Week 4 - Why do we breathe? Flashcards
What are the functions of the respiratory system?
- respiration: ventilation (movement of air), external respiration (gas exchange from the lungs to the blood), transport of gases, internal respiration (gas exchange in the blood to the tissues)
- pH regulation
- voice production
- smell
- protection from dust and microorganisms
What are the structural divisions of the respiratory system?
- lower resp tract: trachea, bronchi, lungs
- upper resp tract: nasal cavity, pharynx, larynx
What are the functional divisions of the respiratory system?
- conducting zone: air through nose to bronchi
- respiratory zone: exchange of air in bronchioles, alveoli, alveoli ducts
What is the external nose comprised of?
bone and cartilage (strat squamous)
What is the nasal cavity comprised of?
- nostrils
- vestibule (entry to nasal cavity, stat squamous)
- hard palate (bone)
- septum (separates into left and right cavity)
What is concha?
bony ridges, psedustratified ciliated columnar
What is the role of concha?
creates airfow and turbulence to increase filtration of particles
What are the functions of the nasal cavity?
- passageway for air
- cleans air
- humidifies and warms air (warm blood, moisture from mucus epithelium)
- olfaction
- sound of voice (resonating chamber)
What are the three regions of the pharynx?
- nasopharynx: posterior to nasal cavity, pseudostratified ciliated columnar, opening for Eustachian tubes, pharyngeal tonsils
- oropharynx: posterior to oral cavity, stratified squamous, palantine and lingual tonsils
- lanryngeopharynx: posterior to epiglottis, stratified squamous
What are the functions of the larynx?
- open passageway for air movement
- directs food into oesophagus
- sound production
- traps debris
What are the cartilage rings in the larynx?
6 paired: arytenoid, corniculate, cuniform
3 unpaired: thyroid, cricoid, epiglottis
Trachea
- anterior to oesophagus
- C shaped hyaline cartilage rings for support
- dense connective tissue, smooth muscles
- lumen = pesudotratified ciliated columnar + goblet cells
What is seen as the trachea moves into the bronchioles?
increase smooth muscle and decrease cartilage
pseudostratified ciliated columnar –> simple ciliated columnar
What is the order of air passage from the trachea to the bronchioles?
trachea –> primary bronchi –> secondary bronchi –> tertiary bronchi –> bronchioles –> respiratory bronchioles –> terminal bronchioles –> bronchioles
Which type of epithelium cells are found in the alveoli?
simple squamous epithelium
What are the two types of pneumocytes?
Type 1: gas exchange through simple diffusion
Type 2: cuboidal, secretes surfactant (prevents collapse, sticking)
What is found on the capillary side of the membrane?
basement membrane, capillary epithelium (simple squamous), RBC
What is the difference between the right and left lungs in regards to lobes, fissures, primary and secondary bronchi
RIGHT: 3 lobes, 2 fissures (horizonal and oblique), 1 primary bronchi, 3 secondary bronchi
LEFT: 2 lobes and cardiac notch, 1 fissure (oblique), 1 primary bronchi, 2 secondary bronchi
What is the hilum?
entry point for blood, nerve supply and blood vessels
What are the factors affecting gas exchange?
- thickness of respiratory membrane
- surface area
- diffusion coefficient
- partial pressure
What are the percentages of oxygen that travels in the plasma and haemoglobin?
RBC (haemoglobin): 98.5%
Plasma: 1.5%
What are the percentages of carbon dioxide that travel in the plasma?
HCO3-: 70%
dissolved in plasma: 7%
haemoglobin: 23%
What occurs during inspiration in the lungs, diaphragm, rib cage, sternum, intercostal muscles?
Lungs: increase volume Diaphragm: inferior, flattens Rib cage: elevated Sternum: elevated Intercostal muscles: contact
What occurs during expiration in the lungs, diaphragm, rib cage, sternum, intercostal muscles?
Lungs: decrease volume Diaphragm: superior, relaxes (dome shape) Rib cage: depresses Sternum: depresses Intercostal muscles: relaxes
What is barometric air pressure?
atmospheric air pressure outside the body
What is intra-alveoli pressure?
pressure inside alveoli
How can alveolar pressure be changed?
- interpleural pressure
- forces which promote aleoli recoil (surfactant, elastic fibres)
- forces which promote lung expansion
Tidal volume
amount of air inspired/expired with each breath
Inspiratory reserve volume
amount of air inspired forcefully after expiration of a tidal volume
Expiratory reserve colume
amount of air expired forcefully after inspiration of tidal volume
Residual volume
volume of air still remaining in respiratory passages and lungs after most forceful expiration
Pulmonary capacities
sum of two or more pulmonary volumes
Inspiratory capacities
amount of air a person can inspire maximally after normal expiration (tidal volume + inspiratory reserve volume)
Functional residual capacity
amount of air remaining in lungs at the end of normal expiration (expiratory reserve volume + residual volume)
Vital capacity
max volume of air that can be expelled from the respiratory tract after max inspiration (inspiratory reserve volume + tidal volume + expiratory volume)
Total lung capacity
inspiratory reserve volume + expiratory reserve volume + tidal volume + residual volume
Minute respiration
total amount of air moved in and out of the system each minute
Anatomic dead space
space formed by nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles; no gas exchange occurs here
alveolar ventilation
volume of air available for gas exchange per minute
What is the difference between static and dynamic lung function testing?
static: time is not a factor
dynamic: time is a factor
What is an example of a dynamic lung function test?
forced vital capacity
What is forced vital capacity? (FVC)
the max volume of air that can be forcefully expired as fast as possible after a deep breath in
What is FEV1 sec?
volume of air expired in the first second
What is FEV1%?
FEV1 sec/FVC x 100
How do you read FEV1 sec and FEV1% on a vitalograph?
FVC = peak on graph
FEV1 sec= volume at 1 second
What are the characteristics of a restrictive lung disease?
low FVC, low FEV1 sec, normal FEV1%, eg pulmonary fibrosis
What are the characteristics of an obstructive lung disease?
normal FVC, FEV1 sec = low, FEV1% = low, eg asthma, emphysema
