Ch. 6: The Respiratory System Flashcards
(62 cards)
func: thoracic cavity
where the lungs and heart are located
its structure is specially designed to perform breathing
where does gas exchange occur in the respiratory tract?
in the lungs
what is the pathway of air through the respiratory system? + what happens to air when it is in the nasal cavity
- enters through external nares of the nose
- passes through the nasal cavity where it is filtered by mucous membranes and nasal hairs
- pharynx
- larynx
- trachea (cartilaginous)
- into one of the two mainstem bronchi
- lungs: bronchi continue to divide into bronchioles
- which divide into alveoli
aka: vibrissae
nasal hairs!
location + pathway contents: pharynx vs. larynx
PHARYNX
- behind the nasal cavity, at the back of the mouth
- pathway for air and food
LARYNX
- lies below the pharynx
- pathway for air only
aka: glottis
larynx
defn + func: epiglottis
covers the larynx during swallowing to keep food out of the respiratory tract
where are the vocal cords located and how are they maneuvered?
where: in the larynx
maneuvered using skeletal muscle and cartilage
what is the purpose of ciliated epithelial cells in the bronchi and trachea?
to catch material that has made it past the mucous membranes in the nose and mouth
defn: alveoli
tiny balloon-like structures in which gas exchange occurs
defn + func: surfactant
coats each alveolus
a detergent that lowers surface tension and prevents the alveolus from collapsing on itself
what does the network of capillaries surrounding each alveolus do?
carry oxygen and CO2
why do the alveoli have such a large surface area?
the branching and minute size allow for a large surface area for gas exchange
defn: pleurae
membranes that surround each lung
pleura form a closed sac against which the lung expands
defn: visceral vs. parietal pleura
VISCERAL PLEURA = the surface adjacent to the lung
PARIETAL PLEURA = the outer part associated with the chest wall
defn: diaphragm
a thin, muscular structure that divides the thoracic cavity from the abdominal cavity
do the lungs fill passively?
no they require skeletal muscle (most importantly the diaphragm) to generate the negative pressure for expansion
is the diaphragm under somatic or autonomic control?
somatic (even though breathing is autonomic)
defn: intrapleural space
the space within the sac, contains a thin layer of fluid which helps lubricate the two pleural surfaces
what ultimately drives breathing?
the pressure differentials that can be created across the pleura (between the intrapleural space and the lungs)
defn: external intercostal muscles
one of the layers of muscles between the ribs
how does inhalation work? (steps: 7)
- we use our diaphragm and external intercostal muscles to expand the thoracic cavity
- as the diaphragm flattens and the chest wall expands outward, the intrathoracic volume (chest cavity volume) increases
- specifically, because the interpleural space closely abuts the chest wall, its volume increases first
- this leads to low pressure in the intrapleural space
- the gas in the lungs is initially at atmospheric pressure (which is now higher than the pressure in the intrapleural space)
- the lungs will therefore expand into the intrapleural space and the pressure in the lungs will drop
- air will then be sucked in from a higher pressure environment (the outside world)
why is the inhalation method called negative-pressure breathing?
the driving force is the lower (relatively negative pressure) in the intrapleural space compared with the lungs
how does simple exhalation work? (steps: 3)
- relaxation of the diaphragm and external intercostal muscles decreases the volume of the chest cavity
- the pressure in the intrapleural space goes up (is now higher than the lungs which are still at atmospheric pressure)
- air will be pushed out (exhalation)