Movements of the Lungs Flashcards
Bucket Handle movement of ribs
The middle of the rib is lower than each of its ends, therefore during inspiration the middle portion lifts upwards & outwards, increasing the lateral dimensions of the thorax.
Pump Handle movement of ribs
Enables thoracic breathing as this occurs when the sternum is thrust forwards. This movement of anterior elevation increases the volume inside the thorax, decreasing the pressure to less than ATM.
Diaphragm
A large, very strong flat muscle just inferior to the ribs & thoracic cavity, separating them from the abdomen. Convex superiorly, never stops. When it contracts the D lowers, decreasing internal pressure- encouraging air to enter the lungs. It contracts, (+continued action during inspiration,) relaxation, forced expires, controlled isotonic lengthens, abdominal pressure controls & spasms (hiccups).
External Intercostal muscles
Outer muscle layer- fibres run downwards and forwards between adjacent rib margins. Anteriorly, muscle fibres are replaced by the external intercostal membrane which connects to the costal cartilages.
Responsible for forced and quiet inhalation, raise the ribs and expand the chest cavity, and O = ribs 1-11, I = ribs 2-12.
Collateral ventilation
Ventilation of alveoli via pathways that bypass normal airways, useful when there’s a blockage in the lungs. Air can travel via the ‘Pores of Kohn’, ‘Canals of Lambert’ and the ‘Interbronchial channels of Martin’. This allows O2 to reach the pulmonary capillaries & therefore the rest of the body but also can potentially mobilise the blockage and possibly allow it to eventually be removed.
Mucociliary escalator
A major barrier against infection, carries debris via the action of the Cilia in mucous (secreted by the goblet cells) as far as the pharynx, where the fluid and mucus is then swallowed and the debris eliminated by the digestive system.
Cough reflex
An expulsive reflex initiated when the respiratory tract is irritated by infection, noxious fumes, dust, or other types of foreign bodies. The reflex results in a sudden expulsion of air from the lungs that carries with it excessive secretions or foreign material from the respiratory tract.
