Transcript Ch 23 _Student Respiratory Lab

Chapter 23
The
Respiratory
System
Functions of Respiratory System
1.
2.
3.
4.
5.
6.
7.
O2 and CO2 exchange between blood and air
Speech and other vocalizations
Smell
pH – regulates CO2
blood pressure –vasoconstrictor (increases blood
flow rate), angiotensin II
pressure gradients -flow of lymph and venous blood
(action of the diaphragm)
Expulsion: expel abdominal contents during
urination, defecation, and childbirth
– Valsalva maneuver - done by closing one's mouth,
pinching the nose shut while pressing out as if blowing up
a balloon; equalizes pressure between ears and sinuses;
test cardiac function
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Respiration
Respiration exchange of gases between the atmosphere,
blood, and cells.
3 step process
• VENTILATION (bringing air into the body): inhalation
(inflow) and exhalation (outflow) between atmosphere
and alveoli of the lungs.
• EXTERNAL (PULMONARY) RESPIRATION: exchange of
gases between alveoli of lungs and blood in pulmonary
capillaries across the respiratory membrane.
• INTERNAL (TISSUE) RESPIRATION: exchange of gases
between blood in systemic capillaries and tissue cells.
Blood loses O2 and gains CO2.
Respiratory system is made up of
nose, pharynx, larynx, trachea,
bronchi & lungs
Structural divisions
 Upper respiratory tract
 above the larynx
 Lower respiratory tract
 below the larynx
Functional divisions
 Conducting portion: cavities
and tubes = passageways for air
Nose, pharynx, larynx, trachea,
bronchi, bronchioles, and
terminal bronchioles.
 Respiratory portion: gas
exchange:
Respiratory bronchioles,
alveolar ducts, alveolar sacs,
and alveoli.
System
Anatomy
• Opens to the outside by two
external nares or nostrils
• Made up of skin and cartilage,
lined with mucous membrane.
• Epithelial mucus membranes
prevent drying of respiratory
tract inhibiting infection
– The Lamina Propria
• Underlying CT areolar
tissue supports respiratory
epithelium
Functions of the nose:
1. Warms, moisturizes, and
filters incoming air
2. Olfactory (smell) stimuli
3. Paranasal sinuses resonating
chambers in bone modifies
speech
Nose
Nasal
Internal
Structures
http://headandneckcancerguide.org/wp-content/uploads/2013/02/44-1-Nasal-Anatomy.jpg
Bony framework: frontal, nasal, and maxillary bones
• Hard Palate separates nasal cavity from oral cavity.
Allows you to breathe while chewing food.
• Connected to the to nasopharynx by 2 (posterior
nares)/(internal nares)/(choanae)
Conchae: 3 folds of tissue overlay the inferior, middle
and inferior bony swellings increases surface area for
warming and moisturizing air.
• Below each conchae is a narrow passageway
(meatus) ensures air contact with mucus membranes
Nasal cavity - 2 chambers separated by nasal septum
(vomer and ethmoid bones).
• Begins in vestibule lined with stratified squamous
epithelium w/ stiff guard hairs block insect / debris
How the Nasal Cycle Operates
• Throughout the day, your nostrils ALTERNATE air flow in a process
of congestion and decongestion called the nasal cycle.
• While breathing through your nose, the majority of the air is moving
in/out of one nostril; causing less air movement thru the other.
• The conchae or turbinates have a thick epithelium with a
vascularized lamina propria (erectile tissue) layer. The venous
plexuses of the mucosa engorge with blood, restricting airflow
and causing air to be directed to the other side of the nose,
which acts in concert by shunting blood out of its turbinates.
• The opening and closing of the two passages is done by
swelling and deflating erectile tissue. This cycle occurs
approximately every two and a half hours.
Nasal
Structures
Movement of substances from one nasal cavity to the other
As fluid fills one side of the nasal cavity it moves into the
opposite side via the internal nares located in the
nasopharynx. The mouth remains open allowing air to
continue to move into the lungs while the nasal cavity is not
operating to pull air into the lungs.
• Extends from internal
nares to cricoid cartilage
of the larynx
• Functions
– passageway for air,
food and drink
– resonating chamber for
speech production
– tonsil (lymphatic tissue)
in the walls protects
entryway into body
• Divided into distinct
regions
 Nasopharynx
 Oropharynx
 Laryngopharynx
Pharynx-throat
• Posterior to the posterior nasal
apertures above the soft palate
(skeletal muscle and glandular tissue)
• Passageway for AIR ONLY
• There are five openings in its wall
– 2 internal nares
– 2 openings that connect with
Eustachian tube - equilibrate
pressure between the middle
ear and atmosphere
– 1 that connects to oropharynx.
• Contains Adenoids or pharyngeal
tonsil.
• Lined by pseudostratified ciliated
columnar epithelium with goblet
cells. Cilia helps in movement of
mucous.
– 90° turn forces air and debris to
collide with mucosa near tonsil
Nasopharynx
Internal nares
Oropharynx
• Soft palate to epiglottis
• Opening in back of throat to epiglottis
is the fauces
• Palatine tonsils found in side walls,
lingual tonsil on back of the tongue
• Common passageway for food and air
• lined by non keratinized stratified
squamous epithelium for contact with
abrasive substances
Fauces
Laryngopharynx
• Extends inferiorly from
hyoid bone
• Common passageway for
food/drink and air
• Lined with non-keratinized
stratified squamous
epithelium
• Has 2 openings at the
inferior end
– Opens into esophagus
– Opens into larynx
pharyngeal tonsil.
lingual tonsil
Palatine tonsils
• A passageway that connects the pharynx
Larynx
with the trachea, via an opening (hole)
termed glottis- air passageway
(Voice Box)
• Primary function is to keep food and drink
out of the airway
– epiglottis – flap of tissue that guards the
superior opening of the larynx
• stands almost vertical at rest
• during swallowing, extrinsic muscles pull
larynx upward tongue pushes epiglottis
down to meet it closes airway and directs
food to the esophagus behind it
• Contains the vocal folds used for voice
production
• Larynx lined mainly with pseudostratified
ciliated columnar epithelium, moves the
mucus backwards, toward the pharynx
• Contains multiple cartilages and the thyrohyoid membrane which
connects the hyoid bone and thyroid cartilage
Larynx Cartilages
Thyroid cartilage: or “Adam’s apple”.
Largest cartilage.
Laryngeal prominence- testosterone
stimulates growth
Epiglottic cartilage: leaf shaped
cartilage. Stem attached, leaf portion
unattached-moves up and down.
Entry of food, dust, smoke or liquids
into larynx, cough reflex initiated.
Cricoid cartilage: a complete ring of
cartilage at the base connects larynx to
trachea
In addition, the larynx consists of three paired cartilages that assist
in speech production and the opening and closing of the glottis
• arytenoids shaped like pyramids; point of attachment for the
vocal cords, allow the opening and closing movement of the
vocal cords necessary for respiration and voice
• corniculate support arytenoids
• cuneiform support the vocal folds and lateral aspects of the
epiglottis
http://www.gbmc.org/Anato
myandPhysiology
Diagram from
Grey’s Anatomy
Textbook
http://upload.wikimedia.org/wikipedia/commons/5/50/Gray956.png
Voice
Production
Mucus membrane of
the larynx has two
pairs of folds
Ventricular/vestibular folds (false vocal cords):
– Close the glottis if holding breath; when lifting weight; used for
screaming, produce deep sonorous tones in Tibetan chant and the
death growl vocal style, keeping food and drink out of the airway;
if surgically removed can REGENERATE COMPLETELY!!
TRUE Vocal folds: for VOICE PRODUCTION
– Sound is produced by the vibrations of true vocal cords
Action of Vocal Cords
Walls of trachea very muscular; Intrinsic muscles control the vocal
cords via the Vagus nerve. The true cords are white due to scant
blood circulation.
– pull on the corniculate and arytenoid cartilages- causing the
cartilages to pivot
– abduct or adduct vocal cords, depending on direction of rotation
– air forced between adducted vocal cords vibrates them
• producing high pitched sound when cords are taut/tight
• produce lower-pitched sound when cords are more slack
» The difference in vocal fold size between men and women
produces differently pitched voices. Genetics also causes
variances amongst the same sex.
» Frequency (# of vibrations ) of the sound generated by the larynx
affects the pitch of a person's voice (deep /high ). In adult male,
frequency averages about 125 Hz, adult females 210 Hz, children
frequency is over 300 Hz. Frequency is influenced by the size,
length, tension, and thickness of the vocal folds.
• loudness – determined by the force of air passing between the
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vocal cords
Vocal
Cords
Vocal cords produce crude
unintelligible sounds that
are formed into intelligible
words by actions of
pharynx, oral cavity,
tongue, and lips
Animations:
http://www.youtube.com/watch?v=wjRsa
77u6OU&feature=related (tutorial)
http://www.youtube.com/watch?v=qpt
0kigakWY (cough)
http://www.youtube.com/watch?v=v9Wd
f-RwLcs
Laryngitis: is an
inflammation of larynx which
causes vocal cords to swell.
Can be caused by
respiratory infection or
irritants like cigarette smoke.
http://www.youtube.com/watch?v=wrsHx
E9bRzA&feature=related
Snoring animation (1.45 min)
http://www.youtube.com/watch?v=iNmSexAKTsM
Singing:
https://www.youtube.com/wa
tch?v=-XGds2GAvGQ
Trachea – a 4-6 inch TUBE
• Made of fibrous and elastic tissues
and smooth muscle lined with
pseudostratified ciliated columnar
epithelium cells; goblet cells
produce mucus to trap inhaled
foreign particles.
• Circular bands of fibrous CT,
annular ligaments, join the
tracheal rings together
• Connects pharynx and larynx to
lungs; allows for passage of air.
Trachea (Windpipe)
http://img.webmd.com/dtmcms/live/webmd/consumer_assets/site_image
s/articles/image_article_collections/anatomy_pages/trachea.jpg
Supported by 16-20 incomplete C shaped cartilage rings that reinforce
trachea to prevent collapsing inward during inhalation.
 “C” shape allows esophagus to expand during swallowing
1. Posterior side, smooth muscle band, trachealis, stabilizes the open
ends of the cartilage rings.
2. Epithelium cilia sweep debris from lungs and back to the throat to be
swallowed via mucociliary escalator; smoking destroys the cilia
Bronchial Tree
CONDUCTING ZONE:
• Primary Bronchi – rings of hyaline cartilage
 CARINA - where primary bronchi branch - most sensitive
area of larynx/trachea; triggers cough reflex
• Secondary bronchi (lobar): 1 to each lobe of the lung; 3 on right,
2 on left. Overlapping cartilage plates
• Tertiary (segmental) bronchi: respiratory epithelium lining lumen
surrounded by a layer of smooth muscle surrounded by irregular
plates of hyaline cartilage that help to maintain the patency
(openness) of the airway. ONE tertiary bronchus forms about
6,500 TERMINAL bronchioles.
– Each lung is separated by connective tissue into independent
compartmental units called bronchopulmonary segments.
Segments are supplied by a tertiary bronchi and an artery.
» 10 SEGMENTS IN THE RIGHT LUNG, 8 IN THE LEFT.
» One segment can be surgically removed without affecting the
function of the other segments. Each segment is subdivided
into approximately 130,000 lobules which receive air via the
bronchioles.
Bronchial Tree
http://cnx.org/content/m44792/latest/Figure_39_01_07.jpg
Bronchopulmonary
Segments
Each segment is subdivided into
approximately 130,000 lobules
Bronchioles
CONDUCTING ZONE
Tertiary (Segmental) bronchi 
primary bronchioles 
terminal bronchioles 
RESPIRATORY ZONE
respiratory bronchioles  2
to 11 alveolar ducts.
• Alveolar ducts have 5 or 6
alveolar sacs. The alveolus
is basic anatomical unit of
gas exchange in the lung.
• Terminal bronchioles are
the smallest bronchioles;
contain no cartilage, no
mucus or goblet cells; cilia
eliminate any mucus
drainage
RESPIRATORY ZONE area of
gas exchange. Extends from
respiratory bronchioles to air
chambers (alveolar sacs).
http://classconnection.s3.amazonaws.com/999/fla
shcards/743999/jpg/alveolar_duct1318887725340.j
pg
http://www.bing.com/images/search?q=Lung+Anatomy&Form=IQFRDR#
view=detail&id=CB29C04F1BD773FA23DFF6987D15CAAB80DEFEE8&se
lectedIndex=107
Structural Components of Bronchial Tree
• Epithelium gradually changes from pseudostratified ciliated
columnar to non-ciliated simple cuboidal epithelium.
• Cartilage: As bronchial tree descends:
– First incomplete cartilage C- rings (trachea & primary bronchi)
– These are replaced with plates of hyaline cartilage (secondary
& tertiary bronchi)
– all supportive cartilage disappears by the bronchiole.
• Muscle: Bronchiole walls contain smooth muscle and no cartilage.
Allows contraction and relaxation, regulating air flow to the alveoli.
 During exercising, sympathetic ANS causes relaxation of
smooth muscles thus dilating the air passageways, increasing
airflow improving lung ventilation.
 Parasympathetic activity of ANS causes constriction of
passageways;
 Allergic reactions cause the release of histamine dilating blood
vessels increasing fluid accumulation which can constrict airways.
These actions can account for an asthma attack.
Muscle Layer
http://www.homebusinessandfamilylife.com/images/inflamed_bronchus.jpg
• Air filled sacs- kept dry to allow
quicker diffusion of gases.
Exchange occurs much slower
thru FLUID.
Alveoli
• Alveoli contain some collagen
and elastic fibers which allow
the alveoli to stretch
Epithelial surface cells:
• Type I alveolar cells: simple
squamous epithelial, form
continuous layer, main site of
gas exchange
• Type II alveolar (Great) cells:
-- Secrete surfactant (mixture of
phospholipids and protein); lowers
surface tension; reduces tendency
of alveoli to collapse; absence of
surfactant would be similar to the
inside of a wet plastic bag.
– Respiratory Distress
Syndrome: deficiency of
surfactant in premature infants
 700
million
alveoli
 40x the
surface
area of
the skin.
 Alveolar macrophages
(dust cells): remove dust
particles; found in the lumen;
100 million perish each day
going up the “escalator”
• Exchange of O2 and CO2
between lungs and blood
occurs by diffusion across
the respiratory membrane
made of alveolar and
capillary walls.
• 0.5 μm (ex: RBC 7.5μm)
allows rapid gas diffusion
• More extensive lymphatic
drainage than any other
organ. Important to prevent
fluid buildup. Fluid slows
gas exchange!
Respiratory Membrane
Alveolar I cell
Layers of the respiratory membrane
• Each alveoli is lined with a THIN layer of tissue fluid essential for
the diffusion of gases (a gas must first dissolve in a fluid in order
to leave or enter a cell) EXCESS fluid retards gas exchange.
• Squamous cells of the alveolar wall
• Epithelial and capillary shared basement membrane
• Capillary endothelium
http://www.mts.net/~alou/Chemistry%2011/images/lesson%202f.jpg
A gas must first dissolve in a fluid in order
to leave or enter a cell
Two lungs - Left and right, cone
shaped in thoracic cavity
separated by mediastinum.
Enclosed and protected by the
pleural membrane.
– Parietal pleura: line the inside
of the thoracic cavity
– Visceral pleura: cover the lungs
– Pleural cavity: space between
visceral and parietal pleural filled
with lubricating, serous pleural
fluid
– Reduces friction
– Creates pressure gradientlung inflation
– Compartmentalizes-prevents
spread of infection
• The broad inferior portion is the
base fits over the diaphragm.
• The narrow superior portion of is
the apex.
Lungs
Lungs
the bronchi, pulmonary vessels,
lymphatic vessels and nerves
enter and exit at hilum.
• right lung has 3 lobes
separated by 2 fissures
(Oblique & horizontal)
• left lung has 2 lobes
separated by the
Oblique fissure
• depression, the
cardiac impression
(notch) accommodates
the heart
Respiration REGULATION: Respiratory Center
Located in Medulla oblongata of brain stem: Medullary rhythmicity
• Dorsal Respiratory group- DRG -posterior – INSPIRATION
– establishes the rhythm of normal quiet inspiratory breathing
– neurons in DRG stimulates nerves to innervate the diaphragm and
external intercostal muscles; the thorax to expands - air rushes in.
• If DRG completely suppressed breathing stops (overdose sleeping
pills, alcohol, etc.)
• Ventral Respiratory group - VRG- anterior - EXPIRATION
– Inspiratory and expiratory area inactive majority of the time; becomes
active to controls voluntary forced exhalation such as during exercise
Located in The Pons of the brain stem:
• Apneustic Center- provides continuous stimulation to its DRG center;
increases the inhalation process. APC
DRG
– Controls intensity of breathing
• Pneumotaxic Centers INHIBIT the apneustic centers; directly inhibits
inhalation.
PC
APC
• limits action potentials in the phrenic nerve, effectively decreasing the
tidal volume (inhaled + exhaled breath); regulating the respiratory rate
– Promote passive or active exhalation by regulating the amount of
air a person can take into the body in each breath
Respiratory
Centers
http://www.physioweb.org/IMAGES/
resp_center.jpg
Breathing Patterns
Eupnea [Eu-true, good / pnea - air, lung] = normal pattern
of quiet breathing
Apnea: [A –without / pnea - air, lung] = breath holding
Dyspnea: [Dys- pain, difficulty/ pnea - air, lung] = painful or
difficult breathing
Tachypnea: [Tachy- fast, irregular / pnea - air, lung] = rapid
breathing
Costal breathing: combinations of various patterns of
external intercostal muscles; during need for increased
ventilation; e.g., exercise
Diaphragmatic breathing: move air by contracting and
relaxing the diaphragm to change the lung volume. “push
stomach out”
Lung Volumes and Capacities
Spirometer or respirometer:
instrument used to measure volume of
air exchanged during breathing.
• Respiratory rate: is the frequency
of breaths per minute.
– Average 12 breaths / minute (bm)
– Range between 10-18 per/min
– 20,000 per day
http://www.adinstruments.com/solutions/images_new/spirometry1.jpg
LUNG CAPACITIES
• Tidal volume (TV): is the volume of air that moves in or
moves out with each inspiration or expiration. This
volume is close to 500ml.
http://classconnection.s3.amazonaws.com/622/flashcard
s/1922622/jpg/thoracic_muscles1350503789673.jpg
Inspiration Muscles
Animation:
Diaphragm - prime mover of
http://www.youtube.com/watch?v=hprespiration attached to inferior
gCvW8PRY
surface of the lungs
As the diaphragm contracts it flattens and pulls the bottom of the
lungs downward expanding them and enlarging the volume of the
thoracic cavity..
• Controlled by the DRG respiratory center via the phrenic nerve.
External intercostal muscles between ribs contract raise the ribs
and elevate the sternum stiffen the thoracic cage during
respiration prevents it from caving inward when diaphragm
descends contribute to enlargement and contraction of thoracic
cage
Respiratory Disorders
• Chronic obstructive pulmonary disease (COPD): chronic and
recurring obstruction of air passageways, increasing air resistance.
– Asthma: partial or complete closure of airways, inflammation and
excess production of mucous. Constriction of bronchial muscles
– Bronchitis: inflammation of the bronchi caused by irritants.
Causes constriction and breathing difficulty. Generally acute
– Emphysema: destruction of the alveolar walls- elastin in the
alveoli walls broken down- less membrane available for gas
exchange
• Cystic fibrosis: inherited disorder affecting secretory cells lining
the lungs; results in the buildup of mucous in the passageways.
• Tuberculosis: inflammation of pleurae and lungs produced by the
bacterial organism Mycobacterium tuberculosis.
• Pulmonary edema: abnormal accumulation of fluid in the interstitial
spaces and alveoli of the lungs.
• Lung cancer: ACCOUNTS FOR MORE DEATHS than any other
form of cancer. Each year, more people die of lung cancer than of
breast, colon, and prostate cancers COMBINED.
– Lung cancer is more common in older adults; rare under age 45
– most prominent cause is smoking (15 carcinogens)
– 90% originate in primary bronchi; cancer of the respiratory epithelium
Effect of Smoking
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Tumors
(a) Healthy lung, mediastinal surface
(b) Smoker's lung with carcinoma
a: © The McGraw-Hill Companies/Dennis Strete, photographer; b: Biophoto Associates/Photo Researchers, Inc.
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