The Respiratory

System

Respiratory Anatomy

• Upper

respiratory tract

– Nose

– Nasal passages

– Pharynx

– Larynx

Respiratory Anatomy

• Functions of the upper respiratory

tract:

– Provide entry for inhaled air

Respiratory Anatomy

• Functions

– Nasal mucosa

• Traps bacteria

& foreign

particles

• Warms &

moistens

incoming air

• Part of natural

immunity

Respiratory Anatomy

• Pharynx • Part of the digestive and respiratory

systems

• Allows for passage of both air and

food

• Mucosa of pharynx is part of immune

system, source of antibodies &

protective substances

Respiratory Anatomy

• Larynx

– Lined with squamous epithelium

and enclosed in cartilage for

support and protection

– Organ of speech

– Improperly functioning larynx can

lead to aspiration of food or liquid

into lungs

Lower Respiratory

Tract

• Trachea

• Bronchii

• Bronchioles

• Terminal alveoli in lungs

Respiratory Anatomy

• Trachea• Leads to the L & R bronchi

• Lined with:

– Ciliated cells

– Mucus producing cells

– Neuroendocrine cells

– Basal cells

• With chronic smoking basal cells change-> basal squamousmetaplasia Lung CA

Respiratory Anatomy

• L and R bronchi enter the L and R

lungs– Branch many times, becoming narrower into bronchioles

then avleolar ducts and alveolar sacs (alveoli)

• Alveoli

– Lined with pneumocytes

• Thin cells that allow for gaseous exhange

• Cells that produce a pulmonary surfactant

that coats the alveoli and keeps them from

collapsing.

Respiratory Anatomy

• Pulmonary

lobules

– many lobules

make up the

pulmonary

lobes• 3 on the Right

and 2 on the

Left

Pulmonary Blood

Supply

• Dual blood supply

– Pulmonary artery

• Brings de-oxygenated (venous) blood

from the R ventricle into the lungs

• Blood is oxygenated in lungs

– Pulmonary vein

• Brings oxygenated blood from lungs

into L atrium

Respiratory Anatomy

• Outer surface of lungs= pleura

– Moist surface

– Filters air, keeps air moist, and

retains large particles and

bacteria.

– Provides protection against

infection

Function of Lungs

• Major function of the lungs:

– Respiration

• Metabolic function of the lungs:

– Maintain acid-base balance

• Prevention of acidosis or alkalosis

– Affects the kidneys, gastrointestinal tract

Important Terminology

• Dyspnea- SOB

• Cyanosis- bluish color of eh skin and

mucous membranes

• Clubbing- thickening and widening of

terminal phalanges of fingers and toes

• Hypoxia- diminished availability of O2 to

body tissues

• Normal resting rate of ventilation: 12-20

breaths per minute

Signs and Symptoms

of Pulmonary Disease

• Cough

• Dyspnea

• Cyanosis

• Chest pain

• Abnormal chest shape

• Abnormal sputum

Respiratory Diseases

• Major Diseases

– Infectious

– Immune

– Environmentally Induced

– Circulatory

– Neoplastic (Tumors)

Infectious Diseases

• Upper Respiratory Infections (URI)

– Etiology & Pathogenesis

• viral

• short lived

• heal spontaneously

• Acute inflammation of the nose, paranasal

sinuses, throat, or larynx

Infectious Disease

• Clinical Findings

– Nasal congestion

– General malaise

– Mild fever

– Rhinorrheah (runny nose)

Infectious Disease

• Middle Respiratory System

– More prevalent among children

– croup

• Barking cough due to spasm of vocal cords

– Whooping cough

Infectious Diseases

• Pneumonia

– Inflammation of the lung

• Bacterial infection (75%) or viral

infection

• Less frequently by fungi, protozoa or

parasites

• Inhalation of smoke, dust, gases

• Aspiration of food or liquid

Infectious Diseases

• Pneumonia

– Clinical manifestations:

• Pleuritic chest pain

• Fever

• Hacking, productive cough

– Blood tinged sputum

• SOB

• Fever

• Generalized fatigue

Infectious Diseases

• Tuberculosis (TB)

– Chronic bacterial infection

• Localized lung infection

• Inhalation of infected airborne

particles

• Remains clinically unrecognized in

95% of the cases

– Ultimately impair lung function and

potentially other organs as well

Tuberculosis

• Symptoms:

– Productive cough

– General body symptoms

• Diagnosis

– Chest x-ray

– Skin test

Chronic Obstructive

Pulmonary Disease

(COPD)• Lung diseases with chronic

airway obstruction

• Includes:

– Chronic bronchitis

– Emphysema

Emphysema

• Enlargement of the airspaces distal

to the terminal bronchioles

• Destruction of the alveolar walls

• Obstruction results from changes in

lung tissues

• Loss of elasticity in lung tissue

narrows or collapses bronchioles

Emphysema

• Clinical manifestations:

– Dyspnea

– Cough is uncommon

– Barrel chest

– Anxiety

Chronic Bronchitis

• Productive cough lasting at least

3 months for 2 years

• Inflammation and scaring of

bronchial lining

• Increases mucus production

Chronic Bronchitis

• Clinical manifestations:

– Persistent, productive cough

– SOB

– Recurrent infections

COPD

• Two prototypic groups

– Predominant bronchitis- “blue bloaters”

• Prolonged coughing, dyspnea, cyanosis

– Predominant emphysema- “pink puffers”

• Chest is over-expanded or barrel chested,

hyper-ventillation, over-inflation with a small

heart

Immune Diseases

• Allergic Rhinitis

– Hay fever

• Type I hypersensitivity reaction

affecting the nasal mucosa to

exogenous allergens

• Acute vasomotor response mediated

by histamine and related vasoactive

substances

Asthma

• Acute, reversible, inflammatory, obstructive

lung disease

• Inflammation of bronchia mucosa,

increased permeability of blood vessels in

bronchi, and contraction and spasm of

smooth muscle in bronchi

• Two major forms:

– Extrinsic (allergic)

– Intrinsic (non allergic)

Asthma

• Signs & Symptoms

– Wheezing

– Dyspnea

– Cough

– Goal is to reduce exposure to the irritant

that induces the bronchospasm

Silicosis & Asbestosis

• Diseases caused by the

inhalation of substances

• Causes various types of lung

diseases

• Symptoms• Pulmonary fibrosis

• Pleural fibrosis & pleural plaques

• Lung cancer

Adult Respiratory

Distress Syndromes

(ARDS)• Severe impairment in oxygenation of blood

• Mechanism of lung injury varies depending on cause:– Shock

• Trauma

• Burns

• Acute cardiac failure

– Pneumonia

• Viral or bacterial

– Toxic lung injury

– Aspiration of fluids

• Near drowning

ARDS

• Clinical manifestations:– Increased respiratory rate

– Pulmonary edema

– Atelectasis

– Dyspnea

– Can progress to MODS (multiple organ

dysfunction syndrome)

– Severe distress

– SOB

ARDS

• Prognosis

– Mortality rate of 50-70%

– Survivors asymptomatic in several

months and have normal lung

function in 1 yr

Ventilatory Failure

• Spinal cord injury

• Poliomyelitis

• Tetanus

• Myesthenia gravis

– Affects the neuromuscular junction

• Muscular dystrophy (Duchenne)

• Cystic fibrosis

Atelactasis

• Incomplete expansion or collapse of

the alveoli

– Deficiency of surfactant

– Compression of the lungs from outside

– Resorption of air distal to bronchial

obstruction

Neoplasms of the

Respiratory Tract

• Carcinoma of the larynx– Linked to smoking & chronic alcohol intake

• Affects males 7x more than females

• Lung Carcinoma– Leading cause of cancer death in the USA &

most other Western industrialized countries

– In most cases, it is caused by smoking

• 90% of patients are smokers

• 5 year survival rate 10-15%, incurable

Lung Carcinoma

• Classified as:

– Small cell lung cancer (SCLC)

– Non SCLC (NSCLC)

• Prognosis:

– Curability is poor

Pleural Diseases

• Accumulation of fluid in the

pleural cavity

– Hydrothorax or Pleural effusion

• Fluid can be transudate or exudate

• Accumulation of air in pleura

cavity

– pneumothorax