Resp 1 Flashcards
function of resp tract; primary and other function
Primarily gas exchange between blood and environment (oxygen intake, CO2 elimination)
Also many non-respiratory functions:
* Communication (sound, pheromones)
* Thermoregulation (e.g. panting)
* Acid-base regulation (e.g. CO2 elimination)
* Metabolism (e.g. angiotensin II, prostaglandins, some drugs)
* Protection against inhaled dust, toxic gases, pathogens
* Enhancement of venous return
what is respiration, ventilation, gas exchange, cellular resp
Respiration refers to all components of the interchange of gases between the atmosphere and the cells of the body
Ventilation
* Movement of air into and out of lungs, alveoli
Gas Exchange
* Diffusion between air in lungs and blood
* Diffusion between the blood and tissues
Cellular Respiration (Aerobic)
* Derivation of energy from the high energy bonds in O2 by reacting it with carbon containing nutrients molecules to generate ATP. CO2 is a
biproduct.
resp tract divisions
Upper tract
-Nose, nasal cavity, pharynx, larynx
Lower tract
-Trachea, bronchi, lungs
parts of the upper resp tract,functions
- External nose (nares)
- Nasal cavity
-Passageway for air
-Cleans the air
-Humidifies, warms air
-Smell
-Resonating chambers for vocalization (along with paranasal sinuses) - Pharynx
-Common opening for digestive & respiratory tracts - Larynx
-Passageway for air
-Epiglottis & vestibular folds prevent swallowed material from entering larynx
-Vocal folds are primary source of sound production
trachea; forms what, juntion name and what happens
- Divides to form primary bronchi
- Junction of bronchi (carina) contains subepithelial irritant receptors -> cough reflex
tracheobronchial tree; conducting zone vs resp zone
Conducting Zone
– Trachea to terminal bronchioles, which is ciliated for removal of debris
– Passageway for air movement
– Cartilage holds tube system open
(trachea & bronchi), and smooth muscle adjusts tube diameter
Respiratory Zone
– Respiratory bronchioles to alveoli
– Site for gas exchange
pulmonary volumes; what is tidal volume, inspiratory reserve volume, expiratory reserve volume, residual volume
Tidal volume (VT)
-Volume breathed in one breath
Inspiratory reserve volume
-Volume between normal inhalation and maximal inhalation
Expiratory reserve volume
-Volume between normal passive
exhalation and maximal exhalation
Residual volume
-Volume of air remaining in lungs after maximal exhalation (i.e. healthy lungs are never completely empty of gas)
what is inspiratory capacity, what it vital capacity, what is functional residual capacity, what is total lung capacity
-Tidal volume + inspiratory reserve volume = inspiratory capacity
-Tidal volume + inspiratory & expiratory reserve volumes = Vital Capacity
-Expiratory reserve volume + residual
volume = functional residual capacity
-Total lung capacity (i.e. total lung volume)
what is minute ventilation
Minute Ventilation (VE)
* Total volume of air breathed per minute
* It is determined by the volume of each breath (Tidal Volume, VT) multiplied by the number of breaths per minute (respiratory frequency)
what is each alveoli surrounded by, surface area
-Each cluster of alveoli is surrounded by elastic fibers and a network of capillaries
-Hundreds of millions of alveoli with surface area ~40x that of skin
alveoli; lined by what and their features
-Alveoli are lined by Type I and Type II
Pneumocytes
-Type I Pneumocytes
* Cover 95% of alveolar surface
* Gas exchange
-Type II Pneumocytes
* Produce surfactant
-Alveolar Macrophages
* Ingestion of foreign material that reaches the alveoli
alveoli diffusion
Alveolar epithelium and capillary
endothelium are in close proximity to
maximize diffusion of O2 and CO 2 down their concentration gradients
surfactant; what would happen without it, inspiration, what secretse it, how does it work
- If alveoli were lined only with aqueous fluid, surface tension would be so great that they would
collapse. - Upon inspiration, only larger alveoli would expand due to relative differences in surface tension
- Type II cells secrete pulmonary
surfactant containing both hydrophilic and hydrophobic molecules (proteins & lipids) - The surfactant lipids (e.g. dipalmitoyl phosphatidylcholine) aggregate on the fluid surface, minimizing surface tension and equalizing it between different alveoli
laplace equation with and without surfactant
-Without surfactant = If surface tension of the fluid film is the same in small and large alveoli, the pressure inside small alveoli will be higher and they will collapse
-With surfactant = The level of surfactant in smaller alveoli is higher than in larger ones, so the pressure is equal
pulmonary and pleural pressure changes; before inhalation, during inhalation, end of tidal inhalation, during exhalation, what do you need to remember
A. Before the start of inhalation, there is no airflow into the lungs because Pb - Palv = 0 cm H2O and the negative pleural pressure is keeping the lung partially inflated (Pb -Ppl = 5 cm H2O).
B. During inhalation, Pb -Ppl = 16 cm
H 2 O in order to enlarge the lung (Palv - Ppl = 8 cm H2O) and make air flow through the airways (Pb -Palv = 8 cm H 2 O). About halfway along the airways, pressure within the lumen (Paw) is - 4cm H2O
C. At the end of a tidal inhalation, flow ceases because Pb -Palv = 0 cm H2O, but the lung contains more air (Palv-Ppl = 11 cm H 2 O).
D. During exhalation, airflow reverses
direction: Pb -Palv = -8 cm H 2 O, the lung volume is still greater than FRC (Palv -Ppl = 10 cm H 2 O), and the total pressure gradient remains slightly positive (Pb -Ppl = 2 cm H2O). About halfway along the airways, pressure within the lumen (Paw) is 4cm H2O.
It is important to remember that these pressure gradients change continually throughout a breath cycle and with changes in tidal volume, respiratory frequency, lung compliance, and airway resistance
