breathing and regulation Flashcards
what does the conducting zone of lower resp tract consist of
trachea 🡪 main bronchus 🡪 lobar / segmental bronchi 🡪 terminal bronchioles)
if someone aspirates an object where would it end up
Right main bronchus large lumen, more vertically orientated than left
respiratory epithelium
Pseudostratified columnar epithelium
Goblet cells
Cilia
histology of trachea
Pseudostratified columnar epithelium
+ Cartilage
+ Smooth muscle
histology of alveoli
simple squamous
function of pores of kohn
help equalise pressure across the air sacks
histology of respiratory bronchioles
cuboidal epithelium
method of respiratory pump
Diaphragm contracts (Flattens)
External intercostals contract (Lift ribs up and out)
Transpulmonary pressure is negative
Air is drawn in until pressure equalizes
Relaxation of muscles causes passive expiration
how does the sternocleidomastoid help with inspiration
helps to bring the ribs up
how does rectus abdominus and internal intercostals help with active expiration
bring the ribs closer together
innervation of diapgram
phrenic c3c4c5
innervation of intercostal mjuscles
intercostalonerves
where are peripheral chemoreceptors and what are they most sensitive to
carotid & aortic bodies. Most sensitive to pO2 change
where are central chemoreceptors situated and what are they most sensitive to
medulla oblongata. Most sensitive to pCO2 change
two main centres for respiratory control and what do they control
medullary : dorsal , inspiration control
Ventral , inspiration and forced expiration
pontine: apneustic centre acts on dorsal respiratory group
Pneumotaxic centre , off switch inhibits apneustic centre
what is Intrapleural pressure (Ppl)
is the pressure difference across the pleura
what is ventilation rate
air flowing into lungs in a given time period
what is perfusion
blood flowing into the capillary beds
what is vq mismatch
Blockage to perfusion (Pulmonary embolism)
Barrier to gas exchange (pneumonia disrupting alveoli)
what is daltons law
The total pressure of a gas mix is equal to the sum of the partial pressures of each component
what is henrys law
At a given temperature, the amount of gas dissolved in a liquid is directly proportional to the partial pressure
what is tidal volume
volume of a normal breath
physiological dead space
Physiological dead space: anatomical + alveolar dead space. (Includes air in poorly perfused or ventilated parts of the lung)
Smooth muscle in bronchioles can constrict airways
parasympathetically?
ach binds to m3 receptors, , bronchoconstriction
Smooth muscle in bronchioles can constrict airways
sympathetically
adrenaline / noradrenaline bind to B2 (adreno) receptor
= bronchodilation
What muscles are involved in respiring ?
diapgram,
abdominal muscles
intercostal muscles - internal and external
What is the costodiaphragmatic recess?
The part of the pleural cavity not occupied by the lung
Describe the alveolar gas equation?
PAO2 = FIO2 x ( patm- ph2o) - PaCO2 /Rrespiratory quotient
What epithelium lines the trachea and upper respiratory tract?
ciliated pseudostratified columnar epithelium with goblet cells
what is the carotid sinus innervated by
glossopharyngeal nerve
What is the air left at the end of expiration of a normal quiet breath called?
Functional residual capacity
How is tidal ventilation calculated?
Tidal ventilation= tidal volume x respiratory rate
What is the residual volume?
The residual volume is the volume left after maximum exhalation
What is the total lung capacity and how do you calculate it?
LC= residual volume+ vital capacity
5.9 L
What is the vital capacity?
Vital capacity is the maximum that can be breathed in or out
What do peripheral chemorecptors respond to and where are they located, what do they respond to?
carotid artery and aortic arch
respond to arterial blood
What do central chemoreceptors respond to and where are they located, what do they respond to?
Central respond to [H+]
Located at medulla of brain
Respond to ECF of brain
Process of inspiration with nerves
Phrenic and motor intercostal nerves cause diaphragm and external intercostal to contract
⬆️ volume ⬇️pressure
Pump handle ribs up and out bucket handle pulling parietal pleura too
⬆️alveolar stretch
💨o2 moves in down pressure grad
Process of expiration with nerves
⬇️ impulses to diaphragm and external intercostal
Decrease volume increase pressure
Alveoli compress as lungs pressure increases
Air passively moves out down conc grad
How do you work out trans pulmonary pressure
Alveolar pressure - intrapleural pressure
How to work out ventilation rate
Tidal volume x respiratory rate
Where is the vq ratio high and low
High at apex of lung due to gravity
Low at the base of lung
Two extremes of vq mismatch
Pulmonary embolism , blockage to perfusion due to dead space
Pul oedema , collapsed alveoli due to fluid build up
Regulation of vq
Local bronchi constriction , air diverted to better ventilated areas
Hypoxic pulmonary vasoconstriction blood diverted to better perfumed areas
What is boyles law
Pressure and volume are always inversely proportional at a given temp of gas
What do j receptors do
Respond to increase in lung pressure because of fluid build such and lead to an increase in ventilation
What do stretch receptors do
In smooth muscle
When the lung expands , receptors initiate the hering bruer reflex which reduces respiratory rate .
What is respiratory drive and what is it controlled by
Intensity of the output by the respiratory centres
Control by medulla oblongata
What does alveolar recruitment refer to
Opening of collapsed alveoli
Laplaces law
As alveoli get smaller at the end of expiration , surface tension increases , surfactant is therefore required to prevent collapse .
Rate of gas diffusion factors
Conc grad
Sa for diffusion
Length of diffusion pathway
Diffusion barrier in the lung layers
Alveolar epithelium Tissue fluid Capillary endothelium Plasma Red cell membrane
main difference between peripheral and chemoreceptors
peripheral detect changes in ph and 02
central only detect changes in h+ and o2
difference and parts of resp zone and conducting zone
resp zone -gas exchange resp , bronchioles to alveolar sacs
conducting zone - air in and out of the lungs ,bronchi to terminal bronchi
