respiratory system

Question 1

how does an asthmatic airway look?

Answer 1

walls inflamed and thickened.

Question 2

surfactant in airways.

Answer 2

The effects of surface tension; the fluid lining the alveoli naturally exerts surface tension which
causes the lungs to want to collapse and resist expansion.
- Surfactant: secreted via the alveoli cells to reduce the surface tension.

Question 3

Patm stands for

Answer 3

Pressure of the atmosphere (outside pressure)

Question 4

Palv stands for?

Answer 4

Pressure within the alveoli (inside pressure)

Question 5

PIp

Answer 5

Intrapleural Pressure or pressure within the pleural cavity. Also
known as negative pressure

Question 6

what are the four divisions in the lung of VOLUMES?

Answer 6

tidal volume. inspiratory reserve volume. expiratory reserve volume. and residual volume.

Question 7

what are the four lung capacity groups?

Answer 7

vital capacity, total lung capacity, inspiratory capacity and functional residual capacity.

Question 8

what is minute ventilation?

Answer 8

Minute Ventilation (VE) = tidal volume (VT) x breathing frequency (f). healthy person at rest will take 12 breaths per minute.

Question 9

what is known as dead space or Vd.

Answer 9

Some of the inhaled air never gets to the alveoli so cannot gas exchange = 150ml

Question 10

Alveolar ventilation

Answer 10

is the amount of air that gets into the alveoli. Alveolar ventilation is tightly regulated to ensure that there is always the right amount of fresh air available in the alveoli for gas exchange.

Question 11

what is increased alveolar ventilation known as?

Answer 11

Hyperventilation – Fast Deep Breathing

Question 12

what is decreased alveolar ventilation known as?

Answer 12

Hypoventilation – Slow Shallow Breathing

Question 13

what does atmospheric air consist of?

Answer 13

• Nitrogen (N 2) = around 78%
• Oxygen (O 2) = around 21%
• Small amounts of carbon dioxide (CO 2) = around 0.04%

Question 14

what is the gradient between alveolar and atmospheric o2?

Answer 14

PAO2 is lower (100mmHg) than atmospheric O2 (160mmHg) because some of the O2 that enters the alveoli leaves by entering the pulmonary capillaries.

Question 15

what is the difference between alveolar CO2 and atmospheric air?

Answer 15

(PACO2) is much higher (40 mmHg) than that in atmospheric air (close to zero)

Question 16

what is the rate at which diffusion occurs?

Answer 16

D(gas) x surface area x ^P(gas) / thickness.
note ^P(gas) = P1 - P2

Question 17

what diffuses quicker CO2 or O2?

Answer 17

CO2 diffuses about 20x faster than O2 due to CO2 higher solubility.

Question 18

gas exchange of O2

Answer 18

O2 = alveoli (100mmHg) -> blood (95mmHg)

Question 19

gas exchange of CO2

Answer 19

CO2 = blood (45mmHg) -> alveoli (40mmHg)

Question 20

how is O2 transported through the blood (two forms)

Answer 20

• Combined with haemoglobin.
• Dissolved in plasma

Question 21

how is co2 transported through the blood (three ways)

Answer 21

• Dissolved in plasma. (7%)
• Combined with haemoglobin
• As bicarbonate -HCO3-

Question 22

how many O2 molecules can 1 Hb carry?

Answer 22

4

Question 23

how is the majority of O2 carried.

Answer 23

bound to Hb

Question 24

O2 binds to haem group with contain iron ions.

Answer 24

yes

Question 25

how much Hb does healthy blood contain?

Answer 25

approximately 150mg per litre and each gram of Hb can carry 1.34ml of O2.

Question 26

what is the Hb-O2 saturation percentage of arterial blood?

Answer 26

98%

Question 26

what is the Bohr effect

Answer 26

describes haemoglobins affinity for oxygen.

Question 26

what is the Hb-O2 saturation percentage of venous blood?

Answer 26

75%

Question 27

what does left shift on the oxy-haemoglobin dissociation curve mean? and how is it caused?

Answer 27

occurs in the lungs and facilitates more loading of oxygen (increased loading). caused by lower levels of CO2/H+ and low temp.

Question 27

what does right shift on the oxy-haemoglobin dissociation curve mean? and how is it caused?

Answer 27

occurs in the tissues and facilitates more release of oxygen (increased unloading). cuased by higher levels of CO2/H+ and high temp.

Question 28

what percent of carbon dioxide is dissolved in plasma ?

Answer 28

7% percent is transported out of the tissues as it is dissolved in plasma.

Question 29

what percent of carbon dioxide is bound to haemoglobin?

Answer 29

Approximately 23% of CO2 is transported out of the tissues in blood, bound reversibly to the protein subunits of haemoglobin (globin chains).
- CO2 bound to Hb, and in this form, Hb has a much lower affinity for O2.

Question 30

What per cent of carbon dioxide is transported as bicarbonate ions?

Answer 30

70%. Most of CO2 is produced by the tissue us carried within the blood as HCO3-.
Conversion from CO2 -> HCO3 happens in red blood cells with the assistance of an enzyme.
HCO3- produced can then move out into the plasma.

Question 31

what is Alkalosis?

Answer 31

increased pH (above normal pH>7.45). due to decreased concentration of H+ ions. can compensate by hypoventilation to increase CO2(breath hold) thus increasing H+ ion concentration in the blood.

Question 32

what is acidosis?

Answer 32

Decreased pH, below normal range (pH < 7.35).
- Due to increased concentration of H+ ions.
- Can be compensated for by Hyperventilating to decrease CO2 (breath more off); thus decrease H+ ion concentration in the blood.