1. Biology, 9th ed, Sylvia Mader
Chapter 37
Chapter 37
Respiratory Systems
Respiratory Systems

2. Human Respiratory System
Outline
Gas Exchange Surfaces
Water Environments
Gills
Land Environments
Lungs
Human Respiratory System
Inspiration versus Expiration
Respiration and Health
Respiratory Disorders

3. Gas Exchange Surfaces Respiration:
The events associated with gas exchange between the cells and the external environment
Consists of
Ventilation
External Respiration
Internal Respiration

4. For diffusion to be effective, gas-exchange regions must be:
Gas Exchange Surfaces
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)

5. Gasses of air can dissolve in water However
Water Environments
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

6. Larger aquatic animals
Gas Exchange
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

7. Animal Shapes and Gas Exchange

8. Anatomy of Gills in Bony Fishes

9. Land Environments: Tracheae
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

10. Tracheae of Insects

11. Land Environments: Lungs of Vertebrates
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

12. Ventilation in Frogs

13. Ventilation in Terrestrial Vertebrates
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

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

15. Respiratory System in Birds

16. Human Respiratory System
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%

17. The Human Respiratory Tract

18. Human Respiratory System
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

19. Human Respiratory System
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

20. Humans breathe using a tidal mechanism
Ventilation
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

21. Inspiration Versus Expiration

22. External and Internal respiration

23. Hemoglobin

24. Gas Exchange and Transport
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

25. Hemoglobin Saturation in Relation to Temperature and Acidity

26. Respiration and Health
Upper Respiratory Tract Infections
Strep Throat
Streptococcus pyogenes
Sinusitis
Infection of sinuses
Tonsillitis
Infection of tonsils
Laryngitis
Infection of larynx

27. Common Bronchial and Pulmonary Diseases

28. Respiration and Health
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

29. Disorders Pulmonary fibrosis Chronic bronchitis Emphysema
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

30. Disorders Asthma Lung Cancer
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

31. Human Respiratory System
Review
Gas Exchange Surfaces
Water Environments
Gills
Land Environments
Lungs
Human Respiratory System
Inspiration versus Expiration
Respiration and Health
Respiratory Disorders

32. Biology, 9th ed, Sylvia Mader
Chapter 37
Ending Slide Chapter 37
Respiratory Systems
Respiratory Systems