The respiratory system

Question 1

What is the upper repiratory tract important in?

Answer 1

Producing sound, humidifying and warming air, defence (mucus and cilia) and sensory functions.

Question 2

What is the lower respiratory tract involved in?

Answer 2

Gas exchange, defence functions and metabolic functions.

Question 3

What is the upper respiratory tract made up of?

Answer 3

The nasal cavity, pharynx and larynx.

Question 4

What is the lower respiratory tract made up of?

Answer 4

The trachea, primary bronchi and lungs.

Question 5

What is the larynx?

Answer 5

A cartilage structure that is used to generate different sounds and tones.

Question 6

What is the pharynx?

Answer 6

It has respiratory and digestive functions - involved in swallowing but also allows the movement of air from the mouth and nose to the larynx.

Question 7

What is the structure of the trachea?

Answer 7

It is made up of rings of cartilage interspersed with connective tissue and smooth muscle.

Question 8

What is the parenchyma?

Answer 8

The functional unit of the lung where gas exchange takes place.

Question 9

What is the conducting zone?

Answer 9

The tubes/airways outside of the lung (extrapulmonary)

Question 10

What are the lung branches called?

Answer 10

Bronchioles. These are small bronchi.

Question 11

What is the equation for airway resistance?

Answer 11

1/conduction.

Question 12

What is airway resistance proportional to?

Answer 12

1/radius^4.

Question 13

What are the largest contributors to the airway resistance?

Answer 13

The conducting zone bronchioles.

Question 14

In what diseases is the airway resistance increased?

Answer 14

Asthma.

Question 15

What happens in asthma?

Answer 15

There is narrowing of the airway that results in a thickened airway wall. There is also increased mucus, contributing to the narrowed airway.

Question 16

What type of epithelium does the bronchi have?

Answer 16

Ciliated, goblet and glandular.

Question 17

What type of epithelium do the bronchioles have?

Answer 17

Ciliated, non-ciliated, goblet and club cells.

Question 18

What type of epithelium does the alveoli have?

Answer 18

Squamous and cuboidal.

Question 19

What are club cells?

Answer 19

A different type of secretory cell.

Question 20

What are the airways made up of?

Answer 20

Goblet cells, a mucus blanket, basement membrane and cilia.

Question 21

What do sensory afferent nerves link?

Answer 21

They are from the airway epithelium and smooth muscles to the brain.

Question 22

What do autonomic fibres link?

Answer 22

The glandular epithelium and smooth muscle from the CNS.

Question 23

What autonomic fibres are involved in airway innervation?

Answer 23

Autonomic fibres to glandular epithelium and smooth muscle from the CNS. There are parasympathetic branches of the vagus nerve (excitatory and inhibitory) and there is very little sympathetic innervation.

Question 24

What are beta adrenoceptors on the airway smooth muscle stimulated by?

Answer 24

Circulating adrenaline.

Question 25

What is the respiratory unit made up of?

Answer 25

A network of airways and airsacs (500 million) to maximise the surface area.

Question 26

What is the surface area of the alveoli?

Answer 26

80 metre squared.

Question 27

What are the alveoli lined with?

Answer 27

Pneumocytes - type I is squamous and there is also a type II.

Question 28

What makes up the lung parenchyma?

Answer 28

The terminal bronchiole, respiratory bronchiole, alveolar duct and pulmonary arteriole and pulmonary vein.

Question 29

What characteristics does the type I alveolar epithelial cells have?

Answer 29

A very large surface area, cover 95% of the alveolus and 10% of all the cells. They are squamous and are involved in gas exchange.

Question 30

What are the characteristics of type II epithelial cells?

Answer 30

They are cuboidal, secrete surfactant and they are precursors for type I.

Question 31

What is surfactant made up of?

Answer 31

Lipid (90% - mostly phospholipid) and proteins such as SP-A, -B, -C and -D.

Question 32

What is the purpose of surfactant?

Answer 32

It reduces the surface tension to prevent alveolar collapse (atelectasis) and they provide an immunity function.

Question 33

What is Infant Respiratory Distress Syndrome?

Answer 33

A syndrome in which babies do not produce surfactant. They can be given it artificially in the form of Beractant or Pumactant.

Question 34

What is the difference between Beractant and Pumactant?

Answer 34

Beractant is from animals whereas Pumactant is synthetic and lipid only.

Question 35

When does the lung epithelium develop in pregnancy?

Answer 35

In the last trimester.

Question 36

How is maturation of the lung epithelium stimulated?

Answer 36

Corticosteroids.

Question 37

How is the fluid in babies lungs emptied at birth?

Answer 37

There is a surge in corticosteroids and catecholamines and an activation of absorptive channels such as epithelial sodium channels (ENaC). There is also pressure changes.

Question 38

What are the two blood supplies to the lungs?

Answer 38

The pulmonary circulation and bronchial circulation.

Question 39

What are the characteristics of the pulmonary circulation?

Answer 39

There is low oxygen but high flow and low pressure. Capillaries pass around the alveoli and the pulmonary vein returns oxygenated blood to the left side of the heart.

Question 40

What are the characteristics of bronchial circulation?

Answer 40

The blood is from the aorta (left ventricle) and is under high pressure. It supplies oxygen and nutrients to the conducting airways and is not involved in systemic respiration processes. It accounts for only 2% of the cardiac outflow.

Question 41

What is ventilation?

Answer 41

The movement of air from the environment into the lungs.

Question 42

How is breathing neuronally controlled?

Answer 42

Levels of oxygen in the blood is detected and in the brain. Signals can be sent back to override these signals consciously if you want to hold your breath.

Question 43

How does muscle innervation occur?

Answer 43

please look at this again

Question 44

What are the internal intercostal responsible for?

Answer 44

Forced exhalation.

Question 45

What are the external intercostal muscles involved in?

Answer 45

Forced and quiet inhalation.