Respiratory physiology

Question 1

What is the pressure of the atmosphere?

Answer 1

760mmHg or 101kPa

Question 2

What is the air pressure in the alveoli?

Answer 2

13kPa oxygen and 5kPa CO2

Question 3

How is maximum oxygen consumption abbreviated?

Answer 3

VO2max

Question 4

What is ATP catalysed by?

Answer 4

Large protein molecules

Question 5

How is ATP formed?

Answer 5

Degradation of hydrocarbons

Question 6

How is air drawn in to the body?

Answer 6

By the nose and mouth via trachea and bronchioles

Question 7

Where do the lungs sit?

Answer 7

In a double layered bag of membranes known as the pleura

Question 8

Why is there a small fall in pleural and alveolar pressure during inspiration?

Answer 8

Because cavities are expanding

Question 9

What is the role of the respiratory tract?

Answer 9

Makes air warm and wet to decreases oxygen pressure

Question 10

What part of the respiratory system is known as dead space?

Answer 10

Everything up to the bronchioles

Question 11

What must air do before entering the alveoli?

Answer 11

Mix with air in the dead space

Question 12

What is the gas exchange reservoir?

Answer 12

Air in the respiratory bronchioles, alveolar ducts and sacs

Question 13

What is tidal volume?

Answer 13

Volume of normal inspirations and expirations (350-500ml)

Question 14

How does volume increase during exercise?

Answer 14

Taking up reserve volumes

Question 15

How can reserve volumes be used?

Answer 15

Contraction of intercostal muscles

Question 16

Where does gas exchange occur?

Answer 16

Respiratory bronchioles and alveoli

Question 17

What are alveolar sacs?

Answer 17

Thin-walled structures where gas exchange occurs via P1 cells

Question 18

Role of P2 cells

Answer 18

Prevents internal collapse by reducing surface tension

Question 19

Why does air in the airways have low oxygen content?

Answer 19

It is saturated with water vapour therefore it has to mix with air in the alveoli

Question 20

What is the oxygen content of alveolar air?

Answer 20

13kPa

Question 21

What is expired air?

Answer 21

Mixture of alveolar and inspired air at 16kPa

Question 22

How much haemoglobin (Hb) is in a litre of blood?

Answer 22

150g

Question 23

When does Hb have a greater affinity for oxygen?

Answer 23

At low pressures

Question 24

What causes blood to fully oxygenate?

Answer 24

Respiratory pigment Hb and 2 and 3 diphosphoglycerate (DPG)

Question 25

What are the 2 conformations of Hb?

Answer 25

T (tense) state and R (relaxed) state

Question 26

Conditions of T state

Answer 26

De-oxygenated, blue

Question 27

Conditions of R state

Answer 27

Oxygenated, red

Question 28

What is the role of DPG?

Answer 28

Stabilising de-oxygenated Hb long enough for oxygen to bind

Question 29

In what state does Hb bind more oxygen?

Answer 29

R state

Question 30

What occurs if all sites of Hb are full?

Answer 30

DPG is released

Question 31

Why does Hb favour T state when oxygen pressure is lower?

Answer 31

Temperature, acidity, CO2 and DPG are elevated

Question 32

How is CO2 carried in the blood?

Answer 32

As bicarbonate

Question 33

What is the chemical reaction for bicarbonate?

Answer 33

CO2 + H2O<>H+ + HCO3-

Question 34

What is the bicarbonate reaction dependent on?

Answer 34

Gas pressure and ability of Hb in T state to bind H+

Question 35

When is CO2 formed instead of bicarbonate?

Answer 35

When oxygen pressure is higher

Question 36

Why can birds fly at higher altitudes and have high heart rates?

Answer 36

Because they have enhanced uptake by Hb and improved respiratory gas exchange

Question 37

How do birds lungs vary to humans?

Answer 37

Finer air capillaries with surrounding blood vessels

Question 38

Role of parabronchi

Answer 38

Lead to gas exchange membrane in air capillaries

Question 39

When are parabronchi used?

Answer 39

During exhalation when posterior sacs empty