RESPIRATORY SYSTEM
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KOMUNITAS BLOGGER UNIVERSITAS SRIWIJAYA
RESPIRATORY SYSTEM
I. FUNCTION
To
It
supply the body with oxygen and dispose carbon dioxide
involves at least 3 distinct process:
Pulmonary
Inflow
Ventilation
and outflow of air between the atmosphere and alveoli of the lungs
External
Diffusion
Internal
Respiration
of oxygen and carbon dioxide between the alveoli and pulmonary capillaries
Respiration
Transport
of oxygen and carbon dioxide via the blood to and from the tissue
II. FUNCTIONAL ANATOMY OF THE RESPIRATORY SYSTEM
A. Conducting Zone
· Also called as “dead space” because there is no gas exchange in
these zones
· Respiratory passages extending from nose to the terminal bronchioles
B. Respiratory Zone
· Actual site of gas exchange
· Composed of the respiratory bronchioles, alveolar ducts, and alveoli
i. Conducting Zone Structures
a. Nose
b. Pharynx
c. Larynx
d. Trachea
e. Bronchi
Right
Left
bronchus bronchus
Diameter Wider
Length
Narrower
Shorter Longer
Direction More
vertical
Oblique
ii. Respiratory Zone Structures
a. Respiratory Bronchioles
b. Alveolar ducts
c. Alveolar sac
d. Alveoli à actual site of gas exchange
The
respiratory membrane is composed of several cell types
A. Type I pneumocytes
· Walls of the alveoli composed of simple squamous epithelium
B. Type II pneumocytes
· Cuboidal secretory cells
· Secrete a fluid containing surfactant that coats the gas exposed alveolar surfaces
· Surfactant decreases the surface tension on the alveolar walls
· L:S ratio
C. Alveolar macrophages
· Dust cells
· Provide primary line of defense against inhaled dust, bacteria, and other foreign
particles
III. LUNGS AND PLEURAL CAVITIES
Lungs
Right
Lung
· 3
Lobes
Left
Lung
2
· 1
1
Fissures horizontal oblique
1 oblique
· (- )
Cardiac
notch
(+)
· (- )
Lingula
(+)
Pleura
IV. MUSCULAR CONTROL OF BREATHING
Inspiration Diaphragm contracts à moves inferiorly and flattens out à increase
height of the thoracic cavity Contraction of the external intercostals muscles à
elevates the rib cage and thrust the sternum forward à expand the diameter of the
thorax
Expiration
· Inspiratory muscles relax à rib cage descends and lungs recoil
V. AIRWAY RESISTANCE AND COMPLIANCE
A. Airway resistance
· Determined chiefly by radium or size of the airway
· Changes in bronchial diameter à alters the rate of air flow for a given
pressure gradient during respiration
· ↑ resistance – greater than normal respiratory effort is required
B. Compliance
· A measure of the elasticity, expandability, and distensibility of the lungs and
thoracic structures
· Normal compliance à lungs and thorax easily stretch and distend when
pressure is applied
· High or ↑ compliance à lungs have lost elasticity and the thorax is
overdistended à ? (example)
· Low or ↓compliance à lungs and thorax are stiff à ? (example)
VI. GAS EXCHANGE IN THE BODY
VII. CONTROL OF RESPIRATION
Medullary Respiratory Centers
Dorsal respiratory group or inspiratory center
Ventral respiratory group or expiratory center
Pons Respiratory Centers
. Pneumotaxic Center à rhythm and prevents over inflation of the lungs
Apneustic Center à inspiratory drive
Chemical Control of Respiration
Central chemoreceptor
i. Located bilaterally in the medulla
ii. Sensitive to small changes in blood CO2 and pH
iii. Hypercapnia / ↑ CO2 à the most powerful respiratory stimulant
iv. Release of H ions in the CSF à reflexive increase in the rate and depth of
breathing
Peripheral chemoreceptor
i. Found within vessels of the neck (carotid and aortic bodies)
ii. Sensitive to arterial oxygen levels
iii. ↓ arterial pressure of oxygen (below 60 mmHg) à becomes the major
stimulus for respiration à ↑ ventilation
ASSESSMENT
Major Signs and Symptoms of Respiratory Diseases
a. Dyspnea
à How much exertion triggers SOB?
à Is there an associated cough?
à Is dyspnea related to the symptoms?
à At what time of day or night does the dyspnea occur?
à Is the SOB worse when the patient is flat in bed?
à Does the SOB occur at rest? With exercise? Running? Climbing stairs?
à Is the SOB worse while walking?
à Management: Identify and correcting its cause, rest, positioning, oxygen
administration
b. Sputum production
à Purulent with change in color – bacterial infection
à Profuse, frothy, pink material – pulmonary edema
à Foul smelling associated with bad breath – lung abscess, bronchiectasis
à Management: ↑ OFI, inhalation of aerosolized solutions, chest physiotherapy
c. Chest Pain
à Sharp, stabbing, and intermittent – pulmonary problem
à Dull, aching, and persistent
à Management: Analgesics
d. Wheezing
à Bronchoconstriction or airway narrowing
à Management: Bronchodilators
e. Hemoptysis
à Most common causes: pulmonary infection, lung Ca, heart or blood vessel
abnormalities, pulmonary artery or vein abnormalities, pulmonary emboli and infarction
à Determine the source and treat the underlying cause of bleeding
f. Cyanosis
à A very late indicator of hypoxia
à Nor a reliable sign of hypoxia
g. Clubbing of the Fingers
à Found in patients with chronic hypoxic conditions, chronic lung infections, lung Ca
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