Lecture Medical assisting: Administrative and clinical procedures with anatomy and physiology (4e) – Chapter 24

 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

The Respiratory

System

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.

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.

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

Organs of the Respiratory System

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

Paranasal Sinuses

• Air-filled spaces within

the skull bones

– Open into the nasal

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

Vocal Cords

• Stretched between the

thyroid cartilage and

the cricoid cartilage

• Upper – false cords

• Lower – true vocal

cords

• Glottis – the opening

between the vocal

False Vocal Cords

Posterior Portion of Tongue

• 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

Bronchial Tree

• Bronchi

– Primary: First

branches off trachea

Bronchial Tree (cont.)

• Alveoli

– Thin sacs of cells

surrounded by capillaries

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

lungs

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:

The Mechanisms of Breathing

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

The Mechanisms of Breathing (cont.)

The Mechanisms of Breathing (cont.)

• Causes of altered breathing patterns

Apply Your Knowledge

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

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

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

Apply Your Knowledge

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!

Respiratory Volumes

• Different volumes of

air move in and out of

lungs with different

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

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

Apply Your Knowledge

_ 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

• Due to vibration of soft

tissues when muscles of

the palate, tongue, and

– May be associated with

obstructive sleep apnea

• Common Causes

– Enlargement of tonsils

or adenoids– Being overweight– Alcohol consumption– Nasal congestion

– Deviated nasal septum

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

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

Common Diseases and Disorders (cont.)

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

Common Diseases and Disorders (cont.)

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

Common Diseases and Disorders (cont.)

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

Common Diseases and Disorders (cont.)

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

Common Diseases and Disorders (cont.)

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

Sinusitis An inflammation of the membranes

lining the sinuses of the skull

Common Diseases and Disorders (cont.)

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

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?

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

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

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

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

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

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

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

End of Chapter 24

The air of ideas

is the only air

worth

~Edith Wharton