1. The Living World Fourth Edition GEORGE B. JOHNSON Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display PowerPoint ® Lectures prepared by Johnny El-Rady 25 Circulation and Respiration

2. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 25.1 Open and Closed Circulatory Systems Cnidarians and flatworms have a gastrovascular cavity that functions in both digestion and circulation Larger animals transport oxygen and nutrients from the environment and digestive cavity to body cells via a circulatory system Fig. 25.1

3. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Open circulatory system In mollusks and arthropods No distinction between circulating fluid (blood) and fluid of the body tissues (lymph) Hemolymph Closed circulatory system In annelids and vertebrates Circulating fluid (blood) is always enclosed within vessels that transport blood away from, and back to a pump (heart) Fig. 25.1

4. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display In vertebrates, blood vessels from a tubular network Arteries carry blood away from the heart Veins return blood to the heart Capillaries connect arteries to veins As blood plasma passes through capillaries, pressure forces fluid out of the capillary walls Some of this interstitial fluid returns directly to capillaries Some enters lymph vessels This lymph is returned to venous blood at specific sites

5. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 1. Transportation Functions of Vertebrate Circulatory Systems Respiratory Transport O 2 to cells for aerobic respiration Transport CO 2 to lungs/gills for elimination Nutritive Transport of absorbed products of digestion to cells Excretory Metabolic wastes and excessive water are filtered in the kidney and excreted in urine

6. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Hormones are transported from endocrine glands to distant target organs Help maintain a constant body temperature in homeotherms Some vertebrates use a countercurrent heat exchange 2. Regulation Fig. 25.2 3. Protection Blood clotting protects against blood loss White blood cells provide immunity against many- disease causing agents Warm blood going out heats cold blood coming in

7. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 25.2 Architecture of the Vertebrate Circulatory System The cardiovascular system of vertebrates consists of 1. Heart Pump 2. Blood vessels Network of tubes 3. Blood Circulating fluid Fig. 25.8 The flow of blood

8. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Fig. 25.3 The capillary network connects arteries with veins Blood loses most of its pressure and velocity as it passes through the vast capillary network

9. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Blood comes from the heart in large pulses Thus the artery must be able to expand Arterial walls are made up of three layers Arteries: Highways from the Heart Arterioles are smaller in diameter than arteries Their surrounding muscle layer can be relaxed to enlarge diameter Fig. 25.4a

10. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Transport oxygen and nutrients from blood to body’s cells and pick up carbon dioxide They have thin walls to allow diffusion to take place Capillaries: Where Exchange Takes Place Individual capillaries have high resistance to flow But the total cross-sectional area of capillaries is greater than that of arteries leading to it Fig. 25.4b

11. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Fig. 25.6 Walls have thinner layers of muscle and elastic fiber than arteries Veins: Returning Blood to the Heart Fig. 25.4c When empty, walls collapse VeinArtery

12. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Veins: Returning Blood to the Heart Blood flow back to the heart is aided by 1. Low pressure in veins 2. Skeletal muscles 3. Unidirectional valves Fig. 25.7

13. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 25.3 The Lymphatic System: Recovering Lost Fluid The cardiovascular system is very leaky To collect and recycle leaked fluid, the body uses a second circulatory system called the lymphatic system Fig. 25.9

14. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Blood pressure forces fluid out of capillaries Most of this interstitial fluid returns by osmosis Excess fluid is drained into lymphatic capillaries In the lymphatic system the fluid is called lymph Fig. 25.10

15. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Lymphatic vessels contain a series of one-way valves Permit movement only in the direction of the neck The lymphatic system has three important functions 1. Returns proteins to circulation If proteins are not returned to the blood, a condition called edema (body swelling) results 2. Transports fats absorbed from the intestine Lymph capillaries, called lacteals, absorb fats from the small intestine 3. Aids in the body’s defense Lymph nodes are filled with white blood cells

16. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 25.4 Blood Blood comprises about 5% of body mass It is composed of A fluid called plasma Several different kinds of cells

17. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Blood plasma is a complex solution of water and 1. Metabolites and wastes Glucose, vitamins, hormones and wastes 2. Salts and ions Chief plasma ions: sodium, chloride, bicarbonate Minor ions: calcium, magnesium, copper 3. Proteins Act as an osmotic counterforce Major protein: serum albumin Other proteins: fibrinogen and antibodies Blood Plasma: The Body’s Fluid

18. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display The fraction of blood volume that is occupied by cells is termed the blood’s hematocrit In humans it is usually about 45% The three principal types of blood cells are Erythrocytes Leukocytes Platelets Blood Cells Circulate Through the Body

19. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Erythrocytes (red blood cells) Carry hemoglobin, and therefore, oxygen to cells Do not contain a nucleus Leukocytes (white blood cells) Defend the body against microbes and foreign substance Neutrophils Monocytes/Macrophages Lymphocytes B cells – Produce antibodies T cells – Drill holes in invading bacteria

20. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Platelets Cell fragments that are bits of the cytoplasm of large bone marrow cells called megakaryocytes Do not contain a nucleus Play a key role in blood clotting Stimulate the formation of fibrin from fibrinogen Fig. 25.11 Fibrin

21. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Fig. 25.12 Types of blood cells

22. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Fig. 25.12 Types of blood cells

23. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 25.5 Fish Circulation The fish heart is a tube consisting of four chambers Sinus venosus and atrium, are collection chambers Ventricle and conus arteriosus, are pumping chambers Fig. 25.13a

24. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display The heart beat in fishes has a peristaltic sequence Starts at the rear (SV) and moves to the front Gill respiration provides fully oxygenated blood to the body However, circulation is sluggish This limits rate of oxygen delivery to rest of body Fig. 25.13b

25. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 25.6 Amphibian and Reptile Circulation The advent of lungs resulted in two circulations 1. Pulmonary circulation Delivers blood to the lungs 2. Systemic circulation Delivers blood to the rest of the body

26. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display The amphibian heart has two structural features that reduce mixing of oxygenated & deoxygenated blood 1. The atrium is divided into two chambers by a septum 2. Conus arteriosus is partially separated by another septum Amphibians in water supplement the oxygenation of blood by a process called cutaneous respiration Fig. 25.14a

27. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Among reptiles, additional modifications have further reduced the mixing of blood in the heart The ventricle is partially divided into two chambers by a septum They thus have completely divided pulmonary and systemic circulation The separation is complete in the crocodiles Fig. 25.14b

28. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 25.7 Mammalian and Bird Circulation Mammals and birds have a four-chambered heart that is really two separate pumping systems One pumps blood to the lungs The other pumps blood to the rest of the body The two pumps operate together within a single unit

29. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Oxygenated blood from lungs empties into the left atrium through the pulmonary veins Then from the atrium to the left ventricle Ventricle contracts forcing blood out in a single strong pulse Bicuspid (mitral) valve prevents backflow Blood then moves into the aorta Aortic valve prevents backflow into ventricle Circulation Through the Heart

30. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Blood eventually returns to the heart The superior vena cava drains the upper body The inferior vena cava drains the lower body Blood passes from the right atrium into the right ventricle through the one-way tricuspid valve Ventricle contracts forcing blood through the pulmonary valve into the pulmonary arteries Oxygenated blood eventually returns to the heart It is then pumped to the rest of the body Circulation Through the Heart

31. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Fig. 25.15 The heart and circulation of mammals and birds

32. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Heartbeat originates in the sinoatrial (SA) node Its membranes spontaneously depolarize This wave of depolarization spreads to the atria, causing them to contract The wave reaches the atrioventricular (AV) node It passes to the ventricles via the Bundle of His It is then conducted rapidly over the surface of the ventricles by Purkinje fibers Ventricular contraction empties the heart How the Heart Contracts

33. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Fig. 25.16 How the mammalian heart contracts

34. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Shows how heart cells depolarize and repolarize Depolarization causes contraction of the heart Repolarization causes relaxation of the heart Electrocardiogram (ECG or EKG) Fig. 25.16 Repolarization of the ventricles Depolarization of the atria Depolarization of the ventricles

35. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Simplest way is to listen to the heart at work using a stethoscope If valves are not fully opening or closing, turbulence is created This can be heard as a heart murmur Monitoring the Heart’s Performance

36. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Another way is to monitor blood pressure A sphygmomanometer is used to record two measurements Systolic pressure – High point Diastolic pressure – Low point Fig. 25.17

37. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 25.8 Cardiovascular Diseases The leading cause of deaths in the US Heart attacks Caused by an insufficient supply of blood to one or more parts of the heart muscle Also called myocardial infarctions Angina pectoris (“Chest pain”) Warning sign of a potential heart attack Strokes Caused by interference with blood flow to brain

38. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Atheroscleroris Accumulation of fatty materials on inner surfaces of artery The lumen (interior) becomes narrower Fig. 25.18 Arterioscleroris Hardening of the arteries Occurs when calcium is deposited in arterial walls

39. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Atherosclerosis is treated with 1. Medications Enzymes Anticoagulants Nitroglycerin 2. Invasive procedures Heart transplants Coronary bypass surgery Angioplasty Treatment of Blocked Coronary Arteries

40. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 25.9 Types of Respiratory Systems Respiration is the uptake of oxygen and the simultaneous release of carbon dioxide Most of the primitive phyla of organisms obtain oxygen by direct diffusion from seawater Fig. 25.19

41. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Aquatic animals possess special respiratory organs called gills Terrestrial arthropods use a network of air ducts called trachea Terrestrial vertebrates use respiratory organs called lungs Fig. 25.19

42. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 25.10 Respiration in Aquatic Vertebrates A fish continuously opens and closes its mouth It pushes water through mouth and out of gills This permits countercurrent flow Oxygenated water flows through the gills in a direction opposite blood flow in the capillaries The higher oxygen concentration in water drives the diffusion of oxygen into blood

43. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Fig. 25.20 Structure of a fish gill

44. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Fig. 25.21 Countercurrent flow Diffusion continues No further net diffusion

45. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 25.11 Respiration in Terrestrial Vertebrates Amphibians on land are able to respire through moist skin However, the main respiration route is the lung A sac with a convoluted internal membrane Reptiles are more active so they need more oxygen But they cannot respire through skin Instead, their lungs contain many more small chambers, greatly increasing the surface area

46. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 25.11 Respiration in Terrestrial Vertebrates Mammals have an even greater oxygen demand because they maintain a constant body temperature They increase the lung surface area even more Alveoli Small chambers in interior of lung Bronchioles Short passageways connecting clusters of alveoli

47. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Fig. 25.22 Evolution of the vertebrate lung

48. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Flying creates a very large oxygen demand Therefore, birds must possess very efficient lungs Air flows through the lungs in one direction This one-way air flow results in Birds Perfect the Lung 1. No dead volume Air is always fully oxygenated 2. A crosscurrent flow Blood leaving the lung can still contain more oxygen than exhaled air

49. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Fig. 25.23 How a bird breathes Most efficient

50. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 25.12 The Mammalian Respiratory System A pair of lungs hang free in the thoracic cavity An air tube called bronchus connects each lung to a trachea Air normally enters through the nostrils It passes to the larynx (voice box) and then the trachea And then through the bronchus to the lungs Lungs contain millions of alveoli Sites of gas exchange between air and blood

51. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Fig. 25.24 The human respiratory system The thoracic cavity is bounded on the bottom by a thick layer of muscle called the diaphragm Each lung is covered by a pleural membrane

52. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Breathing – Active pumping of air in and out of lungs During inhalation Diaphragm contracts and flattens Chest cavity expands downwards and outwards This creates negative pressure in lungs and air rushes in During exhalation Diaphragm relaxes Volume of chest cavity decreases Pressure in lungs increases and air is forced out The Mechanics of Breathing

53. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Fig. 25.25 How breathing works

54. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display In a human, a typical breath at rest moves about 0.5 liters of air called the tidal volume When each breath is completed, the lung still contains a volume of air (~ 1.2 liters) called the residual volume Each inhalation adds from 500 milliliters (resting) to 3,000 milliliters (exercising) of additional air Each exhalation removes approximately the same volume as inhalation added The Mechanics of Breathing

55. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display 25.13 How Respiration Works: Gas Exchange Oxygen moves within the circulatory system carried piggyback on the protein hemoglobin Hemoglobin contains iron, which combines with oxygen in a reversible way Fig. 25.26

56. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Hemoglobin bind O 2 within red blood cells (RBCs) This causes more to diffuse in from blood plasma In the lungs, most hemoglobin molecules carry a full load of O 2 The presence of carbon dioxide (CO 2 ) in tissues speeds up the unloading of O 2 O 2 Transport

57. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display As red blood cells are unloading O 2 they are also absorbing CO 2 from the tissue CO 2 Transport The enzyme carbonic anhydrase combines CO 2 and H 2 O to form carbonic acid (H 2 CO 3 – ) This acid dissociates into bicarbonate (HCO 3 – ) and hydrogen (H + ) A transporter protein moves one bicarbonate out of the RBC and brings in one chloride ion This “chloride shift” facilitates the diffusion of more CO 2 into the RBC

58. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display RBC carry the bicarbonate ions back to the lungs There, the lower CO 2 concentration causes the carbonic anhydrase reaction to occur in reverse CO 2 is released from RBC and ultimately exhaled Hemoglobin can now pick up O 2 again CO 2 Transport

59. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Fig. 25.27 How respiratory gas exchange works

60. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Hemoglobin also has the ability to hold and release the gas nitric oxide (NO) NO Transport NO causes dilates blood vessels Thus, it regulates blood flow and blood pressure Hemoglobin picks up NO in the lungs and releases it in the tissues

61. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Fig. 25.28 25.14 The Nature of Lung Cancer One of the leading causes of deaths among adults in the world The incidence of cancer is not uniform throughout the US This suggests environmental factors Most carcinogens are also mutagens High incidence in cities and Mississippi Delta

62. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Cancer-causing genes are involved in regulating cell growth and division Tumor suppressor genes actively prevent tumors from forming Rb Encodes the Rb protein Slows down cell division by inhibiting DNA replication p53 Encodes the p53 protein Inspects the DNA for damage before If DNA repair is unsuccessful, the cell is destroyed

63. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Fig. 25.29 The roles Rb and p53 play in controlling cell division

64. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display After the incidence of smoking began to increase in the US, so did the incidence of lung cancer Smoking Causes Lung Cancer Fig. 25.30

65. Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display Cigarette smoke contains many powerful mutagens Benzo[a]pyrene binds to three sites in the p53 gene Mutations at these sites inactivate the gene Research found that the p53 gene is inactivated in 70% of all lung cancers Moreover, the inactivating mutations occurred at the binding sites of benzo[a]pyrene! Nicotine in cigarette smoke is an addictive drug! Smoking Causes Lung Cancer