lower respiratory tract Flashcards
rib-movement- describe the two movements?
2 inter-related movements
(i) Superior and anterior (pump handle)
(ii) Lateral shaft elevation (bucket handle)
Movements occur in synchrony
what is the level of carina? what happens here?
division into two main bronchi, at T5
left vs right bronchi
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
blood and sensory nerve supply of trachea
Sensory innervation of trachea: recurrent laryngeal nerve
Arterial supply: inferior thyroid artery
Venous drainage: brachiocephalic, accessory hemiazygos veins and the azygos vein
lung hilum - left vs right layout?
pleura goes around hilum
left hilum:
artery is posterior to bronchus
right hilum:
artery is lateral to bronchus
terminal vs respiratory bronchioles
examples of cells present in each
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)
what are the acinus? function? how many are there? diameter?
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
alveoli- how may in lung? SA produced? Type of cells present and there roles?
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)
volume of air inspired/expired in a minuite
5 litres
are intercostal spaces numbered below or above the rib?
always below, intercostal space 3 will sit below rib 3
what supplies blood to tissue of the lung? how much of LV output? what pressure?
paired branches of bronchial arteries supply bronchial and peri-bronchial tissue and visceral pleura (branch of aorta)
Approximately 2% of LV output.
120mm/80mm
Describe Lung Pleura- 2 layers? innervation of each? where are the continuos with each other?
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
diaphragm- what is it?
domed shaped fibromuscular sheet that seperates abdomen from thorax,
What innervates the diaphragm? where does this nerve arise from? what root does it take to diaphragm?
Phrenic nerve (left and right), Arise from cervical plexus C3, C4, C5,
Neck, thorax, anterior to the lung hilum (lung root)
autonomic and controll
what do abdominal muscles and diaphragm do in inspiration and expiration?
Inspiration: contraction of diaphragm, relaxation of abdominal muscles
expiration: relaxation of diaphragm, contraction of abdomanal muscles
Influences on respiration?
contraction of diaphragm
airflow
perfusion
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?
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
what are the bronchovascular bundles?
vascular bundles run parallel to bronchus
Autonomic plexuses - what are they? contain what types of fibres? what are the origons of these fibres?
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
where is cardiac plexus located?
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
where is pulmonary plexus located?
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.
vagus nerve- what’s it route?
Neck, thorax, posterior to the lung hilum
Sympathetic activity in lungs: Where are neurones seperated? what molecule do they release? what cells does this act upon? overall affect in lung?
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.
Parasympathetic activity:Where are neurones seperated? what molecule do they release? what cells does this act upon? overall affect in lung?
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.
