respiratory system spr07

7/31/2019 Respiratory System Spr07

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Respiratory System

Chapter 21


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Structural Anatomy

throat

voice box

windpipe

Upper respiratory system

Lower respiratory system


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Function of Respiratory System Gas exchange

Contains receptors for sense of smell

Filters and warms inspired air

Produces sound

Eliminates waste


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Gas Exchange

Intake of O2 and elimination of CO2.

Cardiovascular involvement?

4 steps in respiration (atmosphere blood cells) Pulmonary ventilation breathing, inspiration/expiration of air.

External (pulmonary) respiration exchange of gases between airspace of lungs and blood in pulmonary capillaries.

Transport of respiratory gases transport of gases between thelungs and body tissues by cardiovascular system.

Internal (tissue) respiration exchange of gasses between blood insystemic capillaries and tissue cells.


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Functional Anatomy

Conducting portion

hard tubes, interconnecting cavities and rigid tubes

that lead to the sites of gas exchange in microscopiclung tissue.

Nose, pharynx, larynx, trachea, bronchi, bronchioles

and terminal bronchioles, all serve to conduct air into

lungs.

Respiratory portion

soft spaces, consists of those portions where the

exchange of gasses occurs.

Respiratory bronchioles, alveolar ducts, alveolar sacs,

and alveoli, most of lung volume.


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The Nose

Provides:

air passage moistens and warms air

filters air

resonating chamber forsound

houses olfactory (smell)

receptors.


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The Nose(external and internal portion)

External nares

openings Nasal bones

Skeletal framework

provided by nasal

and maxillary bones

Nasal cartilage

Flexible plates of

hyaline cartilage

Lateral, septal, and

alar cartilages


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The Nose(internal portion)


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Nasal cavity space inside the internal nose, divided intohalves by a vertical petition (septum). Septum formed by

hyaline cartilage, vomer and perpendicular plate.

The Nose(internal portion)

Nasal conchaesubdivide the cavity

into a series of groove-

like passages (meatus)

line w/ mucous

membranes.


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Mucous membranes contain capillaries and epithelial

tissue w/ goblet cells.


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Olfactory Receptors

Olfactory receptors

lie in the superior

portion of the nasalcavity, olfactory

epithelium.

Olfactory nervecommunicates with

these recepotrs

through the cribiform

plate of the ethmoidbone.


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Paranasal Sinuses

Air filled spaces lined w/ respiratory mucosa,

located w/in skull bones.


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Paranasal Sinuses These spaces open into the nasal cavity and are lined with mucous

membranes, and can drain secretions into the nasal cavity.

Inflammation and swelling may cause pressure (sinus headache).

Resonators of the voice sounds.


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Pharanyx (Throat) Passage for: 1) food from oral cavity to esophagus and 2) air passing

between nasal cavity and oral cavity to the larynx.


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Pharanyx (Throat) 3 parts: 1) nasopharynx swallowing causes uvula and soft palate to

move superiorly to block food from entering this area.


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Nasopharynx

Openings in the nasopharnyx Pharyngotympanic tubes (auditory tube), drains the

middle ear.

Pharyngeal tonsils (adenoids)


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Oropharynx

Oropharynx intermediate portion of pharynx. Serves as

both passage for air and food.

Palatine tonsil pair of tonsils located in faucal wall.

Lingual tonsil covers posterior base of tongue.


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Laryngopharnyx Connects esophagus (food tube) with the larynx (voice box), where the

food and airway passage diverge.

It is both a respiratory and digestive pathway.

During swallowing, the food has the right of way and air passage is

blocked by the epiglotis in larynx.


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The Larynx Functions:

Airway, routes food and air to

proper channel.

Voice production, voice box.


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The Larynx The walls are made up of 9 pieces of cartilage.


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The Larynx 1 thyroid cartilage prominence (Adams apple). Thyroid

gland sits on this triangular piece. Hyoid bone attached to itvia ligaments.

1 cricoid cartilage ring of hyaline cartilage. Landmark fortracheostomy.


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The Larynx 1 epiglottis cartilage acts as trap door over the glottis.

During swallowing, the larynx rises causing the apparatus to move

down to block liquids and food en route to esophagus.


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The Larynx 2 arytenoid cartilage anchors the vocal chords.

2 corniculate & 2 cuneiform help in support of vocal folds and lateral

aspects of layrnx.


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Voice Production Vocal cords are elastic and when air is directed against them they

vibrate.

Pitch is controlled by the tension of the cords, provided by laryngealmuscles.

Loudness depends on the force of the air across the folds. Inflammation of the cords can cause laryngitis.

Upper respiratory pathway (pharynx & nasal) responsible for formingrecognizable sounds with help of the paranasal sinuses and muscles inthroat and face help in enunciation of words.


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Tubular passageway located anterior to esophagus,

from the larynx down into the thoracic cavity whereit splits into 2 bronchi.

Tracheal cartilage 16-20 C shaped hyaline

cartilage rings.

Trachea


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Opening of cartilage ring pointed posteriorly

which allows for expansion of esophagus asfood passes through.

Rings also keep the trachea from collapsing

and blocking the airway.


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Bronchi and Subdivisions: Bronchial Tree

A branched airway that leads from the trachea tothe microscopic air sacs in lungs.

Primary, Secondary and Tertiary Bronchi.


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Primary Bronchi trachea divide into left and rightprimary bronchi and then enters lung at medial

hilus.


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Secondary (lobar) bronchi primary bronchi divideinto secondary bronchi.

Bronchi undergo successive divisions to create the

bronchial tree, about 23 in all.


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Tertiary (segmental) bronchi supplies a portion ofthe lung called the bronchopulmonary segment.


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Right lung (largest) is divided into 3 lobes upper,

middle, and inferior. Left lung divided into 2 lobes upper and lower.


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Bronchopulmonary Segments

Each lobe is separated by C.T. into segments with tertiarybronchi, veins, and arteries.


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Bronchiole branches of the segmental bronchi under 1 mm in diameterthat enter the lobes of the lungs.

Terminal bronchiole branches from bronchiole under 0.5 mm.

This is where the respiratory system begins!


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Respiratory Bronchiole

Respiratory bronchiole 2 or more branches from eachterminal bronchiole with air sac buds.

This is the first level of air exchange.


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Alveoli are covered in cobweb of pulmonary capillaries.

Comprises some 70-80 sq. meters. Gas exchange is by diffusion through these respiratory

membranes.


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Alveoli are lined with simple squamos epithelium (Type I)

which aid in gas exchange.

Type II, cuboidal epithelial cells are present and secrete

surfactant to prevent alveoli from sticking together.


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Tissue Composition Changes in the

Respiratory Tree

As branching becomes more extensive in the bronchial

tree there are structural changes.epithelia, cartilageand smooth muscle changes.

Epithelia changes epithelium changes frompsuedostratified ciliated columnar in bronchi to

nonciliated simple cuboidal cells in the terminalbronchioloes. (macrophages clear debris at this level)

Cartilage changes incomplete cartilage rings inprimary bronchi give way to cartilage plates which finally

disappear in the distal bronchioles.


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Tissue Composition Changes in the

Respiratory Tree

Smooth muscle dominates the respiratory zone

as cartilage decreases, the amount of smoothmuscle increases.

Contraction of these spiral bands of muscle iscontrolled by the ANS and chemicals

(epinephrine relaxes, histamine contracts). Muscle layer persists to the end of the

respiratory bronchioles.

Excessive contraction can close off airwaysand create life-threatening event (asthma?)


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Lungs and Pleural Cavities Lungs are paired, cone shaped, spongy organs located in the thoraciccavity separated by the heart and mediastinum.

They are enclosed by the diaphragm and thoracic cage.

The bronchi and blood vessels enter medially through the hilus(depression).

Lung tissue is mostly open space with supporting elastic C.T.


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V til ti


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Ventilation

Muscles of inspiration diaphragm and external intercostals Muscles of forced expiration internal intercostals and abdominal

muscles

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