Chapter 37
Respiratory
Systems
Outline
Gas Exchange Surfaces
Water Environments
- Gills
Land Environments
- Lungs
Human Respiratory System
Inspiration versus Expiration
Respiration and Health
Respiratory Disorders
Respiratory
Systems
2
Gas Exchange Surfaces
Respiratory
Systems
Respiration:
The events associated with gas exchange
between the cells and the external environment
Consists of
- Ventilation
- External Respiration
- Internal Respiration
3
Gas Exchange Surfaces
Respiratory
Systems
For diffusion to be effective, gas-exchange
regions must be:
Moist
Thin
Relatively large
Effectiveness of diffusion is enhanced by
vascularization
Delivery to cells is promoted by respiratory
pigments (like hemoglobin)
4
Water Environments
Respiratory
Systems
Gasses of air can dissolve in water
However
When saturated, water contains small fraction of
the O2 in same volume of air, and
Water is much more viscous than air
Aquatic animals expend more energy to breathe
than do terrestrial animals
5
Gas Exchange
Respiratory
Systems
Hydras and planarians
Small animals with large surface area
Most of their cells exchange gases directly with
the environment
Larger aquatic animals
Often have gills
- Finely divided vascularized outgrowths of inner
body surface
- Gills of bony fishes
 Outward
extensions of pharynx
 Ventilation is brought about by combined action of
the mouth and gill covers (operculum)
Countercurrent Exchange
6
Animal Shapes and Gas Exchange
7
Anatomy of Gills in Bony Fishes
8
Land Environments:
Tracheae
Respiratory
Systems
Insects and other terrestrial arthropods
A respiratory system consists of branched
tracheae
Oxygen enters tracheae at spiracles
Tracheae branch until end in tracheoles that are
in direct contact with body cells
9
Tracheae of Insects
10
Land Environments:
Lungs of Vertebrates
Respiratory
Systems
11
Terrestrial vertebrates have evolved lungs
Vascular outgrowths from lower pharyngeal region
Lungs of amphibians
- Possess a short tracheae which divides into two bronchi that
open into lungs
- Many also breathe to some extent through skin
Reptiles
- Inner lining of lungs is more finely divided in reptiles than in
amphibians
Lungs of birds and mammals are elaborately subdivided
All terrestrial vertebrates, except birds, use a tidal
ventilation system
Air moves in and out by the same route
Ventilation in Frogs
12
Ventilation in
Terrestrial Vertebrates
Respiratory
Systems
Inspiration in mammals
Create negative pressure in lungs
The rib cage is elevated
The diaphragm lowers
Thoracic pressure decreases to less than atmospheric
pressure
Atmospheric pressure forces air into the lungs
Expiration in mammals
Create positive pressure in lungs
The rib cage is lowered
The diaphragm rises
Thoracic pressure increases to more than atmospheric
pressure
Forces air out the lungs
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Lungs
Respiratory
Systems
14
Birds use a one-way ventilation mechanism in
lungs
Results in a higher partial pressure of oxygen in
the lungs
Oxygen uptake with each breath is greater than in
other vertebrates
Respiratory System in Birds
15
Human Respiratory System
Respiratory
Systems
As air moves through upper respiratory system
It is filtered to free it of debris
Warmed, and
Humidified
When air reaches lungs
It is at body temperature, and
Its humidity is 100%
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The Human Respiratory Tract
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Human Respiratory System
Respiratory
Systems
Air passes from pharynx through glottis
Larynx and trachea
Permanently held open by cartilage rings
Facilitates movement of air
When food is swallowed
The larynx rises, and
The glottis is closed by the epiglottis
Backward movement of soft palate covers the
entrance of nasal passages into the pharynx
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Human Respiratory System
Respiratory
Systems
19
Trachea divides
Forms two primary bronchi
Bronchi enter the right and left lungs
Bronchi branch until there are a great number of
tiny bronchioles
Each bronchiole terminates in an elongated
space enclosed by alveoli
Ventilation
Respiratory
Systems
20
Humans breathe using a tidal mechanism
Volume of thoracic cavity and lungs is increased
by muscle contractions that lower the diaphragm
and raise the ribs
- Create negative pressure in the thoracic cavity and
lungs, and then air flows into the lungs during
inspiration
Inspiration Versus Expiration
21
External and Internal respiration
22
Hemoglobin
23
Gas Exchange and Transport
Respiratory
Systems
24
Breathing stimulus
Increased H+ and CO2 concentrations in the
blood
Not affected by O2 levels
Oxygen diffuses into pulmonary capillaries
Most combines with hemoglobin in red blood cells
to form oxyhemoglobin
CO2 diffuses out of pulmonary capillaries
Most carbon dioxide is transported in the form of
bicarbonate ion
Some carbon dioxide combines with hemoglobin
to form carbaminohemoglobin
Hemoglobin Saturation
in Relation to Temperature and Acidity
25
Respiration and Health
Upper Respiratory Tract Infections
Strep Throat
- Streptococcus pyogenes
Sinusitis
- Infection of sinuses
Tonsillitis
- Infection of tonsils
Laryngitis
- Infection of larynx
Respiratory
Systems
26
Common
Bronchial and Pulmonary Diseases
27
Respiration and Health
Respiratory
Systems
Lower Respiratory Tract Infections
Acute bronchitis
- Infection of primary and secondary bronchi
Pneumonia
- Viral or bacterial infection of the lungs where
bronchi and alveoli fill with fluid
Pulmonary tuberculosis
- Caused by tubercle bacillus
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Disorders
Respiratory
Systems
29
Pulmonary fibrosis
Fibrous connective tissue builds up in the lungs
Chronic bronchitis
Airways inflamed and filled with mucus
Emphysema
Alveoli are distended and walls are damaged
reducing surface area available for gas exchange
Disorders
Respiratory
Systems
30
Asthma
Airways are unusually sensitive to specific
irritants
- When exposed to the irritants, the smooth muscles
in the bronchioles undergo spasms
Lung Cancer
Begins with thickening and callusing of the cells
lining the airways
Review
Gas Exchange Surfaces
Water Environments
- Gills
Land Environments
- Lungs
Human Respiratory System
Inspiration versus Expiration
Respiration and Health
Respiratory Disorders
Respiratory
Systems
31
Ending Slide Chapter 37
Respiratory
Systems