ch 22 lecture presentation - Mission Collegestreaming.missioncollege.org/.../47ch_22_PPs.pdf2...

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PowerPoint® Lecture Slides prepared by Leslie Hendon University of Alabama, Birmingham

C H A P T E R

Copyright © 2011 Pearson Education, Inc.

Part 1

22 The Respiratory System


The Respiratory System

•  Basic functions of the respiratory system •  Supplies body with oxygen •  Disposes of carbon dioxide

•  Four processes involved in respiration •  Pulmonary ventilation •  External respiration •  Transport of respiratory gases •  Internal respiration


Functional Anatomy of the Respiratory System

•  Respiratory organs •  Nose, nasal cavity, and paranasal sinuses •  Pharynx, larynx, and trachea •  Bronchi and smaller branches •  Lungs and alveoli


Organs of the Respiratory System

Figure 22.1

Nasal cavity

Trachea Carina of trachea

Left main (primary) bronchus

Right main (primary) bronchus Right lung

Parietal pleura

Left lung

Alveoli

Bronchi

Nostril Oral cavity Pharynx

Larynx

Diaphragm


Organs of the Respiratory System

•  Divided into •  Conducting zone •  Respiratory zone


The Nose

•  Provides an airway for respiration •  Moistens and warms air •  Filters inhaled air •  Resonating chamber for speech •  Houses olfactory receptors

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The Nose

•  Size variation due to differences in nasal cartilages

•  Skin is thin—contains many sebaceous glands

Figure 22.2

Frontal bone Nasal bone Septal cartilage Maxillary bone (frontal process) Lateral process of septal cartilage Minor alar cartilages

Major alar cartilages

Dense fibrous connective tissue

(b) External skeletal framework

Epicranius, frontal belly

Ala of nose

Root and bridge of nose

Dorsum nasi

Apex of nose

Philtrum Naris (nostril)

(a) Surface anatomy


The Nasal Cavity

•  External nares—nostrils •  Divided by nasal septum •  Continuous with nasopharynx •  Posterior nasal apertures—choanae


Nasal Cavity

•  Two types of mucous membrane •  Olfactory mucosa • Near roof of nasal cavity • Houses olfactory (smell) receptors

•  Respiratory mucosa • Lines nasal cavity • Epithelium is pseudostratified ciliated

columnar


The Upper Respiratory Tract

Figure 22.3c

Sphenoid sinus Frontal sinus

Nasal meatuses (superior, middle, and inferior)

Nasopharynx

Uvula

Palatine tonsil Isthmus of the fauces

Posterior nasal aperture

Opening of pharyngotympanic tube

Pharyngeal tonsil

Oropharynx

Laryngopharynx

Vocal fold Esophagus

(c) Illustration

Nasal conchae (superior, middle and inferior)

Nasal vestibule Nostril

Nasal cavity

Hard palate Soft palate Tongue Lingual tonsil

Epiglottis Hyoid bone Larynx

Thyroid cartilage Vestibular fold

Cricoid cartilage Thyroid gland

Trachea

Cribriform plate of ethmoid bone


Respiratory Mucosa

•  Consists of •  Pseudostratified ciliated columnar epithelium •  Goblet cells within epithelium •  Underlying layer of lamina propria

•  Cilia move contaminated mucus posteriorly


Nasal Conchae

•  Superior and middle nasal conchae •  Part of the ethmoid bone

•  Inferior nasal conchae •  Separate bone

•  Project medially from the lateral wall of the nasal cavity

•  Particulate matter •  Deflected to mucus-coated surfaces

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The Pharynx

•  Funnel-shaped passageway •  Connects nasal cavity and mouth •  Divided into three sections by location •  Nasopharynx •  Oropharynx •  Laryngopharynx

•  Type of mucosal lining changes along its length


The Nasopharynx

•  Superior to the point where food enters •  Only an air passageway •  Closed off during swallowing •  Pharyngeal tonsil (adenoids) •  Located on posterior wall •  Destroys entering pathogens

•  Contains the opening to the pharyngotympanic tube (auditory tube) •  Tubal tonsil • Provides some protection from infection


The Oropharynx

•  Arch-like entranceway—fauces •  Extends from soft palate to the epiglottis

•  Epithelium •  Stratified squamous epithelium

•  Two types of tonsils in the oropharynx •  Palatine tonsils—in the lateral walls of the

fauces •  Lingual tonsils—covers the posterior surface

of the tongue


The Laryngopharynx

•  Passageway for both food and air •  Epithelium •  Stratified squamous epithelium

•  Continuous with the esophagus and larynx


The Larynx

•  Three functions •  Voice production •  Provides an open airway •  Routes air and food into the proper channels • Superior opening is • Closed during swallowing • Open during breathing


Nine Cartilages of the Larynx

•  Thyroid cartilage •  Shield-shaped, forms laryngeal prominence

(Adam’s apple) •  Three pairs of small cartilages •  Arytenoid cartilages •  Corniculate cartilages •  Cuneiform cartilages

•  Epiglottis •  Tips inferiorly during swallowing

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The Larynx

•  Vocal ligaments of the larynx •  Vocal folds (true vocal cords) • Act in sound production

•  Vestibular folds (false vocal cords) • No role in sound production

•  Epithelium of the larynx •  Stratified squamous—superior portion •  Pseudostratified ciliated columnar—inferior

portion


Anatomy of the Larynx

Figure 22.5a, b

Body of hyoid bone

Cricoid cartilage

Laryngeal prominence (Adam’s apple)

Clavicle

Sternal head Clavicular head

Sternocleidomastoid

Jugular notch

(a) Surface view

Body of hyoid bone

Epiglottis

Cricoid cartilage

Tracheal cartilages

Thyroid cartilage Laryngeal prominence (Adam’s apple) Cricothyroid ligament

Cricotracheal ligament

(b) Anterior view

Thyrohyoid membrane


Anatomy of the Larynx

Figure 22.5c, d

Hyoid bone

Thyroid cartilage

Glottis

(c) Photograph of cartilaginous framework of the larynx, posterior view

Epiglottis

Corniculate cartilage Arytenoid cartilage

Cricoid cartilage

Tracheal cartilages

Thyrohyoid membrane

Epiglottis

Body of hyoid bone Thyrohyoid membrane

Vestibular fold (false vocal cord)

Vocal fold (true vocal cord) Cricothyroid ligament Cricotracheal ligament

Fatty pad

Thyroid cartilage

Cuneiform cartilage

Corniculate cartilage Arytenoid cartilage

Cricoid cartilage

Tracheal cartilages

Arytenoid muscle

(d) Sagittal section (anterior on the right)

Thyrohyoid membrane


Movements of the Vocal Folds

Figure 22.6 (a) Vocal folds in closed position; closed glottis (b) Vocal folds in open position; open glottis

Base of tongue Epiglottis Vestibular fold (false vocal cord) Vocal fold (true vocal cord) Glottis Inner lining of trachea Cuneiform cartilage Corniculate cartilage

Thyroid cartilage Cricoid cartilage Vocal ligaments of vocal cords

Lateral cricoarytenoid muscle Arytenoid cartilage

Posterior cricoarytenoid muscle

Anterior

Posterior

Glottis

Corniculate cartilage


The Larynx

•  Voice production •  Length of the vocal folds changes with pitch •  Loudness depends on the force of air across

the vocal folds •  Sphincter function of the larynx •  Valsalva’s maneuver—straining

•  Innervation of the larynx •  Recurrent laryngeal nerves (branch of vagus)


The Trachea

•  Descends into the mediastinum •  C-shaped cartilage rings keep airway open •  Carina •  Marks where trachea divides into two primary

bronchi •  Epithelium • Pseudostratified ciliated columnar

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The Trachea

Figure 22.7

(a) Cross section of the trachea and esophagus

Hyaline cartilage

Submucosa

Mucosa

Seromucous gland in submucosa

Posterior

Lumen of trachea

Anterior

Esophagus

Trachealis muscle

Adventitia

(b) Photomicrograph of the tracheal wall (250×)

Hyaline cartilage

Lamina propria (connective tissue)

Submucosa

Mucosa

Seromucous gland in submucosa

Pseudostratified ciliated columnar epithelium


Bronchi in the Conducting Zone

•  Bronchial tree •  Extensively branching respiratory

passageways • Primary bronchi (main bronchi) • Largest bronchi

• Right main bronchi • Wider and shorter than the left



Figure 22.8a

Trachea Superior lobe of right lung

Middle lobe of right lung

Inferior lobe of right lung

Superior lobe of left lung Left main (primary) bronchus Lobar (secondary) bronchus Segmental (tertiary) bronchus Inferior lobe of left lung

(a) The branching of the bronchial tree



Figure 22.8b

Mucosa

Pseudostratified epithelium Lamina propria

Fibromusculo- cartilaginous layer

Cartilage plate Smooth muscle

Lumen

(b) Photomicrograph of a bronchus (13×)



•  Secondary (lobar) bronchi •  Three on the right •  Two on the left

•  Tertiary (segmental) bronchi •  Branch into each lung segment

•  Bronchioles •  Little bronchi, less than 1 mm in diameter

•  Terminal bronchioles •  Less than 0.5 mm in diameter


Changes in Tissue Composition along Conducting Pathways •  Supportive connective tissues change •  C-shaped rings replaced by cartilage plates

•  Epithelium changes •  First, pseudostratified ciliated columnar •  Replaced by simple columnar, then simple

cuboidal epithelium •  Smooth muscle becomes important •  Airways widen with sympathetic stimulation •  Airways constrict under parasympathetic

direction

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Structures of the Respiratory Zone

•  Consists of air-exchanging structures •  Respiratory bronchioles—branch from

terminal bronchioles •  Lead to alveolar ducts • Lead to alveolar sacs



Figure 22.9a

Alveolar duct

Alveolar duct Alveoli

Alveolar sac

Respiratory bronchioles

Terminal bronchiole

(a)



Figure 22.9b

Alveolar pores

Alveolar duct

Respiratory bronchiole

Alveoli

Alveolar sac

(b)



•  Alveoli •  ~300 million alveoli account for tremendous

surface area of the lungs • Surface area of alveoli is ˜140 square

meters



•  Structure of alveoli •  Type I cells—single layer of simple

squamous epithelial cells • Surrounded by basal lamina

•  Alveolar and capillary walls plus their basal lamina form the ... • Respiratory membrane



•  Structures of alveoli (continued) •  Type II cells—scattered among type I cells • Are cuboidal epithelial cells • Secrete surfactant • Reduces surface tension within alveoli–

keeps alveoli from collapsing when we exhale

•  Alveolar macrophages

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Copyright © 2011 Pearson Education, Inc. Figure 22.10a, b

Anatomy of Alveoli and the Respiratory Membrane

Elastic fibers

(a) Diagrammatic view of capillary-alveoli relationships

Smooth muscle

Alveolus

Capillaries

Terminal bronchiole Respiratory bronchiole

Copyright © 2011 Pearson Education, Inc. Figure 22.10c

Anatomy of Alveoli and the Respiratory Membrane

Alveolus

Capillary

Type II (surfactant- secreting) cell

Type I cell of alveolar wall

Endothelial cell nucleus Macrophage

Alveoli (gas-filled air spaces)

Red blood cell in capillary

Alveolar pores

Capillary endothelium

Fused basement membranes of the alveolar epithelium and the capillary endothelium

Alveolar epithelium Respiratory membrane

Red blood cell

O2

Alveolus CO2

Capillary

Nucleus of type I (squamous epithelial) cell

(c) Detailed anatomy of the respiratory membrane


The Respiratory Zone

•  Features of alveoli •  Surrounded by elastic fibers •  Interconnect by way of alveolar pores •  Internal surfaces • A site for free movement of alveolar

macrophages


Gross Anatomy of the Lungs

•  Major landmarks of the lungs •  Apex, base, hilum, and root

•  Left lung •  Superior and inferior lobes • Fissure—oblique

•  Right lung •  Superior, middle, and inferior lobes • Fissures—oblique and horizontal


Left superior lobe Oblique fissure Left inferior lobe

(b) Photograph of medial view of the left lung

Left main bronchus

Pulmonary vein Impression of heart Oblique fissure

Lobules

Pulmonary artery

Apex of lung

Hilum

Aortic impression

Gross Anatomy of the Lungs

Anterior View of Thoracic Structures

Figure 22.11a, b

Trachea

Apex of lung

Thymus

Right superior lobe

Horizontal fissure Right middle lobe Oblique fissure Right inferior lobe Heart (in mediastinum) Diaphragm Base of lung

Left superior lobe

Cardiac notch

Oblique fissure Left inferior lobe

Lung Pleural cavity Parietal pleura Rib

Intercostal muscle

Visceral pleura

(a) Anterior view. The lungs flank mediastinal structures laterally.


Bronchopulmonary Segments

Figure 22.12

Right superior lobe (3 segments)

Right middle lobe (2 segments)

Right inferior lobe (5 segments)

Left superior lobe (4 segments)

Left inferior lobe (5 segments)

Right lung Left lung

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Blood Supply and Innervation of the Lungs

•  Pulmonary arteries •  Deliver oxygen-poor blood to the lungs

•  Pulmonary veins •  Carry oxygenated blood to the heart

•  Bronchial arteries (2 on left, 1 on right) •  Supply systemic (oxygenated) blood to the lung

structures (enter lung’s medial surface along with the large pulmonary vessels)

•  Innervation •  Sympathetic, parasympathetic, and visceral sensory

fibers •  Parasympathetic—constrict airways •  Sympathetic—dilate airways


Transverse Cut through the Superior Thorax

Figure 22.11d

(d) Transverse section through the thorax, viewed from above. Lungs, pleural membranes, and major organs in the mediastinum are shown.

Esophagus (in mediastinum)

Right lung

Parietal pleura Visceral pleura Pleural cavity

Pericardial membranes Sternum

Anterior

Posterior Vertebra

Root of lung at hilum

Left lung

Thoracic wall Pulmonary trunk

Heart (in mediastinum) Anterior mediastinum

Left main bronchus Left pulmonary artery Left pulmonary vein


The Pleurae

•  A double-layered sac surrounding each lung •  Parietal pleura •  Visceral pleura

•  Pleural cavity •  Potential space between the visceral and

parietal pleurae •  Pleurae help divide the thoracic cavity •  Central mediastinum •  Two lateral pleural compartments


Diagram of the Pleurae and Pleural Cavities

Figure 22.11a

Trachea

Apex of lung

Thymus

Right superior lobe Horizontal fissure Right middle lobe Oblique fissure Right inferior lobe Heart (in mediastinum) Diaphragm Base of lung

Left superior lobe

Cardiac notch

Oblique fissure Left inferior lobe

Lung Pleural cavity Parietal pleura Rib Intercostal muscle

Visceral pleura

(a) Anterior view. The lungs flank mediastinal structures laterally.


Location of Lungs in Thoracic Cavity

Figure 22.13

Rib

(a) Posterior view

Lung

10 11 12

9 8

(b) Anterior view

Clavicle

Nipple

Midaxillary line

Midclavicular line

Infrasternal angle at the xiphisternal joint Costal margin

Lung

Parietal pleura

Parietal pleura

Rib 3

10 9 8 7 6 5

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The Mechanisms of Ventilation

•  Two phases of pulmonary ventilation •  Inspiration—inhalation •  Expiration—exhalation

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Inspiration

•  Volume of thoracic cavity increases •  Decreases internal gas pressure •  Action of the diaphragm • Diaphragm flattens

•  Action of intercostal muscles • Contraction raises the ribs


Inspiration

•  Deep inspiration requires •  Scalenes •  Sternocleidomastoid •  Pectoralis minor •  Erector spinae—extends the back


Expiration

•  Quiet expiration—chiefly a passive process •  Inspiratory muscles relax •  Diaphragm moves superiorly •  Volume of thoracic cavity decreases

•  Forced expiration—an active process •  Produced by contraction of •  Internal and external oblique muscles •  Transverse abdominis muscles


Changes in Thoracic Volume

Figure 22.14

Ribs are elevated and sternum flares as external intercostals contract.

Diaphragm and intercostal muscles contract (diaphragm descends and

rib cage rises). Thoracic cavity volume increases.

Diaphragm moves inferiorly during contraction.

External intercostals contract.

Changes in superior- inferior and anterior- posterior dimensions

Changes in lateral dimensions (superior view)

(a) Inspiration

Inspiratory muscles relax (diaphragm rises and rib cage descends due to recoil of the costal

cartilages). Thoracic cavity volume decreases.

Ribs and sternum are depressed as external intercostals relax.

External intercostals relax.

Diaphragm moves superiorly as it relaxes.

(b) Expiration


Changes in Thoracic Volume

Figure 22.15

At rest, no air movement: Air pressure in lungs is equal to atmospheric (air) pressure. Pressure in the pleural cavity is less than pressure in the lungs. This pressure difference keeps the lungs inflated.

Inspiration: Inspiratory muscles contract and increase the volume of the thoracic and pleural cavities. Pleural fluid in the pleural cavity holds the parietal and visceral pleura close together, causing the lungs to expand. As volume increases, pressure decreases and air flows into the lungs.

Expiration: Inspiratory muscles relax, reducing thoracic volume, and the lungs recoil. Simultaneously, volumes of the pleural cavity and the lungs decrease, causing pressure to increase in the lungs, and air flows out. Resting state is reestablished.

Trachea

Diaphragm

Lung

Lung

Air flows in

Air flows out

V P

V P

V P

V P

Pleural cavity

Thoracic wall

Air

Air

Main bronchi Parietal pleura Visceral

pleura

Thoracic wall Pleural cavity

At rest Expanded

1

2

3


Neural Control of Ventilation

•  Most important respiratory center •  VRG—ventral respiratory group • Located in reticular formation in the

medulla oblongata • Neurons generate respiratory rhythm

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Respiratory Centers in the Brain Stem

Figure 22.16

Pons

Pons

Ventral respiratory group (VRG) contains rhythm generators whose output drives respiration.

Pontine respiratory centers interact with the medullary respiratory centers to smooth the respiratory pattern.

Medulla

Medulla

To inspiratory muscles

External intercostal muscles

Diaphragm

Dorsal respiratory group (DRG) integrates peripheral sensory input and modifies the rhythms generated by the VRG.


Neural Control of Ventilation

•  Respiratory center •  Generates baseline respiration rate •  In the reticular formation of the medulla oblongata

•  Chemoreceptors •  Sensitive to rising and falling oxygen levels •  Central chemoreceptors—located in medulla •  Peripheral chemoreceptors

•  Aortic bodies •  Carotid bodies


Location of Peripheral Chemoreceptors

Figure 22.17

Brain

Sensory nerve fiber in cranial nerve IX (pharyngeal branch of glossopharyngeal) External carotid artery Internal carotid artery Carotid body Common carotid artery Cranial nerve X (vagus nerve)

Sensory nerve fiber in cranial nerve X Aortic bodies in aortic arch Aorta

Heart


Disorders of Lower Respiratory Structures

•  Bronchial asthma •  A type of allergic inflammation • Hypersensitivity to irritants in the air or to

stress •  Asthma attacks characterized by • Contraction of bronchiole smooth muscle • Secretion of mucus in airways



•  Cystic fibrosis (CF)—inherited disease •  Exocrine gland function is disrupted •  Respiratory system affected by • Oversecretion of viscous mucus



•  Chronic obstructive pulmonary disease (COPD) •  Airflow into and out of the lungs is difficult • Obstructive emphysema • Chronic bronchitis

•  History of smoking

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Figure 22.18 Copyright © 2011 Pearson Education, Inc.

Alveolar Changes in Emphysema

Figure 22.19


Disorders of Upper Respiratory Structures

•  Epistaxis—nosebleed


The Respiratory System Throughout Life

•  By week 4 of development •  Olfactory placodes appear

•  Invaginate to form olfactory pits •  Laryngotracheal bud

•  Forms trachea, bronchi, and bronchi subdivisions •  Reaches functional maturity late in development •  At birth, only one-sixth of alveoli are present •  Those who begin smoking as teenagers

•  Lungs never fully develop •  Additional alveoli never form


The Respiratory System Throughout Life

Figure 22.20

Frontonasal elevation

Olfactory placode

Stomodeum (future mouth)

Future mouth

Eye

Trachea Bronchial buds

Pharynx

Foregut Olfactory placode Esophagus Liver

Laryngotracheal bud (a) 4 weeks: anterior

superficial view of the embryo’s head

(b) 5 weeks: left lateral view of the developing lower respiratory passageway mucosae


Aging of the Respiratory System

•  Number of glands in the nasal mucosa declines

•  Nose dries •  Produces thickened mucus

•  Thoracic wall becomes more rigid •  Lungs lose elasticity •  Oxygen levels in the blood may fall

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