Exam 1: Respiratory System Flashcards
anatomy
morphology; what the body looks like
physiology
functionality; how the body works
primary functions of the respiratory system
- exchange of gases between the atmosphere and the blood
- homeostatic regulation of body pH
- protection from inhaled pathogens and irritating substances
- vocalization
directions in gas exchange
oxygen in, carbon dioxide out
how do the lungs alter pH?
selectively retaining or excreting carbon dioxide
which tissue protects the body from inhaled pathogens and irritating substances?
respiratory epithelium
how does vocalization occur?
vibrations are created by air moving across the vocal cords
pulmonary circulation
process between heart and lungs to reoxygenate the blood
contains 500 mL / ~ 50% of total amounts
bulk flow exchange of air between the atmosphere and the alveoli
inspiration
inhalation; taking in of oxygen
expiration
exhalation; blowing out carbon dioxide
internal (cellular respiration)
exchange of gases between blood and cells (oxygen in, carbon dioxide out)
role of airways
- warming air to body temperature
2 . adding water vapor until air reaches 100% humidity
- filtering out foreign material
why is it important to condition air before it enters the body
- protects alveoli from cold temperatures
- prevents exchange epithelium from drying out
- removes viruses, bacteria, and inorganic particles before they reach the alveoli
which cells secrete the mucus layer?
goblet cells
how is mucus moved?
underlying cilia create an upward motion toward the pharynx
mucus that reaches this point is swallowed
why is mucus important?
mucus contains immunoglobulins (antibodies) that disable pathogens
why does cilia not stick to mucus?
a fluid layer lies between mucus and cilia
saline secretion by the airway epithelium
- NKCC brings Cl- into epithelial cell from ECF
- apical anion channels, including CFTR, allow Cl- to enter the lumen
- Na+ goes from ECF to lumen by the paracellular pathway, drawn by the electrochemical gradient
- NaCl movement from ECF to lumen creates a concentration gradient so water follows into the lumen
upper respiratory system components
neck and above
nasal cavity, tongue, pharynx, vocal cords, esophagus, larynx
lower respiratory system components
neck and below
bronchi, alveoli, lungs, thorax (chest cavity)
how does the velocity of air across different size of lung branches change?
air becomes slower at smaller diameters (thinner branches)
types of alveolar cells
type I alveolar epithelium
type II alveolar epithelium
alveolar macrophage (dust cell)
type I alveolar epithelium
thin squamous cell
occupies 95% of the alveolar surface
function: rapid gas exchange
which alveolar cell covers the majority of its surface?
type I alveolar epithelium
covers 95% of the alveolar surface
type II alveolar epithelium
function: produces pulmonary surfactant
decreases surface tension in the alveoli
helps to expand lungs during breathing
alveolar macrophage (dust cell)
function: ingesting foreign material
what fills the majority of space in between alveoli?
blood vessels
fill 80-90% of space
no muscle because these would block gas exchange
connective tissues contain elastin and collagen which helps to keep alveoli elastic
why is the proximity of capillary blood and alveolar air important?
closer connections allow for the most efficient gas transfer
pressure gradient and resistance determine…
air flow of the respiratory system
pleural membrane
fluid filled sac surrounding the lungs
function: creates moist, slippery surface so that the lungs can move within the thorax and holds lungs tight against the thoracic wall
volume of the pleural fluid
25-30 mL for a 70 kg man
similar to spreading 3 mL of water over the surface of a 3L bottle
SUPER SMALL
boyle’s law
p1v1 = p2v2
as the volume of gas increases, pressure goes down
how does boyle’s law explain how lungs fill with air?
during inspiration, chest volume increases
alveolar pressure decreases
since alveolar pressure is now lower than atmospheric pressure, air will rush in/fill the lungs
dalton’s law
the sum of partial pressures makes up the total pressure of a mixture of gases
pressure contributions from individual gases can be found; explains the rate and direction that gases flow in the alveoli
law of laplace
pressure = 2 * surface tension / radius
explains why out of two alveoli with the same surface tension, the smaller alveoli will have a higher pressure and is therefore more susceptible to collapse/needs more surfactant
pressure gradients law
gases, singly or in a mixture, move from areas of higher pressure to areas of lower pressure
pressure gradients law (single gas example)
oxygen will move from areas of high partial pressure of oxygen to areas of low partial pressure of oxygen regardless of other gases’ partial pressures
physical changes during inspiration
diaphragm, external intercostal muscles, and scalene contract (allowing lungs to have a greater volume)
thoracic cavity expands
physical changes during expiration
diaphragm relaxes
thoracic cavity shrinks/reduces
forced expiration only: internal intercostal and abdominal muscles contract
breathing mechanism
- changing volume makes a pressure difference (by boyle’s law)
- pressure difference makes air flow (by pressure gradients law)
- therefore, changing volume makes air flow
inter/costal
between/rib
scalenes
contribute to inspiration by lifting the sternum and upper ribs
where do ribs attach?
sternum (breast bone)
intercostal muscle control
muscles have their own nerves to regulate contraction (controlled by the brain)
pulls rib cage and sternum up and out
diaphragm
separates chest from abdomen and contributes to respiration
what are the causes of inspiratory volume change?
60-75%: diaphragm contracts to move about 1.5 cm
25-40%: movement of the rib cage
quiet breathing
exhalation is a passive process
contraction of diaphragm, external intercostal muscles, and scalenes still occurs
physical changes during forced exhalation
diaphragm relaxes
thoracic cavity shrinks/reduces
internal intercostal and abdominal muscles contract
diseases affecting ventilation
any neuromuscular disease that weakens skeletal muscles/damages motor neurons can affect ventilation
pyasthenia gravis
acetylcholine receptors of the motor end plats of skeletal muscles are destroyed
polio
viral illness that paralyzes skeletal muscles through damaging motor neurons at the spinal cord
side effects of decreased ventilation
less fresh air enters lungs
loss of the ability to cough can increase risk of pneumonia/other infections
the patient’s respiratory tract and a spirometer form a _______ system
closed
when breathing, air moves from the spirometer into the lungs
tidal volume (Vt)
quiet breathing
~ 500 mL / breath
inspiratory reserve volume (IRV)
maximum inspiration
expiratory reserve volume (ERV)
maximum expiration
residual volume (RV)
air left in the airway and lungs
inspiratory capacity
IRV + Vt
vital capacity (VC)
Vt + IRV + ERV
total lung capacity (TLC)
VC + RV
ventilation rates
normal resting: 12-20 breaths/min
active: 30-40 breaths/min
respiratory minute volume (RMV)
usually ~ 6 L/min
= tidal volume * breaths/min
male vs. female lung capacity
male: TLC ~ 5800 mL
female: TLC ~ 4200 mL
