Gas exchange in mammals Flashcards
in what ‘segment’ of the body are the lunch found
thorax
In what conditions are the lungs suspended and what does this mean
In an airtight compartment, bounded by the diaphragm and ribs so there is only one means of air entering the lungs
Epiglotis
Flap of cartilage responsible for closing off the trachea to direct swallowed food into the oesophagus
Trachea
Air pipe into the lungs
Intercostal muscles?
Muscle between the ribs, involved in ventilation
Bronchi
Air pipes following on from the trachea into the lungs
Bronchioles
Air pipes branching off of bronchi, leading into the alveoli
Diaphragm
Layer of muscle beneath the lungs
Role of the cartilaginous rings on the trachea 4parts
Protect from impact
Support the trachea and bronchi, hold them open to prevent collapse when pressure drops during inspiration: low resistance to air flow
Role of smooth muscle lining trachea
Caan contract and relax to change size of the trachea lumin, controls vol of air that enters
Role of cilliated epithelium in trachea
Waft mucus/ debris up the trachea to be coughed up to the back of the throat ot be swallowed
Role of goblet cells in trachea
Produce mucus to trap debris and pathogens
What is the shape of cartilaginous rings of the trachea
C shaped: incomplete rings
Why are the cartilaginous rings incomplete
To allow the oesophagus to expandin the back of the trachea when a bolus of food is passing down
What type of epithelium are the diluted cells of the trachea
simple cuboidal
What is the specific gas exchange surface in the lungs
alveoli
How are alveoli suited for their role 5
They increase SA
They have a moist surface so gases can dissolve
The walls are thin: short diffusion path
Well ventilated bc of inhalation and exhalation
What are the walls of the alveoli made of
Simple squamous epithelium
Components of trachea
Cartilaginous rings
Elastic fibres
Smooth muscle
Cilliated epithelium
Goblet cells
Function of elastic fibres in the alveolus
Stretch on inhalation, so alveoli expand increasing SA
Recoil on exhalation to force out more air
Where are goblet cells found
Trachea, bronchi, bronchioles
where are cilliated epithelium in gas exchange system
Trachea and bronchi
where is cartilage found in gas exchange systems
Trachea, bronchi, bronchioles
where are elastic fibres found in gas exchange systems
trachea, bronchi, bronchial and alveoli
Where is smooth muscle found in gas exchange systems
Trachea, bronchi, bronchioles
Without surfactant, why would an alveolus have the tendency of collapsing in on itself/ stick together
Has moist surface, cohesion between water molecules pulls the walls of the alveolus inwards
What would be the overall problem caused if surfactant wasnt present 3
Collapsed alveoli
Poor blood oxygenation
Respiratory distress
Surfactant? 3
Phospholipoprotein, stops alveoli from sticking/collapsing by reducing surface tension in alveoli
How many pleural membranes surround the lung
2
Function of the plural membranes
Ensure the thorax is air tight
Pleural space/ cavity
Fluid filled space between pleural membranes
Function of pleural fluid (between membranes) 2
Lubricates: reduces friction as lungs move
Acts as shock absorber
What happens to the external intercostal muscles and diaphragm during inspiration
External intercostal muscles contract, pulls ribcage upward and outward
Effects of the movements of the system during inhalation 3
Vol of lungs and thorax increased
Pressure reduced
Air enters the lungs moving down the pressure grad
What is a reduction in pressure called
negative pressure
Is inspiration an active or passive process, y?
Active bc muscles contract
Is relaxed expiration active or passive and y
Passive bc muscles relax
What happens to external intercostal muscles and ribcage during relaxed expiration
External intercostal muscles relax and ribcage falls under its weight
What happens to the diaphragm during inspiration
Contracts, pulls flat from domed
What happens to the diaphragm during expiration
Relaxes and gut pressure pushes it back to dome
What happens to lung tissue during expiration
elastically recoils
Affect of physical changes during expiration 3
Volume of thorax and lungs decrease
Pressure increases
Air forced out
Ventilation
Movement of air in and out of the lungs via trachea
2 phases of ventilation
Inspiration and expiration
Negative pressure breathing?
For air to enter the lungs, pressure in the lungs must be below atmospheric pressure
what happens to the pleural membranes and alveoli during inspiration
Outer, attached to thoracic cavity wall so move up and out with ribs, inner follows
Lungs expand, increase vol of alveoli
Why is expired air high in water vapour
Alveoli are permanently lined with moisture, some water evapourates and is exhaled
Which intercostal muscles are involved in forced expiration
Internal intercostal muscles
What forces the diaphragm up into a dome during forces expiration
Abdominal muscles contracting
What happens to the internal intercostal muscles during forced expiration
Contract, pulling ribcage in and down
How does movement of the intercostal muscles and ribcage affect the pleural cavity, inner pleural membrane, lungs and alveoli
Pleural membran is pulled out so pressure in pleural cavity drops and inner pleural membrane is pulled outwards pulling th surface of the lungs and causing alveoli to expand.
What is the benefit of internal lungs
minimise heat and water loss
How do frogs do gas exchange when inactive and active
Through Moist skin when inactive
Lungs when active
