Chapter 24 Lecture Outline See PowerPoint Image Slides

1. Chapter 24 Lecture Outline See PowerPoint Image Slides for all figures and tables pre-inserted into PowerPoint without notes.

2. Exchanging Materials: Basic Principles • Large, multicellular organisms need a way to deliver oxygen and nutrients to the cells deep within tissues. • Several organ systems help deliver oxygen, nutrients to and remove wastes from cells. • Circulatory, lymphatic, respiratory, digestive, and excretory systems

3. The Cardiovascular System • Pumps blood around the body • Consists of • Blood • Fluid tissue that transports materials and heat • The heart • A muscular pump that forces fluid through the body • Vessels • “Pipes” that move blood through the body • Arteries carry blood from the heart to the tissues. • Capillaries are small vessels that carry blood through tissues. • Veins carry blood from the tissues to the heart.

4. The Nature of Blood • Consists of • Several types of cells • Called the formed elements • Plasma • Contains different kinds of dissolved molecules

5. Formed Elements • Red blood cells • Lack a nucleus • Contain hemoglobin • Transport oxygen and carbon dioxide • Carbonic anhydrase converts carbon dioxide to bicarbonate that can be dissolved in the blood. • Anemia is a lack of oxygen resulting from a lack of red blood cells.

6. Formed Elements • White blood cells • Also called leukocytes • Lack hemoglobin • Have a nucleus • Include basophils, eosinophils, neutrophils, lymphocytes, and monocytes • Defend the body against microorganisms, damaging chemicals, and cancer

7. Formed Elements • Platelets • Not whole cells • Fragments of white blood cells • Important in blood clotting • Collect at the site of a wound • Release clotting factors • Initiate a sequence of reactions that trap blood cells to form a clot • Eventually the clots (scabs) are replaced by healthy, living tissue.

8. Plasma • Liquid part of the blood • Contains • Salts that serve to • Buffer and maintain blood pH • Maintain osmotic balance • Keeps the tissue fluid between cells at the right solute concentration so that it flows into the capillaries, maintaining blood pressure

9. Plasma • Proteins • Antibodies and other immune proteins • Albumin to maintain osmotic balance • Transports bilirubin from degraded RBCs to the liver • Accumulated bilirubin can cause jaundice • Nutrients • Amino acids • Sugars • Lipoproteins carry fats and cholesterol • Hormones

10. Composition of Blood

11. Functions of Blood • Transports molecules, cells • Oxygen, carbon dioxide • Nutrients • Waste products • Immune cells and antibodies • Hormones • Regulates temperature • If body temperature is too high, blood will be shunted to the body surface to radiate heat. • If body temperature is too low, blood will be shunted to the body core to conserve heat.

12. The Heart • Pumps the blood • Generates the pressure necessary to move blood through vessels • Blood must flow to move nutrients to tissues and waste away from tissues. • Heart must repeatedly contract in order to keep blood moving.

13. Mammalian Heart • Has four chambers with four valves • Two atria and two ventricles • Ventricles • Are larger and more muscular • Force blood through the arteries to the body • The aorta and pulmonary artery flow out of the ventricles. • Atria • Are smaller with thinner walls • Pump blood into the ventricles

14. Mammalian Heart • Atria and ventricles are separated by atrioventricular valves. • Valves ensure that the blood only flows in one direction. • Semilunar valves in the aorta and pulmonary arteries • Act as “check valves” to prevent blood from flowing back into the ventricles when they relax • Damaged valves causes inefficient pumping. • Detected as heart murmurs because some of the blood is being pushed backward

15. The Anatomy of the Heart

16. Mammalian Heart • Two different sides have different jobs • The right atrium receives blood from the body. • The right ventricle pumps the blood to the lungs. • Called pulmonary circulation • Allows for the exchange of carbon dioxide and oxygen in the lungs • The left atrium receives blood from the lungs. • The left ventricle pumps blood to all other parts of the body. • Called systemic circulation • Allows for the delivery of oxygen, nutrient, and waste exchange in the tissues

17. Pulmonary and Systemic Circulation

18. Blood Vessels • The tubes that transport blood from one place to another in the body • Types of blood vessels • Arteries • Veins • Capillaries

19. Arteries • Carry blood away from the heart • Contraction of the ventricles increases the pressure in the arteries. • Called systolic blood pressure • Relaxation of the ventricles decreases the pressure in the arteries. • Called diastolic blood pressure

20. Arteries • Blood pressure readings include both types of blood pressure. • Systolic/diastolic • 120/80 • Have thick, muscular, and elastic walls • Can stretch when pressure increases • Branch into arterioles to take blood throughout the body

21. Veins • Collect blood from the capillaries and return it to the heart • Have very low pressure • Walls not very muscular

22. Veins • Have valves to prevent backflow • Dysfunctional valves cause varicose veins. • Contraction of leg muscles aids in pushing blood through veins. • Sitting or standing for a long time can cause pooling of blood in the feet. • Causes swelling • Can cause fainting because the brain doesn’t get enough blood

23. The Structure of Arteries, Veins, and Capillaries

24. Capillaries • Tiny vessels, one-cell thick • RBC go through capillaries single file • Have thin walls • Only one-cell thick • Allows materials to diffuse into and out of the blood • Allows liquid to be exchanged between the blood and tissue fluid • Are numerous • All cells in the body have a capillary nearby. • Flow of blood through capillaries is slow • Allows time for diffusion and fluid exchange

25. Capillaries

26. The Lymphatic System • A second circulatory system • A collection of thin-walled vessels • Called lymph vessels • Branch throughout body and lymph organs • Functions • Moves fat from digestive system to blood stream • Transports excess fluid back to cardiovascular system • Carries immune cells

27. The Lymphatic System

28. The Lymphatic System • Lymph • Fluid tissue that is moved through the lymph organs via lymph vessels • Emptied into large veins near the heart • Moved through lymph vessels by muscle contraction • Edema • Accumulation of fluid in tissues

29. Lymph Organs • Lymph nodes • Filter lymph • Contain large numbers of white blood cells • Remove microorganisms and foreign particles from the lymph • When an infection is active, the lymph nodes enlarge • Tonsils • Near the throat • Contain the tonsils and the adenoids • Filter pathogens that enter through the mouth and nose

30. Lymph Organs • Spleen • Contains a large number of white blood cells • Filters the blood • Cleans out pathogens and dying RBCs • Located just below the diaphragm • Thymus • Produces WBCs called T-lymphocytes • Most active in children • Shrinks as one ages

31. Lymph Organs • Red bone marrow • Found in children’s bones • Reduced in adult bones • Produces RBCs, WBCs, and platelets

32. The Respiratory System • Moves air into and out of the body • Lungs • Allow gas exchange between air and blood • Trachea • A tube that carries air into and out of the lung • Branches into bronchi then into bronchioles • Bronchioles end in alveoli • Alveoli are small sacs where gas exchange takes place • Air-transport pathway • Includes the nose, mouth, and throat • Pulls air into the trachea

33. Respiratory Anatomy

34. Breathing System Regulation • Breathing is the process of moving air into and out of the lungs. • Involves the diaphragm • A large muscle that separates the chest cavity (containing lungs) from the abdominal cavity • When contracted, the diaphragm moves down • Creates negative pressure in the chest cavity • Pulls air into the lungs • When relaxed, the diaphragm resumes its normal position • Generates positive pressure in the chest cavity • Pushes air out of the lungs

35. Breathing Movements

36. Breathing During Exercise • Exercise increases the body’s demand for oxygen. • Requires faster gas exchange in lungs • Accomplished by • Increased breathing rate • Can involve greater diaphragm contraction to pull in more air

37. Breathing During Exercise • Can also involve contraction of abdominal muscles to fully empty the lungs • This happens when carbon dioxide concentration increases in the blood and blood pH. • Sensed by brain, then brain causes increased contraction of the diaphragm and intercostal muscles • Increased air exchange volume in each breath

38. The Control of Breathing Rate

39. Lung Function • Lungs are specialized so that blood and air can come very close together. • This facilitates gas exchange between them. • Blood flows through capillaries in the lungs that come very close to the air in the alveoli. • Oxygen and carbon dioxide cross the alveoli and capillary walls. • Therefore, the surface area of the alveoli must be very large (collectively). • This is why there are so many alveoli.

40. The Association of Capillaries with Alveoli

41. Lung Function • Gas exchange is facilitated by blood and air movement. • Blood enters the lungs high in carbon dioxide and low in oxygen. • Air enters the lungs high in oxygen and low in carbon dioxide. • Therefore, carbon dioxide diffuses from the blood to the air and oxygen diffuses from the air to the blood.

42. Disrupting Lung Function • Interfering with blood flow or gas exchange will reduce the efficiency of the organism. • A poorly pumping heart reduces the amount of blood that is sent to the lungs. • Constriction of bronchioles (asthma) reduces the amount of air that can enter the alveoli. • Reducing the number of alveoli (emphysema) reduces the surface area for gas exchange.

43. The Digestive System • Responsible for processing and distributing nutrients • Mechanical processing • Chemical processing • Nutrient uptake • Chemical alteration • Consists of • A muscular tube • Glands that secrete digestive juices

44. The Digestive System

45. Mechanical and Chemical Processing • The process of taking large pieces of food and breaking them down into individual molecules that can be absorbed • Mechanical processing • Chewing in the oral cavity generates a food bolus. • Increases surface area of food • Allows digestive enzymes greater access to the food

46. Mechanical and Chemical Processing • Salivary glands produce saliva containing some digestive enzymes. • Chewing mixes the food with the saliva. • Salivary amylase begins to break down starch. • Tongue • Tastes food • Pushes food back toward throat

47. Mechanical and Chemical Processing • Food bolus passes through the esophagus to the stomach • Moves from mouth to the pharynx into the esophagus • Contractions of the pharynx move the food toward the stomach. • In the stomach, food is churned. • Mixes food with digestive juices • Pepsin breaks down proteins. • Low pH denatures proteins • The food then moves to the small intestine where chemical breakdown is completed.

48. Mechanical and Chemical Processing • Chemical processing in the small intestine • Also known as the duodenum • Receives digestive enzymes and bicarbonate ions from the pancreas • Digestive enzymes complete the chemical processing of food. • Bicarbonate neutralizes the low pH of the food coming from the stomach. • Receives bile from the liver by way of the gall bladder • Emulsifies fat into smaller fat globules • Allows digestive enzymes greater access to the fats

49. Mechanical and Chemical Processing • Finally, the remainder of the undigested food passes from the small intestine to the large intestine (colon). • 1.5 meters long • Water is reabsorbed. • Contains bacteria that utilize the undigested food • These bacteria produce vitamins that we need.

50. Digestive Enzymes