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24The Respiratory System

PowerPoint® Lecture Presentations prepared bySteven BassettSoutheast Community College Lincoln, Nebraska

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Introduction

Cells obtain oxygen and eliminate carbon dioxide.

The respiratory system facilitates the exchange of gases between the air and the blood.

Blood carries oxygen to peripheral tissues.

Blood accepts the carbon dioxide from peripheral tissues.

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An Overview of the Respiratory System

•The upper respiratory system•Consists of:

•Nose, nasal cavity, sinuses, and pharynx

•The lower respiratory system•Consists of:

•Larynx, trachea, bronchi, bronchioles, and alveoli

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Figure 24.1 Structures of the Respiratory System

Nasal cavity

Sphenoidal sinus

Internal nares

Nasopharynx

Esophagus

Clavicle

Ribs Diaphragm

Bronchioles

Bronchus

Trachea

Larynx

NoseNasal conchae

Frontal sinus

Tongue

Hyoid bone

RIGHTLUNG

LEFTLUNG

UPPERRESPIRATORY

SYSTEM

LOWERRESPIRATORY

SYSTEM

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An Overview of the Respiratory System

Functions of the Respiratory System Providing an area for gas exchange Moving air to and from the exchange surface Protecting respiratory surfaces Defending the respiratory system and other tissues

from invasion by pathogenic microorganisms Producing sounds involved in speaking, singing, or

nonverbal communication Assisting in the regulation of blood volume, blood

pressure, and the control of body fluid pH

Difficult or labored breathing is called dyspnea.

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An Overview of the Respiratory System

The Respiratory System Includes the nose, nasal cavity and sinuses,

pharynx, larynx, trachea, and conducting passageways

The respiratory tract consists of the following: Conduction portion Respiratory portion

The respiratory bronchiles The alveoli

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The Upper Respiratory System

Structures in the head are part of the upper respiratory system. Nose

The outer opening of the nose is called external nares. Nose is the main organ to filter, warm and humidify the air.

Nasal cavity Paranasal sinuses Nasal septum is made of ethmoid and vomer bones. the separation between nasal and oral cavity is provided by:

Soft palate Uvula: seals the opening between oral cavity and nasopharynx. Hard palate

Palatine process of maxilla Palatine bone

Pharynx the common pathway of food and air. Has three sections: nasopharynx (contains auditory tube),

oropharynx, laryngopharynx.

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Figure 24.4a Respiratory Structures in the Head and Neck, Part II

A sagittal section of the head and neck

Nasal cavity

Internal nares

Nasopharynx

Pharyngeal tonsil

Entrance to auditory tube

Soft palate

Palatine tonsil

Oropharynx

Epiglottis

Aryepiglotticfold

Laryngopharynx

Glottis

Vocal fold

Esophagus

Frontal sinus

Superior

Middle

Inferior

Nasalconchae

Nasal vestibule

External nares

Hard palate

Oral cavity

Tongue

Mandible

Lingual tonsil

Hyoid bone

Thyroid gland

Trachea

Cricoid cartilage

Thyroid cartilage

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The Lower Respiratory System

Structures in the neck and thoracic cavity are parts of the lower respiratory system

Larynx Trachea Bronchi Bronchioles Alveoli

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Figure 24.6a Anatomy of the Larynx

Anterior view of the intact larynx

Trachea

Larynx

Cricoid cartilage

Thyroidcartilage

Tracheal cartilages

Cricotracheal ligament(extrinsic)

Cricothyroid ligament(intrinsic)

Laryngealprominence

Thyrohyoid ligament(extrinsic)

Hyoid bone

Lesser cornu

Epiglottis

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Figure 24.6b Anatomy of the Larynx

Posterior view of the intact larynx

Tracheal cartilages

Epiglottis

Cricoidcartilage

Thyroidcartilage

Vestibularligament

Vocalligament

Arytenoid cartilage

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Figure 24.7ab The Vocal Cords

Glottis in the openposition

Glottis in the closedposition

ANTERIOR

POSTERIOR

Aryepiglotticfold

Glottis (open)

Corniculatecartilage

Cuneiformcartilage

Vestibularfold

Vocal fold

Epiglottis

Root of tongue

Corniculate cartilage

Glottis (closed)

Vocal fold

Vestibular fold

Epiglottis

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Figure 24.7bc The Vocal Cords

Glottis in the closedposition

This photograph is a representativelaryngoscopic view. For this view thecamera is positioned within theoropharynx, just superior to the larynx.

ANTERIOR

POSTERIOR

Corniculate cartilage

Glottis (closed)

Glottis (open)

Vocal fold

Vestibular fold

Epiglottis

ANTERIOR

POSTERIOR

Cuneiform cartilagein aryepiglottic fold

Root of tongue

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Figure 24.8 Movements of the Larynx during Swallowing

Tongue forcescompacted bolusinto oropharynx.

Laryngeal movementfolds epiglottis;pharyngeal musclespush bolus intoesophagus.

Bolus moves alongesophagus; larynxreturns to normalposition.

Hard palate

Soft palate

Tongue

Bolus

Epiglottis

Larynx

Trachea

Soft palate

Bolus

Epiglottis

Bolus

Epiglottis

Trachea

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The Trachea

Also called the windpipe Walls contain cartilage rings Enters thoracic cavity anterior to esophagus Bifurcates at the carina

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Figure 24.9a Anatomy of the Trachea and Primary Bronchi

Anterior view showing the plane of section for part (b)

Larynx

Trachea

Hyoidbone

Annularligaments

Tracheal cartilages

Location of carina(internal ridge)

Root ofleft lung

Root ofright lung

Superiorlobar bronchus

Lungtissue

Middle lobarbronchus

Primarybronchi

Secondarybronchi

Inferiorlobar bronchi

Superiorlobar bronchus

RIGHT LUNG LEFT LUNG

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The Primary Bronchi

Wall structure similar to tracheal wall One per lungThe right primary bronchus supplies the right lung, and the left supplies the left lung.

Right bronchus has three branches and left one has two.The middle lobar bronchus is only found in the right lung.

Right has a larger diameter, descends toward lung at steeper angle, less resistant to air flow and wider; easier for

foreign objects to get lodged there

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Figure 24.11 Bronchi and Bronchioles

Primary bronchus

Cartilage ring

Root of lung

Secondary (inferiorlobar) bronchus

Cartilage plates

Visceral pleura

Respiratoryepithelium

Smooth muscle

BRONCHIOLE

Lobule Respiratorybronchioles

Terminalbronchiole

Bronchioles

Tertiarybronchi

Secondary(superior lobar)bronchus

LEFT LUNG

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The Lungs

Lungs are divided into lobes: 3 lobes on right: superior, middle, and inferior 2 lobes on left: superior and inferior

Left lung contains cardiac impression and cardiac notch.

Fissures divide the lungs into lobes.

Bronchi branch out into smaller bronchioles.

Bronchioles lead to alveoli.

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Figure 24.10ab Superficial Anatomy of the Lungs

Anterior view of the opened chest,showing the relative positions ofthe left and right lungs and heart.

Diagrammatic views ofthe lateral surfaces ofthe isolated right andleft lungs

Superior lobe

RIGHT LUNG

Horizontal fissure

Middle lobe

Oblique fissure

Inferior lobe

Liver,right lobe

Liver,left lobe

Boundary betweenright and leftpleural cavities

LEFT LUNG

Superior lobe

Oblique fissure

Fibrous layer of pericardium

Inferior lobe

Falciform ligament

Cut edge ofdiaphragm

Apex Apex

Horizontalfissure

Obliquefissure

Base

RIGHT LUNG LEFT LUNG

Superiorlobe

Middlelobe

Inferiorlobe

Inferiorlobe

Superior lobe

Cardiacnotch

Obliquefissure

Base

Lateral Surfaces

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Figure 24.10c Superficial Anatomy of the Lungs

Diagrammatic views ofthe medial surfaces ofthe isolated right andleft lungs

RIGHT LUNG LEFT LUNG

Inferiorlobe

Inferiorlobe

Superiorlobe

Superiorlobe

Middlelobe

Cardiacimpression

Pulmonaryveins

Horizontalfissure

Obliquefissure

Groove foresophagus

Apex

Superior lobar bronchus

Pulmonary arteries

Middle lobar bronchus

Superior lobar bronchus

Inferior lobar bronchus

Hilum

Base

Groovefor aorta

Pulmonaryveins

Obliquefissure

Diaphragmaticsurface

Medial Surfaces

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Figure 24.13a Bronchi and Bronchioles

The structure of one portion of a single pulmonary lobule

Bronchopulmonarysegment

Alveoli in apulmonary

lobule

Smallerbronchi

Tertiarybronchi

Secondarybronchus

Visceralpleura

Leftprimary

bronchus

Trachea

Bronchioles

Terminal bronchiole

Respiratory bronchiole

Branch ofpulmonary

vein

Capillarybeds

Elastic fibers

Respiratorybronchiole

Terminalbronchiole

Bronchial artery (red),vein (blue), and

nerve (yellow)

Bronchiole

Respiratoryepithelium Branch of

pulmonaryartery

Smooth musclearound terminalbronchiole

Arteriole

Alveolarduct

Lymphaticvessel

Alveoli

Alveolar sac

Interlobularseptum

Visceral pleura

Pleural cavity

Parietal pleura

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The Lungs

• Epithelium of the lung includes:– Simple squamous epithelium, type I cell, which

are respiratory epithelium.– Septal cells, type II, which produces

surfactant. Surfactant reduces the surface tension in the fluid coating alveolar surfaces.

– Roaming macrophages.

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Figure 24.14cd Alveolar Organization

Diagrammatic sectional view of alveolar structureand the respiratory membrane

Pneumocytetype I cell

Alveolarmacrophage

Endothelialcell ofcapillary

Alveolarmacrophage

Pneumocytetype II cell

Elasticfibers

Capillary

The respiratory membrane

Alveolar air space

Capillary lumen

Red blood cell

Nucleus ofendothelial

cell

Endothelium

SurfactantAlveolarepithelium

Fusedbasal

laminae

0.5 µ m

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The Pleural Cavities and Pleural Membranes

Parietal pleura lines the pleural cavity. Visceral pleura covers the lungs. Pleural fluid causes membranes to stick together but still slide on one another.

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Figure 24.15 Anatomical Relationships in the Thoracic Cavity

Left lung,inferior lobe

Posteriormediastinum

Bronchi

Parietal pleura

Left pleural cavity

Visceral pleura

Left lung,superior lobe

Body of sternum

Ventricles

Rib

Pericardialcavity

Right lung,middle lobe

Right pleuralcavity

Right lung,inferior lobe

Oblique fissure

Atria

Esophagus

Aorta

Spinal cord

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Respiratory Muscles and Pulmonary Ventilation

Inspiratory muscles Diaphragm External intercostal muscles

Expiratory muscles Usually not needed due to elastic recoil of lungs and thoracic

cavity Accessory respiratory muscles

Inspiration Sternocleidomastoid, serratus anterior, pectoralis minor, and

scalene muscles Expiration

Transversus thoracis, oblique, and rectus abdominis muscles Internal intercostal muscles

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Figure 24.16b Respiratory Muscles

The primary and accessorymuscles of respiration

Sternocleidomastoidmuscle

Scalene muscles

Pectoralisminor muscle

Serratusanterior muscle

Accessory Musclesof Inspiration

Diaphragm

Accessory Musclesof Exhalation

External intercostal muscles

Internal intercostal muscles

Transversus thoracismuscle

External oblique muscle

Internal oblique muscle

Rectus abdominus

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Figure 24.16c Respiratory Muscles

Inhalation, showing the primary and accessory respiratorymuscles that elevate the ribs and flatten the diaphragm.

Diaphragm

Sternocleidomastoidmuscle

Scalenemuscles

Pectoralisminor muscle

Serratusanterior muscle

Externalintercostal

muscles

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Figure 24.16d Respiratory Muscles

Exhalation, showing the primary and accessory respiratorymuscles that depress the ribs and elevate the diaphragm.

Transversus thoracis muscle

Internal intercostalmuscles

Rectus abdominisand other abdominalmuscles (not shown)

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Figure 24.17 Respiratory Centers and Reflex Controls

KEY= Stimulation

= Inhibition

Phrenic nerve

Motor neuronscontrolling other

respiratory muscles

Dorsalrespiratorygroup (DRG)

Ventralrespiratorygroup (VRG)

Respiratoryrhythmicitycenters

Motor neuronscontrollingdiaphragm

Spinalcord

Stretchreceptorsof lungs

Diaphragm

Chemoreceptors andbaroreceptors of carotid

and aortic sinusesN X

N IX and N X

Pneumotaxiccenter

Apneusticcenter

Medullaoblongata

CSFCHEMORECEPTORS

Pons

Cerebrum

HIGHER CENTERSCerebral cortexLimbic systemHypothalamus

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Aging and the Respiratory System

Elastic tissue deteriorates, reducing the lungs’ ability to inflate and deflate. Movements of the rib cage are restricted by arthritic changes. Some degree of emphysema is normally found in individuals age 50–70.