Transcript Chapter 14- Respiration

• Which of the following is a pressure wave
created by the expansion and recoiling of
arteries?
• A) Circulation
• B) Pulse
• C) Blood flow
• D) Blood pressure
Respiration & Immunity
Chs 14 & 13
Outline
• Respiration
– Overview- structure and function
• The Lungs & gas exchange
• The throat
– Breathing mechanisms
– Transport and management of gases
– Control of breathing
– Disorders of the respiratory sytem
Communication and gas exchange are the
primary purposes of the respiratory system
• In the respiratory system, oxygen and carbon
dioxide are exchanged across a moist body
surface
• Pressure changes within the lungs cause
breathing
• Blood transports gases between the lungs and
the cells
• Breathing is controlled primarily by respiratory
centers in the brain
• Respiratory disorders have many causes
Gas exchange at the organismal level, called, external
respiration, is necessitated by gas exchange at the
cellular level, called internal respiration
Breathing moves air
in and out of the lungs.
External respiration
is the exchange of
oxygen and carbon
dioxide between the
lungs and the blood.
Gas transport
moves oxygen and
carbon dioxide
between the lungs
and the body tissues.
Internal respiration is
the exchange of oxygen
and carbon dioxide
between blood and the
body tissues.
Oxygen
transport
Lungs
Gas diffusion
Carbon
dioxide
transport
Gas diffusion
Tissue
Structures of the Respiratory System
UPPER RESPIRATORY
SYSTEM
• Filters, warms, and
moistens air
Sinuses
• Cavities in skull
• Lighten head
• Warm and moisten
air
Nasal cavity
• Produces mucus
• Filters, warms, and
moistens air
• Olfaction
Pharynx
• Passageway for
air and food
RESPIRATORY
MUSCLES
• Cause breathing
Intercostal
muscles
• Move ribs during
breathing
Diaphragm
• Muscle sheet between
chest and abdominal
cavities with a role in
breathing
Figure 14.2 (1 of 2)
The Lower Respiratory System
LOWER RESPIRATORY
SYSTEM
• Exchanges gases
Larynx
• Air passageway
• Prevents food and drink
from entering lower
respiratory system
• Produces voice
Bronchi
• Two branches of
trachea that conduct
air from trachea to
each lung
Bronchioles
• Narrow passageways
to conduct air from
bronchi to alveoli
Epiglottis
• Covers larynx during
swallowing
Lungs
• Structures that contain
alveoli and air
passageways
• Allow exchange of
oxygen and carbon
dioxide between
atmosphere and blood
Trachea
• Connects larynx with
bronchi leading to
each lung
• Conducts air to and
from bronchi
Alveoli
• Microscopic chambers
for gas exchange
Figure 14.2 (2 of 2)
The Respiratory System
• The nose
– Cleans incoming air
– Warms and moistens the air
– Provides for the sense of smell
Figure 14.4a
The Respiratory System
• The sinuses
– Lighten the head
– Adjust air quality
• The pharynx
– The space behind the nose and mouth
– Provides a passageway for food and air
The Respiratory System
• The larynx
– An adjustable entrance to the respiratory system
– Controls the position of the epiglottis to prevent
materials from entering the lower respiratory
system
– The source of the voice
The Respiratory System
Epiglottis
Larynx
Upper
trachea
Front view
(a) The epiglottis is open during breathing but covers the
opening to the larynx during swallowing to prevent
food or drink from entering the trachea.
Figure 14.5a
The Respiratory System
Vocal cords
Glottis
Top view of larynx
During quiet breathing, the
vocal cords are near the
sides of the larynx, and the
glottis is open.
Top view of larynx
During speech, the vocal
cords are stretched over the
glottis and vibrate as air
passes through them,
producing the voice.
(b) The vocal cords are the folds of connective tissue above the
opening of the larynx (the glottis) that produce the voice.
Figure 14.5b
The Respiratory System
• The trachea
– Tube that conducts air between the environment
and the lungs
• Heimlich maneuver
– Can be used to dislodge food from the trachea
The Heimlich maneuver is only a last resort
A person who is choking cannot speak
or breathe and needs immediate help.
The Heimlich maneuver is a
procedure intended to force a large
burst of air out of the lungs and
dislodge the object blocking air flow.
Step 1: Stand behind the choking
person with arms around the waist.
Step 2: Make a fist and place the
thumb of the fist beneath the
victim’s rib cage about midway
between the navel (belly button) and
the breastbone.
The Heimlich maneuver saves lives, but also breaks
ribs- try a whack on the back first
Step 3: Grasp the fist with your
other hand and deliver a rapid “bear
hug” up and under the rib cage with
the clenched fist. Be careful not to
press on the ribs or the breastbone
because doing so could cause
serious injury.
Step 4: Repeat until the object
is dislodged.
Blocking
object
The Respiratory System
• The trachea divides into the bronchial tree
which conducts air to each lung
The trachea branches off into bronchioles, which
terminate in the alveoli
Figure 14.7
The Respiratory System
• The alveoli
– Functional units of the respiratory system
– Minute sacs where oxygen diffuses from the air
into the blood
• For alveoli to function properly they are
coated with phospholipid molecules called
surfactant that keep them open
The Respiratory System
Figure 14.8
The Respiratory System
• Carbon dioxide produced by the cells diffuses
from the blood into the alveolar air to be
exhaled
• Which of the following is a thin-walled,
rounded chamber surrounded by a vast
network of capillaries?
• A) Surfactant
• B) Alveolus
• C) Diaphragm
• D) Glottis
Pressure Changes within the Lungs Cause
Breathing
• Pressure changes within the lungs cause
breathing
Pressure Changes within the Lungs
Cause Breathing
• When the diaphragm
and intercostal muscles
contract, the volume of
the thoracic cavity
increases, causing the
pressure in the lungs to
decrease
Pressure Changes within the Lungs Cause
Breathing
• Expiration
– When the same muscles relax, pressure in the
lungs increase
• Inspiration
– Occurs when the pressure in the lungs decreases
Lungs contain no muscle tissue
Inhalation
Rib cage
moves up
and out
Air flow
Intercostal
muscles
contract
Diaphragm
contracts
and flattens
The chest cavity increases
in size, and pressure within
the lungs decreases.
Diaphragm
contracts
The lungs expand, and
air moves in.
(a)
Figure 14.9a
The diaphragm and intercostal muscles fill and empty
the lungs by changing pressure in the pleural cavity
Exhalation
Air flow
Rib cage
moves down
and inward
Intercostal
muscles relax
Diaphragm
relaxes and
moves upward
The chest cavity decreases
in size, and pressure
within the lungs increases.
Diaphragm
relaxes
The lungs recoil,
and air moves out.
(b)
Figure 14.9b
Lung volumes are dependent on energy
expenditure and the need for residual air to
prevent collapse of the lungs
• The volume of air inhaled or exhaled during a
normal breath is called the tidal volume
• The volume of air moved into and out of the
lungs is an indication of health
Pressure Changes within the Lungs Cause
Breathing
6000
Lung Volume (ml)
5000
Inspiratory
reserve
(forced
inhalation)
volume
4000
Total
lung
capacity
Vital
capacity
Tidal volume
3000
2000
Expiratory reserve
(forced exhalation)
volume
1000
Residual
volume
0
Figure 14.10 (1 of 2)
Pressure Changes within the Lungs Cause
Breathing
Tidal volume
(~500 ml)
Amount of air inhaled or exhaled
during an ordinary breath
Inspiratory reserve volume
(~1900–3300 ml)
Amount of air that can be inhaled
in addition to a normal breath
Expiratory reserve volume
(~1000 ml)
Amount of air that can be exhaled
in addition to a normal breath
Vital capacity
(~3400–4800 ml)
Maximum amount of air that can
be inhaled or exhaled in a single
forced breath
Residual volume
(~1100–1200 ml)
Amount of air remaining in the
lungs after maximum exhalation
Total lung capacity
(4500–6000 ml)
Total amount of air in the lungs
after maximal inhalation (vital
capacity + residual volume)
Figure 14.10 (2 of 2)
Blood Transports Gasses between the
Lungs and the Cells
• Most oxygen is carried by the blood where it is
bound to hemoglobin in a molecule called
oxyhemoglobin
• The carbon dioxide produced as the cells use oxygen
is removed by the blood in one of three ways
1. Dissolved in the blood
2. Carried by hemoglobin
3. As a bicarbonate ion
•
In the lungs, O2 passes in to the bloodstream, and
CO2 passes out to the lungs
Figure 14.11 (2 of 2)
By what process does O2 enter the
capillaries of the lungs?
a.
b.
c.
d.
Active transport
Osmosis
Simple diffusion
Facilitated diffusion
By what process does CO2 leave the
capillaries for the lungs?
a.
b.
c.
d.
Active transport
Osmosis
Simple diffusion
Facilitated diffusion
In the body, CO2 leaves cells into the blood
Figure 14.11 (1 of 2)
Gas exchange affects blood pH
• CO2 dissolved in the blood affects its pH
• CO2 +H2O H+ + HCO3-
CO2 +H2O H+ + HCO3according to the equation, CO2 in the blood acts as a
a. Acid
b. Base
•
Blood Transports Gasses between the
Lungs and the Cells
• CO2 dissolved in the blood affects its pH
• CO2 +H2O H+ + HCO3• This chemical reaction can also go backward,
or further forward
• HCO3- H+ + CO32• When sodium from the diet is added, much
bicarbonate ion that also serves as a buffer
• In the lungs, removal of CO2 causes removal
of H+ from the bloodstream
Blood Transports Gasses between the
Lungs and the Cells
•
•
•
•
CO2 dissolved in the blood affects its pH
CO2 +H2O H+ + HCO3This chemical reaction can also go backward
When sodium from the diet is added, much
bicarbonate ion that also serves as a buffer
• In the lungs, removal of CO2 causes removal
of H+ from the bloodstream
Breathing Is Controlled by Respiratory
Centers in the Brain
• The basic rhythm of breathing
– Controlled by a breathing center located in the
medulla
Breathing Is Controlled by Respiratory
Centers in the Brain
Figure 14.12 (1 of 2)
Breathing Is Controlled by Respiratory
Centers in the Brain
Figure 14.12 (2 of 2)
Respiratory Centers in the Brain
• Changes in depth and rate of breathing
– Affected by chemoreceptors located in the
medulla
Respiratory Centers in the Brain
• Carbon dioxide
– The most important chemical influencing
breathing rate
Respiratory Centers in the Brain
Increased blood level of carbon
dioxide (increased acidity, H+)
Increased carbon dioxide level
(increased acidity, H+) in
cerebrospinal fluid
Sensed by chemoreceptors
in medulla
Sensed by peripheral
chemoreceptors in aortic and
carotid bodies
Medulla breathing center
stimulated
Breathing rate increased
(more carbon dioxide
exhaled)
Carbon dioxide
level in blood
returns to normal
Figure 14.13
Respiratory Centers in the Brain
• Under extreme circumstances, oxygensensitive chemoreceptors in the aortic and
carotid bodies can increase breathing
Respiratory Disorders Have Many
Causes
• The common cold
– Caused by several types of viruses
• Some with many variants
Respiratory Disorders Have Many
Causes
• Influenza
– Caused by only two types of viruses
• There are many variants of these two types
Respiratory Disorders Have Many
Causes
• Pneumonia
– An inflammation of the lungs that causes fluid to
accumulate in the alveoli, reducing gas exchange
Respiratory Disorders Have Many
Causes
• Strep throat
– Caused by Streptococcus bacteria
– Soreness accompanied by swollen glands and
fever
Respiratory Disorders Have Many
Causes
• Tuberculosis
– Infection caused by bacteria
– Results in fibrous tissue forming in the lungs
Respiratory Disorders Have Many
Causes
• Bronchitis
– An inflammation of the mucous membrane of the
bronchi
– Caused by viruses, bacteria, or chemical irritation
– Inflammation results in the production of excess
mucus, which triggers a deep cough
Respiratory Disorders Have Many
Causes
• Emphysema
– Caused by the destruction of alveoli, usually by
smoking
– Reduction in the surface area available for gas
exchange and the increased dead air space results
in shortness of breath
Respiratory Disorders Have Many
Causes
Figure 14.14
Lung Cancer
• Lung Cancer
– Changes in the cells of the airway linings
• Eventual uncontrolled cell division forms a tumor
– Often caused by inhaled carcinogens, including
those found in tobacco smoke
PLAY
| Secondhand Smoke
Lung Cancer
Figure 14.4b
Lung Cancer
Figure 14.15