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Flashcards in Respiratory Deck (33)
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1
Q

Spirometer measures

A

Tidal volume
respiratory rate
IRV
ERV

2
Q

Vital Capacity is

A

the volume of air expired from full inspiration to full expiration

3
Q

Vitalograph measures

A

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

4
Q

FEV1

A

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

5
Q

FVC

A

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

6
Q

restrictive lung disease

A

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

7
Q

obstructive lung disease

A

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

8
Q

What does the flow-volume loop measure?

A

measures airflow rate during forced expiration and forced inspiration

9
Q

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

A

position of the abdominal contents.

10
Q

PEF

A

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

11
Q

What does PIF stand for?

A

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

12
Q

Reason for small airway closure in Asthma compared to Emphysema

A

Asthma - small airway resistance causes SAC

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

13
Q

Cause of water tension in the alveolar

A

Water molecules wanting to get close together, creating inward pressure

14
Q

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

A

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)

15
Q

How does pulmonary surfactant molecule prevent small alveolar collapse

A

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

16
Q

Closed chamber formed by Visceral and parietal pleura

A

Pleural cavity (intrapleural space)

17
Q

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?

A

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.

18
Q

Explain the process of forced expiration & dynamic small airway closure

A
  • 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)
19
Q

Explain what asthma is (not consequences)

A
  • Inflammation of inner lining of small airways and mucus is produced
  • Smooth muscle around airways tightens (bronchoconstriction)
20
Q

Phases of an asthma Attack

A
  • Immediate phase where immune cells produce histamine which create bronchospasm
  • Last phase where inflammation caused by immune cells producing chemotaxis
21
Q

Why do asthma patients have increase residual volume?

A

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

22
Q

Ealy small airways closure in emphysema

A

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

23
Q

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

A
  • 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
24
Q

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

A
  • 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
25
Q

What is a physiological shunt and when does it occur?

A
  • 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
26
Q

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

A
  • 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
27
Q

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

A
  • Pons

- Medullary

28
Q

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

A
  • 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
29
Q

What is the role of the pons in respiratory control

A

Fine tunes the pacemaking activity of the rostral medulla

30
Q

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

A

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

31
Q

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

A
  • 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
32
Q

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

A
  • 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
33
Q

Apnea vs Dyspnea

A

Apnea - person forgets to breathe

Dyspnea - person feels ventilation is inadequate