Lungs
Name the organs of respiration. Describe the location, coverings and features of lungs.
Organs of respiration
Nose
Nasopharynx
Larynx
Trachea
Major bronchi
Minor bronchi
Bronchioles
Respiratory ducts
Alveoli
Accessory Organs of Respiration : -
Respiratory muscles : Intercostal muscles, Diaphragm
The Location of the lungs
Two lungs - one on each side of the midline in the thoracic cavity
Features
Cone shaped
Has an apex, a base, costal surface and medial surface
The apex
Rises into the root of neck one inch above the middle of the clavicle
The base
concave - touching the diaphragm
The costal surface
convex - touching the costal cartilages, the ribs and intercostal muscles
The medial surfacre
concave - has hilum for vessels and nerves to enter and exit
structures at hilum : 1 bronchus, 1 pulmonary artery, 2 pulmonary veins, 1 bronchial artery, bronchial veins, lymph vessels, parasympathetic and sympathetic nerves
The portion between the right and left lungs is called the mediastinum
Lobes
Right lung 3 lobes - upper, middle and lower -
Left lung 2 lobes - upper and lower
Interior of the lungs
Composed of the bronchi and smaller air passages, alveoli, connective tissue, blood vessels, lmph vessels and nerves.
Each lobe has a large number of lobules.
Coverings
Each lung are covered by serous membrane called the pleura - secretes pleural fluid - two layer - one adherent to the lung - the other to the chest wall : called the visceral and parietal layers respectively.- the space between them is pleural cavity; a potential cavity; contains a thin film of pleural fluid for lubrication.
Blood supply to the lungs
The pulmonary from the heart divides into two; one for each lung - deoxygenated blood - capillaries - alveoli lie adjacent to the capillary - gas in alveoli is separated from the blood in capillary by only two layers of flattened epithelium.
Right and left bronchial arteries for the passages
Bronchial veins
Nerve supply
Vagus - parasympathetic - contraction of the smooth muscles of the bronchi
Sympathetic - from the sympathetic chain - dilatation
Lymph drainage
Hilar lymph nodes, paratracheal and parabronchial lymph nodes - draining into the thoracic duct on the left and the right lymphatic duct on the right side.
Applied anatomy - Trachea
Trachea situated in front of oesophagus - tracheo-oesophageal fistula - acquired due to ca oesophagus or congenital defects
