ventilation Flashcards
trachea
passage of air, cells lined with cillia and have rings of cartilage
bronchi
initial branching of the trachea
bronchioles
deliver air to and from the lungs
alveoli
increases surface area of lungs + site of gas exchange
capillary network
brings C02 to lungs and removes 02 - site of gas exchange
pleural membrane
secretes pleural fluid to reduce friction when breathing
intercostal muscles
contracts to move ribs up and out
diaphragm
contracts and flattens
ciliated epithelial cell
found in the lining of trachea, bronchi and bronchioles
secretes mucus from goblet cells and cillia and traps the mucus along with pathogens + harmful substances
- travels in waves, transporting the mucus out of the airways so that they can be removed
what happens to intercostal muscles and diaphragm when contracting
IM gets shorter & D contracts
explain inspiration/inhalation
- external intercostal muscles contracts moving the ribs outwards and upwards
- diaphragm also contracts causing it to flatten
- volume of thoracic cavity increases
- pressure of lungs decreases that of atmospheric pressure (lower compared to outside)
- air moves into the lungs down a pressure gradient
what type of process is inhalation/inspiration?
active
explain exhalation/expiration
- external intercostal muscles relaxes causing the ribcage to move inwards and downwards
- diaphragm also relaxes causing it to return to its domed position
- volume of thoracic cavity decreases
- pressure in lungs increases above that of atmospheric pressure
- air moves out of the lungs down pressure gradient
tidal volume
amount of air that an individual breathes in and out at rest
inspiratory reserve volume
volume of extra air that can be breathed out
expiratory reserve volume
volume of EXTRA air that can be exhaled during a forceful breath out
vital lung capacity
total amount of air after maximum exhalation
total lung capacity
volume of air exhaled during a forceful breath out
residual volume
volume of air that remains after a forceful expiration
peak expiratory flow
volume of air expelled from the lungs in one quick exhalation
what does peak expiratory flow indicate
whether airways are narrowed
forced vital capacity
maximum air that is forcibly exhaled from the lungs after fully inhaling
what is forced vital capacity used to diagnose
COPD and other respiratory related conditions
why should peak flow score be repeated
to calculate an average of results & repeat 3x
fick’s law
law stating that diffusion is directly proportional to surface area and concentration but not the thickness of membrane
using fick’s law explain how the lungs are adapted for efficient gas exchange
- alveoli walls is thin + 1 cell thick so so short diffusion pathway between alveolar walls and capillary network
- layer of water surrounding alveoli so moisture as gases can diffuse easily and efficiently + contains a surfactant which reduces surface tension preventing the alveolar walls from collapsing and sticking together
- alveoli and capillaries have large total surface area
squamous endothelial cells squashed cells to allow short diffusion pathway due to being thin
good blood supply - maintains high concentration gradient for both gases
how does oxygen enter the blood?
oxygen passes through the epithelial cell of the alveoli by diffusion
2. then diffuses into the endothelial cell of alveoli
3. combines with haemoglobin on red blood cells forming oxyhaemoglobin
