1. Chapter 42
Internal Transport

2. Diffusion Small, simple invertebrates
Sponges, cnidarians, and flatworms

3. Invertebrates with no circulatory system

4. Specialized circulatory system
Larger animals
Blood
Heart
System of blood vessels
Spaces through which blood circulates

5. Interstitial fluid Tissue fluid between cells
Brings oxygen and nutrients into contact with cells
All animals

6. Open circulatory system
Arthropods and most mollusks
Blood flows into a hemocoel
Bathes the tissues directly

7. Closed circulatory system
Some invertebrates
All vertebrates
Blood flows through a continuous circuit of blood vessels

8. Closed circulatory system

9. Vertebrate circulatory system
Muscular heart
Arteries
Capillaries
Veins

10. Vertebrate circulatory system
Transports nutrients, oxygen, wastes, and hormones
Helps maintain
Fluid balance
Appropriate pH
Body temperature
Defends body against disease

11. Plasma Water Salts Substances in transport Plasma proteins Albumins
Globulins
Fibrinogen

12. Blood components

13. Red blood cells (erythrocytes)
Transport oxygen and carbon dioxide
Produce large quantities of hemoglobin
Red pigment that binds with oxygen

14. White blood cells (leukocytes)
Defend the body against disease organisms
Agranular white blood cells
Lymphocytes
Monocytes

15. Granular white blood cells
Neutrophils
Eosinophils
Basophils

16. Platelets Patch damaged blood vessels
Release substances essential for blood clotting

17. Blood clotting
Damaged cells and platelets release substances that activate clotting factors
Prothrombin is converted to thrombin

18. Thrombin catalyzes the conversion of fibrinogen to an insoluble protein, called fibrin
Fibrin forms long threads that form the webbing of the clot

19. Blood clotting

20. Arteries Veins Carry blood away from the heart
Return blood to the heart

21. Arterioles Constrict (vasoconstriction) Dilate (vasodilation)
Regulate blood pressure and distribution of blood to the tissues

22. Capillaries
Thin-walled exchange vessels through which blood and tissues exchange materials

23. Blood flow through a capillary network

24. Vertebrate heart One or two atria One or two ventricles Receive blood
Pump blood into the arteries

25. Fish heart Single atrium and ventricle
Part of a single circuit of blood flow

26. Terrestrial vertebrates
Complex circulatory systems separate oxygen-rich from oxygen-poor blood
Allows the higher metabolic rate needed to support an active terrestrial lifestyle

27. Amphibians Two atria and a ventricle
Blood flows through a double circuit
Oxygen-rich blood is partly separated from oxygen-poor blood

28. Most reptiles
Wall that partly divides the ventricles, minimizing the mixing of oxygen-rich and oxygen-poor blood

29. Birds and mammals
Four-chambered hearts separate oxygen-rich blood from oxygen-poor blood

30. Human heart Enclosed by a pericardium
Valves that prevent backflow of blood

31. Right atrioventricular (AV) valve (tricuspid valve)
Between right atrium & ventricle
Mitral valve
Between left atrium and ventricle
Semilunar valves
Guard the exits from the heart

32. Human heart

33. Cardiac muscle fibers are joined by intercalated discs
The sinoatrial (SA) node (pacemaker) initiates each heartbeat
A specialized electrical conduction system coordinates heartbeats

34. Cardiac cycle One complete heartbeat Contraction occurs during systole
Period of relaxation is diastole

35. Beginning of ventricular systole
Closing of the AV valves
Low-pitched “lub” sound
Beginning of ventricular diastole
Closing of the semilunar valves
Short, loud, sharp “dup” sound

36. Cardiac output (CO) Stroke volume times heart rate
Stroke volume depends on venous return and on neural messages and hormones, especially epinephrine and norepinephrine

37. Starling’s law of the heart
The more blood delivered to the heart by the veins, the more blood the heart pumps

38. Heart rate Regulated mainly by the nervous system
Influenced by hormones and body temperature

39. Blood pressure
Force blood exerts against the inner walls of the blood vessel
Greatest in the arteries
Decreases as blood flows through the capillaries

40. Blood pressure depends on
Cardiac output
Blood volume
Resistance to blood flow

41. Peripheral resistance
Resistance to blood flow
Blood viscosity
Friction between blood and blood vessel wall

42. Blood
pressure

43. Baroreceptors Sensitive to blood pressure changes
Send messages to the cardiac and vasomotor centers in the medulla of the brain

44. When blood pressure increases
Cardiac center stimulates parasympathetic nerves that slow heart rate
Vasomotor center inhibits sympathetic nerves that constrict blood vessels
Blood pressure is reduced

45. Angiotensin Aldosterone Hormone that raises blood pressure
Helps regulate salt excretion
Affects blood volume and blood pressure

46. Pulmonary circulation Systemic circulation
Connects heart and lungs
Systemic circulation
Connects heart and tissues

47. Pulmonary circulation
Right ventricle pumps blood into the pulmonary arteries, one going to each lung
Blood circulates through pulmonary capillaries in the lung
Blood is conducted to the left atrium by a pulmonary vein

48. Systemic circulation Left ventricle pumps blood into the aorta
Aorta branches into arteries leading to the body organs
Blood flows through capillary networks within various organs

49. Blood flows into veins that conduct it to the superior vena cava or inferior vena cava
Blood returns to the right atrium

50. Systemic and
pulmonary
circulation

51. Coronary arteries Hepatic portal system
Supply the heart muscle with blood
Hepatic portal system
Circulates nutrient-rich blood through the liver

52. Lymphatic system Collects interstitial fluid Returns it to the blood
Plays an important role in homeostasis of fluids
Defends body against disease
Absorbs lipids from the digestive tract

53. Lymph Lymphatic vessels Formed from interstitial fluid
Conduct lymph to the thoracic duct and right lymphatic duct in the shoulder region
Ducts return lymph to the blood circulatory system

54. Lymphatic capillaries