respiratory system Flashcards
respiratory system is comprised of
nose pharynx (throat) larynx (voice box) trachea (windpipe) bronchi lungs
upper respiratory
nose, nasal cavity, pharynx, larynx associated structures
lower respiratory
trachea, bronchi, lungs
conducting zone
outside lungs. nose nasal cavity, pharynx, larynx , bronchi, bronchioles, terminal bronchioles. function is to filter warm and moisten air to conduct to lungs
respiratory zone
tubes and tissue where gas exchange happens. respiratory bronchioles, alveolar ducts , alveolar sacs, alveoli.
nose
warm air (capillaries), moisten air (mucus) and filter, detect olfactory stimuli, and modify speech
pharynx
funnel shaped tube 5 inches long. starts at internal nares and extends to level of cricoid cartilage. made of skeletal muscle and is lined with mucous. can relax and contract. passageway for air and food
three anatomical regions of pharynx
- )naso pharynx: nasal cavity to soft palate.
- )oropharynx: soft palate inferior to hyoid bone (where the opening of the mouth is and is a passageway for air and food).
- ) laryngopharynx: hyoid bone inferior to esophagus (posteriorly) and larynx (anteriorly)
larynx
short passageway that connects laryngopharynx with trachea. 3 single pieces. thyroid epiglottis and cricoid 3 paired also
thyroid
adams apple- 2 fused plates of hyaline cartilage that form anterior wall of larynx
epiglottis
large leaf shaped elastic cartilage covered by epithelium. stem attached to anterior rim of thyroid cartilage and hyoid bone. leaf portion unattached and free to move up and down like a trap door. cover larynx during swallowing and opens up to allow air
swallowing
pharynx and larynx rise. elevation of larynx causes epiglottis to move down and form a lid over vocal cords
trachea
5 inches long with 1 inch diameter. located anterior to esophagus. extends from larynx to superior border of 5th thoracic vertebrae. divides into left and primary bronchi
layers of tracheal wall
mucosa, submucosa, hyaline cartilage, adventitia. has 16-20 hyaline cartilage ring stacked
carina
point where trachea divides into bronchi
difference between right and left primary bronchi
right is more vertical, wider, and shallower. aspirated objects likely to lodge here
primary bronchi to end of conducting zone
primary bronchi > secondary bronchi goes to each lobe (right has 3 and left has 2)> tertiary bronchioles > branch repeatedly to terminal bronchioles
cartilage to smooth muscle ratio down bronchial tree
cartilage decreases and smooth muscle increases
constriction of airways (smooth muscle) can be caused by
muscle spasms (asthma attack), PNS and allergic reactions (histamine)
dialation of airways
EPI/NE BY SNS. INCREASES VENTILATION
Difference between bronchus and bronchiole
bronchus has cartilage which allows larger diameter and prevention of airway collapse
hilum
medial region that contains the bronchi, pulmonary vessels, lymphatics and nerves
vagus nerve
parasympathetic causes bronchial smooth muscle constriction and sympathetic NE/EPI causes bronchial dilation. interesting!!!
parietal pleura
adherent to chest wall highly sensitive to pain
visceral pleura
adherent to surface of lung and doesn’t feel pain
pleural cavity
space between pleura contains serous fluid that lubricate lung surface during respiration and surface tension so lungs adhere to chest wall
left lung
contains concavity (cardiac notch) where apex sits, and thus is 10% smaller than right
right lung
thicker broader and shorter due to diaphragm being higher to accommodate liver
lobes
1 or 2 fissure divide lung into lobes.
- )left lung has oblique fissure which divides superior and inferior lobes
- )right lung has oblique fissure which separates superior from inferior lobe and inferior from middle lobe. also has horizonatal fissure which separates superior and middle lobe
each lobe receives…
secondary bronchus. right gets superior inferior and middle. left gets superior and inferior secondary bronchus
how many tertiary bronchi in each lung
10
how many alveoli in lung
300 million
surface area of alveoli
70 m^2
alveolar sac
has 2 or more alveoli
alveolus
cup shaped out pouching
surfactant
phospholipids and lipoproteins that lower surface tension of alveolar fluid, which reduces tendency for alveoli to collapse and maintains patency
respiratory membrane
alveolar wall (2 types of cells), epithelial basement membrane, capillary basement membrane (fused to epithelial basement membrane) capillary endothelium. all of this is under .5 micrometers!!
blood supply of lungs
pulmonary arteries 1 for each lung and pulmonary veins 2 from each lung
hypoxia on pulmonary blood vessels
constriction. all other body tissues hypoxia causes dilation. this vasoconstriction allows for better ventilation/perfusion coupling. BF matches extent of ventilation alveoli are recieving
lungs have dual blood supply
- )pulmonary circ. pulm. arteries> capillaries > pulmonary veins
- )bronchial circ. oxygen rich blood via bronchial arteries (branches of the thoracic aorta). supply terminal bronchioles, outer walls of pulmonary vessels and supporting tissue.
