1. Copyright © 2009 Pearson Education, Inc.  Giraffes have –Very strong hearts –Higher blood pressure –Sinuses that function like check valves to lower pressure to head when bending down –Valves in veins of legs to keep blood moving upward

2. Blood and respiratory gasses are passed through which organ system?

3. Copyright © 2009 Pearson Education, Inc.  Circulatory system  All cells need –Nutrients –Gas exchange –Removal of wastes  Diffusion alone is inadequate for large and complex bodies

4. Copyright © 2009 Pearson Education, Inc. ◦ A gastrovascular cavity in cnidarians and flatworms serves –Digestion –Distribution of substances ◦ Most animals use a circulatory system –Blood –Heart –Blood vessels

5. Copyright © 2009 Pearson Education, Inc. 1. Open circulatory systems –Arthropods and many molluscs –Heart pumps blood through open-ended vessels –Cells directly bathed in blood Pores Tubular heart

6. Copyright © 2009 Pearson Education, Inc. 2. Closed circulatory systems –Vertebrates, earthworms, squids, octopuses –Blood stays confined to vessels –A heart pumps blood through arteries to capillaries; veins return blood to heart Capillary beds Artery (O 2 -rich blood) Arteriole Artery (O 2 -poor blood) Heart Ventricle Atrium Vein Venule Gill capillaries

7. Copyright © 2009 Pearson Education, Inc.  Land vertebrates have double circulation –Separate pulmonary (lung) and systemic (body) circuits –Two circuits that do not mix –Right side pumps blood from body to lungs –Left side pumps blood from lungs to body Lung capillaries Pulmonary circuit V Right Systemic capillaries AA Left Systemic circuit V

8. Lung capillaries Pulmonary circuit V Right Systemic capillaries AA Left Systemic circuit V ◦ Four-chambered hearts –Crocodilians, birds, mammals –Two atria and two ventricles –Higher blood pressure –Supports more efficient movement of blood

9. Copyright © 2009 Pearson Education, Inc. THE HUMAN CARDIOVASCULAR SYSTEM

10. Superior vena cava Pulmonary artery Capillaries of right lung 8 9 2 3 Aorta 4 5 10 1 6 Pulmonary vein 9 Right atrium Inferior vena cava Right ventricle 4 8 3 Pulmonary artery Capillaries of left lung Aorta Pulmonary vein Left atrium Left ventricle 2 7 Capillaries of head, chest, and arms Capillaries of abdominal region and legs

11. Copyright © 2009 Pearson Education, Inc. ◦ The mammalian heart –Two thin-walled atria that –Pump blood –To ventricles –Two thick-walled ventricles that –Pump blood –To lungs and all other body regions Right atrium To lung From lung Semilunar valve Atrioventricular (AV) valve Left atrium To lung From lung Semilunar valve Atrioventricular (AV) valve Right ventricle Left ventricle

12. Copyright © 2009 Pearson Education, Inc. ◦ During diastole, blood flows Veins  heart ◦ During systole, blood flows Atria  ventricles Semilunar valves closed 1 Heart is relaxed. AV valves are open. Diastole 0.4 sec 2 Atria contract. Systole 0.1 sec Semilunar valves are open. 3 Ventricles contract. AV valves closed 0.3 sec

13. Copyright © 2009 Pearson Education, Inc. ◦ Cardiac output –Amount of blood/minute pumped into systemic circuit ◦ Heart rate –Number of beats/minute ◦ Heart valves –Prevent the backflow of blood ◦ Heart murmur –A defect in one or more heart valves

14. Copyright © 2009 Pearson Education, Inc. ◦ The pacemaker (SA node) –Sets the rate of heart contractions –Generates electrical signals in atria ◦ The AV node –Relays these signals to the ventricles

15. Pacemaker (SA node) AV node Right atrium 1 Pacemaker generates signals to contract 2 Signals spread through atria and are delayed at AV node ECG 3 Signals relayed to apex of heart 4 Signals spread through ventricle Apex Specialized muscle fibers

16. Copyright © 2009 Pearson Education, Inc. ◦ An electrocardiogram (ECG or EKG) –Records electrical changes in heart ◦ Heart rate normally adjusts to body needs ◦ Abnormal rhythms may occur in a heart attack

17. Heart

18. Copyright © 2009 Pearson Education, Inc.  A heart attack is damage to cardiac muscle –Typically from a blocked coronary artery Blockage Dead muscle tissue Right coronary artery Superior vena cava Pulmonary artery Aorta Left coronary artery

19. Copyright © 2009 Pearson Education, Inc.  Stroke –Death of brain tissue from blocked arteries in the head

20. Copyright © 2009 Pearson Education, Inc.  Atherosclerosis –Plaques develop inside inner walls of blood vessels –Plaques narrow blood vessels –Blood flow is reduced Plaque Epithelium Connective tissue Smooth muscle

21. Copyright © 2009 Pearson Education, Inc.  Capillaries –Thin walls—a single layer of epithelial cells –Narrow—blood cells flow in a single file –Increase surface area for gas and fluid exchange Nuclei of smooth muscle cells Red blood cell Capillary

22. Diffusion of molecules Capillary Interstitial fluid Tissue cell

23. Copyright © 2009 Pearson Education, Inc. ◦ Blood and interstitial fluid exchange substances –By diffusion –By pressure flow through clefts between epithelial cells ◦ Blood pressure forces fluid out of capillaries at the arterial end ◦ Osmotic pressure draws in fluid at the venous end Capillaries allow the transfer of substances through their walls

24. Tissue cells Osmotic pressure Interstitial fluid Net fluid movement in Blood pressure Osmotic pressure Venous end of capillary Arterial end of capillary Blood pressure Net fluid movement out

25. Copyright © 2009 Pearson Education, Inc.  Arteries and veins –Lined by single layer of epithelial cells; smooth muscle in walls –Veins have one-way valves that restrict backward flow Connective tissue Capillary Venule Smooth muscle Arteriole ArteryVein Valve Epithelium Basal lamina Epithelium Smooth muscle Epithelium Connective tissue

26. Copyright © 2009 Pearson Education, Inc. –Pressure from muscle contractions –Squeezes veins –One-way valves limit blood flow to one direction, towards heart Direction of blood flow in vein Valve (open) Skeletal muscle Valve (closed)

27. Copyright © 2009 Pearson Education, Inc. –Deep Vein Thrombosis (DVT) –Blood pools deep within body- usually lower leg or thigh –Clot can form- travel to lungs- pulmonary embolism

28. Copyright © 2009 Pearson Education, Inc. –Maintain healthy weight –Don’t smoke –Stretch or move legs on long flights or car rides –Compression garments –Blood thinners

29. Copyright © 2009 Pearson Education, Inc. ◦ Blood pressure –The force blood exerts on vessel walls –Depends on –Cardiac output –Resistance of vessels –Decreases as blood moves away from heart

30. Systolic pressure Diastolic pressure 120 100 80 60 40 20 0 Relative sizes and numbers of blood vessels Pressure (mm Hg) Velocity (cm/sec) 50 40 30 20 10 0 Aorta Venae cavae Arteries CapillariesVenulesVeinsArterioles

31. Copyright © 2009 Pearson Education, Inc.  Blood pressure is –Highest in ________ –Lowest in _________  Blood pressure is measured as –Systolic pressure—caused by ventricular contraction –Diastolic pressure—low pressure between contractions

32. Copyright © 2009 Pearson Education, Inc.  Hypertension is a serious cardiovascular problem –Consistent pressures above either –140 systolic –90 diastolic Typical blood pressure 120 systolic 70 diastolic Pressure in cuff above 120 120 Rubber cuff inflated with air Artery closed Artery 1 2 Pressure in cuff at 120 120 Sounds audible in stethoscope 3 70 Sounds stop 4 Pressure in cuff at 70

33. Copyright © 2009 Pearson Education, Inc.  Hypertension causes –Heart to work harder, weakening heart over time –Increased plaque formation from tiny ruptures –Increased risk of blood clot formation  Hypertension can cause –Heart attacks –Strokes –Kidney failure

34. Copyright © 2009 Pearson Education, Inc. STRUCTURE AND FUNCTION OF BLOOD

35. Copyright © 2009 Pearson Education, Inc.  Plasma is about 90% water  Plasma contains –Various inorganic ions –Proteins, nutrients –Wastes, gases –Hormones

36. Plasma (55%) Constituent Osmotic balance, pH buffering, and maintaining ion concentration of interstitial fluid Solvent for carrying other substances Water Ions (blood electrolytes) Major functions Sodium Potassium Calcium Magnesium Chloride Bicarbonate Plasma proteins ClottingFibrinogen Osmotic balance and pH buffering DefenseImmunoglobulins (antibodies) Substances transported by blood Nutrients (e.g., glucose, fatty acids, vitamins) Waste products of metabolism Respiratory gases (O 2 and CO 2 ) Hormones Centrifuged blood sample

37. Copyright © 2009 Pearson Education, Inc. ◦ Red blood cells (erythrocytes) –Transport O 2 bound to hemoglobin ◦ White blood cells (leukocytes) –Function inside and outside the circulatory system –Fight infections and cancer ◦ Platelets

38. Cellular elements (45%) Centrifuged blood sample Number per µL (mm 3 ) of blood Cell type Functions Erythrocytes (red blood cells) 5–6 million Transport of oxygen (and carbon dioxide) Leukocytes (white blood cells) Basophil Lymphocyte Defense and immunity Eosinophil 5,000–10,000 250,000– 400,000 Neutrophil Monocyte Blood clotting Platelets

39. Plasma (55%) Constituent Osmotic balance, pH buffering, and maintaining ion concentration of interstitial fluid Solvent for carrying other substances Water Ions (blood electrolytes) Major functions Sodium Potassium Calcium Magnesium Chloride Bicarbonate Plasma proteins ClottingFibrinogen Osmotic balance and pH buffering DefenseImmunoglobulins (antibodies) Substances transported by blood Nutrients (e.g., glucose, fatty acids, vitamins) Waste products of metabolism Respiratory gases (O 2 and CO 2 ) Hormones Cellular elements (45%) Centrifuged blood sample Number per µL (mm 3 ) of blood Cell typeFunctions Erythrocytes (red blood cells) 5–6 million Transport of oxygen (and carbon dioxide) Leukocytes (white blood cells) Basophil Lymphocyte Defense and immunity Eosinophil 5,000–10,000 250,000– 400,000 NeutrophilMonocyte Blood clotting Platelets

40. Copyright © 2009 Pearson Education, Inc. ◦ Function: ◦ If too few: –Anemia: abnormally low amounts of hemoglobin or red blood cells –Causes fatigue due to lack of oxygen in tissues

41. Copyright © 2009 Pearson Education, Inc.  Function: Clot formation during tissue damage ◦ When a blood vessel is damaged –Platelets help trigger the conversion of fibrinogen to fibrin –Fibrin forms a net with cells (clot) that plugs the leak

42. Platelets adhere to exposed connective tissue 1 Epithelium Connective tissue Platelet

43. Platelets adhere to exposed connective tissue 1 Epithelium Connective tissue Platelet Platelet plug forms 2 Platelet plug

44. Platelets adhere to exposed connective tissue 1 Epithelium Connective tissue Platelet Platelet plug forms 2 Platelet plug Fibrin clot traps blood cells 3