PBL 1 Flashcards
name 2 roles of the gas exchange system
- conducts oxygen into the body
2. removes co2 from the body
what is the purpose of the pleura and pleural fluid?
the 2 pleura allow optimal expansion and contraction of the lungs. the pleural fluid acts as a lubricant, allowing the layers to slide smoothly over each other friction free
what is the order of air passages from the trachea?
trachea —> primary bronchus —> secondary lobar bronchi —> tertiary segmental bronchi —> conducting bronchioles —> terminal bronchioles —> respiratory bronchioles
how many lobes do the lungs have and what are they divided by?
right has 3 — superior, middle, inferior
left has 2 — superior, inferior
separated by fissures — oblique and horizontal (only on right)
which lung is smaller and why?
left lung is smaller as it shares its side of the thorax with the heart
what borders do the lungs have?
anterior, inferior and posterior borders
what surfaces do the lungs have?
costal, mediastinal, diaphragmatic
what kind of epithelium is present in the trachea?
ciliated epithelium — protective barrier with cilia to waft things out of the respiratory tract
what are basal cells?
lung stem cells which replaced damaged cells
what are goblet cells?
secrete mucus
what are serous cells?
secretory cells
type 1 vs type 2 alveolar cells
type 1 — very thin simple squamous cells, non-ciliated, main site of gas exchange — covers 90% of alveolus
type 2 — produce surfactant to keep airways open (reduce surface tension), preventing airway collapse. also renew type 1 cells
what happens to the cells and cilia as you move down the airways?
cells start to become thinner and cilia start to disappear
name the lining cells
ciliated, intermediate, brush (stunted cilia — under research), basal epithelium
what makes up the contractile component in airways?
smooth muscle — controls calibre
what makes up the connective tissue in airways?
fibroblasts (produce matrix proteins that provide support/strucutre), intersitital cells (produce elastin), collagen, proteoglycans, cartilage
what immune cells are present in the airways?
mast, dendritic, lymphocytes, neutrophils, eosinophils, macrophage
what are submucosal glands?
sit under epithelial layer, surrounded by smooth muscle (causes mucus production when it contracts)
role of mucus
traps inhaled toxins, transports them out of the lungs by ciliary beating and cough reflex
role of smooth muscle in airways
- surrounds all airways
- responsible for calibre
- controls level of surfactant protein and mucus production if it contracts around the gland
- very thinly spread out in lower airways — blood vessels fused to the epithelial cells in alveoli (decreased diffusion distance)
describe the effects of disease on airways
- airway narrows
- mucus accumulation
- muscular layer thickening
- inflammatory cell infiltration
what is the forced vital capacity?
- exhale as forcefully as you can
- total volume of air exhaled
how does forced expiratory volume differ to forced vital capacity?
it is the same but in a specified amount of time
what is the effect of bronchodilators on airways and when are they used in asthma treatment?
- they are RELIEVERS = usually blue or green
- cause smooth muscle to relax
- short acting (1-2 hours) and long acting (up to 12 hours)
- usually used when asthma symptoms appear