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pulmonary ventilation

movement of air in and out of the lungs

external respiration

gas exchange that occurs in lungs between air and blood

internal respiration

gas exchange that occurs at cell membranes between the blood and body cells

transport of respiratory gases

transport of oxygen and carbon dioxide between lungs and other body tissues via blood

cellular respiration

chemical reactions in which cells use oxygen and produce carbon dioxide in the breakdown of glucose (or other molecules) to release energy, some of which is stored in ATP and available for cells to use

conducting zone

interconnecting system of respiratory passageways that carries air to and from sites of gas exchange in the lungs

terminal bronchioles

The conducting zone ends at the ________

warm, humidify, filter

Conduction zone structures _____, ______, and ______ incoming air

respiratory zone

interconnecting system of respiratory passageways in which gas exchange occurs

respiratory bronchioles

The respiratory zone starts at the ______


Where does most of the gas exchange occur in the lungs?


coarse hairs just insigne the external nares that screen out larger debris (dust particles, lint, pollen, etc.)

nasal septum

a vertical partician that divides the nasal cavity into left and right sides

superior, middle, inferior nasal conchae

medial projections from the lateral walls of the nasal cavity that divide it into groove like passageways; they increase surface area and air turbulence in nasal cavity

ethmoid, sphenoid, hard palate, soft palate

The nasal cavity is separated from the cranial cavity by the ______ and ______ bones, and anteriorly from the oral cavity by the ______ (supported by maxillary and palatine bone, and posteriorly by the ______ (muscular, not supported by bone)

internal nares

openings between nasal cavity and pharynx

pseudostratified ciliated columnar, goblet

The nasal cavity is lined with ___________ epithelium containing many ____ cells

warms, moistens, filters, smells, resonant chamber

Nasal cavity functions:
1. _____ air radiating from blood vessel near surface of mucous membrane
2. _____ air by evaporation of water from mucus on mucous membrane surface (and from water that drains into nasal cavity in tears
3. ______ air by trapping particles of debris in mucus layer and conveying them by action of cilia to pharynx where debris ladened mucus is swallowed or spit out
4. ______ air and aids in taste discrimination via olfactory receptors
5. act as ________, along with paranasal sinuses, oral cavity, and pharynx, to affect voice quality and gives voice its individual characteristics

paranasal sinuses

mucous membrane-lined sinuses continuous within maxillary, frontal, ethmoid, and sphenoid bones (named after them ) that open into the nasal cavity

nasal cavity

The mucous membrane of the paranasal sinuses is continuous with that of the ______, and also aids in the warming and moistening of the air

paranasal sinuses, sinus headache

__________ are prone to infection due to poor drainage into the nasal cavity (resulting from human's erect posture) and when their mucous membranes are swollen with infection or allergic reaction, drainage may be totally blocked-pressure builds up- resulting in a painful ______

paranasal sinuses

_________ reduce the weight of the skull, and act as a resonant chamber along with the nasal cavity, oral cavity, and pharynx


common passageway for both respiratory and digestive systems; in respiratory system, connects nasal cavity to larynx and in digestive system, connects oral cavity to esophagus


most superior portion of pharynx extending from just posterior of the nasal cavity (connected with it via internal nares) to the plane of the soft palate


The _______ is lined with mucous membrane of pseudo stratified ciliated columnar epithelium, cilia of which move debris-ladened mucus down the pharynx; It also usually conducts only air


______ tubes that open on lateral walls allow for pressure equalization on either side of the tympanic membrane (eardrum), and connects the nasopharynx with the middle ear

pharyngeal tonsil (adenoid)

mass of lymphatic tissue embedded in superior portion of nasopharynx posterior wall


middle portion of pharynx extending from the plane of soft palate to epiglottis


piece of cartilage that when food is swallowed, covers the glottis


opening to the larynx


The _______ is the part of the pharynx that conducts both air and food

palatine tonsils

pair of lymphatic tissue masses embedded int he lateral walls of the oropharynx

lingual tonsil

mass of lymphatic tissue at the base of the tongue


most inferior portion of the pharynx extending from the epiglottis to the point where the larynx and esophagus diverge; joins the esophagus posteriorly and larynx anteriorly


The _____ is lined with a mucous membrane of stratified squamous epithelium and conducts both air and food


air passageway that connects the pharynx to the trachea and lies anterior to the 4th and 6th vertebrae


The ______ is composed of 9 pieces of cartilage connected by ligaments and membranes

thyroid cartilage

single shield-shaped cartilage (consists of two fused pieces) that forms the anterior wall of the larynx, and is visible as a projection in the anterior neck

thyroid cartilage

______ is larger in males than in females due to growth stimulation by male sex hormones

laryngeal prominence

anterior, medial projection from thyroid cartilage

cricoid cartilage

single ring of cartilage that forms the inferior wall of the larynx and attaches to the trachea inferiorly; most of the inferior part of the larynx, thus a landmark for doing a tracheotomy


spoon-shaped elastic cartilage with its "handle" anchored on the anterior rim of thyroid cartilage, and its other end covering the glottis when swallowing occurs

cough reflex

If a substance other than air enters the larynx, ______ is initiated to expel it, unless person is unconscious

arytenoid, corniculate, cuneiform

____, _____, and _____ are smaller paired cartilages that form part of the lateral and posterior walls of larynx

vocal folds, arytenoid cartilage, thyroid cartilage

pair of ligaments composed of elastic fibers covered with stratified squamous epithelium that vibrate, producing sounds when air passes over them; attach to ________ which also attach to muscles, enabling their movement; at the other end, they are anchored to _______


Sounds are converted into words by changing the shape of the _____ and oral cavity, using the tongue and lips


Pitch of vocal sound is controlled by changing the tension of the vocal cords; greater tension = ______ pitch

air, louder

Loudness of vocal sound is controlled by the force of ____ passing over the vocal cords; stronger force= ______ sound

vestibular folds

pairs of folds in the mucous membrane superior to true vocal cords that are not involved in sound production, but when folds brought together, aid in breath-holding and in helping to keep substances out of the trachea

stratified squamous, pseudostratified ciliated columnar, goblet cells

The portion of the larynx superior to the true vocal cords is lined with _______ epithelium, while that inferior to the cords is lined with ________ epithelium containing mucus secreting _______; cilia here move debris-laden mucus up toward the pharynx

pharynx, trachea, trachea, sounds, air

Larynx function:
1. carry air between the ____ and _____
2. prevent foreign objects from entering the ____
3. produce ______
4. filter _____


flexible, cylindrical tube anterior to esophagus, and extending from the larynx to there it divides into the left and right primary bronchi

pseudostratified ciliated columnar, filter, moisten

The trachea is lined with ________ epithelium containing mucus secreting goblet cells, and as in the larynx, cilia moves mucus up toward the pharynx; Thus the trachea serves to ____ and _____ air


The ______ has 16-20 C-shaped pieces of cartilage embedded in the wall to keep it from collapsing

trachealis muscle

smooth muscle that connects the open posterior part of the C-shaped cartilages, which along with some connective tissue adjacent to the esophagus, allow it to expand anteriorly when food passes through it (by partially collapsing the trachea

trachealis muscle

Contraction of the ________ reduces the diameter of the trachea, causing more forceful expulsion of air when coughing

bronchi, bronchioles

system of branching tubes that carry air between the trachea and alveoli

right and left primary bronchi; right primary bronchi, left primary bronchi

formed by the division of the trachea; the ______ is shorter, wider, and more vertical than the ________, and thus more likely to be the site in which a foreign object lodges

pseudostratified ciliated columnar epithelium

primary bronchi lined with _______ (filters and moistens air) and supported by incomplete rings of cartilage

secondary (lobar) bronchi, 3, 2

branches from the primary bronchi within the lungs and enter the lobes of the lungs ( ____ lobes in right lung; _____ in left lung)

tertiary (segmental) bronchi

branches of the secondary bronchi that enter segments within the lobes of the lungs


bronchi divide into smaller bronchi which eventually divide into ______- natural air passages less than 1mm in diameter

terminal bronchioles

Bronchioles, in turn divide into even smaller ones, and eventually into _______- those less than .5mm in diameter

respiratory bronchioles

smallest bronchioles that branch off the terminal bronchioles; scattered alveoli extend from their walls; continuous with alveolar ducts

alveoli, 64

Many ______ protrude from the walls of alveolar ducts which lead into ____ alveolar sacs-terminal grape like clusters of alveoli

cartilage, smooth muscle, smooth muscle, thins, terminal, respiratory

Changes occur in walls as respiratory passages become smaller:
1. the amount of _____ in walls decreases. Elastic fibers occur only in walls of bronchi and bronchioles
2. Amount of ______ in walls increases with the decrease in size of passages. There is a complete layer of circularly arranged _____ in the walls of bronchioles
3. Epithelial lining _____. Epithelium changes from pseudo stratified ciliated columnar to simple cuboidal in _____ bronchioles, and to simple squamous in ______ bronchioles and beyond


There are about ____ million alveoli in an adult lung which greatly increases surface area for gas exchange to 70m squared

simple squamous

The walls of alveoli are composed of ______ epithelium and thin elastic basement membrane secreted by it

pulmonary, simple squamous

Alveoli are surrounded by a dense network of _______ capillaries with walls composed of a basement membrane and ________ epithelium which which gas exchange occurs

type I, type II, type I

Alveolar epithelium consists of _______ alveolar cells, which are simple squamous epithelium cells and ______ alveolar cells which are scattered among the layer of _____ cells that secrete alveolar fluid

alveolar fluid

______ keeps alveolar cells moist, and contains a surfactant


substance to lower surface tension of a liquid, which helps keep wet walls of alveoli from sticking together and collapsing the alveoli

elastic fibers, alveolar pores

Alveoli are surrounded by fine _______ (as walls of respiratory passageways) and have ______- small openings between adjacent alveoli that allow equalization of pressure throughout the lung and provide alternate route into alveoli

alveoli pores

small openings between adjacent alveoli that allow equalization of pressure throughout the lung and provide an alternate route into alveoli

alveolar macrophages

(dust cells) wandering macrophages occurring inside the alveoli that remove inhaled debris, including microorganisms

respiratory muscles

muscles involved in breathing

inspiratory muscles

muscles involved in normal inspiration

diaphragm, external intercostals

what are the inspiratory muscles?

expiratory muscles

The _______ are to a lesser extent involved in breathing

expiratory muscles

The ______ are involved in forced expiration

abdominal wall muscles, internal intercostals

The expiratory muscles are ____ and _____

respiratory, trachea

The lungs are contained within sealed thoracic cavity formed by ______ muscles and rib cage. The ______ is the only natural opening of the thoracic cavity to the outside.


horizontally positioned, dome-shaped muscle that forms the floor of the thoracic cavity

external intercostal muscles

muscles laying between ribs that together with rib cage form sides and top of thoracic cavity


double-layered serous membrane that surrounds and protects each lung

parietal pleura

outer layer of pleural membrane that lines the wall of the thoracic cavity, including each lung

visceral pleura

inner layer of pleura membrane that covers external surface of lungs

pleural cavity

narrow space between the parietal and visceral pleura filled with pleural fluid

pleural fluid

lubricating fluid secreted by both membrane layers that reduces friction between them as they move during breathing; also causes parietal and visceral pleura to adhere to each other, so when the wall of the thoracic cavity moves, lungs move with it

intrapleural pressure

pressure within the pleural cavity; normally slightly less than both intrapulmonary (intra-alveolar) pressure and atmospheric pressure


inflammation of the pleura due to underproduction of pleural fluid resulting in sharp pain when parietal and visceral pleura move across one another


overproduction of pleural fluid can also cause _______ (though less painful) and by putting pressure on lungs, can interfere with breathing


air filling pleural cavity, usually a result of puncture of thoracic wall, allowing air to rush in and equalize pressure that may collapse the lung; it can be reversed by closing the wound in the chest wall and sucking air out of pleural cavity


In ________, the diaphragm contracts, moving inferiorly and the external intercostal muscles contract moving the rib cage superiorly and outward


The movements of ______ increase the size and volume of the thoracic cavity which also expands the lungs and increases their volume (since the lungs are stretchy due to elastic fibers within them, and are attached to the chest wall via pleura and thus move with it)


In inspiration, as lungs expand, air pressure within them _______, causing air pressure in the lungs to be lower than atmospheric pressure, so air rushes in to equalize pressure

Boyle's law

the pressure of a gas varies inversely with its volume if temperature is constant


air flows into lungs that are already expanded; it does not cause them to expand


In _______, the diaphragm relaxes, moving superiorly and the external intercostal muscles relax, moving the rib cage interiorly and inward

size, volume

The movements of expiration decrease the size and volume of the thoracic cavity, causing the lungs to decrease in ______ and _____


A decrease in the volume of the lungs leads to _____ in air pressure above that of atmospheric air pressure, so air rushes out to equalize the pressure


Contraction of abdominal wall muscles forces abdominal organs superiorly against diaphragm, pushing it ______, and contraction of internal intercostal muscles pull rib cage inferiorly and inward.

These movements expel air from the lungs more forcefully and quickly

tidal volume

the volume of air moved in and out of lungs with each breath during normal quiet breathing

inspiratory reserve volume

volume of air that can be forcibly inhaled beyond tidal volume

expiratory reserve volume

volume of the air that can be forcible exhaled beyond normal tidal volume

residual volume

volume of air that remains in the lungs even after the most forceful exhalation; amount of air remaining in lungs at all times that keeps alveoli partially inflated

inspiratory capacity

total amount of air that can be inhaled after tidal exhalation


formula for inspiratory capacity

functional residual capacity

total amount of air remaining in lungs after tidal exhalation


formula for functional reserve capacity

vital capacity

maximum amount of air that can be exhaled after the deepest possible inhalation; total amount of air that can be moved in and out of the lungs


formula for vital capacity

total lung capacity

total of all respiratory volumes; total volume of air that lungs can hold


formula for total lung capacity

anatomical dead space

volume of respiratory passages (trachea, bronchi, to terminal bronchioles) where no gas exchange occurs; volume of the air that does not reach the alveoli and thus not available for gas exchange- 150 ml

alveolar dead space

volume of air in nonfunctional alveoli (due to alveolar collapse or obstruction)

total dead space

anatomical dead space+alveolar dead space. In a healthy young adult, alveolar dead space is usually negligible, so 150ml

alveolar ventilation rate

volume of new atmospheric air moved into alveoli and available for gas exchange during a given time; AVR(ml/min)= TV-Total dead space (ml) x breathing rate (breaths/min)

AVR=TV-Total Dead Space X breathing rate

Formula for alveolar ventilation rate


increasing the volume of inspiration _____ AVR more than does increasing breathing rate since anatomical dead space is constant in the same person


Slower deeper breaths are _____ effective ventilation than rapid shallow breaths

External respiration

______ is gas exchange in lungs; O2 diffuses across alveolar and capillary walls from alveoli into blood since O2 concentration in alveoli is greater than that in blood; CO2 diffuses across the alveolar and capillary walls in the opposite direction since CO2 concentration in blood is greater than in the alveoli

internal respiration

______ is gas exchange in other tissues; O2 in systemic capillaries diffuses across capillary walls and cell membrane from blood into cells, since O2 concentration is greater in blood than in cells; CO2 diffuses across cell membranes and across capillary walls from cells to blood since CO2 concentration is greater in cells than in blood

Dalton's law of partial pressures

the total pressure of gas mixture is equal to the sum of pressures that each gas in the mixture would exert independently (as if other gases not present)

partial pressure

the pressure exerted by each gas in the mixture= the product of total pressure of gas mixture x its percentage total


Po2 ______ as pressure decreases with higher altitude


Since the amount of gas in the blood is directly proportional to its partial pressure (since blood temp is relatively constant), as Po2 decreases, the O2 concentration in blood _______


Since O2 is not very soluble in water, only 1.5% of O2 carried by blood is dissolved in plasma (mostly water); ____% of O2 carried is bound to hemoglobin

oxygen loading

when hemoglobin combines with O2


HHb- when oxygen combines with hemoglobin


Ah Hb molecule is fully _______ with all 4 of its Heme Groups are bound to )- bound to all for Iron atoms in heme group


An Hb is partially ______ when 1, 2, or 3 O2 are bound to it. Percentage of Hb saturation= amount of O2 bound to Hb

O2, acidity, CO2, BPG

HB saturation with O2 affected by
1. Partial pressure of _____ (Po2)
2. _______
3. Partial pressure of _____ (Pco2)
4. Temperature
5. Amount of _____ in blood

O2 loading

High Po2 promotes ________, so Hb binds with more O2


The higher the _____, the less O2 released from Hb to surrounding tissues (as in capillaries around alveoli)


Hb's affinity for O2 _____ the more acidic the environment (higher H+ concentration), so more O2 is released to the surrounding tissues


Hb's decreased affinity for )2 due to a change in its 3 dimensional shape

unloading, more

High Pco2 promotes O2 _____ by increasing the acidity, so _____ O2 is released to surrounding tissues

carbonic acid, carbonic anhydrase

As CO2 is taken up by the blood, much of it is converted to H2CO3 (________), calatlysed by an enzyme in RBCs, ________, which increases H+ ion concentration

unloading, decreases

Increasing temperature also promotes O2 ______, since heat changes the Hb's 3 dimensional structure, _____ its affinity for )2

BPG, unloading, reducing

(2, 3-Biphosphaglycerate)- a substance produced by RBCs when they breakdown glucose in glycolysis that enhances O2 ________ by combining with HB, ____ its affinity for O2


Increase in BPG, which results in an increase in RBC metabolic rate, results in _____ O2 released by Hb into tissues

Hb, Po2, fever

Factors that increase RBC metabolic rate:
1. Low ____ concentration (anemia)
2. Low _____ (high altitudes)
3. ______ (increase in temperature)
4. Certain hormones (thyroxine, human growth hormone, epinephrine, norepinephrine, testosterone

thyroxine, epinephrine, norepinephrine, human growth hormone, testosterone

Hormones that increase RBC metabolic rate:

heat, CO2, Po2

Actively metabolizing cells generate and release _____ and _____, and have a lower _____, all of which enhance O2 unloading in their vicinity

bicarbonate ions (HCO3), Hb, plasma

CO2 is transported in blood from tissue cells to lungs in 3 forms:
1. as _______ in plasma. Most CO2 is transported in this form
2. Chemically bound to _____ in RBCs. Less CO2 transported in this form. CO2 combines with amino acids of _____ portion.
3. CO2 dissolved in ______. Least CO2 transported in this form


also called acidemia; condition in which pH of extracellular fluid is lower than normal (blood pH below 7.35)

respiratory acidosis, carbonic acid

results from hypoventilation or any condition that interferes with breathing or gas exchange; when the rate of CO2 generation exceeds its excretion in lungs= high H2CO3 (_______) production and decrease in pH

injury, airway, respiratory

Hypoventilation usually due to
1. disease or pathological condition
2. depression of respiratory centers in the brain due to _____ or drug overdose
3. ______ obstruction
4. dysfunction of ____ muscles

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