Respiratory physiology Flashcards

1
Q

What are the functions of the respiratory system?

A

Gas exchange - oxygen added to blood from air and carbon dioxide removed from blood into the air.
Acid-base balance - regulation of body pH.
Protection from infection.
Communication via speech.

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2
Q

Which of the functions is most important in the respiratory system.

A

Gas exchange

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3
Q

Why do we breathe?

A

Method of obtaining oxygen which can be burned to release energy required to fuel cells.

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4
Q

What is the respiratory system responsible for?

A

Acquiring oxygen and removing carbon dioxide.

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5
Q

How does the cardiovascular system help out the respiratory system?

A

Transports oxygen towards tissues and transports carbon dioxide away from tissues.

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6
Q

What is meant by external respiration?

A

Integration of respiratory and cardiovascular systems to allow movement of gases between the air and the body’s cells.

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7
Q

How does pulmonary circulation differ from systemic circulation?

A

The pulmonary circulation has opposite function to systemic. The pulmonary artery carries deoxygenated blood away from the heart and the pulmonary vein carries oxygenated blood towards heart.

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8
Q

Give an example of the intimate relationship between the CV and respiratory systems?

A

During exercise - Increase in energy demand by working muscle leads to:
Respiratory system increasing rate and depth of breathing and speeding up oxygen acquisition and waste disposal.
This causes the CV system to increase heart rate and force of contraction. Also speeds up substrate delivery to muscle via blood and the removal of waste via blood.

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9
Q

Where does gas exchange occur?

A

Occurs in the Alveolar of the lungs and at the Systemic capillaries.

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10
Q

What are the average volumes of gas that are exchanged per minute?

A

250 ml oxygen exchanged (consumed)

200 ml carbon dioxide exchanged (produced)

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11
Q

What are the average breathing rates of adults at rest and during exercise?

A

10-20 breaths/min at rest

40-50 breaths/min during max exercise

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12
Q

What is the epiglottis?

A

Small flap of tissue that folds over the trachea and prevents food entering when you swallow.

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13
Q

What structures make up the upper respiratory tract?

A

Pharynx, nasal cavity, Larynx, mouth

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14
Q

What structures make up the lower respiratory tract?

A

Trachea, bronchi and lungs.

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15
Q

How many lobes does each lung have?

A

Right has 3 lobes and left has 2 lobes.

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16
Q

What makes the right bronchi the one more likely to have aspirated foreign bodies commonly lodge here?

A

Tha right bronchi is more vertical and is wider than the left bronchi so it is easier for foreign particles to get lodged within it.

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17
Q

What is meant by latency?

A

Patency is the condition of being open or unobstructed. Therefore a patent airway is an open airway.

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18
Q

What maintains the patency of the trachea and bronchi?

A

C - shaped rings of cartilage.

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19
Q

Why does most resistance to airflow occur in the trachea and not the smaller alveoli?

A

We only have 1 trachea however we have thousands of alveoli. The surface of the thousands of alveoli is greater than the surface area of the trachea so in total they have less resistance.

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20
Q

How can bronchial smooth muscle activity alter the diameter and therefore resistance to airflow?

A

Contraction decreases diameter = increases resistance

Relaxation increases diameter = decreases resistance

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21
Q

What makes up the lining of the respiratory tract?

A
Epithelium (psuedo-stratified, ciliated, columnar)
Glands
Lymph nodes
Blood vessels (nutritive)
Ciliated
Mucous
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22
Q

What happens to the lining as it progresses form the nose down towards the Alveoli?

A

Epithelium becomes more squamous
Cilia lost
Mucous cells lost (before cilia)

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23
Q

What is the role of mucous?

A
Moistens air
Traps particles
Provides large surface area for cilia to act on
Goblet cells
Subepithelial glands
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24
Q

What are the 3 types of cells that make up Alveoli?

A

Type 1 pneumocytes - site of gas exchange
Type 2 pneumocytes - production of surfactant
Macrophages - gathers residual dirt

25
Q

What is Boyle’s law?

A

Boyle’s law states hat the pressure exerted by a gas is inversely proportional to its volume.

26
Q

What does the visceral membrane coat?

A

Coats the outer surface of the lungs. (visceral means organs so closet to the organs)

27
Q

What does the parietal membrane coat?

A

Coats the inner surface of the ribs.

28
Q

What is the function of pleural fluid?

A

It lies between visceral and parietal membranes, essentially sticking the lungs to the ribs and diaphragm.

29
Q

Why is inner pleural pressure always negative in healthy individuals?

A

It is always negative because the lungs and the ribs are always trying to pull apart due to elastic recoil. However the pleural fluid prevents this.

30
Q

What 2 muscles does inspiration use?

A

Intercostal muscles and the diaphragm.

31
Q

What muscles does expiration use?

A

At rest exasperation is passive however under severe respiratory load they use internal intercostal muscles and abdominal muscles.

32
Q

What is Asthma?

A

Over-reactive constriction of bronchial smooth muscle. Increases resistance, making expiration difficult.

33
Q

What is Pneumothorax?

A

A collapsed lung that is no longer attached to the ribs or the diaphragm.

34
Q

Describe Intra thoracic pressure (alveolar)?

A

Pressure inside the thoracic cavity, (essentially pressure inside the lungs). May be negative or positive compared to atmospheric pressure.

35
Q

Describe intra pleural pressure?

A

Pressure inside the pleural cavity, ALWAYS negative (in healthy lungs at least!)

36
Q

Describe transpulmonary pressure?

A

Difference between alveolar pressure and intra-pleural pressure. ALWAYS positive (in health) because Pip is always negative. PT = PA – Pip.

37
Q

What happens when Alveolar pressure is negative?

A

Air will move into the lungs and we inspire.

38
Q

What happens when Alveolar pressure is positive?

A

Air will move out of the lungs and we expire.

39
Q

What is airway resistance?

A

It determines how much air flows into the lungs at any given pressure difference between atmosphere and alveoli. The major determinant of airway resistance is the radii of the airways.

40
Q

What is anatomical dead space?

A

The volume of gas occupied by the conducting airways and this gas is not available for exchange. Average is about 150ml.

41
Q

What is tidal volume?

A

The volume of air breathed in or out of the lungs at each breath.

42
Q

What is inspiratory reserve volume?

A

The maximum volume of air which can be drawn into the lungs at the end of a normal inspiration.

43
Q

What is expiratory reserve volume?

A

The maximum volume of air which can be expelled from the lungs at the end of a normal expiration.

44
Q

What is residual volume?

A

The volume of gas in the lungs at the end of a maximal expiration.

45
Q

What is vital capacity?

A

Tidal volume + inspiratory reserve volume + expiratory reserve volume.

46
Q

What is total lung capacity?

A

vital capacity + the residual volume

47
Q

What is meant by ventilation?

A

The movement of air in and out of the lungs.

48
Q

What is partial pressure?

A

The pressure that would be exerted by one of the gases in a mixture if it occupied the same volume on its own.

49
Q

What is surfactant?

A

Detergent like fluid released by type 2 pneumocytes. Reduces surface tension on alveolar surface membrane thus reducing tendency for alveoli to collapse.

50
Q

When does surface tension occur?

A

Where ever there is an air-water interface and refers to the attraction between water molecules.

51
Q

Why is surfactant more effective in smaller alveoli than larger?

A

Surfactant molecules can get closer together and are therefore more concentrated.

52
Q

What is compliance?

A

Change in volume relative to changes in pressure. Represents the stretchability of the lungs.

53
Q

What happens when there is high compliance and when there is low compliance?

A

High compliance = large increase in lung volume for small decrease in pressure.
Low compliance = small increase in lung volume or large decrease in pressure.

54
Q

What is emphysema?

A

Loss of elastic tissue means expiration requires effort.

55
Q

What is fibrosis?

A

Inert fibrous tissue means effort of inspiration increases.

56
Q

What is meant by obstructive lung disease?

A

Obstruction of air flow, especially on expiration.

e.g Asthma, COPD - chronic bronchitis, emphysema.

57
Q

What is meant by restrictive lung disease?

A

Restriction of lung expansion.

e.g fibrosis, infant respiratory distress syndrome.

58
Q

What is spirometry?

A

Technique commonly used to measure lung function. Can be static and dynamic.