A. function: supplies body with oxygen and removes carbon dioxide. a. O2 diffuses from air into pulmonary capillary blood

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Strong/Fall 2008 page 1

A. function: supplies body with oxygen and removes carbon dioxide 1. ventilation = movement of air into and out of lungs

2. diffusion:

a. O2 diffuses from air into pulmonary capillary blood b. CO2 diffuses from pulmonary capillary blood into air B. organization

1. by function

a. conducting zone = airways (no gas diffusion)

b. respiratory zone = areas where O2 and CO2 diffuse between air and blood (respiratory bronchioles, alveolar ducts, alveoli)

2. by location

a. upper respiratory structures = superior to larynx

b. lower respiratory structures = larynx and all structures inferior to it C. nose = external nose + nasal cavity

1. functions: a. airway

b. moistens, warms and filters inhaled air c. resonating chamber

d. olfaction 2. structure

a. external nose external nares

vestibule - lined with skin b. nasal cavity

nasal septum

conchae (turbinates) cause turbulent air flow through meatuses posterior nasal aperatures (internal nares, choanae)

mucous membrane:

pseudostratified ciliated columnar epithelium with goblet cells lamina propria contains seromucous glands

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3. paranasal sinuses open into nasal cavity D. pharynx

connects nasal cavity to larynx connects mouth to esophagus

1. nasopharynx - from internal nares to soft palate a. pseudostratified ciliated e.

b. openings of auditory tubes c. pharyngeal and tubal tonsils

2. oropharynx - from soft palate to epiglottis a. stratified squamous e.

b. fauces = opening between oral cavity and oropharynx c. palatine and lingual tonsils

d. uvula = projection of soft palate

3. laryngopharynx - posterior to larynx, superior to esophagus a. stratified squamous e.

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E. larynx

1. functions:

a. connects laryngopharynx and trachea b. voice production

c. controls opening to trachea (sphincter function)

2. structure = cartilages connected by ligaments and membranes + intrinsic muscles a. cartilages (9)

1 thyroid - anterior and superior

thyrohhyoid membrane suspends it from the hyoid bone 1 cricoid - inferior, continuous ring, larger posteriorly

1 epiglottis -

projects superiorly and posteriorly attached at base and free at top

tips over to cover glottis during swallowing 2 arytenoid

superior to cricoid in posterior larynx

anchor vocal cords

position controlled by intrinsic muscles

controls length and tension of vocal cords

2 corniculate - attached to arytenoid cartilage 2 cuneiform

b. vocal folds (vocal cords)

vocal cords consist of vocal ligaments (bands of elastic tissue) covered by mucous membrane

run from arytenoid cartilage to thyroid cartilage

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c. opening between folds = glottis (rima glottidis) d. vestibular folds - superior to vocal folds

e. epithelium

above glottis - stratified squamous e. below glottis - pseudostratified ciliated e. F. trachea

1. location - anterior to esophagus and inferior to larynx 2. gross structure

bifurcates in mediastinum to form primary bronchi carina = ridge on inside of last cartilage

3. histology

a. mucosa (mucous membrane)

pseudostratified ciliated e. (mucociliary escalator) lamina propria = c.t. under epithelium

b. submucosa = c.t. seromucous glands

blood vessels, nerves, lymphatics c. adventitia

tracheal cartilages: hyaline cartilage, C-shaped, open posteriorly ligaments connect cartilages together

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G. bronchial tree (23 orders) = tubes that carry air from trachea to respiratory zone epithelium gradually changes from ciliated pseudostratified to ciliated simple

cuboidal

the amount of smooth muscle increases as tubes become smaller in diameter

the amount of cartilage decreases as tubes become smaller in diameter 1. bronchi are all supported by irregular hyaline cartilage plates

a. primary bronchi enter lung at hilus; right is shorter and wider than left b. secondary or lobar bronchi go to lung lobes

3 right and 2 left

c. tertiary or segmental bronchi go to bronchpulmonary segments 10 per lung

2. bronchioles = muscular tubes < 1 mm in diameter, no cartilage a. terminal - last part of conducting zone

b. respiratory - first part of respiratory zone

asthma is caused by constriction of bronchioles

H. respiratory zone

1. respiratory bronchioles

2. alveolar ducts branch from respiratory bronchioles 3. alveoli sacs are terminal clusters of alveoli

I. alveoli = major surface area for gas diffusion between air and blood (1500 square feet)

thin-walled, spherical

extend from walls of respiratory bronchioles, alveolar ducts, and alveolar sacs

connected by pores walls composed of

o type I cells - diffusion o type II cells - surfactant o macrophages

o fine elastic fibers

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J. respiratory membrane – allows diffusion of oxygen and carbon dioxide between alveolar air and pulmonary capillary blood

alveolar wall (type I cells) basal lamina

pulmonary capillary wall

K. lungs

1. location - thoracic cavity lateral to mediastinum 2. anatomical features

a. surfaces: costal, medial (mediastinal) b. apex is superior, just behind clavicle c. base rests on diaphragm

d. hilus - medial indentation

e. root - structures that attach lung to mediastinum (blood vessels, bronchi, nerves, lymph vessels)

f. cardiac notch - indentation in medial, inferior left lung g. lobes and (fissures)

right: upper (horizontal fissure) middle (oblique fissure) lower left: upper (oblique fissure) lower

h. bronchopulmonary segments i. lobule - subdivision of a segment

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L. pleurae = serous membranes surrounding lungs visceral

pleural space (cavity) contains pleural fluid secreted by serous pleurae fluid provides lubrication and fluid cohesion

parietal

M. respiratory control centers - part of reticular formation in brainstem 1. medulla oblongata

a. rostral ventrolateral medulla oblongata - pacemaker for respiratory rate b. dorsal respiratory group - controls inspiratory and expiratory muscles

(diaphragm and intercostals)

c. ventral respiratory group - controls inspiratory and expiratory muscles (diaphragm and intercostals)

2. pons

a. apneustic center b. pneumotaxic center 3. sensory input from

a. chemoreceptors

central in medulla oblongata

peripheral in aortic bodies and carotid bodies b. stretch receptors in lungs