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Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Ch.37 Respiration.

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Presentation on theme: "Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Ch.37 Respiration."— Presentation transcript:

1 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Ch.37 Respiration

2 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Ch.37 Gas Exchange Respiration involves three events – – External respiration - gas exchange occurs between air and blood (O 2 from air to blood; CO 2 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 (O 2 from blood to tissue fluid; CO 2 from tissue fluid into blood). Bodies’ cells exchange gases (O 2 taken in; CO 2 released) with tissue fluid. Blood carries carbon dioxide from cell to lungs

7 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Gas exchange occurs across specialized respiratory surfaces Gas exchange supplies oxygen for cellular respiration and disposes of carbon dioxide

8 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings (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 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Gas Exchange Hydras and planarians – Small animals with large surface area – Most of their cells exchange gases directly with the environment –

11 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Types of respiratory systems Skin Gills Tracheal system Lungs

12 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The feathery gills projecting from a salmon – Are an example of a specialized exchange system found in animals

15 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings In some invertebrates – The gills have a simple shape and are distributed over much of the body

16 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Many segmented worms have flaplike gills – That extend from each segment of their body

17 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The gills of clams, crayfish, and many other animals – Are restricted to a local body region

18 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The effectiveness of gas exchange in some gills, including those of fishes is increased by ventilation and countercurrent flow of blood and water

20 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Most terrestrial animals have respiratory surfaces that are infoldings (invaginations) of the body surface This protects the respiratory surface and keeps it moist

23 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The tracheal tubes supply O 2 directly to body cells and are filled with fluid for gas exchange

25 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings How an Amphibian Breathes An amphibian such as a frog – Ventilates its lungs by positive pressure breathing, which forces air down the trachea

28 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings How a Mammal Breathes Mammals ventilate their lungs by negative pressure breathing, which pulls air into the lungs

29 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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 CO 2 reacts with H 2 O to form carbonic acid, which lowers the pH of the blood

39 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings By monitoring pH, the medulla regulates CO 2 levels in the blood

40 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Sensors in the aorta and carotid arteries – Monitor O 2 and CO 2 concentrations in the blood –

41 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Respiratory Pigments Respiratory pigments are proteins that transport oxygen and greatly increase the amount of oxygen that blood can carry O 2 is not very soluble in water, so blood transports very little dissolved O 2

42 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Hemoglobin is composed of four polypeptide chains, each polypeptide chain contains a heme group which contains an iron atom.

43 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Like all respiratory pigments – Hemoglobin must reversibly bind O 2, loading O 2 in the lungs and unloading it in other parts of the body

44 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Gas Exchange and Transport Oxygen diffuses into pulmonary capillaries – Most combines with hemoglobin in red blood cells to form oxyhemoglobin CO 2 diffuses out of pulmonary capillaries – Most carbon dioxide is transported in the form of bicarbonate ion –

45 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Loading and unloading of O 2 – Depend on cooperation between the subunits of the hemoglobin molecule –

46 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Carbon Dioxide Transport Hemoglobin also helps transport CO 2 and assists in buffering the pH of the blood

47 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Carbon dioxide from respiring cells – Diffuses into the blood plasma and then into erythrocytes and is ultimately released in the lungs

48 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings CO 2 transport Some CO 2 dissolves in the plasma, but most enters the red blood cells Some CO 2 binds to hemoglobin, but most reacts with H 2 O to form carbonic acid (H 2 CO 3 ) Carbonic acid forms more easily in RBC’s with the help of the enzyme carbonic anhydrase H 2 CO 3 dissociates to become (H +) hydrogen ion and (HCO 3 - ) bicarbonate ion

49 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Respiration and Health Upper Respiratory Tract Infections – Strep Throat Streptococcus pyogenes – Sinusitis Infection of sinuses – Tonsillitis Infection of tonsils – Laryngitis Infection of larynx

51 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Disorders Pulmonary fibrosis – Fibrous connective tissue builds up in the lungs Chronic bronchitis – Airways inflamed and filled with mucus Emphysema –

53 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Disorders Asthma – Airways are unusually sensitive to specific irritants When exposed to the irritants, the smooth muscles in the bronchioles undergo spasms Lung Cancer –


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