module 8 the respiratory system Flashcards
Describe the visceral and parietal pleura
- They cover the lung surface
- and the inner chest wall
- They form one continuous membrane forming a sealed envelope surrounding the lungs.
What generates the subatmospheric pressure in the airless space between the pleura membranes?
- oppositely directed recoil forces of the lungs and chest wall.
- lungs pull in
- chest wall pulls out
What supplies the alveoli and participates in gas exchange?
- The pulmonary circulation.
- the bronchial system also supplies the lungs, but does not supply the alveoli or participate in gas exchange
what is responsible for the normal difference between alveolar gas and arterial blood oxygen pressures?
- a small amount of deoxygenated bronchial system venous blood mixes with oxygenated blood in the pulmonary veins, creating a small anatomical shunt, this is responsible for the difference
what type of innervation does the lung recieve?
- only autonomic
- consisting of sympathetic (adrenergic) and parasympathetic (cholinergic), and the nonadrenergic, and noncholinergic (NANC) systems.
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What is the parasympathetic system responsible for?
airway smooth muscle resting tone
what causes bronchoconstriction?
Cholinergic stimulation
what causes bronchodilation?
adrenergic stimulation
What do B2 - adrenergic agonist (stimulators) and cholinergic antagonist (blockers) drugs do?
both elicit bronchodilation and reduced resistance to airflow
How does sympathetic stimulation of airway smooth muscle occur?
Indirectly through adrenal gland secretion of circulating epinephrine.
Sensory afferent nerves from the lung are__________ in origin
and include __________, __________,and ______________
- parasympathetic
- slowly adapting stretch receptors
- rapidly adapting irritant receptors,
- C-fibers
the last two are extremely important in defense of the airways because they evoke powerful reflexes that limit penetration of harmful substances into the respiratory tract.
List 4 processes of the respiratory system
- pulmonary ventilation
- external respiration
- transport of respiratory gases
- internal respiration
list the three major functions of the respiratory system
- continuous supply of O2 for metabolic activities in body cells
- removal of CO2 from body cells
- regulation of the pH of the blood
pulmonary ventilation
- breathing
- consists of breathing in (inhalation) and breathing out (exhalation)
external respiration
- exchange of gases (oxygen and carbon dioxide) between the blood and the lungs
how are respiratory gases transported?
- in the red blood cells and blood plasma
internal respiration
- exchange of gases (oxygen and Carbon dioxide) between the blood and tissue cells
What two zones comprise the respiratory system?
- conducting zone (macroscopic) - passageways for conduction of air - nose, pharynx (throat), larynx (voice box), trachea, bronchi, and terminal bronchioles
- Respiratory Zone (microscopic) - consists of sites involved with the exchange of oxygen and carbon dioxide - respiratory bronchioles, alveolar ducts, alveoli
list the functions of the nose (conducting zone)
- airway for respiration
- moistens and warms air\
- cleans and filters unwanted particles
- aids in speech
- provides a site for the olfactory receptors (for smell)
external nares
anterior portion of each nostril is called the vestibule, contains hairs
nasal cavities
- nose separated into right and left halves by the nasal septum
- three bony projections called conchae are located on the lateral walls of the nasal cavities; these increase the surface area
- rich supply of blood that warms and moistens air
- mucus to trap particles
internal nares
- posterior openings that provide a connection between the nose and the pharynx (throat)
paranasal sinuses
beside nose
maxillary
frontal
ethmoidal and
sphenoidal sinuses provide sites for mucus drainage
lighten the skull
warm and moisten air and provide chambers for speech resonance
pharynx
throat
- consists of three regions
- nasopharynx
- oropharynx
- laryngopharynx
nasopharynx - air passageway
oropharynx and laryngopharynx - food and air passageway
Larynx
voice box
contains vocal chords
connects pharynx to trachea
provides an open passageway for air
epiglottis, which covers the opening of the larynx closes off the larynx during swallowing
trachea
- Windpipe
- passageway
- cleans, warms moistens
- c shaped rings of cartilage
bronchi
- Trachea branches into two tubes
- left bronchus and right bronchus
- lead to left and right lung
- bronchi clean, warm, and moisten air
- provide passageway
terminal bronchioles
passageway into the respiratory zone
respiratory bronchioles
formed from branchings of terminal bronchioles
alveolar ducts
- respiratory bronchioles lead into alveolar ducts
- alveolar ducts lead into clusters of alveoli
alveolar air sacs
- 300 million alveoli in each lung lot of surface area for exchange of gasses
- clusters called alveolar sacs
what are two important cell types found in the alveoli?
- Type 1 alveolar cells (simple squamous epithelium) provide the site for gas exchange between the capillaries and the alveoli
- Type ll alveolar cells (septal cells): produce surfactant a compound that prevents the alveoli from collapsing, reduces surface tension between fluid molecules inside the alveoli so they do not adhere to each other and collapse
- Macrophages (dust cells) wander around cleaning up foreign material
how much do the lungs weigh and why
1 kg, 2.2 pounds because they consist of many air spaces
hilus
area in each lung where blood vessels, lymphatic vessels, nerves and the bronchus enter and leave the lung
cardiac notch
- area where the heat snuggles into the left lung
bronchopulmonary segments
- lobes of both lungs divided into bronchopulmonary segments, each segment has its own artery and vein
lobules
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pleura
- sac that covers each lung
serous membrane of the pleura consists of two layers
- visceral layer
- parietal layer
visceral layer hugs lung surface including area between lobes
parietal layer lines the thoracic chest (wall and upper surface of the diaphragm)
