Respiration Flashcards
Lungs
Site of gas exchange
external nares
Air enters here
nasal cavity
passing of air after it enters thru external nares, where its filtered by mucous membrane and nasal hairs.
Pharynx and larynx
air passes through here, larynx is covered by epiglottis.
Trachea and Bronchi
One on each side.
Bronchioles
Bronchi divides into this
Alveoli
division of bronchioles
site of gas exchange.
branching increases the surface area for gas exchange.
surfactant
a detergent that lowers the surface tension and prevents alveolus from collapsing.
-it covers the alveoli.
Pathway of air during respiration
Nasal cavity–>pharynx–>larynx–>trachea–>bronchi–>bronchioles–>alveoli
Thoracic cavity
lungs are here in addition to the heart
diaphragm
seprates the thoracic cavity from the organs of digestion.
muscle that is necessary for inspiration, skeletal muscle with somatic control.
pleurae
membrane surrounding the lungs
visceral pleura
membrane that directly touches the outside of the lungs
parital pleura
outer layer membrane that is associated with the chest wal
intrapleural space
space between visceral and parietal pleura in which contains a thin layer of fluid.
the pressure differential between the intrapleural space and the lungs is critical!
Stages of ventilation
Inhalation and exhalation
Inhalation
An active process.
- thoracic cavity expands and pushes down the diaphragm.
- chest wall moves out and the volume of the intapleural space is increased–> means that the pressure is decreased.
Negative-pressure breathing
the gas in the lungs is at atmospheric pressure, which is at higher pressure than the intrapleural space. So lungs expands as air is sucked in from a high pressure environment.
Exhalation
the reverse process of inhalation.
simple relaxation results in exhalation.
-diaphragm and external intercostals relax, causing the chest cavity volume to decrease, which increases the pressure in the intrapleural space becoming higher than the pressure of the air in the lungs, so air is pushed out.
process can be sped up by using internal intercostal muscles which decrease the volume of the cavity.
control of ventilation
nervous system has an input for breathing.
medulla oblongata
rythmically firing neurons cause regulater contraction of respiratory muscles.
neurons are sensitive to CO2 concentration.
function of chemoreceptors on neurons
they monitor the changes in pH which in fact monitors the changes in CO2 concentration.
spirometer
used to measure the amount of air normally present in lungs and the rate of ventilation, depends on O2 abundance.
total lung capacity (TLC)
6-7 liters- total amount of air in lungs if we breath in as much as possible.
Vital capacity (VC)
total amount of air forced out
Residual volume (RV)
amount of air left over in lungs
TLC =?
VC + RV
Tidal volume (TV)
amount of air needed to breathe
ERV
use of muscle to push out last bit of air
IRV
amount of extra air we can take after TV
VC=?
TV + ERV + IRV
pulmonary capillaries
surround each alveolus
pulmonary artery
carries deoxygenated blood, when approaches alveolar layer–> diffusion of CO2 from blood to lungs and O2 in opposite direction.
pulmonary vein
carries oxygenated blood to the heart.
Pressure differential of gases
Is the driving force of gas exchange between blood and lungs, no energy is required.
Hemoglobin
used to transport O2 in blood.
