 10.5 grams/dl
Which of the followings sets of results would be expected for him during climbing stairs? – Select one answer: Normal values
PCO2 4.7‐6.1, PO2 12.0‐14.7
A. %Saturation: 90%, PO2: 8.3, and PCO2: 4.8
B. %Saturation: 97%, PO2: 11.3, and PCO2: 5.9
C. %Saturation: 98%, PO2: 12.6, and PCO2: 3.4
D. %Saturation: 90%, PO2: 9.4, and PCO2: 6.7
E. %Saturation: 95%, PO2: 8.3, and PCO2: 7.1

Saturation 90%
pO2 9.4
pCO2 6.7

52

Q10) From the list below select the ONE MOST LIKELY set of arterial blood gases in this patient
A 32‐year‐old woman with type 1 diabetes that is usually well‐controlled. She is admitted with a 2 day history of dysuria, urinary frequency and vomiting. On arrival, she is comatose, with deep, ‘sighing’ respiration, and a temperature of 38.2oC.Normal values
pH 7.36‐7.44, PCO2 4.7‐6.1, HCO3‐ 24‐30, PO2 12.0‐14.7
A. pH 7.26 PCO2 3.2 HCO3‐ 8 PO2 12
B. pH 7.08 PCO2 5.2 HCO3‐ 8 PO2 11.8
C. pH 7.1 PCO2 7.1 HCO3‐ 26 PO2 10.2

pH 7.26, pCO2 3.2, HCO3- 8, pO2 12

53

Q11) Which of the followings is correct about Functional Residual Capacity? Select ONE BEST OPTION
A. Is usually increased in obese subjects
B. Is measured by spirometry
C. Is decreased in COPD
D. Is normally about 20% of total lung capacity
E. Is approximately about 2.2 litres in a young adult man

~2.2 litres

54

Q12) Which of the followings is correct about normal lungs? Select ONE BEST OPTION
A. A low PO2 causes pulmonary vasoconstriction
B. Larger airways are supplied by pulmonary circulation
C. Beta 1 agonists causes bronchodilation
D. Parasympathetic stimulation causes bronchodilation
E. The surface area for gas exchange remains constant in the absence of disease

Low pO2 causes pulmonary vasoconstriction

55

Which of the following is true in a tension pneumothorax
A. The intra‐pleural pressure becomes more negative
B. The trachea may deviate to the same side
C. Patient is likely to be hypotensive
D. Breath sounds are increased
E. Chest pain is not a symptom

Patient is likely to be hypertensive

56

Q14) A 35‐year‐old man has been diagnosed with severe anaemia. What is his saturation and PO2 likely to be, if he is breathing air ‐ Select ONE OPTION
Normal values
PO2 12.0‐14.7
A. Saturation 90%, PO2 PO2 9.2 kPa
B. Saturation 99%, PO2 13.1 kPa
C. Saturation 88%, PO2 13.1 kPa
D. Saturation 99%, PO2 8.6 kPa
E. Saturation 95%, PO2 16.9 kPa

Saturation 99% and pO2 13.1