respiratory system Flashcards
what is exernal respiration?
transfer of gas from the atmosphere and from cells and vice versa
key functions of the respiratory system?
gas exchange
host defence
metabolism
what is the conducting zone?
left
used in moving gasses to and from atmosphere and the lungs
trachea and bronchi
what is the respiratory zone
right
where gasses are exchanged
alveoli
what does the conducting airways compose of?
nasalcavity mouth pharynx larynx trachea bronchi bronchioles
featues of the conducting airway
warms air and filters it
mucus and cillia are used to remove particles
are the conducting airways rigid or flexible?
rigid but flexible under pressures of inhalation and exhalation
use cartilage
what type of epithelila cells are found in the conudcting airwarys
pseudostratified columar epithialium with a rigid structure
what other cells are found in the conducting airways and what are their functions
goblet cells: secrete musuc to trap particles
cilia: projections to move trapped particles
serousgland: ssecree antibacterial substance
what is the function of the basal layer in coductign airways
contains stem cells for injuru which push up new cells if needed
why is the nasal cavity crucial
humidification, warming and filtering of the air
prefered route for breathing at rest
what provides the surface area for the nasal cavity to do its function?
three conchae bones
what is the oropharynx?
provides a common path for both food and air
what is the larynx?
connects the oropharynx to the trachea and contains vocal chords to allow us to speak
directs food and air through the epiglottis
what does the trachea do?
connects the larynx to the lungs
shape and structure of the trachea
c shaped cartilage rings between smooth muscle and tisue
non collapsing but flexibe, osephague close next to it so can accommodate some change in shape
what does the trachea form when it branches?
two primary left and riht bronchi
what is the right bronchi like?
larger
splits into 3 secondary
what is the left bronchi like?
splits into two secondary and 2 lobes
also has tertiary bronchi becoming brochioles
difference between a bronhi and bronchioles
bronchi have cartilage and diffuse plates
bronchioles only have smooth musle and more collapseible
where does has exchange take place
respiraotry bronchiiles and alveolar ducts
what is the respiratory zone?
lobules of the lung, small functional unit
made of respiratory broncioles and alveolar ducts
what are type 1 cells i the alevoli?
thin sqamous epithelia
what are squamous epithelia
flatterened cells forming a barrier to diffusion
thin
make up most of the alveoli
what are type 2 cells in the alveoli
small cubiodal cells
they secrete surfactant to stop collapsing
what are macrophages
remove small particles and bacteria in the lung base
phagocytose bacteria in the alveoli
what is the function of aleolar surfactant?
lowers the surface etension and stabilises the structures
coats the lining surface of the lungs
what is surfactant a mix of?
phospholipids
proteins
why are proteins and lipids key in surfactant?
stops structures collapsing anf hydrophobic and hydrophillic parts
where are most cilia found?
near the top
larynx
treachea
bronchi
where are the most goblet cels found
near the top
larynx
trachea
where is cartilge NOT foun
alveoli
respiratrory brochioles
terminal bronchioles
where is most smooth muscle found?
terminal bronchioles
bronchioles
what is the pleura
encasing for the lungs creating a gas tight seal
formed of two membranes
what pleura contacts the throacic wall?
parietal p;eural layer
which pleura contacts the lungs
viceral pleura
what is pleural fluid?
in between the two layers and airs air movement and lubrication
what is a pleural effusion?
build up of this fluid
what do pulomary arteries do?
carry deoxygenated blood from the heart or alveoli via pulmonary circulation to be oxygenated
then flows in venous system to left side of heart to supply body with oxygen
what is the bronchial ciruculation?
carries oxygenated blood to conducting airways and supporting tissue
what is ventilation?
exchange of gas
distrubution of this will depend on boy position an gravity
when will ventilation be at its peak?
when standing apex
what is dead space?
area where gas exchange cannot and doesnt take place
on an anatomical level what is dead space?
trachea and bronchi
what is perfusion?
pulmonary circulation alows gas exchage over tha aveoli and the gas to move
what is the pressure like in pulmonary capillaries
low
when standing what is the purfusion like?
capillaries at apex constricted due to pressure
at the base they are distant due to gravity
what is hypoxia-induced vasocontraction?
pulmonary vessels constricting at low oxygen
what does the combination of ventilation and perfusion cause?
three zones
what is zone 1 of the lung like?
well ventilated but poorly perfused
what is zone 2 of the lungs like?
well ventilated and well perfused
what is zone 3 of the lungs like?
poorly ventilated but well perfused
what is the air we breathe?
combined pressure of all the gases:
nitrgen, oxgen, argon, water vapour, carbon dioxide
what is a partial pressure?
pressure exerted by a single gas in a mixture
the percetage of a partial prssure of each gas wont change unless the mixture does
when do partial pressures of air change?
altitude for example
what is the partial pressure at sea level?
760 mm of mercury
what causes the partial pressure changes in atitude?
pressure percentage of oxygen the same but due to barometric change the amount of pressure the oxygen exerts has alters
how do gasses move?
alway from greater pressure to lower pessure
what are gasses like in high volume?
low pressure
what are gasses like at low volumes?
high pressure
define ventilation
movement of gases in and out of the lungs
what do lungs rely on to work efficiently?
the mechanical manipulation of the chest cavity to exploit the gas laws
eg low pressure draws air in
what three factors affect ventilation
respiratory pressures
compliance of inflamation
airway resistance
what drives inspiration
active process, uses muscle such as the diaphram
what aids inspiration?
external interostal muscles
what happens during inspiration?
increased chest cavity size
reduced pressure
larger volume
air mves in
what dries expiration
passive process
pressure inside lungs allows air to leave
muscles recoil naturally
what happens during expiration
the pressure inside higher than atmospphere, muscles recoil and air moved along gradient of pressue
pressure decreases as air moves out
define intrapulmonary/ alveolar pressure
pressure inside airways and alveoli
define an intrapleural pressure
pressure in the pleural cavity
define an intrathoracic pressure
pressure in the thoracic cavity
define transpulmonary pressure
difference between intrapulmonary and intrapleural pressures
the positive pressure at rest so lungs stay inflated
how do changes in pressure relate to mechanical movement
decrease in intrapleural pressure expansion of the chest decreases it further increases transpulmonaryy pressue lungs expand pressure down air flows into lungs
what happens to pressure as we breathe in
transplumonary pressure increases allowing air into the lungs
volume increases
interpulmonary down below atomspheric
what happens to pressure as we breathe out
intrapleural pressure increases a bit higher
decrease in volume, transpulmonary inceaes
interpulmonary increases as air is expelled
largely driven by changes in transpulmonary pressure
what is lung compliance
how easy it is to inflate the lungs
moe compliant means ore easy
what twofactors induce lung compliance
elasticity
surface tension
what makes inflation of the lungs harder?
collagen fibres
comes with age, elastic fibres are replaced with this. scar tissue
what might cause small alveli to collapse?
high surface tension
what stops small alveoli collapsing
surfactane from type 2 cells
forms a monolayer disrupting tension
what does lowering the tension increase?
compliance
lungs are easier to inflate
why are mall alveoli at risk of colapse
law says that the same surface tension in a small and large alveoli means when we breathe out the smalle one has more pessure so air goes into large ones easier and small collapses
what is the flow in and out of ungs related to?
inversely related to resitance
higher resistance the smaller the air flow
which part of the air ways has the smallest resistance
bronchioles and aveoli
tidal volume
air moving in and out during normal reathing
inspiratry reserve volume
max air taken in after tidal volume
largest
expiratory reserve volume
max air expelled after tidal volume
residua volume
air that cannot be forced out of the lung
dead space
vital vapacity
useable air in the lungs
what measures lung volumes
spirometer
what is FEV
forced vital capacity
full inspiration the forced maxial expiration
what is FEV used for?
to diagnose diease and inspect lungs
if diseased, time taken to expec vital cavpacity is reduced
obstrctuve dISEAE
Expiration is laboured
emphysema
restrictive diease
fibrosis
vital capacity if reduced
can only breate in a certain amount
minute volume
amount of air moved in and out in one minte
TV x breaths per minutes
