1. Ch.37 Respiration

2. Essential knowledge 4.B.2:
Cooperative interactions within organisms promote efficiency in the use of energy and matter.
a. Organisms have areas or compartments that perform a subset of functions related to energy and matter, and these parts contribute to the whole.

3. Essential knowledge 4.A.4:
Organisms exhibit complex properties due to interactions between their constituent parts.
a. Interactions and coordination between organs provide essential biological activities.
b. Interactions and coordination between systems provide essential biological activities.

4. Essential knowledge 2.D.2:
Homeostatic mechanisms reflect both common ancestry and divergence due to adaptation in different environments.
a. Continuity of homeostatic mechanisms reflects common ancestry, while changes may occur in response to different environmental conditions.
b. Organisms have various mechanisms for obtaining nutrients and eliminating wastes.
c. Homeostatic control systems in species of microbes, plants and animals support common ancestry.

5. Essential knowledge 2.A.3:
Organisms must exchange matter with the environment to grow, reproduce and maintain organization.
a. Molecules and atoms from the environment are necessary to build new molecules.
b. Surface area-to-volume ratios affect a biological system’s ability to obtain necessary resources or eliminate waste products.

6. Ch.37 Gas Exchange Respiration involves three events
External respiration - gas exchange occurs between air and blood (O2 from air to blood; CO2 from blood into air) within the lungs and oxygen is carried to other parts of the body by circulatory system
Internal respiration - gas exchange occurs between blood and tissue fluid (O2 from blood to tissue fluid; CO2 from tissue fluid into blood). Bodies’ cells exchange gases (O2 taken in; CO2 released) with tissue fluid. Blood carries carbon dioxide from cell to lungs

7. Gas exchange occurs across specialized respiratory surfaces
Gas exchange supplies oxygen for cellular respiration and disposes of carbon dioxide

8. Animals require large, thin, moist respiratory surfaces for the adequate diffusion of respiratory gases between their cells and the respiratory medium, either air or water
(1)This means that respiratory surfaces must be kept moist for oxygen and carbon dioxide to diffuse through the cell’s plasma membrane

9. (2)Respiratory surfaces must be extensive enough (large surface area) to take up enough oxygen and get rid of carbon dioxide for the entire body
(3)These delicate moist tissues of respiratory surfaces need to be protected

10. Gas Exchange Hydras and planarians
Small animals with large surface area
Most of their cells exchange gases directly with the environment

11. Types of respiratory systems
Skin
Gills
Tracheal system
Lungs

12. Skin
Skin - animals such as earthworms have no specialized gas exchange surfaces
Oxygen diffuses into capillaries beneath the skin
They must live in damp places or in water to keep respiratory surfaces moist

13. Gills in Aquatic Animals
Gills are featherlike outfoldings (evaginations) of the outer or inner body surface specialized for gas exchange, and occur in aquatic animals
Gills have finely subdivided surfaces to provide adequate surface area and contain a rich blood supply for transport (vascularization)

14. The feathery gills projecting from a salmon
Are an example of a specialized exchange system found in animals

15. In some invertebrates
The gills have a simple shape and are distributed over much of the body

16. Many segmented worms have flaplike gills
That extend from each segment of their body

17. The gills of clams, crayfish, and many other animals
Are restricted to a local body region

18. Oxygen makes up 0.45% of seawater, but 21% of air
This means that aquatic animals have a greater problem obtaining enough oxygen than do terrestrial animals and expend much more energy doing so (25% compared to1-2% of their energy)
Diffusion is also 1000X slower in water than in air (water is 1000X more dense than air)

19. The effectiveness of gas exchange in some gills, including those of fishes is increased by ventilation and countercurrent flow of blood and water

20. Counter-current exchange
This maintains a favorable gradient between blood and the water at every point of exchange, this maximizes the amount of oxygen the blood removes from the water

21. Respiratory systems
Land animals have two advantages: air contains more oxygen than an equal volume of water and air is lighter and easier to move.
Terrestrial animals expend much less energy than an aquatic animal in gas exchange

22. Most terrestrial animals have respiratory surfaces that are infoldings (invaginations) of the body surface
This protects the respiratory surface and keeps it moist

23. Land Environments: Tracheae
Insects and other terrestrial arthropods
A respiratory system consists of branched tracheae
Tracheae branch until end in tracheoles (surface area) that are in direct contact with body cells so they do not require circulatory system to transport gases

24. The tracheal tubes supply O2 directly to body cells and are filled with fluid for gas exchange

25. Lungs
Spiders, land snails, and most terrestrial vertebrates have internal lungs
Lungs are invaginated
Lungs are restricted to one part of the body, so a circulatory system is needed to transport gases from lungs to the rest of the body

26. Land Environments: Lungs of Vertebrates
Terrestrial vertebrates have evolved lungs
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

27. How an Amphibian Breathes
An amphibian such as a frog
Ventilates its lungs by positive pressure breathing, which forces air down the trachea

28. How a Mammal Breathes
Mammals ventilate their lungs by negative pressure breathing, which pulls air into the lungs

29. Ventilation in Terrestrial Vertebrates
Inspiration (inhalation) in mammals
Create negative pressure in lungs
The rib cage is elevated (rib muscles contract)
The diaphragm lowers (contracts)
Thoracic pressure decreases (volume increases) to less than atmospheric pressure

30. Ventilation in Terrestrial Vertebrates
Expiration (exhalation) in mammals
Create positive pressure in lungs
The rib cage is lowered
The diaphragm rises
Thoracic pressure increases,(thoracic cavity volume decreases) to more than atmospheric pressure

31. Besides lungs, bird have eight or nine air sacs
How a Bird Breathes
Besides lungs, bird have eight or nine air sacs
That function as bellows that keep air flowing through the lungs

32. Every exhalation completely renews the air in the lungs
Lungs do not have alveoli, but contain tiny parallel tubes called parabronchi
Air flows one direction and blood flows in the opposite direction acting as counter-current exchange

33. 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

34. 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

35. 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 which greatly increase the surface area of the respiratory surface
Alveoli are air sacs lined with a thin layer of epithelial cells which form the respiratory surface

36. 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

37. Control of Breathing in Humans
The main breathing control centers
Are located in two regions of the brain, the medulla oblongata and the pons

38. The centers in the medulla regulate the rate and depth of breathing in response to pH changes (H+) in the blood and cerebrospinal fluid
The medulla adjusts breathing rate and depth to match metabolic demands
CO2 reacts with H2O to form carbonic acid, which lowers the pH of the blood

39. By monitoring pH, the medulla regulates CO2 levels in the blood

40. Sensors in the aorta and carotid arteries
Monitor O2 and CO2 concentrations in the blood

41. Respiratory Pigments
Respiratory pigments are proteins that transport oxygen and greatly increase the amount of oxygen that blood can carry
O2 is not very soluble in water, so blood transports very little dissolved O2

42. Hemoglobin is composed of four polypeptide chains, each polypeptide chain contains a heme group which contains an iron atom.

43. Like all respiratory pigments
Hemoglobin must reversibly bind O2, loading O2 in the lungs and unloading it in other parts of the body

44. Gas Exchange and Transport
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

45. Loading and unloading of O2
Depend on cooperation between the subunits of the hemoglobin molecule

46. Carbon Dioxide Transport
Hemoglobin also helps transport CO2 and assists in buffering the pH of the blood

47. Carbon dioxide from respiring cells
Diffuses into the blood plasma and then into erythrocytes and is ultimately released in the lungs

48. CO2 transport
Some CO2 dissolves in the plasma, but most enters the red blood cells
Some CO2 binds to hemoglobin, but most reacts with H2O to form carbonic acid (H2CO3)
Carbonic acid forms more easily in RBC’s with the help of the enzyme carbonic anhydrase
H2CO3 dissociates to become (H+) hydrogen ion and (HCO3-) bicarbonate ion

49. Bicarbonate ions buffer the blood pH by combining with H+ ions and removing them from the blood, or by releasing H+ ions when needed

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

51. 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

52. Disorders Pulmonary fibrosis Chronic bronchitis Emphysema
Fibrous connective tissue builds up in the lungs
Chronic bronchitis
Airways inflamed and filled with mucus
Emphysema

53. 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