Q5: Lungs Flashcards
Why are mammalian lungs located inside the body?
2 reasons
- Air isn’t dense enough to support and protect these delicate structures
- The body as a whole would otherwise lose a great deal of water and dry out
Why is volume of oxygen to be absorbed me carbon dioxide to be removed large in mammals?
2 reasons
- They are relatively large organisms with a large volume of living cells
- They maintain a high body temperature which is related to them having high metabolic and respiratory rates
Lungs
Pair of lobed structures which have evolved to ensure efficient gas exchange between air and the blood and are made up of bronchioles.
Trachea
Flexible airway that is supported by rings of cartilage which prevents the trachea from collapsing during inhalation.
What are tracheal walls made up of?
Made up of muscle
Lined with ciliates epithelium and goblet cells
Bronchi
Two division of the trachea, each leading one lung.
Bronchi structure
Similar in structure to the trachea and both produce mucus to trap dirt particles and have cilia that move the dirt laden mucus towards the throat.
The larger bronchi are supported by cartilage and the amount of it is reduced as the bronchi get smaller.
Alveoli structure
Minute air sacs at the end of the bronchioles which are lined with epithelium.
The alveolar membrane
Is the site of gas exchange
What is between alveoli
Collagen and elastic fibres
Role of elastic fibres between alveoli
Allow the alveoli to stretch as they fill with air when breathing in, can spring back during expiration in order to expel carbon dioxide rich air.
Rib cage
A bony box which supports and protects the lungs.
The lungs are ventilated by …
A tidal stream of air
Diaphragm
A sheet of muscle that separates the thorax from the abdomen.
Intercostal muscles location
Lie between the ribs
