Lungs and Lung Disease (UNIT 1) Flashcards
Why are lungs situated inside the body? (2)
-Air is not dense enough to support and protect delicate structures -They would lose a great deal of water and dry out
What do the rings of cartilage supporting the trachea do?
Prevent trachea collapsing as air pressure inside falls when breathing in.
What are the tracheal walls made up of and what is the function of these things.
Muscle lined with: ciliated epithelium and goblet cells- goblet cells produce mucus that traps dirt particles and bacteria from the air breathed in. The cilia move the mucus full of dirt and microorganisms, up the throat, from where it passes down the oesophagus into the stomach.
What are the bronchi?
Two divisions of the trachea, each leading to one lung. Supported by cartilage. Produce mucus to trap dirt particles and have cilia to move it up throat and down oesophagus.
What are the bronchioles and what allows them to do their job?
Series of branching subdivisions of bronchi. Walls made up of muscle lined with epithelial cells. Muscles allow them to constrict so they can control the flow of air in and out of the alveoli.
What are the alveoli?
Minute air-sacs at the end of the bronchioles.
What do the alveoli contain and what do these allow them to do?
They contain COLLAGEN and ELASTIC FIBRES, they are lined with EPITHELIUM.
The elastic fibres allow them to stretch as they fill with air when breathing in.
They then spring back during breathing outin order to expel CO2 rich air.
ALVEOLAR MEMBRANE IS THE GAS EXCHANGE SURFACE.
Explain ventilation
Air constantly moving in and out of lungs to maintain diffusion across the alveolar epithelium.
Explain inspiration.
When the air pressure of the atmosphere is greater than the air pressure inside the lungs, air is forced into the alveoli. INHALING
Explain expiration
When the air pressure inside the lungs is greater than that of the atmosphere, air is forced out of the lungs. EXHALATION
What is the diaphragm?
A sheet of muscle that separated the thorax from the abdomen.
Where are the intercostal muscles?
Between the ribs.
Explain the PROCESS of inspiration.
ACTIVE PROCESS (Uses energy) -External intercostals contract, while internal relax. -Ribs pull upwards and outwards, increasing volume of thorax. -Diaphragm muscles contract, causing it to flatten, increasing vol. of thorax. -Increased vol. of thorax results in reduction of pressure in lungs. -Atmospheric pressure>pulmonary pressure. AIR FORCED IN.
Explain the PROCESS of expiration.
Largely PASSIVE PROCESS(not much energy needed) - Internal intercostal muscles contract, while external relax. -Ribs move downwards and inwards, decreasing volume of thorax. -Diaphragm muscles relax (return to domed position), decreasing vol. of thorax. -Increased pressure in lungs. -Pulmonary pressure>atmosphere AIR FORCED OUT
What is PULMONARY VENTILATION?
The total volume of air that is moved into the lungs in one minute. Tidal volume- air normally taken in at each breath at rest. Ventilation- number of breaths taken in one minute PV(dm3min-1)=tidal vol.(dm3)xventilation rate(min-1