Blood and circulation- Unit 5

10 IB biology

1. : What are the three main elements of the cardiovascular system?

Pumping Mechanism (Heart), Transport Medium (Blood), Transport Vessels (Arteries, Veins, Capillaries)

2. : What is the role of the heart in the cardiovascular system?

The heart pumps deoxygenated blood to the lungs and oxygenated blood to the rest of the body.

3. : What is plasma?

The fluid (non-living) portion of blood, making up about 55% of blood volume.

4. : What is the function of hemoglobin?

Hemoglobin is an iron-containing molecule that binds with oxygen to transport it throughout the body.

5. : What are the two factors that determine when oxygen is picked up and released by hemoglobin?

Concentration of Oxygen and Acidity of the Surrounding Fluid.

6. : What are erythrocytes?

Specialized for oxygen transport, mature erythrocytes have no nucleus and are packed with hemoglobin.

7. : What is the role of hemoglobin in erythrocytes?

Hemoglobin binds with oxygen to transport it throughout the body.

8. : What are leukocytes?

White blood cells that help protect the body from disease-causing agents.

9. : What are the two categories of leukocytes?

Granulocytes and Agranulocytes.

10. : What are granulocytes?

Leukocytes with granules in the cytoplasm, including neutrophils, eosinophils, and basophils.

11. : What are neutrophils?

Granulocytes with a 3-lobed nucleus, found in pus.

12. : What are eosinophils?

Granulocytes with a b-shaped nucleus, active in allergic reactions.

13. : What are basophils?

Granulocytes with a kidney bean-shaped nucleus.

14. : What are agranulocytes?

Leukocytes without granules in the cytoplasm, including lymphocytes and monocytes.

15. : What are lymphocytes?

Agranulocytes with a light blue nucleus, involved in the body's acquired immune response.

16. : What are monocytes?

Agranulocytes that engulf and destroy foreign material.

17. : What are platelets?

Fragments of cells that play an important role in blood clotting.

18. : What is the process of blood clotting?

Blood clotting occurs in 5 steps: attraction of platelets to the site, release of chemicals by platelets, production of thromboplastin, formation of thrombin, and production of fibrin.

19. : Who identified the 4 major blood groups and in what year?

Karl Landsteiner in 1901.

20. : What are the 4 major blood groups?

A, B, AB, and O.

21. : What characterizes each blood group?

The presence or absence of protein markers (antigens) on the walls of red blood cells.

22. : What are antibodies responsible for?

The agglutination (clumping) of blood cells when incompatible blood groups are mixed.

23. : What is the rhesus factor (Rh)?

Another antigen found on red blood cells.

24. : What does it mean to be Rh positive (Rh+)?

Carrying the Rh antigen.

25. : What does it mean to be Rh negative (Rh-)?

Not carrying the Rh antigen.

26. : When does the anti-Rh antibody appear in the blood?

After exposure to the Rh antigen.

27. : What is the risk for an Rh- mother carrying an Rh+ baby?

The mother may produce anti-Rh antibodies that can destroy the baby's red blood cells.

28. : How can Rh incompatibility be prevented?

By giving the mother an injection of RhIg to suppress her ability to react to Rh+ red blood cells.

29. : What are the three main types of blood vessels in the mammalian circulatory system?

Arteries, Veins, Capillaries.

30. : What do arteries carry?

Blood away from the heart (mostly oxygenated blood).

31. : What is the exception to arteries carrying oxygenated blood?

The Pulmonary Artery, which carries deoxygenated blood from the heart to the lungs.

32. : What are the three layers of arteries and arterioles?

Outer layer (connective tissue and elastic fibers), Middle layer (thickest, circular bands of smooth muscle), Inner layer (one cell thick, smooth epithelial cells).

33. : What is the distinguishing feature of arteries?

The thick elastic middle layer, which allows arteries to expand and snap back, helping keep blood flowing in the right direction.

34. : What is the largest artery in the body?

The Aorta (2.5 cm in diameter).

35. : What does the Aorta transport?

Large volumes of oxygen-rich blood from the heart to other arteries in the body.

36. : What arteries supply blood to the neck and head?

Carotid Arteries.

37. : What arteries supply blood to the arms?

Subclavian, Axillary, Brachial, Radial, and Ulnar Arteries.

38. : What arteries supply blood to the legs?

Iliac Arteries and Femoral Arteries.

39. : What arteries supply blood to the heart?

Coronary Arteries.

40. : What arteries supply blood to the digestive system?

Celiac Trunk and its branches (Hepatic, Gastric, Mesenteric Arteries).

41. : What arteries supply blood to the liver?

Hepatic Arteries.

42. : What arteries supply blood to the kidneys?

Renal Arteries.

43. : What arteries supply blood to the stomach?

Gastric Artery.

44. : What arteries supply blood to the intestines?

Mesenteric Arteries.

45. : What do veins carry?

Blood towards the heart (mostly deoxygenated blood).

46. : What is the exception to veins carrying deoxygenated blood?

The Pulmonary Vein, which carries oxygenated blood from the lungs to the heart.

47. : How do veins keep blood flowing towards the heart?

Gravity for regions above the heart, skeletal muscle contractions for regions below the heart, and one-way valves to prevent backflow.

48. : What are capillaries?

The smallest blood vessels, reaching every corner of the body.

49. : What is the structure of capillary walls?

One cell thick, with a diameter just large enough for the largest blood cells to pass single file.

50. : What do capillary walls regulate?

The movement of materials into and out of the bloodstream.

51. : How many chambers does the mammalian heart have?

4 chambers: Left and right Atrium, Left and right Ventricle.

52. : How do the atria and ventricles contract?

The two atria contract simultaneously, followed by the two ventricles contracting simultaneously shortly after.

53. : What is the pathway of blood through the heart starting from the body?

Superior vena cava → Right atrium → Right ventricle → Pulmonary artery → Lungs → Pulmonary vein → Left atrium → Left ventricle → Aorta → Systemic circulation.

54. : What is the role of the right atrium?

Pumps blood into the right ventricle.

55. : What is the role of the right ventricle?

Pumps blood to the lungs via the pulmonary artery.

56. : What is the role of the left atrium?

Pumps blood into the left ventricle.

57. : What is the role of the left ventricle?

Pumps blood out through the aorta to the systemic circulation.

58. : Why do the atria have relatively thin walls?

They only have to pump blood into the ventricles and do not generate much force.

59. : Why do the ventricles have thicker walls?

They can push blood out through blood vessels into the pulmonary and systemic circulation.

60. : Which ventricle has the thickest walls and why?

The left ventricle, because it must force blood the greatest distance.

61. : What is the function of the atrioventricular valves?

Prevent blood from flowing the wrong way between the atria and ventricles.

62. : What are the names of the atrioventricular valves?

Tricuspid valve (right side) and Bicuspid valve (left side).

63. : What are the semilunar valves?

Valves between the left ventricle and the aorta and between the right ventricle and the pulmonary artery.

64. : What causes the “lub-dub” sound of the heartbeat?

The opening and closing of the atrioventricular and semilunar valves.

65. : What does the “lub” sound represent?

The sound of the atrioventricular valves closing.

66. : What does the “dub” sound represent?

The sound of the semilunar valves snapping shut following the contraction of the ventricles.

67. : Where does the impulse that triggers the heartbeat originate?

In the heart itself, specifically the sinoatrial (SA) node.

68. : What is the SA node?

A bundle of specialized muscle tissue in the wall of the right atrium that acts as the heart's pacemaker.

69. : What does the SA node do?

Generates an electrical impulse that spreads over the atria, causing them to contract simultaneously.

70. : What happens when the impulse reaches the atrioventricular (AV) node?

The signal is delayed for 0.1 seconds while the atria empty into the ventricles.

71. : What are the Bundle of His and Purkinje fibers?

Specialized muscle fibers that conduct the electrical signal to the apex of the heart and throughout the ventricular wall.

72. : What triggers the contraction of the ventricles?

The electrical signal conducted by the Bundle of His and Purkinje fibers.

73. : What happens when you are relaxed?

The SA node fires regularly, about 70 times per minute.

74. : What happens when you exercise?

The increased activity in your muscles produces a faster rate of cellular respiration, leading to an increase in CO2 in your blood.

75. : What role does the medulla oblongata play in controlling heart rate?

It sends an impulse along the nervous system to release noradrenalin, which increases the heart rate.

76. : What happens to your heart rate after you finish exercising?

It gradually returns to resting rate, controlled by the medulla oblongata.

77. : How does a faster heart rate affect blood pressure?

It increases blood pressure since blood is being pumped more quickly through the vessels.

78. : What role do receptors in blood vessels play in controlling heart rate?

They sense changes in blood pressure and transmit this information to the medulla oblongata.

79. : What does the medulla oblongata release to slow the heart rate?

Acetylcholine, which slows the firing of the SA node.

80. : What is the cardiac cycle?

The sequence of events of a heartbeat, consisting of alternate contractions (systole) and relaxations (diastole).

81. : What happens during atrial systole and ventricular filling?

The ventricles relax and blood flows into them from the atria. 70% of the blood flows passively, and the atria contract during the last third of ventricular filling.

82. : What occurs during ventricular systole?

The atria relax, the ventricles contract, and blood is pumped from the ventricles into the aorta and the pulmonary artery.

83. : What happens during the short period of atrial and ventricular diastole?

The semilunar valves close to prevent backflow into the ventricles, and the cycle begins again.

84. : What is an electrocardiogram (ECG)?

A trace recorded on a heart monitor that shows the electrical currents generated by the heart.

85. : What does the P wave represent in an ECG?

The spread of the impulse from the SA node through the atria, causing them to contract.

86. : What does the QRS complex represent in an ECG?

The spread of the impulse through the ventricles, which contract.

87. : What does the T wave represent in an ECG?

88. : What is cardiac output?

The amount of blood pumped by the heart, measured as the volume of blood pumped from each ventricle per unit time.

89. : What does cardiac output indicate?

The level of oxygen delivery to the body and the total level of work the muscles can perform.

90. : What are the two factors that affect cardiac output?

Heart Rate (beats/min) and Stroke Volume (amount of blood forced out of the heart with each heartbeat).

91. : How is cardiac output calculated?

Cardiac Output = Stroke Volume x Heart Rate.

92. : What is the average stroke volume and resting heart rate for a person?

Average stroke volume is about 70mL, and average resting heart rate is about 70 beats/min.

93. : Calculate the cardiac output for an average person.

Cardiac Output = 70mL x 70 beats/min = 4900mL/min (or 4.9L/min).

94. : How often does the total volume of blood circulate through the heart in an average person?

About once every minute.

95. : What does a low resting heart rate indicate?

Physical fitness, as it means that stroke volume is high.

96. : What is maximum heart rate?

The highest heart rate attainable during all-out physical effort, which diminishes with age.

97. : Is maximum heart rate related to physical fitness?

No, it is not related to physical fitness.

98. : What is recovery time?

The time it takes for the heart rate to return to resting after physical activity.

99. : How does recovery time indicate physical fitness?

A lower recovery time indicates higher physical fitness.

100. : What factors affect stroke volume?

How easily the heart fills with blood and how readily the heart empties again.