Respiratory

Question 1

Spirometer measures

Answer 1

Tidal volume
respiratory rate
IRV
ERV

Question 2

Vital Capacity is

Answer 2

the volume of air expired from full inspiration to full expiration

Question 3

Vitalograph measures

Answer 3

amount of air that can be forcefully exhaled over a period of time.

Question 4

FEV1

Answer 4

The volume of air expelled within the first second is the Forced Expiratory Volume in one second

Question 5

FVC

Answer 5

The maximum amount of air that can be expelled from the lungs following a maximum inspiration is the Vital Capacity (VC)

Question 6

restrictive lung disease

Answer 6

cannot fully expand their lungs, so less capacity for lungs to take in more air

Question 7

obstructive lung disease

Answer 7

make it hard to exhale all the air in the lungs.

Question 8

What does the flow-volume loop measure?

Answer 8

measures airflow rate during forced expiration and forced inspiration

Question 9

The main difference between standing and lying with regard to respiration is the

Answer 9

position of the abdominal contents.

Question 10

PEF

Answer 10

Peak Expiratory Flow, should be achieved before 15% of vital capacity has been exhaled - driven by muscle force and recoil

Question 11

What does PIF stand for?

Answer 11

Peak Inspiratory Flow, should be achieved at about 50% of volume inhaled

Question 12

Reason for small airway closure in Asthma compared to Emphysema

Answer 12

Asthma - small airway resistance causes SAC

Emphysema - loss of elasticity, causing intrapleural pressure to increase causes SAC

Question 13

Cause of water tension in the alveolar

Answer 13

Water molecules wanting to get close together, creating inward pressure

Question 14

What reduces the attraction of water molecules to each other in the alveolus

Answer 14

Type 2 cells in the alveolar wall produce pulmonary surfactant molecules, that dispense between the water molecules and reduce the water tension (alveolar surface tension)

Question 15

How does pulmonary surfactant molecule prevent small alveolar collapse

Answer 15

The alveolar produce a set amount of pulmonary surfactant. Therefore, the concentration of surfactant molecules is higher in small alveolar then the neighbouring in the larger ones, therefore the water tension is reduced more, reducing the tendency of smaller alveolar to collapse into larger ones

Question 16

Closed chamber formed by Visceral and parietal pleura

Answer 16

Pleural cavity (intrapleural space)

Question 17

At rest, the pressure outside the lungs is the same as in the alveolar (760). The interpleural space pressure however is below atmospheric pressure (756) , why? and what is this difference called?

Answer 17

The fluid lining in the alveolar creates the alveolar surface tension, which pulls the visceral pleura inward. This increases the size of the interpleural space and the pressure drops. This creates the transmural pressure gradient.

Question 18

Explain the process of forced expiration & dynamic small airway closure

Answer 18

• Firstly, forces inspiration takes place, stretching the connective tissue and creating extra recoil
• Pressure in the interpleural space increases dramatically due to muscle action (abdominal mucus and intercostal muscles) because there is less space so higher pressure
• This causes a pressure increase in the alveolar. Which forms a pressure gradient between alveolar and interpleural space
• Air now flows faster through the small airways to the large airways and then out
• Pressure is lost more rapidly, until the pressure in the small airways equalises with the high interpleural pressure
• The high interpleural pressure starts to compress the small airways and closes them off, trapping some air behind in the alveolar (residual volume)

Question 19

Explain what asthma is (not consequences)

Answer 19

• Inflammation of inner lining of small airways and mucus is produced
• Smooth muscle around airways tightens (bronchoconstriction)

Question 20

Phases of an asthma Attack

Answer 20

• Immediate phase where immune cells produce histamine which create bronchospasm
• Last phase where inflammation caused by immune cells producing chemotaxis

Question 21

Why do asthma patients have increase residual volume?

Answer 21

Increase in airway resistance in the small airway, therefore more pressure is lost quicker, and early dynamic small air way closure happens faster, resulting in a higher residual volume

Question 22

Ealy small airways closure in emphysema

Answer 22

Interpleural pressure is higher in the first place, which means the pressure in the airways becomes equal with the interpleural pressure quicker, and early dynamic small air way closure happens, resulting in a higher residual volume

Question 23

What is a physiological dead space and when does it occur?

Answer 23

• There is a constriction in an arteriole that doesn’t allow blood flood into the capillary bed, preventing gas exchange occurring. The alveolar cannot be ventilated and, therefore it becomes a dead space.
• It occurs when V/P >1

Question 24

Explain what happens when ventilation (air flow) is greater than blood flow (perfusion)

Answer 24

• Increase oxygen causes dilation of blood vessel, which increase blood flow to help balance
• Low CO2 causes a contraction of airways smooth muscles, which increases airway resistance and decreases air flow to help balance

Question 25

What is a physiological shunt and when does it occur?

Answer 25

• When there is an abnormal bronchial constriction, the alveolar cannot be ventilated even through blood can still flow into the capillary bed. A vesicle forms that allows blood to flow from right side to left side of the heart without taking part in gas exchange.
• It occurs when V/P <1

Question 26

Explain what happens when ventilation (air flow) is less than blood flow (perfusion)

Answer 26

• Increased CO2 causes decreased airway resistance, which increases airflow to help balance
• Decreased O2 causes an increase of vascular resistance which decrease blood flow to help balance

Question 27

What are the two control centres for respiratory in the brain stem

Answer 27

• Pons

- Medullary

Question 28

What are the controls in the medullary respiratory control centre and what are they responsible for?

Answer 28

• Rostral – identifies peacemaking potential and is responsible for respiration rhythm
• Dorsal – innovated diaphragm during quiet breathing
• Ventral – Takes over from Dorsal in forced breathing and activated abdominal and intercostal muscles

Question 29

What is the role of the pons in respiratory control

Answer 29

Fine tunes the pacemaking activity of the rostral medulla

Question 30

What occurs when the arterial partial pressure of oxygen (Po2) goes below 60mm Hg? (100mm Hg is normal)

Answer 30

The peripheral chemoreceptors monitor oxygen and signal the medullary respiratory centre to increase ventilation, which increases arterial Po2 (partial pressure of oxygen)

Question 31

Explain what happens with the partial pressure of CO2 increases (in blood)?

Answer 31

• Carbon dioxide rapidly crosses the blood brain barrier
• Increase in partial pressure of carbon dioxide causes an increase in brain ECF partial pressure of CO2
• carbonic anhydrase causes a change in brain ECF brain ph. Central chemoreceptors monitor the brain PH
• When the brain PH decreases, the central chemoreceptors stimulate the medulla centre to increase ventilation which reduced partial pressure of CO2

Question 32

What happens when the blood PH becomes acidic due to metabolic processes and you are in metabolic acidosis?

Answer 32

• Peripheral chemoreceptors detect this and stimulate the medullary respiratory centre to increase ventilation and decrease arterial CO2 – H+ and relieve the acidosis
• The central chemoreceptors don’t monitor it as H ions cannot penetrate the blood brain barrier

Question 33

Apnea vs Dyspnea

Answer 33

Apnea - person forgets to breathe

Dyspnea - person feels ventilation is inadequate