pulmonary Flashcards
respiratory system functions
- Exchange of gases between the atmosphere and the blood
- Homeostatic regulation of body pH
- Protection from inhaled pathogens and irritating substances (food)
- Vocalization (talking)
ventilation
– Exchange of air between atmosphere and lungs
▪ Expiration vs inspiration
- the physics behind breathing
respiration
– Exchange of oxygen and carbon dioxide between lungs and the blood
- chemical exchange
when you inhale and exhale what happens to the pressure in your lungs?
- inhale: decreases
- exhale: increases
bulk flow takes place from ___ pressure to ___ pressure
high, low
upper respiratory tract
- mouth basal cavity, pharynx, larynx
lower respiratory tract
- trachea, 2 primary bronchi, their branches, lungs
site of gas exchange
- alveoli
what keeps the diaphragm alive?
C3, C4, C5
thoracic cage
- Bones and muscles of the thorax surround the lungs
- Spine and rib cage
- Diaphragm, intercostal muscles, sternocleidomastoids, scalenes
- Pleural sacs each surround a lungs
pleural fluid
– Lowers friction between membranes
– Holds lungs tight against the thoracic wall
type I alveolar cells
- gas exchange (respiration)
pleural sac
- maintains pressure in thoracic cavity
- forms a double membrane surrounding the lung, similar to a fluid-filled balloon surrounding an air-filled balloon
- collapsed lung = puncture in sac
type II alveolar cells
- produce surfactant
- surfactant = ease diffusion of O2 and CO2
hypercapnia
- high levels of CO2 (acid in the blood)
- decreases pH
- bicarbonate buffer system kicks in
hypoxia
- too little O2
- decreases pH
inspiration
- breathing in
- occurs when alveolar pressure decreases
- volume increases
expiration
- breathing out
- occurs when alveolar pressure increases
- volume decreases
you NEED to ____ in order to ____
ventilate, respirate
you can _____ but not _____
ventilate, respirate
tidal volume (Vt)
- volume that moves during a respiratory cycle
inspiratory reserve volume (IRV)
- additional volume above tidal volume
- breathe in
expiratory reserve volume (ERV)
- forcefully exhaled after the end of a normal expiration (breathe out)
anatomic dead space
- portion of inspired air that does not take part in gas exchange
- can only be measured if you’re dead
residual volume (RV)
- volume of air in the respiratory system after maximal exhalation
- expel out all air but stops bc your body reaches a limit
vital capacity
- VT + IRV + ERV
total lung capacity
- VT + IRV + ERV + RV
what creates pressure gradients?
- muscular pumps
pressure gradient
- causes fluid to flow from regions of higher pressure to regions of lower pressure
intrapleural pressure during the respiratory cycle
- inspiration: pressure drops
- expiration: pressure returns to normal value
inside cavity – when you breathe in, the volume in the inside of the lungs ____ while the pressure ____
- increase in volume
- decrease in pressure
outside cavity – when you breathe in, the volume in the outside of the lungs __ while the pressure ___
- decrease volume
- increase pressure
total pulmonary ventilation
- volume of air moved in and out of lungs per minute
- ventilation rate x tidal volume
alveolar ventilation
- more accurate
- ventilation rate x (tidal volume-dead space)
- Low alveolar PO2 alveolar ventilation is inadequate
(hypoventilation)- Decreased lung compliance
- Increased airway resistance
- CNS depression: alcohol poisoning, drug overdose
acidosis
- happens when you exercise, blood pH low/acidic
alkalosis
- decreases ventilation, decreased CO2, higher oxygen
partial pressure of the gas
- pressure of an individual gas in a mixture
- total pressure equals sum of all partial pressures (Pgas)
high compliance
- stretches easily
low compliance
▪ Requires more force
▪ Restrictive lung diseases (inability to breathe in)
– Fibrotic lung diseases (fibrosis)
– Inadequate surfactant production (NRDS)
carbon dioxide and epi bind to what receptors
- Beta 2 receptors
elastance
- ability to return to resting volume when stretching force is released
bronchoconstriction
- increases resistance
- parasympathetic – bind to muscarinic via ach
bronchodilation
- decreases resistance
- sympathetic: beta 2 receptors on smooth muscles relax in response to epi
airway diameter
- wider airways have less resistance
hemoglobin that binds to oxygen creates what?
- oxyhemoglobin
- oxygen bound to it and travel thru the blood
- 4 hemes, so 4 O2 binding sites
hemoglobin transports most ___ to the tissues
oxygen
regulation of ventilation
- Neural networks in the brain stem behaves like a central pattern generator
- Respiratory neurons in the medulla control inspiratory and
expiratory muscles - Neurons in the pons integrate sensory information and interact with medullary neurons to influence ventilation
- Rhythmic pattern of breathing arises from a neural network of
spontaneously discharging neurons - Ventilation is subject to continuous modulation by
chemoreceptor- and mechanoreceptor-linked reflexes and higher brain centers
- Respiratory neurons in the medulla control inspiratory and
pons
- controls respiratory
gas exchange btw alveoli and blood
- PO2 alveolar air > PO2 blood
- PCO2 blood > PCO2 alveolar air
gas exchange between blood and tissues
- PO2 blood > PO2 tissue
- PCO2 tissue > PCO2 blood
pulmonary gas exchange and transport
- oxygen enters the blood at alveolar-capillary interface
- oxygen is transported in blood dissolved in plasma or bound to hemoglobin inside RBCs
- Oxygen diffuses into cells
- CO2 diffuses out of cells
- CO2 is transported dissolved bound to hemoglobin, or as HCO3
- CO2 enters alveoli at alveolar-capillary interface
% saturation of hemoglobin and how it affects oxygen’s binding affinity for hemoglobin
- PCO2: increase this will decrease saturation and affinity
- pH: decrease this will decrease saturation and affinity
- temp: increase this will decrease saturation and affinity
venous
- higher levels of CO2 except in pulm vein
arterial
- higher levels of O2 except pulm artery
to avoid hypoxia and hypercapnia, the body responds to three regulated variables
- oxygen
- carbon dioxide
- pH
fick equation
- used to estimates oxygen consumption
carbon dioxide is transported in 3 ways
- dissolved in plasma (7%) or diffuses into RBCs (93%) with bound to hemoglobin (23%) or converted to HCO3 (70%)
fresh air into lungs =
10% total lung volume at the end of inspiration
what is an example of ventilating but not respirating?
asthma
what buffer system brings the blood pH back to normal?
bicarbonate
