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Hole’s Human
Anatomy and Physiology
Eleventh Edition
Shier w Butler w Lewis
Chapter
19
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1
Chapter 19
Respiratory System
Respiration is the process of exchanging gases between the
atmosphere and body cells. Consists of the following
events:
• ventilation
• external respiration
• transport
• internal respiration
• cellular respiration
2
Organs of the
Respiratory System
3
Organs of the
Respiratory System
4
Upper Respiratory Tract
5
Mucous in Respiratory Tract
Cilia move mucus and trapped particles from the nasal cavity
to the pharynx
6
Sinuses
Air-filled spaces in maxillary, frontal, ethmoid, and
sphenoid bones
7
Pharynx
8
Larynx
9
Vocal Cords
10
Trachea
11
Tracheostomy
Performed to allow air to bypass an obstruction
within the larynx
12
Bronchial Tree
13
Alveoli
14
Diffusion Across Respiratory
Membrane
15
Lungs
16
Transverse Section of Lungs
17
Breathing Mechanism
• Breathing or ventilation is the movement of air
from outside the body into the bronchial tree and
alveoli
• air movements of inspiration and expiration
• changes in the size of the thoracic cavity due
to changes in pressure
18
Inspiration
• Moving the
plunger of a syringe
causes air to move in
or out
• Air movements in
and out of the lungs
occur in much the
same way
19
Lungs at Rest
When lungs are at rest, the pressure on the inside of the
lungs is equal to the pressure on the outside of the thorax
20
Inspiration
• Intra-alveolar
pressure decreases to
about 758mm Hg as
the thoracic cavity
enlarges
• Atmospheric
pressure forces air
into the airways
21
Inspiration
Shape of thorax at end
of normal inspiration
Shape of thorax at end of maximal
inspiration aided by contraction of
sternocleidomastoid and pectoralis minor
muscles
22
Major Events in Inspiration
23
Expiration
• due to elastic recoil of the lung tissues and abdominal organs
24
Maximal Expiration
• contraction of
abdominal wall
muscles
• contraction of
posterior internal
intercostal muscles
25
Major Events in Expiration
26
Respiratory Volumes and
Capacities
27
Respiratory Volumes and
Capacities
28
Alveolar Ventilation
minute ventilation
• tidal volume
multiplied by
breathing rate
• amount of air that is
moved into the
respiratory
passageways
alveolar ventilation rate
• major factor affecting
concentrations of oxygen
and carbon dioxide in the
alveoli
• volume of air that
reaches alveoli
• tidal volume minus
physiologic dead space
then multiplied by
breathing rate
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Nonrespiratory Air Movements
30
Respiratory Center
31
Respiratory Center
32
Factors Affecting Breathing
Decreased blood
oxygen concentration
stimulates peripheral
chemoreceptors in the
carotid and aortic
bodies
33
Factors Affecting Breathing
• motor impulses travel from the
respiratory center to the
diaphragm and external
intercostal muscles
• contraction of these muscles
causes lungs to expand
• expansion stimulates stretch
receptors in the lungs
• inhibitory impulses from
receptors to respiratory center
prevent overinflation of lungs
34
Factors Affecting Breathing
35
Alveoli
• gas exchanges between the air and blood
occur within the alveoli
• alveolar pores allow air to pass from one
alveolus to another
36
Respiratory Membrane
• consists of the walls of the alveolus and the capillary
37
Diffusion Through
Respiratory Membrane
Gases are exchanged between alveolar air and capillary
blood because of differences in partial pressure
38
Oxygen Transport
• Most oxygen binds to hemoglobin to form oxyhemoglobin
• Oxyhemoglobin releases oxygen in the regions of body cells
• Much oxygen is still bound to hemoglobin in the venous blood
39
Oxygen Release
Amount of oxygen released from oxyhemoglobin increases as
• partial pressure of carbon dioxide increases
• the blood pH decreases
• blood temperature increases
40
Carbon Dioxide Transport
• dissolved in plasma
• combined with hemoglobin
• in the form of bicarbonate ions
41
Chloride Shift
• bicarbonate ions diffuse out RBCs
• chloride ions from plasma diffuse into RBCs
• electrical balance is maintained
42
Carbon Dioxide in Lungs
43
Gases Transported in Blood
44
Life-Span Changes
• reflect accumulation of environmental influences
• reflect the effects of aging in other organ systems
• cilia less active
• mucous thickens
• swallowing, gagging, and coughing reflexes slow
• macrophages in lungs lose efficiency
• increased susceptibility to respiratory infections
• “barrel chest” may develop
• bronchial walls thin and collapse
• dead space increases
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Clinical Application
The Effects of Cigarette Smoking on the
Respiratory System
• cilia disappear
• excess mucus produced
• lung congestion increases lung
infections
• lining of bronchioles thicken
• bronchioles lose elasticity
• emphysema fifteen times more
common
• lung cancer more common
• much damage repaired when
smoking stops
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