Physiology of the respiratory system

Question 1

Air pressure at altitude

Answer 1

-higher altitude pressure drops
-lower altitude pressure increases
-sea level air pressure= 760mmHg= 1 atm

Question 2

Boyles law

Answer 2

-applies to containers with flexible walls eg. thoracic cage
-volume and pressure are inversely related

Question 3

Dalton’s law

Answer 3

-applies to mixture of gases
-pressure exerted of each gas is proportional to the percentage of that gas in the total mixture
eg. O2= 21% of atmosphere
0.21 x 760 mmHg= 159.6 mmHg of O2 at sea level

Question 4

Henry’s law

Answer 4

-deals gases and solutions
-increasing partial pressure of gas over solution will result in more of the gas dissolving into the solution

Question 5

Pulmonary ventilation
definition and how it works

Answer 5

-movement of air between the atmosphere and alveoli
-made possible by changes in intrathoracic volume

Question 6

External respiration

Answer 6

gas exchange between alveoli and blood

Question 7

Internal respiration

Answer 7

gas exchange between capillaries and body tissues

Question 8

What is the primary muscle of respiration

Answer 8

diaphragm

Question 9

3 factors that affect the ease we ventilate

Answer 9

1. surface tension of alveolar fluid
2. High lung compliance- how well the lungs inflate and chest expands
3. larger diameter of airway, therefore lower resistance

Question 10

Poiseuilles law

Answer 10

If bronchioles dilate a little, resistance drops by the power of 4

Question 11

Tidal volume

Answer 11

Volume of air inspired during normal quiet breathing (500ml)

Question 12

Inspiration reserve volume

Answer 12

Volume inspired during a deep inspiration (3100ml- dependent on height and gender)

Question 13

Expiratory reserve volume

Answer 13

Volume expired during forced exhalation (1200ml)

Question 14

Vital capacity

Answer 14

all the air that can be exhaled after max inspiration
sun of inspiration reserve, tidal volume, expiratory reserve

Question 15

Residual volume

Answer 15

air present in lungs after force exhalation (1200ml)

Question 16

Measuring ventilation

Answer 16

-70% of tidal volume reaches respiratory zone
-30% remains in conducting zone
If tidal vol = 500ml only 350ml makes respiratory zone

Question 17

Nitrogen and why doesn’t dissolev into blood

Answer 17

-most air we breathe is N2, very little dissolves into blood because of low solubility

Question 18

Transport of O2

Answer 18

-in blood some O2 dissolved in plasma, 1.5%
-most carried by Hb as oxyhaemoglobin

Question 19

Transport CO2

Answer 19

-7% dissolved in plasma
-70% converted carbonic acid
-23% attached to Hb (dif binding sites to O2)

Question 20

Normal pulse oximetry reading

Answer 20

94-98%

Question 21

Graph that shows oxygen saturation

Answer 21

oxygen-haemoglobin saturation curve
-higher PO2 dissolved in plasma, the lower SpO2 (saturation Hb) as oxygen will be off loaded from the Hb and dissolve into plasma

Question 22

Control of respiration

Answer 22

-Medulla rhythmicity area in brainstem control inspiration and expiration
-Inspiratory centre stimulates the diaphragm via phrenic nerve
-Exhalation is passive process caused elastic recoil lungs
-Forced exhalation- stimulate interna intercostal muscles and abdominals
-Pneumotaxic centre- limit inspiration to prevent hyper expansion
-Apneustic centre
coordinates the transition
between inhalation and exhalation