CHAPTER © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24 The Respiratory System

CHAPTER

© 2011 The McGraw-Hill Companies, Inc. All rights reserved.

24The Respiratory

System


24-2

Learning Outcomes

24.1 Explain the functions of the respiratory system.

24.2 Explain the difference between internal respiration and external respiration.

24.3 Describe how the larynx produces voice sounds.

24.4 List the structures contained within the lungs.

24.5 Describe the coverings of the lungs and chest cavity.


24-3

Learning Outcomes (cont.)

24.6 Describe the events that lead to the inspiration and expiration of air.

24.7 Explain how the brain controls breathing and how normal breathing patterns can be disrupted.

24.8 Describe how oxygen is transported from the lungs to body cells.


24-4

Learning Outcomes (cont.)

24.9 Describe how carbon dioxide is transported from body cells to the lungs.

24.10List and explain various respiratory volumes and tell how they are used to diagnose respiratory problems.

24.11Describe the causes, signs and symptoms, and treatments of various diseases and disorders of the respiratory system.


24-5

Introduction• Function

– Move air in and out of lungs (ventilation)

– Delivers oxygen (O2) – Removes carbon dioxide (CO2)

• External respiration– Occurs in the lungs

• Internal respiration– Occurs in the hemoglobin

O2

O2

O2

CO2

CO2

CO2

Lungs


24-6

Organs of the Respiratory System

Nose

Pharynx

Larynx

Trachea

Bronchial tree

Lungs


24-7

Nasal Cavity

• Nasal septum divides the cavity into right and left portions– Nares – openings of the nose

• Nasal conchae extend from walls of nasal cavity

• Mucous membrane warms and moistens the air

• Cilia help eliminate particles


24-8

Paranasal Sinuses

• Air-filled spaces within the skull bones– Open into the nasal

cavity

• Reduce the weight of the skull

• Equalize pressure

• Give the voice its certain tone

• Skull bones with sinuses include:– Frontal– Sphenoid– Ethmoid– Maxillae bones


24-9

Pharynx and Larynx

• Pharynx– Serves both the respiratory and digestive systems

• Larynx

– Also called the “voice box”

– Moves air in and out of the trachea and produces voice

– Composed of three cartilages:

• Thyroid cartilage

• Epiglottic cartilage

• Cricoid cartilage


24-10

Vocal Cords• Stretched between the

thyroid cartilage and the cricoid cartilage

• Upper – false cords

• Lower – true vocal cords

• Glottis – the opening between the vocal cords

• Stretch = pitch of voice

Glottis

True Vocal Cords

False Vocal Cords

Posterior Portion of Tongue


24-11

Trachea• Referred to as the windpipe• Tubular organ made of rings of

cartilage and smooth muscle• Extends from the larynx to the

bronchi• Lined with cells possessing

cilia (microscopic hair-like projections)

Cilia move mucus up to the throat, where it is swallowed. Smoking destroys cilia.

Trachea


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Bronchial Tree

• Bronchi – Primary: First

branches off trachea

– Secondary– Tertiary

• Bronchioles– Branch off tertiary

bronchi

Bronchi

BronchiolesBronchioles


24-13

Bronchial Tree (cont.)

• Alveoli– Thin sacs of cells

surrounded by capillaries

– Secrete surfactant• Fatty substance• Helps maintains the

inflation of the alveoli between inspirations


24-14

The lungs contain connective tissue, the bronchial tree, nerves, lymphatic vessels, and blood vessels.

Lungs

• Cone-shaped organs

• Right lung – three lobes

• Left lung – two lobes

• Pleura – membranes surrounding the lungs


24-15

Apply Your Knowledge

Which of the following sites would be the most lethal if obstructed by a foreign body?

a.Right bronchus

b.Left bronchus

c. Trachea

ANSWER:


24-16

The Mechanisms of Breathing

Inspiration Expiration

Breathing, or pulmonary ventilation, consists of inspiration (inhalation) and expiration (exhalation).

Air rich in O2 enters the lungs from the atmosphere

The diaphragm contracts or flattens

The intercostal muscles raise the ribs

Air rich in C02 exits the lungs

The diaphragm relaxes

The intercostal muscles lower the ribs


24-17

The Mechanisms of Breathing (cont.)

• Respiratory center of the brain

– Medulla oblongata – controls rhythm and depth of breathing

– Pons – controls the rate of breathing

• Other factors

– CO2 levels in the blood

– pH of the blood

– Fear and pain

– Inflation reflex


24-18

The Mechanisms of Breathing (cont.)

• Causes of altered breathing patterns– Coughing

– Sneezing

– Laughing

– Crying

– Hiccups

– Yawning

– Speaking


24-19


Indicated whether each statement refers to (I) inhalation or (E) exhalation:

__ The intercostal muscles lower the ribs

__ The diaphragm contracts or flattens

__ The intercostal muscles raise the ribs

__ The diaphragm relaxes

__ Air rich in O2 enters the lungs from the atmosphere

__ Air rich in C02 exits the lungs

ANSWER:

E

E

E

I

I

I


24-20

The Transport of Oxygen and Carbon Dioxide in the Blood

• Most of the oxygen binds to hemoglobin – Oxyhemoglobin – Bright red in color

• Some oxygen remains dissolved in plasma

• If CO2 combines with hemoglobin at O2 sites, it forms carboxyhemoglobin


24-21

The Transport of Oxygen and Carbon Dioxide in the Blood (cont.)

• Carbon dioxide gets into the bloodstream

– Reacts with water in plasma and forms carbonic acid

– Carbonic acid ionizes and releases hydrogen and bicarbonate ions

– Bicarbonate ions attach to hemoglobin

• Exhaled as waste product in the lungs


24-22


Describe what happens to carbon dioxide in the blood.

ANSWER: Carbon dioxide can combine with hemoglobin and form carboxyhemoglobin. Most reacts with water in plasma to form carbonic acid. The carbonic acid ionizes and releases hydrogen and bicarbonate ions. The bicarbonate ions then attach to hemoglobin and are exhaled as a waste product from the lungs.

Super!


24-23

Respiratory Volumes

• Different volumes of air move in and out of lungs with different intensities of breathing

• Measured to assess health of respiratory system


24-24

Respiratory Volumes (cont.)

Amount of air that moves in or out of the lungs during a normal breath

Amount of air that can be forcefully inhaled following a normal inhalation

Amount of air that can be forcefully exhaled following a normal exhalation

Tidal VolumeTidal Volume

InspiratoryReserve Volume

InspiratoryReserve Volume

ExpiratoryReserve Volume

ExpiratoryReserve Volume


24-25

Respiratory Volumes (cont.)

Amount of air that can be forcefully exhaled after the deepest inhalation possible

Volume of air that always remains in the lungs even after a forceful exhalation

The total amount of air the lungs can hold

Residual Volume

Residual Volume

Total LungCapacity

Total LungCapacity

Vital Capacity

Vital Capacity


24-26


___ Amount of air that moves during a normal breath

___ Amount of air that always remains in the lungs

___ Total amount of air the lungs can hold

___ Amount of air forcefully exhaled after deepest inhalation possible

A. Total lung capacity

B. Residual volume

C. Tidal volume

D. Vital capacity

Match the following: ANSWER:

C

A

B

D

Good Job!


24-27

Snoring• Due to vibration of soft

tissues when muscles of the palate, tongue, and throat relax

• Affects approximately 50% of men and 25% of women over the age of 40

• Causes daytime sleepiness

– May be associated with obstructive sleep apnea

• Common Causes– Enlargement of tonsils

or adenoids

– Being overweight

– Alcohol consumption

– Nasal congestion

– Deviated nasal septum


24-28

Snoring (cont.)

Mayo Clinic’s Sleep Disorders Center rating of snoring:

Heard from close proximity

Heard from anywhere in the bedroom

Heard from just outside the bedroom door with door open

Heard outside the bedroom door with the door closed


24-29

Snoring (cont.)

• Lifestyle modifications to reduce snoring– Lose weight– Change sleeping position– Avoid using alcohol or medications that induce sleep– Use nasal strips to widen the nasal passages– Use dental devices to keep airways open

• Treatments– CPAP– Surgery (uvulotomy)– Laser surgery


24-30

Common Diseases and Disorders

Disease Description

Allergic rhinitis

Hypersensitivity reaction to various airborne allergens

Asthma A condition in which the tubes of the bronchial tree become obstructed due to inflammation

Atelectasis Collapsed lung

Bronchitis Inflammation of the bronchi often follows a cold; one type of COPD


24-31

Common Diseases and Disorders (cont.)

Disease Description

Chronic obstructive pulmonary disease (COPD)

A group of lung disorders that limit airflow to lungs and usually cause enlargement of the alveoli

Emphysema A chronic condition associated with smoking that damages the alveoli; one type of COPD

Influenza A viral disease that attacks the respiratory system; commonly called the flu


24-32


Disease Description

Laryngitis An acute inflammation of the larynx causing hoarseness (dysphonia)

Legionnaire’s disease

Acute bacterial pneumonia caused by Legionnaire bacteria that usually grows in the standing water of air conditioning systems

Lung cancer Cancer closely associated with smoking and exposure to second-hand smoke; four types of lung cancers

Pleural effusion A buildup of fluid in the pleural cavity


24-33


Disease Description

Pleuritis/Pleurisy Inflammation of the membranes that cover the lungs, known as pleura

Pneumoconiosis Lung diseases that result from years environmental or occupational exposure to different types of dust; three types

Pneumonia/ Pneumonitis

An inflammation of the lungs that is most often caused by a bacterial, viral, or fungal infection


24-34


Disease Description

Pneumothorax A collection of air in the chest around the lungs, which may cause atelectasis

Pulmonary edema

A condition in which fluids fill spaces within the lungs, making it very difficult for the lungs to oxygenate the blood

Pulmonary embolism

A blood clot (embolism) that travels usually from the legs and blocks an artery in the lungs


24-35


Disease Description

Respiratory distress syndrome (RDS)

Syndrome in which a lack of surfactant in the lungs allows the alveoli to collapse on exhalation, resulting in poor oxygenation

Severe acute respiratory syndrome (SARS)

A viral respiratory disease that is very contagious and sometimes fatal

Sinusitis An inflammation of the membranes lining the sinuses of the skull


24-36


Disease Description

Sudden infant death syndrome (SIDS)

A syndrome without characteristic signs or symptoms; usually a baby with this disorder simply goes to sleep and never wakes up

Tuberculosis Primarily a respiratory disease caused by various strains of the bacterium Mycobacterium tuberculosis

Upper respiratory (tract) infection (URI)

Coryza, or the common cold


24-37

The medical assistant working for a general practitioner is taking the medical history of a new patient. The patient states, “Even after sleeping 8 to 9 hours, I still feel really tired.” The patient’s spouse states, “Well, you sure snore loud, as if the sleep is so good.” Which of the following is a possible cause for the excessive fatigue?

a. Sleep apneab. Depressionc. Tuberculosis


ANSWER:


24-38

In Summary

24.1 The function of the respiratory system is to move air in and out of the lungs in a process known as ventilation, respiration, or breathing.

24.2 The exchange of oxygen and carbon dioxide in the lungs is called external respiration. The same exchange within the hemoglobin of red blood cells is internal respiration.

24.3 The larynx contains the vocal cords, which stretch between the thyroid and cricoid cartilages. The muscles of the lower (true) vocal cords stretch and relax them to produce different sounds.


24-39

In Summary (cont.)

24.4 The lungs contain connective tissue, the bronchial tree, nerves, lymphatic vessels, and blood vessels.

The left lung consists of two lobes (upper and lower), and the right lung consists of three lobes (upper, middle, and lower).

Within each lung are the primary, secondary, and tertiary branches of the bronchi, the bronchioles, and the alveoli.

24.5 The lungs are covered by, and the chest cavity is lined with, the pleura. The outer membrane is the parietal pleura and the inner membrane is the visceral pleura.


24-40

In Summary (cont.)

24.6 During inspiration, the diaphragm contracts and the intercostal muscles raise the ribs, increasing the space in the thoracic cavity.

This decreases the pressure within the cavity so that the air outside the body passively flows into the thoracic cavity.

During expiration, the diaphragm relaxes, pushing up into the thoracic cavity, and the intercostal muscles lower the ribs, forcing the air to flow out of the body.


24-41

In Summary (cont.)

24.7 Breathing is controlled by the respiratory center of the brain located in the pons and medulla oblongata. Carbon dioxide levels and pH levels of the blood also affect breathing. Everyday situations such as coughing, sneezing, laughing, crying, hiccups, yawning, and speaking also alter breathing patterns.

24.8 Most of the oxygen in the bloodstream binds to the hemoglobin within red blood cells, resulting in oxyhemoglobin, although a small amount does not bind to hemoglobin and remains dissolved in the plasma.


24-42

In Summary (cont.)

24.9 Carbon dioxide binds to hemoglobin, resulting in carboxyhemoglobin.

Most of the carbon dioxide that enters the body reacts with water in blood and cerebral spinal fluid to form carbonic acid.

As carbonic acid ionizes, it releases hydrogen and bicarbonate ions, which attach to hemoglobin making its way back to the lungs to be exhaled.


24-43

In Summary (cont.)

24.10Respiratory volumes are measured to check the health of the respiratory system.

The volumes are listed here and the normal capacities are found in the chapter: tidal volume, inspiratory and expiratory reserve volumes, residual volume, inspiratory capacity, functional residual capacity, vital capacity, and total lung capacity.


24-44

In Summary (cont.)

24.11The diseases and disorders of the respiratory system are many and varied, as are the causes and treatments of these diseases. Many of the more common respiratory disorders, with their individual causes and treatments, are discussed in detail in the Pathophysiology section of this chapter.


24-45

End of Chapter 24

The air of ideas is the only air

worth breathing.

~Edith Wharton

Documents

CHAPTER © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24 The Respiratory System