concept 3b part 1 Flashcards
(129 cards)
anatomy of respiratory system
nasal cavity pharynx larynx trachea bronchi lungs (left and right) horizontal fissure oblique fissure
nares
external part of the nose
air enters respiratory tract here
then passes thought the nasal cavity where it is filtered thought mucous membranes and nasal hairs (vibrissae)
nose and mouth
serve important functions in breathing by removing dirt and particulate matter from the air and warming and humidifying it before it reaches lungs
pharynx
resides behind the nasal cavity at the back of the mouth
common pathway for air destined for the lungs and food destined for the esophagus
air passes here from the nasal cavity
larynx
lies below the pharynx
only a pathway for air
opening (glottis) is covered by the epiglottis during swallowing to keep food out of larynx
contains 2 vocal cords that move using skeletal muscle and cartilage
air passes from the larynx into the trachea
trachea
cartilaginous tube that connects the pharynx to the bronchi
contain ciliated epithelial cells to catch material that has made it past the mucous membranes in the nose and mouth
bronchi
tubelike passages for air that connect the trachea to the bronchioles
in the lungs the bronchi continue to divide into smaller structures known as bronchioles, which continue to divide until they end at the alveoli
alveoli
basic functional unit of the lung
time sac specialized for passive gas exchange b/w lungs and blood
coated with surfactant, detergent that lowers surface tension and prevents the alveolus from collapsing on itself
pleurae
membrane that surround each lung
forms a closed sac against which the lung expands
surface adjacent to the lung is the visceral pleura
the outer part is the parietal pleura
diaphragm
most important muscle in the lung
thin muscular strict that divides the thoracic (chest) cavity from the abdominal cavity
under somatic control, breathing itself is under autonomic control
intrapleural space
fluid filled potential space b/w the parietal and visceral pleura that lubricates that 2 pleural surfaces and allows for a pressure differential b/w the intracellular space and the lungs
thoracic cavity during inhalation
use diaphragm and external intercostal muscles to expand the thoracic cavity by contracting
diaphragm flattens and chest wall expands outward, the intrathoracic volume increases
increase in volume leads to decrease in intracellular pressure
lungs during inhalation
gas in lungs is initially at atmospheric pressure, higher than pressure in intracellular space
lungs expand into the intracellular space, pressure in lungs will drop
air is then sucked into lungs from environment
referred to as negative-pressure breathing
negative-pressure breathing
mechanism of inhalation into the lungs
driving force is lower (relatively negative) pressure in the intracellular space compared with the lungs
thoracic cavity during exhalation
relaxation of external intercostal muscles will reverse process of inhalation
diaphragm and external intercostals relax, the chest cavity decreases in volume
intracellular pressure increases, it is now higher pressure than in the lungs so air is pushed out
can be assisted by contraction of internal intercostal muscles and abdominal muscles
inhalation
air flow into the lungs, breathing in
increase volume of chest cavity
contract diaphragm and external intercostals
active process
exhalation
air flow out of the lungs, breathing out
decrease volume of chest cavity
relax diaphragm and external intercostals
contract internal intercostals and abdominal muscles to pull rib cage down
does not have to be an active process
spirometer
instrument used to measure lung capacities and volumes
cannot measure the amount of air remaining in the lung after complete exhalation (residual volume) but provides a number of measure useful in medicine
commonly tested lung volumes
total lung capacity (TLC) residual volume (RV) vital capacity (VC) tidal volume (TV) expiratory reserve volume (ERV) inspiratory reserve volume (IRV)
total lung capacity (TLC)
the maximum volume of air in the lungs when one inhales completely
usually around 6 to 7 liters
residual volume (RV)
the minimum volume of air in the lungs when one exhales completely
vital capacity (VC)
the difference b/w the minimum and maximum volume of air in the lungs
VC=TLC-RV
tital volume (TV)
the volume of air inhaled or exhaled in a normal breath
expiratory reserve volume (ERV)
the volume of additional air that can be forcibly exhaled after a normal exhalation