Exchange Surfaces and Breathing Flashcards
Module 2
What are the features of the mammalian lung that allow for efficient diffusion
Many Alveoli - increase s.a
0.1um thick alveoli - decrease diffusion distance
Dense network of capillaries outside alveolus - maintains steep diffusion grad
Well ventilated - steep diffusion grad
Moisture - surfactant gases allows gasses to dissolve and stops alveoli from sticking together
What happens when you inhale
Diaphragm - contracts and moves down
Rib cage - External intercostal muscles contract to move rib up and out
Volume of thorax increases
Pressure in lungs falls with respect to to atmospheric pressure
Order of main tissues and cells in the airways (largest to smallest)
Trachea, Bronchus, Bronchiole, Alveolus
Size of Alveolus
250um
What is in the trachea
Cartilage, Goblet cells, ciliated cells, smooth muscle, elastin fibres
What is in a bronchus
Cartilage, Goblet cells, ciliated cells, smooth muscle, elastic fibres
What is in Bronchioles
Goblet cells, ciliated cells, smooth muscle, squamous epithelium at end, elastin fibres
What is in Alveoli
Squamous epithelium and elastin fibres
What are three main factors that affect the need for an exchange system
Size
Surface area to volume ratio
level of activity
How does size effect the need for a exchange system
In large multicellular organisms, the diffusion pathway would be longer. Meaning diffusion is too slow to enable a sufficient supply to innermost cells
How does surface area to volume ratio effect the need for an exchange surface
Larger organisms have a small surface area to volume ratio. This means the surface area will not be large enough to provide all cells with sufficient oxygen
How does level of energy effect the need for a exchange system
More metabolically active organisms need more oxygen which may not be able to be delivered by diffusion
Function of Cartilage
Support for trachea and bronchus
Prevents collapse
Large ring shaped block in trachea
C shaped rings in bronchi
Function of Goblet cells
Secretes Mucus which is sticky and collects particles of dust, spores and bacteria
Function of ciliated cells
Brushes mucus up the airways towards the mouth
Function of smooth muscle
Contract to constrict airway