respiratory Flashcards
clara cells: structure and function
- secrete surfactant
- dome-shaped w/ microvilli
- reserve cells for worn out epithelium
type I alveolar cells: structure and function
- simple squamous
- gaseous diffusion barrier
type II alveolar cells: structure and function
- cuboidal, round nuclei, prominent nucleoli
- secretes surfactant
dust cells
macrophages of respiratory system
layers of blood-air barrier
- plasma membrane, cytoplasm of type I alveolar cells
- dual basal lamina: type I alveolar, endothelial cells
- plasma membrane and cytoplasm of endothelium
- plasma membrane of RBCs
lung volumes: VT
- tidal volume
- amount of air entering/exiting lung per breath
lung volumes: RV
- residual volume
- volume remaining after maximal exhalation
lung volumes: VC
- vital capacity
- max achievable tidal volume (max inhalation and exhalation)
lung volumes: FRC
- functional residual capacity
- air in lungs after quiet expiration
- elastance of lungs at rest
lung volumes: TLC
- total lung capacity
- maximum lung volume
bulk flow in inspiration
- lower airways have a progressive surface area, cross sectional diameter increase
- bulk flow velocity decreases, allowing for diffusion
- total resistance decreases
respiratory cycle pressures: intrapulmonary
- end of quiet exhalation: alveolar pressure = atmospheric
- during inhalation: lungs expand, alveolar pressure decreases, bulk flow inward
- end of inspiration: alveolar pressure = atmospheric
- exhalation: elastic recoil of lungs pulls them in, volume decreases, pressure increases, creating outward bulk flow
respiratory cycle pressures: intrapleural
end of quiet exhalation: intrapleural pressure is negative
during inhalation: muscles expand pleural space, pressure decreases
end of inspiration: inspiratory muscles still contracting, pressure more negative
exhalation: slow return to baseline
*pressure is negative due to opposing recoil forces
surfactant: function in ventilation
- reduces surface tension
- increases lung compliance, reducing work of breathing
elastic recoil affecting ventilation
- FRC pulls lungs in while chest wall has outward recoil. exactly negate each other
- structures pull at pleural space, creating negative pressure that vacuum seals lungs, chest wall together
- lungs and chest wall move as unit
minute ventilation vs alveolar ventilation
minute: air moved in/out of respiratory system per min
alveolar: air moved in/out of respiratory zone/minute (volume that participates in gas exchange)
dead spaces: anatomic vs alveolar vs physiologic
anatomic: VT that stays in conducting zone
alveolar: VT in resp zone that doesn’t exchange w/ blood
physiologic: total
pulmonary function test: obstructive vs restrictive
in obstructive: FEV1/FVC decreases
in restrictive: FEV1/FVC stays the same
lung volumes: FVC
- forced vital capacity
- amount of air that can be exhaled after max inhalation
lung volumes: FEV1
how much air a person can exhale in 1 second after max inhalation
lung kinetics in disease
gas exchange slows
- patient feels normal at rest
- notices SOB during exercise
lung kinetics in hypoxemia
slow, low supply of oxygen (less PaO2)
- patient feels fatigued, SOB
increased blood flow: effect on pulmonary vascular resistance
- increases pressure, opens closed vessels (recruitment)
- increases diameter of open vessels (distension)
lung volume: effect on PVR
- pulmonary vessels compress as volume moves away from FRC
- PVR increases
ventilation-perfusion in upper vs lower lungs
- at FRC: alveoli in base of lungs are smaller than apex bc of gravity. when air enters, more air goes to lower lungs
- higher Q (perfusion) in lower lungs
V/Q < 1
some blood remains deoxygenated bc there’s more blood than air can oxygenate
V/Q > 1
- more air w/ more oxygen than blood can transport
- exhaled
pulmonary edema: effects
- thickened blood-air barrier
- reduced surface area
- decreased ventilation
Low PiO2: effects
affects ventilation
- pAO2 decreases
- pACO2 decreases or stays the same
- pA-aO2 stays the same
- oxygen supplementation is useful
hypoventilation: effects
affects ventilation
- pAO2: decreases
- pACO2: increases
- pA-aO2: stays the same
- oxygen supplementation useful
how to differentiate PiO2 and hypoventilation
in PiO2, pACO2 decreases or stays the same
in hypoventilation, pACO2 increases
abnormal diffusion: effects
- pA-aO2 increases
- pAO2 and pACO2 can change, not always
- oxygen supplement is useful
V-Q mismatch: effects
- pA-aO2 increases
- oxygen supplement is useful
right to left shunt: effects
- pA-aO2 increases
- oxygen supplement not useful
factors that decrease oxygen affinity
- increased pH, pCO2
- increased 2, 3- DPG
anemic hypoxia
- decreased oxygen carrying capacity in blood leads to insufficient/defective Hb
- less oxygen enters blood, less oxygen to tissues
- caused by hemorrhage, anemia
factors that increase oxygen affinity
- decreased pH, pCO2
- decreased 2, 3-DPG
hypoxic hypoxia
- abnormal lung oxygenation
- not enough saturated oxygen
- less oxygen entering blood, less oxygen delivery to tissues
histotoxic hypoxia
- normal oxygen delivery, but cells can’t uptake oxygen due to toxic substances
- oxygen extraction and uptake inhibited
circulatory hypoxia
- issue w/ CO: inadequate blood supply to tissues
- heart failure, thromboembolic diseases
- less blood flow, less oxygen delivery to tissues
peripheral chemoreceptors: locations, functions
- in carotid sinus, aortic arch
- sense PaO2, PaCO2, pH
- send signals to medulla, pons
CO2 carried in blood
- most converted to bicarbonate w/ carbonic anhydrase
- some dissolves in plasma
- unloads when oxygen pressure is high
central chemoreceptors: locations, functions
- found along spinal cord
- sense changes in PaCO2, changing pH of CSF
central controller: functions
medulla and pons
- initiates breathing, sets rhythm (modulated by signal inputs)
- receives afferent signals from chemoreceptors
- sends info to effectors to set resp rate
effectors: functions
respiratory muscles, airways
- maintain resp rate set by CNS
set points
PaO2, pH, PaCO2
- respiratory rate should maintain
chemoreceptors (in relation to brainstem)
- recognize changes in set points
- send signals to CNS for modulation
cerebral cortex: respiration
- voluntary control
airway function: air conditioning
upper airway warms and humidifies air
airway function: phonation
voice production
airway function: host defense
- epithelium, cilia, mucus, mucociliary escalator
- traps inhaled particles, clears by moving towards pharynx
- coughing, sneezing: forceful exhalation
- bronchial associated lymphoid tissue
airway function: metabolism, conversion
- angiotensin I to II
- serotonin metabolism
nasal cavity: lateral wall
- formed by middle and inferior nasal conchae
- create turbulent flow: all air contacts epithelium, maximizes entrapment of particles
nasal cavity: vibrissae, sebaceous glands function
trap particulate matter
nasal cavity: structure that warms air
blood vessels in lamina propria
olfactory cells: portions
bipolar
- apical region: olfactory knob (dendrite) has olfactory receptors for odor molecules
- basal region: axons, olfactory fila pass thru cribriform plate to olfactory bulb
- sustentacular cells: support
larynx: functions
- airway passage
- sound production
- closing trachea during swallowing
first portion of respiratory tract with no cartilage
terminal bronchioles
trachea: mucosa characteristics
- ciliated pseudostratified
- serous and mucus glands present in lamina propria
- elastic lamina
trachealis muscle: fiber type
smooth muscle
lobar bronchi: mucosa characteristics
- ciliated pseudostratified to ciliated simple columnar
- lamina propria w/ more elastic fibers, has serous and mucus glands, blood vessels
- complete muscularis mucosa
trachea: submucosa characteristics
- dense irregular CT
- fibroelastic w/ serous and mucus glands
- MALT
lobar bronchi: submucosa characteristics
- fibroelastic, sparse glands
segmental bronchi: mucosa characteristics
- ciliated simple columnar
- more elastic fibers in thinner lamina propria
- complete muscularis mucosa
terminal bronchioles: mucosa characteristics
- ciliated simple columnar to ciliated cuboidal
- clara cells present: dome shaped w/ microvilli, secrete surfactant
- thin lamina propria, no glands
- complete muscularis mucosa
respiratory bronchioles: mucosa characteristics
- ciliated simple cuboidal
- clara cells
- simple squamous alveoli interrupt wall continuity
- no muscularis mucosa
alveolar ducts: mucosa characteristics
- low cuboidal to type I alveolar (simple squamous)
- thin for diffusion
- smooth muscle knobs bulge into lumen to regulate diameter of opening
alveoli: characteristics
- type I simple squamous alveolar cells: gaseous diffusion barrier, occluding junctions between cells
- type II cuboidal, round nuclei, prominent nucleoli, granules to release surfactant
