Lower Respiratory Tract

Question 1

Name the organs/components of the lower respiratory tract.

Answer 1

Trachea
Bronchi
Alveoli
Lungs

Question 2

Where does the trachea extend to and from?

Answer 2

C6 - T5

Question 3

Which structure provides support and flexibility to the trachea?

Answer 3

C-shaped hyaline cartilage

Question 4

Where does the trachea bifurcate into the right and left bronchi?

Answer 4

T4/5 (carina)

Question 5

Which bronchus has a higher choking risk (from particulates being trapped)?

Answer 5

Right bronchus as it is shorter and less angled.

Question 6

Describe the divisions of the right bronchus.

Answer 6

Right bronchus divides into:
upper lobe
middle lobe
lower lobe

10 segmental branches

Question 7

Describe the divisions of the left bronchus.

Answer 7

Left bronchus divides into:
upper lobe
lower lobe

8 segmental branches

Question 8

Describe the divisions after the segmental branches.

Answer 8

Segmental branches > terminal bronchioles > respiratory bronchioles > alveolar ducts > alveoli

Question 9

Name the two types of alveolar cell and state which one secretes surfactant.

Answer 9

Type I pneumocytes

Type II pneumocytes - these secrete surfactant

Question 10

Which structure interconnects alveoli?

Answer 10

pores of Kohn

Question 11

Describe the structure of an alveolar cell.

Answer 11

Basement membrane
Columnar ciliated epithelium
Contains alveolar macrophages

Question 12

State the lobes of the right and left lung.

Answer 12

Right lung: superior, middle, inferior

Left lung: superior, inferior

Question 13

Where does the pulmonary plexus lie?

Answer 13

Behind each hilum

Question 14

Where does the pulmonary plexus receive innervation from?

Answer 14

Vagus (CN X)

T2-T4 ganglia of sympathetic trunk

Question 15

What effect does sympathetic innervation have on the lungs?

Answer 15

Bronchodilation

Question 16

What effect does parasympathetic innervation have on the lungs?

Answer 16

Bronchoconstriction

Question 17

Describe the two layers of lung pleura.

Answer 17

1. VISCERAL: applied to lung surface
   - Only autonomic innervation, no pain sensation
2. PARIETAL: applied to internal chest
   - Pain sensation via phrenic nerve

Fluid lies between the two layers.

Question 18

Name the 2 types of circulation within lungs.

Answer 18

Bronchial and pulmonary (main circulation of lung)

Question 19

How many branches are there of the left and right pulmonary arteries?

Answer 19

17

Question 20

Compare the differences between pulmonary and systemic circulation.

Answer 20

PULMONARY:

• vessel walls are thin
• minor muscularisation
• no need for redistribution
• lower pressure

SYSTEMIC:

• vessel walls are thick
• significant muscularisation
• redistribution required
• higher pressure

Question 21

Name the three divisions of the autonomic nervous system.

Answer 21

Sympathetic: fight or flight
Parasympathetic: rest & digest
Enteric: GI tract

Question 22

Describe parasympathetic innervation of the lower respiratory tract.

Answer 22

Neurotransmitter: acetylcholine
Receptors: Muscarinic cholinergic (M3)

• Innervates lungs via vagus nerve
• Innervates vasculature, glands & airways in lungs
• Top much parasympathetic activation leads to bronchoconstriction

Question 23

Describe sympathetic innervation of the lower respiratory tract, including how it causes adrenaline release.

Answer 23

Neurotransmitter: noradrenaline
Receptors: adrenergic

• innervates lung via sympathetic trunk
• innervates vasculature and glands but not airways of lungs
• causes release of adrenaline from adrenal glands. adrenaline binds to beta-2-adrenoreceptors to cause bronchodilation

Question 24

Name the two types of alpha-adrenergic receptor.

Answer 24

Alpha-1: Acts postsynaptically to either stimulate/inhibit the activity of K+ channels
Alpha-2: Acts presynaptically to inhibit noradrenaline release

Question 25

Which type of beta-adrenergic receptor is found in the lungs?

Answer 25

Beta-2

Question 26

Describe how adrenaline causes bronchodilation.

Answer 26

1. Adrenaline binds to a beta-2 receptor 2. Receptor couples with G protein 3. G protein activates adenyl cyclase 4. Adenyl cyclase catalyses the conversion of ATP to cyclic AMP (cAMP) 5. cAMP acts as a second messenger in the lungs. It causes a decreases in Ca2+ as well as activating protein kinase A. 6. These effects result in bronchodilation

Question 27

Describe how acetylcholine stimulates bronchoconstriction.

Answer 27

1. Acetylcholine binds to M3 receptor 2. Receptor couples with Gq protein 3. Gq protein activates phospholipase C 4. Phospholipase C catalyses the breakdown of a plasma membrane phospholipid to diacylglycerol (DAG) and inositol triphosphate (IP3) 5. DAG acts as a second messenger and activates protein kinase C 6. IP3 binds to ligand gated Ca2+ receptors, causing the release of Ca2+ 7. Ca2+ stimulates bronchoconstriction

Question 28

Name the two types of receptor ligand.

Answer 28

1. AGONIST - molecule binds to a receptor and activates it. Has both affinity and efficacy 2. ANTAGONIST - molecule blocks the effect of an agonist by competing for its binding site, but cannot activate the receptor. Has affinity but zero efficacy.

Question 29

Name 2 types of bronchodilators given to those with asthma and COPD.

Answer 29

Beta-2-agonists - these increase bronchodilation Muscarinic antagonists - these decrease bronchoconstriction

Question 30

Name a short acting and long acting beta-2-agonist.

Answer 30

Short acting: Salbutamol | Long acting: Salmeterol

Question 31

Name a short acting and long acting muscarinic antagonist.

Answer 31

Short acting: Ipratropium | Long acting: Tiotropium

Question 32

Name the distinguishable feature of thoracic vertebrae.

Answer 32

Costal facets to articulate with ribs

Question 33

Which component do the lungs provide in the renin-angiotensin aldosterone system?

Answer 33

Angiotensin converting enzyme (ACE)