Transcript File respiratory system chapter_022

The Human Body in Health and
Illness, 4th edition
Barbara Herlihy
Chapter 22:
Respiratory System
LESSON 22-1 OBJECTIVES
Describe the structure and functions of the organs of the respiratory system.
Trace the movement of air from the nostrils to the alveoli.
Describe the role of pulmonary surfactants.
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©
2011,
2007 BY SAUNDERS, AN IMPRINT OF
ALL RIGHTS RESERVED.
ELSEVIER
INC.
STRUCTURE: ORGANS OF THE
RESPIRATORY SYSTEM
Respiratory System divided
into two sections:
•Upper respiratory tract:
Organs located outside the
chest
•Lower respiratory tract:
Organs located inside the
chest
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COPYRIGHT
©
2011,
2007 BY SAUNDERS, AN IMPRINT OF
ALL RIGHTS RESERVED.
ELSEVIER
INC.
UPPER RESPIRATORY SYSTEM
Nose and nasal cavities
Pharynx
Nasopharynx
Oropharynx
Laryngopharynx
Larynx
Vocal cords
Upper trachea
Cartilaginous rings: rings of the
trachea prevent its collapse, helping
maintain an open airway
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FUNCTIONS OF UPPER
RESPIRATORY STRUCTURES
•Nose and nasal passages: Warm, moisturize, and conduct
air
•Pharynx (throat): Conducts air to lower structures
•Larynx (voice box): Vibrates vocal cords, produces sound,
and conducts air to lower structures
•Trachea (windpipe): Conducts air to right bronchus and
left bronchus
•WHY DO WE HAVE A RIGHT BRONCHUS AND
A LEFT BRONCHUS?
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LOWER RESPIRATORY SYSTEM
Lower trachea
Bronchi
Bronchioles
Alveoli
Lungs
Pleural membranes
Muscles of respiration
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BRONCHIAL TREE
Right and left bronchi
Cartilaginous rings
Carina: a cartilaginous ridge within the
trachea
Bronchioles
Smooth muscle
Alveoli
Single layered membrane
Bronchial
Tree
THE MUCOUS
MEMBRANE OF THE
CARINA IS THE MOST
SENSITIVE AREA OF
THE TRACHEA AND
LARYNX FOR
TRIGGERING A
COUGH REFLEX.
WIDENING AND
DISTORTION OF THE
CARINA IS A SERIOUS
SIGN BECAUSE IT
USUALLY INDICATES
CARCINOMA OF THE
LYMPH NODES
AROUND THE
REGION WHERE
THE TRACHEA
DIVIDES.
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©
2011,
2007 BY SAUNDERS, AN IMPRINT OF
ALL RIGHTS RESERVED.
ELSEVIER
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BRONCHIAL TREE: FUNCTIONS
Bronchi: Conduct air to
bronchioles
Bronchioles: Smooth
muscle determines
diameter, regulates air flow
to the alveoli
Alveoli: Small grapelike
structures; air sacs that
exchange O2 and CO2 with
blood in pulmonary
circulation
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GAS EXCHANGE AND THE
ALVEOLI
O2 moves from
alveoli into
pulmonary
capillaries.
CO2 moves from
pulmonary
capillaries into
alveoli.
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LUNGS
•Large, soft, cone-shaped
organs; contain structures
of lower respiratory tract
•Apex (top), base (bottom)
•Right lung: Three lobes
–Superior
–Middle
–Inferior
•Left lung: Two lobes
–Superior
–Inferior
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COPYRIGHT © 2011, 2007
BY SAUNDERS, AN IMPRINT
OF ELSEVIER INC. ALL
RIGHTS RESERVED.
THREE STEPS OF RESPIRATION
Ventilation
Inhalation (inspiration)
Exhalation (expiration)
Respiratory cycle = one inhalation + one exhalation
Exchange of O2 and CO2
At the lungs (alveoli)
At the tissue level
Transport of O
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2
and CO2 by the blood
BOYLE’S LAW: INHALATION
Respiratory muscles
contract to increase
thoracic volume.
As thoracic volume
increases, intrathoracic
pressure decreases.
Air moves in.
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COPYRIGHT
©
2011,
2007 BY SAUNDERS, AN IMPRINT OF
ALL RIGHTS RESERVED.
ELSEVIER
INC.
BOYLE’S LAW: EXHALATION
Respiratory muscles relax
to decrease thoracic
volume.
As volume decreases,
intrathoracic pressure
(P2) increases.
Air moves out.
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RESPIRATORY MUSCLES AND NERVES
Diaphragm
Innervated (supplied with
nerves) by phrenic nerve (C3C5); if this nerve is severed,
ventilation stops
Intercostal muscles
Innervated by intercostal nerves
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GAS EXCHANGE: LUNGS AND
TISSUE
Lungs
O2 moves into blood from
alveoli.
CO2 moves into alveoli from
blood.
Tissue
O2 moves from blood to
tissue.
CO2 moves from tissue to
blood.
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CONTROL OF RESPIRATION
Ner vous
Chemical
Medulla oblongata: fires
Pco2 (carbon dioxide) major
regulator.
Chemoreceptors: regulate the
rate and depth of respiration
rhythmically and stimulates the
phrenic and intercostal nerves
• primary control center
for respirations
• Inspiratory neurons
• Expiratory neurons
Central (CNS)
Peripheral: Carotid bodies (The
• Pons
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carotid body functions as a sensor: it
responds to a stimulus, primarily O2
partial pressure), aortic bodies (It
measures changes in blood pressure
and the composition of arterial blood
flowing past it, including the partial
pressures of oxygen and carbon
dioxide)
COMMON RESPIRATORY TERMS
Eupnea: Normal, quiet breathing
Apnea: Temporary cessation of breathing
Dyspnea: Difficult or labored breathing
Tachypnea: Rapid breathing
Bradypnea: Abnormally slow breathing
Orthopnea: Difficulty in breathing relieved
by sitting up
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COMMON RESPIRATORY TERMS
(CONT’D.)
Hyperventilation: Increase in rate and depth
Hypoventilation: Decrease in rate and depth
Hypoxemia: Abnormally low concentration of O 2
in the blood
Hypercapnia: Abnormally high concentration of
CO2 in the blood
Hypocapnia: Abnormally low concentration of
CO2 in the blood
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F.Y.I
• The alveoli form the terminal end of the respiratory tract. The
purpose of the entire respiratory system is to move air to the
alveoli so that gas exchange can occur with the capillaries.
• A tracheoesophageal (TE) fistula is an opening between the
trachea and esophagus found in some newborns. It must be
corrected with surgery to prevent aspiration, severe
respiratory distress, and death.
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