lower respiratory tract

Question 1

rib-movement- describe the two movements?

Answer 1

2 inter-related movements

(i) Superior and anterior (pump handle)
(ii) Lateral shaft elevation (bucket handle)

Movements occur in synchrony

Question 2

what is the level of carina? what happens here?

Answer 2

division into two main bronchi, at T5

Question 3

left vs right bronchi

Answer 3

Right main bronchus more vertically disposed
1cm - 2.5cm long, related to the R pulmonary artery

Left main bronchus
5cm long, related to the aortic arch

right is more likely to be aspirated

Question 4

blood and sensory nerve supply of trachea

Answer 4

Sensory innervation of trachea: recurrent laryngeal nerve
Arterial supply: inferior thyroid artery
Venous drainage: brachiocephalic, accessory hemiazygos veins and the azygos vein

Question 5

lung hilum - left vs right layout?

Answer 5

pleura goes around hilum

left hilum:
artery is posterior to bronchus

right hilum:
artery is lateral to bronchus

Question 6

terminal vs respiratory bronchioles
examples of cells present in each

Answer 6

terminal bronchioles - last conducting airways

respiratory bronchioles- some respiratory ability, gas exchange, Lined with ciliated cuboidal epithelium
Contain some secretory cells called Clara cells or Club Cells.

(in prem babies the only thing they can use as alveoli not developed yet)

Question 7

what are the acinus? function? how many are there? diameter?

Answer 7

The lung portion distal to a terminal bronchiole, Supplied by a respiratory bronchiole, holds functional units of gas exchange, interconnections (pores of Kohn)

Approx 30,000 acini per lung
Diameter of approx. 3.5mm

Question 8

alveoli- how may in lung? SA produced? Type of cells present and there roles?

Answer 8

300 million alveoli, 80m2 for gas exchange

• type I pneumocytes (90-95%)
  flat, squamous epithelia that resemble plate-like structures that allow gas exchange
• type II pneumocytes (5-10%)
  Surfactant producing
• Occasional brush cells (type III)

Question 9

volume of air inspired/expired in a minuite

Answer 9

5 litres

Question 10

are intercostal spaces numbered below or above the rib?

Answer 10

always below, intercostal space 3 will sit below rib 3

Question 11

what supplies blood to tissue of the lung? how much of LV output? what pressure?

Answer 11

paired branches of bronchial arteries supply bronchial and peri-bronchial tissue and visceral pleura (branch of aorta)

Approximately 2% of LV output.

120mm/80mm

Question 12

Describe Lung Pleura- 2 layers? innervation of each? where are the continuos with each other?

Answer 12

visceral pleura: autonomic innervation

Parietal pleura: pain sensation

visceral pleura goes into lung fissures

small amount of fluid sit between layers
cotinuous with each other at lung root

Question 13

diaphragm- what is it?

Answer 13

domed shaped fibromuscular sheet that seperates abdomen from thorax,

Question 14

What innervates the diaphragm? where does this nerve arise from? what root does it take to diaphragm?

Answer 14

Phrenic nerve (left and right), Arise from cervical plexus C3, C4, C5,

Neck, thorax, anterior to the lung hilum (lung root)

autonomic and controll

Question 15

what do abdominal muscles and diaphragm do in inspiration and expiration?

Answer 15

Inspiration: contraction of diaphragm, relaxation of abdominal muscles
expiration: relaxation of diaphragm, contraction of abdomanal muscles

Question 16

Influences on respiration?

Answer 16

contraction of diaphragm
airflow
perfusion

Question 18

Pulmonary circulation- from heart to lungs:
thickness of vessels leading to aleveoli?
red cell transit time?
number of capillaries, alveoli and surface area?
typical normal pressure of pulmonary?

Answer 18

17 orders of branching in pulmonary circulation:

Elastic (>1mm ) and non elastic
Muscular (<1mm )
Arterioles (<0.1mm )
Capillaries

red cell transit time ≈ 5 seconds.

280 billion capillaries and 300 million alveoli
Surface area for gas exchange 50 – 100 m2

Typical normal pressure 24mm/10mm Hg

Question 19

what are the bronchovascular bundles?

Answer 19

vascular bundles run parallel to bronchus

Question 20

Autonomic plexuses - what are they? contain what types of fibres? what are the origons of these fibres?

Answer 20

large network of nerves that create a conduit for the distribution of sympathetic (from sympathetic trunk), parasympathetic (from vagus nerve), and afferent fibres, carry afferents and efferents

Question 21

where is cardiac plexus located?

Answer 21

The cardiac plexus is located around the bifurcation (division point) of the trachea and roots of the great vessels of the base of the heart

Question 22

where is pulmonary plexus located?

Answer 22

The right and left pulmonary plexuses join with the cardiac plexus.
They are situated around the primary bronchi and pulmonary arteries, at the roots of the lungs.

Question 23

vagus nerve- what’s it route?

Answer 23

Neck, thorax, posterior to the lung hilum

Question 24

Sympathetic activity in lungs: Where are neurones seperated? what molecule do they release? what cells does this act upon? overall affect in lung?

Answer 24

2 neurones seperated by ganglion in a chain adjacent to spinal cord. (short initial axon and synapse very close to spinal cord)

Release of noradrenaline activates adrenergic receptors (2 main types, alpha and beta). Innervate Beta cells in smooth muscle in airways causing dilation of airways (by activating adenylate cyclase, raising cAMP).

Adrenegic stimulation causes constriction.

Question 25

Parasympathetic activity:Where are neurones seperated? what molecule do they release? what cells does this act upon? overall affect in lung?

Answer 25

2 neurones seperated by ganglion very close or within effector organ. (Long initial axon and synapse very close to effector organ)
Vagus nerve neurons terminate in the parasympathetic ganglia in the airway wall. Parasympathtic fibres release acetylcholine which act on muscarinic receptors of the M3 subtype on the muscle cells, stimulating airway smooth muscle constriction.