lung segments and movement Flashcards
where are the lungs anatomically located?
on either side of the mediastinum
what structure is each lung surrounded by?
-plueral cavity - which is formed by the visceral & parietal pleura
what is the fluid in the plural cavity?
a fluid which acts as a lubricant and also acts to maintain a negative pressure in the cavity to prevent lung collapse
what is pneumothorax?
air in the plueral cavity
what does each lung consist of?
-apex - the superior end of the lung
-base - inferior surface which sits on diaphragm
-lobes - 2 or 3
-3 surfaces - costal, mediastinal and diaphragmatic
-borders - the edges of the lung anterior, inferior, posterior
how many lobes does the right lung vs the left lung have?
-right lung - 3 lobes - superior, middle and inferior
-left lung - 2 lobes
how are the lobes in the lungs divided from eachother?
by fissures
what is the oblique fissure?
-present in both lungs
-separates lower lobe
what is the horizontal fissure?
-present in right lung only
-separates upper and middle lobes
what is the mediastinal surface of the lung?
- the surface that faces the lateral aspect of the middle mediastinum
-contains the lung hilum
what is the diaphragmatic surface of the lung?
- the surface that rests on the dome of the diaphragm
-it has a concave shape
what are the surface anatomy markings on the body for the oblique fissure?
T4 to costal cartilage 6
what is the hilum of the lung?
-region on each lung where structures such as blood vessels, bronchi, lymph vessels, and nerves enter and exit the organ
-serves as a point of connection between mediastinum & lung
Briefly describe the bronchial tree
-trachea divides into left and right bronchus
-each bronchus enters the root of the lung, passing through the hilum, and then they divide to form lobar bronchi - one supplying each lobe
-each lobar bronchus then further divides into several tertiary segmental bronchi- which provides air to a bronchopulmonary segment
- the segmental bronchi give rise to terminal bronchioles which gives off a response bronchiole - which give off alveoli
what is a bronchopulmonary segment?
an area of the lung that is supplied by a segmental bronchus and branch of pulmonary artery
how many segments are there in the right lung vs the left lung?
-10 segments in right lung
-8-10 segments in right lung
what are alveoli and what is their function?
-thin walled sacs
-function - gas exchange
Describe the vasculature of the lungs
-lungs supplied with deox blood by the pulmonary arteries, once this blood is oxygenated it leaves the lungs via 4 pulmonary veins (2 for each lung)
-bronchi, visceral pleura and supporting tissues supplied by bronchial arteries which arise from the descending aorta
-bronchial veins provide venous drainage - and they drain into the azygos and accessory hemiazygos veins
Describe the nerve supply of the lungs
-derived from the pulmonary plexus
-sympathetic, parasympathetic and visceral afferent fibres
-parasym derived from vagus nerve
-symp derived from sympathetic trunks
-visceral afferent - conduct pain impulses to sensory ganglion of vagus
what does the parasympathetic vs sympathetic system do to the bronchial smooth muscle?
- parasympathetic- bronchoconstriction
-symp- bronchodilation
what mvts occur to the lungs, diaphragm, ribs etc during inspiration?
-diaphragm moves downwards
-ribs are lifting up - bucket handle movement (think of how the handle moves when u lift it)
-size of thoracic cavity increases
-lungs increase in size
what happens to the sternum during inspiration?
the sternum moves forward during inspiration because of rib elevation
Describe normal vs forced expiration
- Normal
-passive
-intercostal muscles relax and ribcage falls
-diaphragm recoils and elevates - Forced
-active
-internal intercostals contract
-abdominal wall muscles contract which causes the diaphragm to rise
