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Flashcards in deck_1286481 Deck (25):
1

State Boyles law

• Pressure is inversely proportional to volume for a fixed quantity of gas in a container of given size

2

State Charles law

• Pressure is directly proportional to absolute temperature for a fixed quantity of gas in a container of a given size (kelvin)

3

State the universal gas law

• Pressure is inversely proportional to volume for a fixed quantity of gas and directly proportional to absolute temperature• PV = nRT (n = number of molecules of gas in moles) (R = the universal gas constant)

4

What is STP?

• 273 deg K (0*C), 101.1 kPa (temperature sometimes corrected for body temperature)

5

Define the term partial pressure

• Provided the constituents of a gas mixture do not combine chemically, each component of a gas mixture can be said to exert a partial pressure • Same proportion of the total pressure as the volume fraction of the gas in the mixture

6

Proportion of O2 in dry atmospheric air is 20.9% - what is the partial pressure of O2 if total atmospheric pressure is 101.1kPa

• pO2 = 101.1 x 0.209 = 21.1299 21l1 kPa

7

Define 'vapour pressure'

• The pressure exerted by water vapour entering a gas

8

Define 'saturated vapour pressure'

• If a gas mixture is in equilibrium (molecules enter and leave water at same rate) with water, then the vapour pressure is maximum - the saturated vapour pressure• 6.28 kPa at 37*C

9

Define 'tension'

• The partial pressure exerted by gas molecules entering a liquid• Indicates how readily gas will leave the liquid

10

Define solubility

• The amount of gas that needs to enter a liquid in order to establish a given pressure• Content/tension

11

Define 'content' of a gas in a liquid

• The amount of gas in a liquid• Total content of gas = reacted gas (O2 bound to haem) + dissolved gas (O2 free in plasma)Content = solubility x tension

12

Why is 13.3 kPa significant?

• The average kPa of O2 blood is exposed to

13

At normal levels, how many mmol.l-1 O2 are bound to haemoglobin per litre?

• 8.8 mmol.l-1

14

What's the minimum amount of O2 that the body must pick up per minute per 5l of blood

• 12mmol

15

Define 'tidal volume'

• The volume of air drawn into the lungs with each breath

16

Define the term 'respiratory rate'

• Number of breaths per minute

17

Define the term 'pulmonary ventilation rate'

• Tidal volume x respiratory rate

18

How can the larynx cause difficulty breathing?

• Laryngeal or vocal cord tumours• Laryngeal oedema due to ○ Allergic reactions ○ Severe infections such as croup or acute epiglottis• Bilateral vocal cord paralysis

19

How can problems in the nose cause difficulty breathing?

• Polyps, tumors

20

How can problems in the pharynx cause difficulty breathing?

• Tumours • Airway of an unconscious person may become blocked if their tounge falls backwards into their pharynx• Sleep apnoea syndrome - loss of tone in pharyngeal muscles during sleep can cause them to become floppy and obstruct airways

21

How can viral URTIs spread to the sinuses and the middle ear?

Sinuses via opening into nasal cavityMiddle ear via eustachian tube, which connects nasopharynx to middle ear

22

What is emphysema caused by?

• Alpha-1-antitrypsin deficiency or smoking

23

What occurs in emphysema?

• Aveolar walls normally hold bronchioles open - however, when they are damaged bronchioles collapse and air becomes trapped, making it difficult for the lungs to empty.

24

What is pneumonia?

• Inflammation of the lung caused by bacteria• The lungs fill with inflammatory fluid, increasing the difficulty of breathing

25

Give three different causative agents of pneumonia

• Streptococcus pneumoniae • Mycoplasm pneumoniae• Saphylococcus aureus