Respiratory System 1 Flashcards
functions of the respiratory system?
- gas exchange: take in o2, eject co2
- regulate blood pH: alters co2 levels
- voice production: air movement past vocal cords
- olfaction: in nasal cavity
- innate immunity: physical protection of blood
upper respiratory system includes…
- nose
- nasal cavity
- pharynx
lower respiratory system includes…
- larnyx
- trachea
- bronchi
- lungs
what are the functions of the nose?
- passageway for air
- cleans air
- humidifies + warms air
- smell
- along with paranasal sinuses, = resonating chambers for speech
what is the pharynx?
common passageway for respiratory system
nasopharynx
- auditory tubes empty here
- elevated when swallow + held open when sneeze
- pharyngeal tonsils located here
what is the soft palate?
floor of nasopharynx, posterior portion = uvula
oropharynx
extends from uvula to epiglottis
- oral cavity opens into oropharynx
- lined with stratified epithelium
- 2 tonsils
laryngopharynx
extends from epiglottis to oesophagus
food + drink
functions of the larynx
- maintains open air tube
- voice production
- allow us to hold breath
- closes air tube when swallow —> prevents food from entering trachea
what is the larynx
complex assortment of cartilages
trachea
= windpipe
- connective tissue + smooth muscle, supported by cartilage
- cartilage protects trachea + maintains OPEN airway; smooth muscle constricts airway
what are the effects of smoking on the trachea?
- destroyed ciliated cells
- mucous collects
- microorganisms not ejected
bronchi
- symmetrical branches from trachea
- extensions with same tissue types
parasympathetic division
innervates bronchial smooth muscle + submucosal glands
what does the stimulation of parasympathetic division cause?
- bronchial smooth muscle contraction
- inc mucuc secretion
effects mediated by M3 ACh receptors
sympathetic division
no innervation of bronchial smooth muscle
supplies submucosal glands + smooth muscle of blood vessels
what does stimulation of sympathetic division cause?
- bronchial smooth muscle relaxation
- decreased mucus secretion
- inc mucociliary clearance
mediated via beta2-adrenoreceptors
neuronally rel by NA
lung structure
- divided into lobes (R=3, L=2) divided by septa
- bronchioles divide unto alveolar ducts + alveoli
- as bronchi + bronchioles divide, cartilage dec + smooth muscle inc
during exercise, what happens to the diameter of the alveolar duct?
inc
during an asthma attack, what happens to the diameter of the alveolar duct?
dec
describe the respiratory membrane?
- thin fluid layer lines alveolus
- alveolar epithelium = simple squamous
- interstitial space = THIN
- capillary epithelium = simple squamous
what is inspiration + expiration caused by?
changes in thoracic volume
produces change in air pressure in lungs
muscle of expiration include…
- abdominals
- internal intercostals
muscles of inspiration include…
- diaphragm
- external intercostals (scalenes etc)
at the end of expiration, what does Patm =
Palv
no air flow
during inspiration, what does Patm =
> Palv
inc thoracic vol dec Palv
air flows into alveoli
at the end of inspiration, what does Patm =
Palv
no air flow
during expiration, what does Patm =
< Palv
dec thoracic vol = inc pressure in alveoli
air flows out of lungs
premature babies lack surfactant, what does this put them at a risk of?
respiratory distress syndrome
when does lung compliance and ventilation decrease?
when lungs become diseased and fibrotic (COPD)
passive expiration occurs due to…
lung recoil
what are the 2 causes of lung recoil?
- elastic fibres in connective tissue of lung
- surface tension of h2o molecules pull on alveolar walls
surfactant …. lung recoil
opposes
what is a surfactant secreted by and what does it consist of?
by cells of alveolar epithelium
lipoproteins + interferes with surface tension produced by water
what is a surfactant?
detergent like substance which dec surface tension
define tidal volume
vol of air inspired/expired during normal inspiration/expiration
define inspiratory reserve vol
amount air inspired forcefully after inspiration of normal tidal volume
define expiratory reserve vol
amount air expired forcefully after expiration of normal tidal vol
define residual vol
vol air remaining in respiratory passages + lungs after most forceful expiration
define inspiratory capacity
tidal vol plus inspiratory reserve vol
define functional residual capacity
expiratory reserve vol plus residual vol
define vital capacity
sum of inspiratory reserve vol, tidal vol, expiratory reserve vol
define total lung capacity
sum of inspiratory + expiratory reserve vol + tidal vol + residual vol
what is vital capacity also known as?
max amount air one can forcefully inspire + expire
what is vital capacity, influenced by?
- age
- sex
- body size
- training
what is the dead space?
some inspired air never contributes to gas exchange
what is the anatomical dead space?
vol of conducting zone conduits (~150ml)
what is the alveolar dead space?
alveoli that cease to act in gas exchange due to collapse/obstruction
what is the total dead space?
sum of anatomical dead space + alveolar dead space
what is a spirometer?
pulmonary function test
instrument used to measure respiratory vol + capacities
what can spirometry distinguish between?
- obstructive pulmonary disease (bronchitis)
- restrictive disorders (TB_
what is minute ventilation?
total amount of gas flow into/out of respiratory tract in 1 min
what is forced vital capacity? (FVC)
gas forcibly expelled after taking deep breath
what is forced expiratory volume? (FEV)
amount gas expelled during specific time intervals of FVC
inc in TLC, FRC, RV may show signs of …
obstructive disease
dec in VC, TLC, FRC, RV may show signs of …
restrictive disease
define alveolar ventilation rate?
flow of gases into/out of alveoli during certain time
formular to find AVR (ml/min)?
frequency (breaths/min) X (TV-dead space) ml/breath
what is dead space normally in alveolar ventilation?
constant
rapid, shallow breathing …. AVR
dec
