CH. 16 Respiratory System: Pulmonary Ventilation Flashcards
What is internal respiration?
- What process does it utilize?
how cells use oxygen
- oxidative phosphorylation
What is external respiration?
how do we get oxygen to blood
- occurs through exchanges between blood (i.e lungs and body tissue)
What are the 3 air passages of the head and neck?
- nasal cavities
- oral cavity
- pharynx
What are the 3 airways from the pharynx to lungs?
- larynx
- conducting zone
- respiratory zone
What are the 7 components of the conducting zone composed of?
- larynx
- glottis
- epiglottis - trachea
- bronchi
- secondary bronchi
- tertiary bronchi
- bronchioles
- terminal bronchioles
What are 3 functions of the conducting zone?
- air passageway
- increases air temperature to body temperature
- humidifies air as there is a lot of water vapor in the lungs
What is the epithelium of the conducting zone comprised of?
- goblet cells: secrete mucus
- ciliated cells: move particles toward mouth
- mucus escalator
What is the function of the respiratory zone?
- exchange of gases between air and blood
2. mechanism of action: diffusion
What are the four structures of the respiratory zone?
- respiratory bronchioles
- alveolar ducts
- alveoli
- alveolar sacs
What is the epithelium of the respiratory zone comprised of?
a respiratory membrane
- epithelial cell layer of alveoli
- endothelial cell layer of capillaries
Where is the site of gas exchange in the respiratory tract?
alveoli
How do alveoli have a rich blood supply?
capillaries form sheet over alveoli
What are the differences between Type I and Type II alveolar cells?
Type I alveolar: make up wall of alveoli
Type II alveolar: secrete surfactant
How do type II alveoli maintain shape of alveoli when stretched?
surfactant is released which disrupts hydrogen bonds between water molecules
What structures make up the chest wall?
- rib cage
- sternum
- thoracic vertebrae
- muscles: internal and external intercostals, diaphragm
What gradient drives the flow of air?
pressure gradient
What does the pressure need to be for inspiration and expiration?
Inspiration: pressure in lungs less than atmospheric pressure
Expiration: pressure in lungs greater than atmospheric pressure
What is the transpulmonary pressure?
Intra-alveolar pressure - Intrapleural pressure
-distending pressure across the lung wall
What is the intra-alveolar pressure? and when is it negative/positive in relation to inspiration/expiration?
pressure of air in alveoli; what moves air in and out of lungs
- during inspiration = negative
- during expiration = positive
What is the intra-alveolar pressure? and when is it negative/positive in relation to inspiration/expiration?
pressure of air in alveoli; what moves air in and out of lungs
- during inspiration = negative
- during expiration = positive
What is the intrapleural pressure? and when is it negative/positive?
pressure inside pleural sacs
- always negative under normal conditions due to elasticity of lungs and chest wall
What is the transpulmonary pressure? and when is it positive/negative?
distending pressure across the lung wall
- always positive
How does Boyle’s law explain how air moves in and out of the lungs?
as pressure increase, volume decrease; air would passively move into lungs
What factors determine intra-alveolar pressure?
- quantity of air in alveoli
2. volume of alveoli
What occurs when lungs expand?
- Intra-alveolar pressure decreases
2. pressure gradient drives air into lungs
What occurs as lungs recoil?
Intra-alveolar pressure increases
- pressure gradient drives air out of lungs
What inspiratory muscles increase the volume of the thoracic cavity?
diaphragm and external intercostals
What expiratory muscles decrease volume of thoracic cavity?
internal intercostals and abdominal muscles
What are the ways in which expiration occur?
- normally a passive process
2. active expiration requires expiratory muscles
What is lung compliance? and what does a larger lung compliance allow?
ease with which lungs can be stretched
- easier to inspire
- smaller change in transpulmonary pressure needed to bring in a given volume of air
What factors affect lung compliance?
- elasticity: more elastic -> less compliant
2, surface tension of lungs: greater tension -> less compliant
What needs to be present to overcome surface tension?
surfactant secreted from type II cells
Why is airway resistance relatively low?
pressure gradient is needed for air flow
What factors affect airway resistance?
- passive forces
- contractile activity of smooth muscle
- mucus secretion
What are two passive forces that affect airway resistance?
- changes in transpulmonary pressure during respiratory cycle
- tractive forces
What enables sympathetic control of bronchiole radius?
norinepinephrine
What enables parasympathetic control of bronchiole radius?
acetylcholine
What is the intrinsic control of bronchiole radius comprised of?
- Histamine: bronchoconstriction
2. CO2: bronchodilation
What are two pathological states that increase airway resistance?
- asthma
2. chronic obstructive pulmonary diseases
What are obstructive pulmonary diseases?
associated with increased airway resistance
What are restrictive pulmonary diseases?
more difficult for lungs to expand
What is a forced vital capacity?
maximum-volume inhalation followed by exhalation as fast as possible
What is forced expiratory volume?
percentage of FVC that can be exhaled within a certain time frame
What is a peak expiratory flow rate?
maximum rate at which a person can exhale
What is minute ventilation?
total volume of air entering and leaving the respiratory system each minute
What is the anatomical dead space?
air in conducting zone that does not participate in gas exchange
What is alveolar ventilation?
volume of air reaching the gas exchange areas per minute
