Title: Anatomy and Physiology by Rod R Seeley 6th edition chapter 23 power-point
1 Anatomy and Physiology, Sixth Edition
Rod R. SeeleyIdaho State University Trent D.
StephensIdaho State University Philip
TatePhoenix College
Chapter 23 Lecture Outline
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Copyright The McGraw-Hill Companies, Inc.
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2Chapter 23
3Respiration
- Ventilation Movement of air into and out of
lungs - External respiration Gas exchange between air in
lungs and blood - Transport of oxygen and carbon dioxide in the
blood - Internal respiration Gas exchange between the
blood and tissues
4Respiratory System Functions
- Gas exchange Oxygen enters blood and carbon
dioxide leaves - Regulation of blood pH Altered by changing blood
carbon dioxide levels - Voice production Movement of air past vocal
folds makes sound and speech - Olfaction Smell occurs when airborne molecules
drawn into nasal cavity - Protection Against microorganisms by preventing
entry and removing them
5Respiratory System Divisions
- Upper tract
- Nose, pharynx and associated structures
- Lower tract
- Larynx, trachea, bronchi, lungs
6Nasal Cavity and Pharynx
7Nose and Pharynx
- Nose
- External nose
- Nasal cavity
- Functions
- Passageway for air
- Cleans the air
- Humidifies, warms air
- Smell
- Along with paranasal sinuses are resonating
chambers for speech
- Pharynx
- Common opening for digestive and respiratory
systems - Three regions
- Nasopharynx
- Oropharynx
- Laryngopharynx
8Larynx
- Functions
- Maintain an open passageway for air movement
- Epiglottis and vestibular folds prevent swallowed
material from moving into larynx - Vocal folds are primary source of sound
production
9Vocal Folds
10Trachea
- Windpipe
- Divides to form
- Primary bronchi
- Carina Cough reflex
Insert Fig 23.5 all but b
11Tracheobronchial Tree
- Conducting zone
- Trachea to terminal bronchioles which is ciliated
for removal of debris - Passageway for air movement
- Cartilage holds tube system open and smooth
muscle controls tube diameter - Respiratory zone
- Respiratory bronchioles to alveoli
- Site for gas exchange
12Tracheobronchial Tree
13Bronchioles and Alveoli
14Alveolus and Respiratory Membrane
15Lungs
- Two lungs Principal organs of respiration
- Right lung Three lobes
- Left lung Two lobes
- Divisions
- Lobes, bronchopulmonary segments, lobules
16Thoracic WallsMuscles of Respiration
17Thoracic Volume
18Pleura
- Pleural fluid produced by pleural membranes
- Acts as lubricant
- Helps hold parietal and visceral pleural
membranes together
19Ventilation
- Movement of air into and out of lungs
- Air moves from area of higher pressure to area of
lower pressure - Pressure is inversely related to volume
20Alveolar Pressure Changes
21Changing Alveolar Volume
- Lung recoil
- Causes alveoli to collapse resulting from
- Elastic recoil and surface tension
- Surfactant Reduces tendency of lungs to collapse
- Pleural pressure
- Negative pressure can cause alveoli to expand
- Pneumothorax is an opening between pleural cavity
and air that causes a loss of pleural pressure
22Normal Breathing Cycle
23Compliance
- Measure of the ease with which lungs and thorax
expand - The greater the compliance, the easier it is for
a change in pressure to cause expansion - A lower-than-normal compliance means the lungs
and thorax are harder to expand - Conditions that decrease compliance
- Pulmonary fibrosis
- Pulmonary edema
- Respiratory distress syndrome
24Pulmonary Volumes
- Tidal volume
- Volume of air inspired or expired during a normal
inspiration or expiration - Inspiratory reserve volume
- Amount of air inspired forcefully after
inspiration of normal tidal volume - Expiratory reserve volume
- Amount of air forcefully expired after expiration
of normal tidal volume - Residual volume
- Volume of air remaining in respiratory passages
and lungs after the most forceful expiration
25Pulmonary Capacities
- Inspiratory capacity
- Tidal volume plus inspiratory reserve volume
- Functional residual capacity
- Expiratory reserve volume plus the residual
volume - Vital capacity
- Sum of inspiratory reserve volume, tidal volume,
and expiratory reserve volume - Total lung capacity
- Sum of inspiratory and expiratory reserve volumes
plus the tidal volume and residual volume
26Spirometer and Lung Volumes/Capacities
27Minute and Alveolar Ventilation
- Minute ventilation Total amount of air moved
into and out of respiratory system per minute - Respiratory rate or frequency Number of breaths
taken per minute - Anatomic dead space Part of respiratory system
where gas exchange does not take place - Alveolar ventilation How much air per minute
enters the parts of the respiratory system in
which gas exchange takes place
28Physical Principles of Gas Exchange
- Partial pressure
- The pressure exerted by each type of gas in a
mixture - Daltons law
- Water vapor pressure
- Diffusion of gases through liquids
- Concentration of a gas in a liquid is determined
by its partial pressure and its solubility
coefficient - Henrys law
29Physical Principles of Gas Exchange
- Diffusion of gases through the respiratory
membrane - Depends on membranes thickness, the diffusion
coefficient of gas, surface areas of membrane,
partial pressure of gases in alveoli and blood - Relationship between ventilation and pulmonary
capillary flow - Increased ventilation or increased pulmonary
capillary blood flow increases gas exchange - Physiologic shunt is deoxygenated blood returning
from lungs
30Oxygen and Carbon Dioxide Diffusion Gradients
- Oxygen
- Moves from alveoli into blood. Blood is almost
completely saturated with oxygen when it leaves
the capillary - P02 in blood decreases because of mixing with
deoxygenated blood - Oxygen moves from tissue capillaries into the
tissues
- Carbon dioxide
- Moves from tissues into tissue capillaries
- Moves from pulmonary capillaries into the alveoli
31Changes in Partial Pressures
32Hemoglobin and Oxygen Transport
- Oxygen is transported by hemoglobin (98.5) and
is dissolved in plasma (1.5) - Oxygen-hemoglobin dissociation curve shows that
hemoglobin is almost completely saturated when
P02 is 80 mm Hg or above. At lower partial
pressures, the hemoglobin releases oxygen. - A shift of the curve to the left because of an
increase in pH, a decrease in carbon dioxide, or
a decrease in temperature results in an increase
in the ability of hemoglobin to hold oxygen
33Hemoglobin and Oxygen Transport
- A shift of the curve to the right because of a
decrease in pH, an increase in carbon dioxide, or
an increase in temperature results in a decrease
in the ability of hemoglobin to hold oxygen - The substance 2.3-bisphosphoglycerate increases
the ability of hemoglobin to release oxygen - Fetal hemoglobin has a higher affinity for oxygen
than does maternal
34Oxygen-HemoglobinDissociation Curve at Rest
35Oxygen-HemoglobinDissociation Curve during
Exercise
36Shifting the Curve
37Transport of Carbon Dioxide
- Carbon dioxide is transported as bicarbonate ions
(70) in combination with blood proteins (23)
and in solution with plasma (7) - Hemoglobin that has released oxygen binds more
readily to carbon dioxide than hemoglobin that
has oxygen bound to it (Haldane effect) - In tissue capillaries, carbon dioxide combines
with water inside RBCs to form carbonic acid
which dissociates to form bicarbonate ions and
hydrogen ions
38Transport of Carbon Dioxide
- In lung capillaries, bicarbonate ions and
hydrogen ions move into RBCs and chloride ions
move out. Bicarbonate ions combine with hydrogen
ions to form carbonic acid. The carbonic acid is
converted to carbon dioxide and water. The
carbon dioxide diffuses out of the RBCs. - Increased plasma carbon dioxide lowers blood pH.
The respiratory system regulates blood pH by
regulating plasma carbon dioxide levels
39Carbon Dioxide Transportand Chloride Movement
40Respiratory Areas in Brainstem
- Medullary respiratory center
- Dorsal groups stimulate the diaphragm
- Ventral groups stimulate the intercostal and
abdominal muscles - Pontine (pneumotaxic) respiratory group
- Involved with switching between inspiration and
expiration
41Respiratory Structures in Brainstem
42Rhythmic Ventilation
- Starting inspiration
- Medullary respiratory center neurons are
continuously active - Center receives stimulation from receptors and
simulation from parts of brain concerned with
voluntary respiratory movements and emotion - Combined input from all sources causes action
potentials to stimulate respiratory muscles - Increasing inspiration
- More and more neurons are activated
- Stopping inspiration
- Neurons stimulating also responsible for stopping
inspiration and receive input from pontine group
and stretch receptors in lungs. Inhibitory
neurons activated and relaxation of respiratory
muscles results in expiration.
43Modification of Ventilation
- Chemical control
- Carbon dioxide is major regulator
- Increase or decrease in pH can stimulate chemo-
sensitive area, causing a greater rate and depth
of respiration - Oxygen levels in blood affect respiration when a
50 or greater decrease from normal levels exists
- Cerebral and limbic system
- Respiration can be voluntarily controlled and
modified by emotions
44Modifying Respiration
45Regulation of Blood pH and Gases
46Herring-Breuer Reflex
- Limits the degree of inspiration and prevents
overinflation of the lungs - Infants
- Reflex plays a role in regulating basic rhythm of
breathing and preventing overinflation of lungs - Adults
- Reflex important only when tidal volume large as
in exercise
47Ventilation in Exercise
- Ventilation increases abruptly
- At onset of exercise
- Movement of limbs has strong influence
- Learned component
- Ventilation increases gradually
- After immediate increase, gradual increase occurs
(4-6 minutes) - Anaerobic threshold is highest level of exercise
without causing significant change in blood pH - If exceeded, lactic acid produced by skeletal
muscles
48Effects of Aging
- Vital capacity and maximum minute ventilation
decrease - Residual volume and dead space increase
- Ability to remove mucus from respiratory
passageways decreases - Gas exchange across respiratory membrane is
reduced