Respiratory System Flashcards
(38 cards)
2 stages of breathing
ventilation and oxygenation
ventilation
movement of air into and out of the lungs so that cells of the body can produce energy
oxygenation
the exchange of gases between the atmosphere and blood, supplying oxygen to the blood and removing carbon dioxide
2 zones of the respiratory system
conducting zone and respiratory zone
what does the conducting zone consist of
mouth, nose, larynx, pharynx, trachea, primary bronchi, and all successive branchings of the bronchioles up to and including the terminal bronchioles
functions of the conducting zone
conducting air into the respiratory zone, warming and humidification of inspired air, filtration and cleaning
what does mucus secreted by cells of conducting zone do
saturates air with water vapour as it flows over mucous membranes, traps small particles of inspired air (filtration)
function of respiratory zone
gas exchange
adaptations for gas exchange
large surface area of alveoli, alveoli one cell thick so short diffusion distance
what is anatomical dead space
the volume of air contained within the conductive airways of the respiratory system (nose, trachea and bronchi)
why is it considered anatomical dead space
volume of air does not penetrate gas exchanging regions, so dead space does not participate in gas exchange
what is physiological dead space
the volume of air that fills conducting airway plus the volume of air that penetrates gas exchanging regions but does not involve gas exchange. simply= combination of anatomical dead space and alveolar dead space
which muscles are used in breathing
inspiratory muscles and expiratory muscles
inspiratory muscles and what they do
external intercostal (raises rib cage), sternocleidomastoid muscles (lift upwards on the sternum), anterior serrati (lift many of the ribs)
scaleni (lift the first 2 ribs)
expiratory muscles
abdominal recti, internal intercostal muscles
what is boyle’s law
the pressure of a gas is inversely proportional to the volume of the gas
what happens during inspiration
- external intercostal muscles and diaphragm contract simultaneously
- this enlarges the thoracic cavity in all directions
- contraction of external intercostal muscles lifts the ribcage upwards and outwards, expanding the thorax
- when the diaphragm contracts, its muscle fibres shorten and the central tendon is pulled downwards, lengthening the thoracic cavity
- lung tissue pulled upwards and outwards with rips and downwards with diaphragm
- this expands the lungs
- pressure within the alveoli and air passage falls, drawing air into lungs
what happens during expiration
- relaxation of the external intercostal muscles and diaphragm results in downward and inward movement of the ribcage
- this increases the pressure inside the lungs and expels air from the respiratory tract
how is pulmonary function assessed
spirometry
tidal volume
the volume of gas inspired or expired in an unforced respiratory cycle
inspiratory reserve volume
the maximum volume of gas that can be inspired during forced breathing in addition to tidal volume
expiratory reserve volume
the maximum volume of gas that can be expired during forced breathing in addition to tidal volume
residual volume
the volume of gas remaining in the lungs after a maximum expiration
total lung capacity
vital capacity + residual volume
total amount of gas in the lungs after a maximum inspiration
