respiratory Flashcards
what is the pathway airflow
nasal cavity
pharynx
larynx
trachea
primary bronchi
many smaller bronchi
bronchioles
alveoli
what parts are in the upper respiratory system
nasal cavity
pharynx
larynx
what parts are in the lower respiratory system
trachea
primary bronchi
many smaller bronchi
bronchioles
alveoli
what are the main functions of the respiratory system
- gas exchange - O2 uptake and CO2 release
- homeostatic regulation of body pH
- conditioning inspired air (warming and filtering)
-protection (filtering and clearing foreign particles) - vocalization (vocal cords, larynx)
what is the pH of blood plasma
7.4
inspiration
inhale, air moves into lungs
expiration
exhale, air moves out of the lungs
how does the respiratory and circulatory system coordinate?
to move O2 and CO2 between atmosphere and cells
explain external respiration
- the movement of gases between internal environment of body and external environment
- exchange 1: atmosphere to lung (ventilation) moving respiratory medium over respiratory surface
- exchange 2: lung to blood (alveoli)
- transport of gases in the blood
- exchange 3: blood to cells (tissues)
how many lobes on each side of the lungs
3 right, 2 left
cardiac notch
where the heart sits
in normal quiet breathing which muscles are used at rest and what do they do?
external intercostals and diaphragm contract and expand lungs for air to flow in
what do the sternocleidomastoids and scalenes do
increase volume
what do the external intercoastals to during breathing
pull ribs up and out
what does the diaphragm do during inhalation
create a pressure gradient for air to move into the lungs
pleural membranes
fluid filled balloon that surrouds the lungs
- each is made of a thin layer of secretory epithelial cells and a thin layer of connective tissue
parietal: stuck to rib cage
visceral: surrounds lung tissue
both move together and are stuck together via pleural fluid
pleural sac
- fluid filled
- protects lungs
- surrounds lungs, sticking tightly to thoracic wall to keep lungs inflated
- lubricates membranes to reduce friction, which allows them to slide against each other wile lungs move during breathing
ciliated epithelium
lining trachea and bronchi to filter foreign substances
what do the airways do
warm air to body temperature, add water vapour
conditioning air before it enters alveoli cells
submucosal glands
secrete saline and mucous
what does cilia do in the airway
moves mucous layer toward pharynx, removing trapped pathogens and particulate mattwer
cartilage ring
area can’t be changed unless something is obstructing it, airway is then reduced
surrounds trachea and bronchi
flow is proportional to
delta P/V
resistance is proportional to
Ln/r^4
what does obstructive lung diseases do to resistance
increase airway resistance
How can brochioles change their radius
neutral, hormonal and paracrine effects on smooth muscle. Cross sectional radius is large so resistance is low - bronchoconstriction can increase resistance to reduce flow to/from alveoli
bronchiodilation
decrease resistance to air flow
ie/ at the gym
paracrine response to CO2
SNS response
need to increase blood flow
what is the SNS response in bronchodilation
noepinephrine/epinephrine bind to B2-adrenergic receptors
cause relaxation of bronchiole smooth muscle
GS-AC-cAMP-PKn
bronchoconstriction
increased resistance to air flow
paracrine response to histamine being released by local mast cells in an immune response
PNS response
PNS response in bronchoconstriction
Ach binds to muscarinic receptors (M3) causing constriction of bronchiole smooth muscles
Gq-PLC-IP3- IP3R - Ca2+
Alveoli
site of gas exchange
make up bulk of lung tissue
each alveolus is made of one layer epithelial cells
type 1 alveolar cells
gas exchange
95% of alveolar SA
Type 2 alveolar cells
make and secrete surfactant
surfactant
- secreted by type 2 alveolar cells
- lines inside surface of alveoli
- decrease surface tension inside alveoli therefore decreasing pressure which makes alveoli easier to expand/inflate
- preventing alveoli from collapsing
why are alveoli optimized for diffusion
very thin, little interstitual fluid, alveolus and capillary held close together by fused basement membranes
why at an air- fluid interface, surface of the fluid is under a tension?
attractive forces between fluid molecules which causes inward directed pressure that is a function of the surface tension of the fluid
law of laplace equation
P= 2T/r
what does the law of laplace tell you about pressure
pressure is greater in a smaller bubble if they have the same surface tension
what happens in alveoli when theres too much pressure
makes them collapsible and difficult to inflate
- why we need surfactant to help
what does surfactant do to pressure in alveoli
equalization of pressure between alveoli
air flow equalized to all alveoli
decreases surface tension
smaller alveoli have more surfactant
why is intrapleural pressure always negative
because the membranes are always pulling away from each other
equation for transpulmonary pressure
Palv-Pip = 4 mm hg
functional residual capacity
at the end of normal expiration, volume of air left in lungs
are Palv and Patm equal
yes, 0 mm Hg
pressure inside the alveoli=pressure of outside air
what does the elastic recoil of lungs inward equals
elastic recoil of chest walls outwards
result of elastic recoil of the lungs
negative intrapleural pressure and lungs pulled towards chest wall due to resultant forces on pleural membranes
positive transpulmonary pressure
= distending pressure
the force inflating the lungs
pressure during inspiration and expiration
more neg
less neg
position of the pleural fluid in the normal lung at rest
pleural fluid keeps the lung adhered to the chest wall
Pneumothorax
air enters the pleural sac
intrapleural pressure is no longer negative
the bond holding the lung to the chest wall is broken and the lung collapses (To unstretched size) creating a pneumothorax
air in thorax
sealed pleural cavity is opened to the atmosphere, air flows in
tidal volume value
500mL
when does air stop flowing into the lungs
when Palv=Patm
lung compliance
ability of the lung to stretch
the change in volume for a given change in pressure exerted on the lung
high compliance of the lungs allows them to move outward with little force required
loss of compliance disease
fibrosis
elastance in lungs
ability of lung to spring back after being stretched
due to the presence of elastin fibers throughout the lung interstitial space
elastic recoil of the lung creates an inward pull
loss of elastin in lung cause what
emphysema - problem with forcing air out of the lungs
boyles law equation
P1V1=P2V2
if volume increases, then pressure decreases
what happens in ventilation when inspiratory muscles contract
lung volume increases, pressure inside lungs decreases, air is sucked into lungs
moves down pressure gradient into lungs
what happens in ventilation when the inspiratory muscles relax
diapragm moves down
lung volume decreases
pressure inside lungs increases
air is blown out of the lungs
moves down a pressure gradient out of the lungs
during quiet inspiration
diaphragm contracts and flattens
muscles of inspiration contract and pull ribs up and out; sternum lifts up
thoracic and lung volumes increase
Pip and Palv decrease
Patm>Palv
air flows in
during passive expiration
diaphragm relaxes and moves upward
muscles of inspiration relax; ribs and sternum “fall” back down
thoracic and lung volumes decrease
Pip ans Palv increase
Palv>Patm
air flows out
how many mL is the dead space in the lungs
150
inspiratory capactity
tidal volume + IRV
vital capacity
Vt+ IRV+ERV
total lung capacity
Vt+IRV +ERV+RV
functional residual capacity
ERV+RV
total pulmonary ventilation
ventilation rate x tidal volume
12 breaths/min x 500mL = 6L/min
alveolar ventilation
volume of air moved in/out of the alveoli per minute
= ventilation rate x (VT - dead space volume Vd)
= 12 breaths/min x (500-150mL) = 4.2 L/min
alveolar ventilation and anatomical dead space
- at the end of inspiration, dead space is filled with fresh air (150o2, 2. exhale 500mL (tidal volume)
- at the end of respiration, the dead space is filled with “stale” air from alveoli
- inhale 500mL of fresh air (tidal volume)
