RESPIRATORY SYSTEM
Chapter 22
Major function is respiration: supply body with _______________ for cellular respiration
and dispose of _______________
Major organs: _______________, _______________ _______________,
_______________ _______________, _______________, _______________,
_______________, _______________and their branches, _______________ and
_______________
Involves two systems: _______________ system and _______________ system
_______________ _______________: site of gas exchange
 Composed of _______________ _______________: respiratory bronchioles,
alveolar ducts, and
alveoli
_______________ _______________: conduits to gas exchange sites
 Includes all other respiratory structures which _______________,
_______________, and _______________ air
 _______________ and other respiratory _______________ promote ventilation
Functions of the nose:
 Provides an _______________ for respiration
 _______________ and _______________ entering air
 _______________ and _______________ inspired air
 Serves as resonating chamber for _______________
 Houses _______________ _______________
Two regions of the nose:
 _______________ _______________
 _______________ _______________: within and posterior to external nose
The Nasal Cavity
 Divided by midline _______________ _______________
 Posterior nasal cavity open into _______________
 Roof composed of the _______________and _______________ bones
 Floor composed of _______________ _______________and _______________
_______________
 _______________ _______________: nasal cavity superior to nostrils
 _______________ (hairs) filter coarse particles from inspired air
Nasal Mucosa
 _______________ _______________: composed of olfactory epithelium
 _______________ _______________: composed of pseudostratified ciliated
columnar epithelium
 _______________ and _______________ secretions contain lysozyme and
defensins
 _______________ move contaminated mucus posteriorly to throat
 Inspired air warmed by plexuses of _______________ and _______________
 Sensory nerve endings trigger _______________
Nasal conchae (_______________,_______________, and _______________)
 Protrude medially from lateral walls
 _______________ mucosal area
 _______________ air turbulence
 _______________ _______________: groove inferior to each concha
 During inhalation, conchae and nasal mucosa _______________,
_______________, and _______________ air
 During exhalation these structures reclaim _______________ and
_______________
Paranasal Sinuses
 In frontal, sphenoid, ethmoid, and maxillary _______________
 _______________ skull; secrete _______________
_______________: muscular tube (skeletal muscle) which connects nasal cavity and
mouth to larynx and esophagus
Three regions:
1. _______________: air passageway posterior to nasal cavity
 _______________ _______________and _______________ close
nasopharynx during swallowing
 _______________ _______________ (adenoids) on posterior wall
 _______________ (auditory) _______________ drain and equalize
pressure in middle ear; open into lateral walls
2. _______________: passageway for food and air from level of soft palate to
epiglottis
 _______________ of _______________: opening to oral cavity
 _______________ _______________: in lateral walls of fauces
 _______________ _______________: on posterior surface of tongue
3. _______________: passageway for food and air
Larynx Functions:
 Provides patent _______________
 Routes air and food into _______________ _______________
 _______________ _______________; houses vocal folds
Larynx cartilages: _______________ total
_______________ _______________:
_______________ _______________with laryngeal prominence (Adam's
apple)
Ring-shaped _______________ _______________
Paired _______________, _______________, and _______________
cartilages
_______________ _______________:
_______________: covers laryngeal inlet during swallowing; covered in taste
bud-containing mucosa
_______________ _______________form core of vocal folds (true vocal cords)
 Attach_______________cartilages to _______________ cartilage
 Contain _______________ fibers
 Folds _______________to produce sound as air rushes up from lungs
_______________: opening between vocal folds
_______________ _______________ (false vocal cords) are superior to vocal folds
 No part in sound production
 Help to close _______________ during swallowing
Speech is created by intermittent release of expired _______________ while opening and
closing _______________
 _______________ determined by length and tension of vocal cords
 _______________depends upon force of air
 Chambers of pharynx, oral, nasal, and sinus cavities _______________ and
_______________ sound
 Sound is "shaped" by_______________of pharynx, tongue, soft palate, and lips
_______________: windpipe extends from larynx into mediastinum
 Wall composed of three layers
o _______________: ciliated pseudostratified epithelium with goblet cells;
lamina propria (connective tissue)
o _______________: connective tissue with seromucous glands
o _______________: outermost layer made of connective tissue; encases Cshaped rings of hyaline cartilage
 _______________ _______________: connects posterior parts of cartilage rings
and contracts during
coughing to expel mucus
 _______________: point where trachea branches into two main bronchi
Subdivisions of conducting zone structures:
 _______________ lead into the right and left main (primary) bronchi
 Each _______________ (primary) _______________ enters at the
_______________ of the lung
o _______________main bronchus wider, shorter, more vertical than left
 Each main bronchus branches into _______________ (secondary)
_______________ (three on right, two on left), each lobar bronchus supplies one
lobe
 Each lobar bronchus branches into _______________ (tertiary)
_______________which divide repeatedly
 Branches become smaller and smaller
o _______________: less than 1 mm in diameter
o _______________ _______________: smallest, less than 0.5 mm
diameter
Subdivision of respiratory zone structures:
 Begins as _______________ _______________which become respiratory
bronchioles
 _______________ _______________become alveolar ducts
 _______________ _______________dead end into alveolar sacs
 _______________ _______________contain clusters of alveoli
o ~300 million alveoli make up most of lung volume
o Sites of _______________ _______________
_______________ or _______________ to _______________ to _______________to
_______________to _______________ (primary)
_______________to_______________ (secondary) _______________to
_______________ (tertiary) _______________ to _______________ to
_______________ _______________ to _______________ _______________to
_______________ _______________to _______________ _______________
Respiratory Membrane: composed of _______________ and _______________ walls
and their fused _______________ _______________ (~0.5-μm-thick)
 Gas exchange across membrane by _______________ _______________
Alveolar walls: single layer of squamous epithelium (_______________
_______________ _______________) with scattered cuboidal _______________
_______________ _______________ secrete surfactant and antimicrobial proteins
Alveoli Structure:
 Surrounded by fine _______________ _______________and pulmonary
_______________
 Alveolar _______________ connect adjacent alveoli to equalize air pressure
throughout lung
 Alveolar _______________ keep alveolar surfaces sterile
Lungs Anatomy
 Composed primarily of _______________
 _______________: elastic connective tissue which surrounds and supports the
alveoli
 _______________: superior tip; deep to clavicle
 _______________: inferior surface; rests on diaphragm
 _______________: on mediastinal surface; site for entry/exit of blood vessels,
bronchi, lymphatic vessels, and nerves
 Left lung _______________ than right
o _______________ _______________: concavity for heart
o Separated into superior and inferior lobes by _______________
_______________
 Right lung
o Separated into superior and middle lobes by _______________
_______________
o Separated into middle and inferior lobes separated by _______________
_______________
Lung: Blood Supply
 _______________ _______________
o _______________ _______________: deliver systemic venous blood to
lungs for oxygenation
o Branch profusely; feed into pulmonary _______________
_______________
o _______________ _______________: carry oxygenated blood from
respiratory zones to heart
 _______________ _______________
o _______________ _______________: provide oxygenated blood to lung
tissue
o Arise from _______________ and enter lungs at hilum
o Supply all lung tissue except _______________
Lung: Pleurae
 Thin, _______________ _______________ _______________which divides
thoracic cavity into two pleural compartments and mediastinum
o _______________ _______________: on thoracic wall, superior face of
diaphragm, around heart, between lungs
o _______________ _______________: on external lung surface
o _______________ _______________: fills slitlike pleural cavity,
provides _______________
Pulmonary ventilation consists of two phases:
 _______________: gases flow into lungs
 _______________: gases exit lungs
_______________ _______________ (Patm): pressure exerted by air surrounding body;
_______________ at sea level
Respiratory pressures described relative to Patm
 _______________ respiratory pressure is less than Patm
 _______________ respiratory pressure is greater than Patm
 _______________ respiratory pressure is equal to Patm
_______________ _______________: pressure in alveoli, intra-alveolar, fluctuates with
breathing
_______________ _______________ :pressure in pleural cavity, fluctuates with
breathing, always about 4 mm Hg _______________then intrapulmpnary pressure,
prevents lungs from collapsing
_______________ _______________: difference between Ppul and Pip,keeps airways
open
If _______________ = _______________ lungs will collapse
_______________ _______________: mechanical processes that depends on
_______________ changes in thoracic cavity
 _______________ changes cause _______________ changes
o _______________ _______________: relationship between pressure and
volume of a gas, pressure (P) varies inversely with volume (V); P1V1 =
P2V2
o _______________ volume results in _______________ pressure
o _______________ volume results in _______________ pressure
 Pressure changes allows gases flow to _______________ _______________
_______________: active process of breathing in
 Inspiratory muscles (diaphragm and external intercostals) contract and thoracic
volume _______________ - intrapulmonary pressure _______________ (to -1
mm Hg)
 Air flows into lungs, down its _______________ _______________, until Ppul =
Patm
_______________: “quiet expiration” normally passive process of breathing out
 Inspiratory muscles relax and thoracic cavity volume _______________, elastic
lungs recoil - intrapulmonary pressure _______________ (Ppul rises to +1 mm
Hg)
 Air flows out of lungs down its _______________ _______________until Ppul = 0
 _______________ _______________ is and active process: uses abdominal and
internal intercostal muscles to force air out
Three physical factors influence the ease of air passage and the amount of energy
required for ventilation:
1. _______________ _______________
o Resistance usually_______________
2. _______________ _______________ _______________
o _______________ _______________: contractive tendency of the surface
of a liquid that allows it to resist an external force
o _______________: compounds that lowers the surface tension of a liquid
o Produced by _______________alveolar cells
o Reduces surface tension of alveolar fluid and discourages alveolar
_______________
3. _______________ _______________
o Measure of change in _______________ _______________that occurs
with given change in transpulmonary pressure
o Higher lung compliance; _______________ to expand lungs
o Normally high due to: _______________of lung tissue and
_______________
o Diminished by: nonelastic _______________ _______________replacing
lung tissue (fibrosis), reduced production of _______________, decreased
_______________ of thoracic cage
Respiratory Volumes: used to assess respiratory status
 _______________ _______________ (TV): Amount of air inhaled or exhaled with
each breath under resting conditions
 _______________ _______________ _______________ (IRV): Amount of air
that can be forcefully inhaled after a normal tidal volume inspiration
 _______________ _______________ _______________ (ERV): Amount of air
that can be forcefully exhaled after a normal tidal volume expiration
 _______________ _______________ (RV): Amount of air remaining in the lungs
after a forced expiration
Respiratory Capacities: combinations of respiratory volumes
 _______________ _______________ (IC): Maximum amount of air that can be
inspired after a normal tidal volume expiration: IC = TV + IRV
 _______________ _______________ _______________ (FRC): Volume of air
remaining in the lungs after a normal tidal volume expiration: FRC = ERV + RV
 _______________ _______________ (VC): Maximum amount of air that can be
expired after a maximum inspiratory effort: VC = TV + IRV + ERV
 _______________ _______________ _______________ (TLC): Maximum
amount of air contained in lungs after a maximum inspiratory effort: TLC = TV +
IRV + ERV + RV
_______________: instrument for measuring respiratory volumes and capacities
_______________ _______________of Partial Pressures: total pressure exerted by
mixture of gases equals the sum of pressures exerted by each gas
 _______________ _______________: pressure exerted by each gas in mixture,
directly proportional to its _______________ in mixture
_______________ _______________: each gas dissolves in a liquid proportional to its
partial pressure, at equilibrium, partial pressures in the two phases will be equal
 Amount of each gas that will dissolve depends on:
o _______________: CO2 20 times _______________ soluble in water than
O2
o _______________: as temperature rises, solubility _______________
External Respiration: exchange of O2 and CO2 across _______________
_______________
External respiration is influenced by:
 _______________ and _______________ _______________of respiratory
membrane
o 0.5 to 1 um thick
o Large total _______________ _______________ (40 times that of skin)
for gas exchange
o _______________ if lungs become waterlogged and edematous results in
inadequate gas exchange
o Reduced surface area in _______________ (walls of adjacent alveoli
break down), tumors, inflammation, mucus
 _______________ _______________gradients and gas _______________
o Steep partial pressure gradient for O2 in lungs drives oxygen flow to
_______________
 Venous blood Po2 =_______________mm Hg
 Alveolar Po2 = _______________ mm Hg (alveolar O2 into the
blood)
o Equilibrium reached across respiratory membrane in
_______________seconds
o Partial pressure gradient for _______________ in lungs less steep
 Venous blood Pco2 = _______________ mm Hg
 Alveolar Pco2 = _______________ mm Hg (venous CO2 into
alveolar)
 Though gradient not as steep, CO2 diffuses in _______________
_______________with oxygen because it is
_______________more soluble in plasma than oxygen
 _______________ _______________coupling
o _______________: blood flow reaching alveoli
 Changes in Po2 in alveoli cause changes in _______________of
arterioles
 Where alveolar O2 is high, arterioles_______________
 Where alveolar O2 is low, arterioles _______________
 Directs most blood where alveolar _______________
_______________
o _______________: amount of gas reaching alveoli
 Changes in Pco2 in alveoli cause changes in _______________ of
bronchioles
 Where alveolar CO2 is high, bronchioles _______________
 Where alveolar CO2 is low, bronchioles _______________
 Allows elimination of CO2 more _______________
o _______________ and _______________ matched (coupled) for efficient
gas exchange
Internal Respiration: capillary gas exchange in _______________ _______________
 Partial pressures and diffusion gradients _______________ compared to external
respiration
 Tissue _______________ always lower than systemic arterial blood
 _______________ moves from blood to tissues; _______________ moves from
tissues to blood
 Venous blood Po2 _______________ mm Hg and Pco2 _______________ mm Hg
O2 Transport in the Blood
 1.5% _______________ in plasma
 98.5% loosely bound to each _______________ of hemoglobin (Hb) in RBCs
(_______________O2 per Hb)
o _______________ (HbO2): hemoglobin-O2 combination
o _______________ (HHb): hemoglobin that has released O2
Loading and unloading of O2 facilitated by _______________ in _______________ of
Hb
 As O2 binds, Hb affinity for O2 _______________
 As O2 is released, Hb affinity for O2 _______________
_______________ _______________ _______________ _______________:
hemoglobin saturation plotted against Po2, not linear but an S-shaped curve
Rate of loading and unloading of O2 affected by:
 _______________
 _______________
 _______________
 _______________
 _______________ (byproduct of glycolysis)
_______________ _______________: CO2 and H+ affect the affinity of HB for O2
 _______________ in temperature, H+(decreased pH), Pco2, and BPG
 Modify structure of hemoglobin; _______________its affinity for O2
 Occur in _______________ _______________
 Enhance O2 _______________ and CO2 _______________ from blood
 Shift O2-hemoglobin dissociation curve to_______________
_______________ _______________: O2 affect the affinity of HB for CO2 and H+
 _______________ in temperature, H+, Pco2, and BPG
 Modify structure of hemoglobin; _______________its affinity for O2
 Occur in _______________ _______________
 Enhance O2 _______________ and CO2 _______________ into blood
 Shift O2-hemoglobin dissociation curve to _______________
_______________: inadequate O2 delivery to tissues
 _______________ hypoxia: too few RBCs; abnormal or too little Hb
 _______________hypoxia: impaired/blocked circulation
 _______________hypoxia: abnormal ventilation; pulmonary disease
CO2 transported in blood in three forms:
 7 to 10% dissolved in _______________
 20% bound to _______________ of hemoglobin (carbaminohemoglobin)
 70% transported as _______________ _______________ (HCO3–) in plasma
CO2 combines with _______________ to form _______________ _______________
(H2CO3), which quickly dissociates into _______________ _______________ (HCO3-)
and _______________ _______________ (H+)
Carbonic acid–bicarbonate _______________ _______________: resists changes in
blood _______________
 If H+ concentration in blood _______________, excess H+ is _______________
by combining with HCO3 to form H2CO3
 If H+ concentration begins to _______________, H2CO3 _______________,
releasing H+
Medullary Respiratory Centers
 _______________ _______________ _______________ (VRG): rhythmgenerating and integrative center
o Sets _______________: (12–15 breaths/minute) normal respiratory rate
and rhythm
o Inspiratory neurons _______________ inspiratory muscles
o Expiratory neurons _______________ inspiratory neurons
 _______________ _______________ _______________ (DRG): integrates input
from peripheral stretch and chemoreceptors
o Sends information to the _______________
Pontine Respiratory Centers
 Influence and modify activity of _______________
 Smooth out _______________ between inspiration and expiration and vice versa
 Transmit impulses to VRG and _______________and _______________
_______________breathing rhythms during vocalization, sleep, exercise
_______________ _______________: monitor pH and CO2 levels
 Located in the _______________
 Most potent; most closely controlled
 Functional process:
o If blood Pco2 levels _______________, CO2 accumulates in
_______________
o CO2 in brain is hydrated to form _______________ _______________
(pH drops)
o Central chemoreceptors synapse with respiratory regulatory centers
_______________to _______________ respiration
_______________ _______________: monitor pH, O2, and CO2 levels
 Located in the _______________ and _______________ bodies
 Excited by a _______________ in pH and O2
 Excited by an _______________ in CO2
 Functional process:
o When excited, cause respiratory centers to _______________ventilation
(_______________ to _______________)
o A slight decline in O2 has _______________ _______________ (huge
O2 reservoir bound to Hb); a large decline in O2 becomes
_______________ _______________for respiration
o Decrease in _______________ can modify respiratory rate and rhythm
even if CO2 and O2 levels normal
_______________ controls act through _______________ _______________to modify
rate and depth of respiration
 Example: breath holding that occurs in anger or gasping with pain
_______________ controls direct signals from cerebral _______________cortex that
bypass medullary controls
 Example: voluntary breath holding
_______________: respond to irritants to promote reflexive constriction of air passage
 Located in the nose, lungs, GI tract, and brochioles
 Communicate with respiratory centers via _______________ _______________
(lungs, GI tract, bronchioles) and _______________ _______________ (nose)
_______________ _______________ _______________ (inflation reflex): stretch
receptors in pleurae and airways stimulated by lung inflation send
_______________signals to medullary respiratory centers end _______________and
allow _______________ (protective response)