11 - Blood Flashcards Preview

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Flashcards in 11 - Blood Deck (107):
1

Blood is considered what major category of tissue?

Connective.

2

Blood is a type of connective tissue that consists of two major parts. Which?

1. The plasma
2. The formed elements

3

How much of total blood volume does the plasma account for?

Plasma accounts for slightly more than half of the total blood volume.

4

Plasma consists of x% water, y% protein and z% other components.

Plasma consists of 91% water, 7% proteins and 2% other components.

5

What are the types of proteins found in plasma?

1. Albumins
2. Globulins
3. Fibrinogen

6

Simplify: what is the function of albumins in blood?

Albumins maintain osmotic pressure and act as transport molecules.

7

Simplify: what is the function of globulins in blood?

Globulins act as transport molecules.

8

Simplify: what is the function of fribrinogen in blood?

Helps form clots.

9

What is serum?

Serum is plasma without the clotting factors.

10

What are the formed elements?

Formed elements make up about 45% of the blood. About 95% of the volume of the formed elements consists of red blood cells (RBCs), or erythrocytes. The remaining 5% of the volume of the formed elements consists of white blood cells (WBCs), or leukocytes, and cell fragments called platelets, or thrombocytes.

11

Another word for red blood cells is ...

erythrocytes.

12

Another word for white blood cells is ...

leukocytes.

13

Another word for platelets is ...

thrombocytes.

14

What is hematopoiesis?

Hematopoiesis is the name of the process of blood cell production.

15

Where does hematopoiesis occur?

Hematopoiesis occurs mainly in red bone marrow, but some white blood cells are produced in lymphatic tissues.

16

Explain the shape of the red blood cells.

Normal red blood cells are disk-shaped with edges that are thicker than the center of the cell. The biconcave shape increases the cell's surface area. The greater surface area makes it easier for gases to move into and out of the red blood cell.

17

Red blood cells contain the important protein ...

hemoglobin.

18

Describe the structure of the hemoglobin protein.

Hemoglobin consists of four protein chains and four heme groups. Each protein, called globin, is bound to one heme, a red pigmented-molecule. Each heme contains one iron atom, which is necessary for the normal function of hemoglobin. Each iron in heme can reversibly bind to an oxygen molecule.

19

Which molecules can bind to hemoglobin?

Oxygen molecules, but also carbon monoxide and carbon dioxide.

20

Carbon monoxide binds to the iron in hemoglobin about x timer more/less readily than does oxygen.

Carbon monoxide binds to iron about 210 times more readily than does oxygen. It also tends not to unbind.

21

Carbon monoxide keeps oxygen from binding to the hemoglobin, which is very dangerous. Prolonged exposure can lead to nausea, headache, unconsciousness and death. Why is carbon dioxide less dangerous?

It binds to the globin, protein, part of the hemoglobin molecule. So the iron molecule is still available for oxygen transport.

22

How is carbon dioxide transported in the blood?

About 70% of the carbon dioxide in blood is transported as bicarbonate ions, 23% bound to globin in hemoglobin, and the remaining 7% dissolved in plasma.

23

Write the equality equation for bicarbonate transport in blood.

CO2 + H2O H+ + HCO3-

24

Which deficiencies can cause problems in normal red blood cell production?

Folate, Vitamin B12, or iron.

25

Red blood cell production is stimulated by ...

low blood oxygen levels.

26

What is erythropoietin (EPO)?

Erythropoietin is a glycoprotein that is primarily released by the kidneys in response to low blood oxygen. Erythropoietin stimulates red bone marrow to produce more red blood cells.

27

The production of erythropoietin by the kidneys is an example of a positive or negative feedback mechanism?

Negative. A decrease in blood oxygen sets of a mechanism that results in increased blood oxygen.

28

A typical source of carbon monoxide is...

Cigarette smoke.

29

What is jaundice?

Jaundice is a condition that is caused by a liver defect, or when the flow of bile from the liver is hindered. When red blood cells become old, abnormal or damaged, they are removed from the blood by macrophages in the liver of spleen. The heme molecules are converted into bilirubin, which is realised by the liver with the bile. Jaundice happens when bilirubin builds up in the circulation.

30

How are white blood cells different from red blood cells?

- They are bigger
- They have a nucleus
- Lack hemoglobin, therefore are not red.

31

How are white blood cells able to leave the blood?

By ameboid movement.

32

What is ameboid movement?

White blood cells can leave the blood and travel by ameboid movement through the tissues. In this process, the cell projects a cytoplasmic extension that attaches to an object. Then the rest of the cell's cytoplasm flows into the extension.

33

What are the two functions of white blood cells?

1. To protect the body against invading microorganisms and other pathogens.
2. To remove dead cells and debris from the tissues by phagocytosis.

34

White blood cells can be divided into two major groups. Which?

1. Granulocytes
2. Agranulocytes

35

What gives rise to the granulocyte and agranulocyte names?

Each white blood cell type is named according to its appearance in stained preparations. Those containing large cytoplasmic granules are granulocytes, and those with very small granules that cannot be seen easily with the light microscope are agranulocytes.

36

Each white blood cell type is named according to its appearance in stained preparations. Those containing large cytoplasmic granules are granulocytes, and those with very small granules that cannot be seen easily with the light microscope are agranulocytes. There are three types of granulocytes. Which?

1. Neutrophils
2. Basophils
3. Eosinophils

37

What are neutrophils?

A granulocyte type white blood cell. It's the most common type of white blood cell. Neutrophils usually remain in the blood for a short time (10-12 hours), move into other tissues, and phagocytise microorganisms and other foreign substances. Dead neutrophils, cell debris, and fluid can accumulate as pus at sites of infection.

38

What are basophils?

A granulocyte type white blood cell. It's the least common of all white blood cells. Basophils release histamine and other chemicals that promote inflammation. They also release heparin, which prevents the formation of clots.

39

What are eosinophils?

A granulocyte type white blood cell. Eosinophils are involved in inflammatory responses associated with allergies and asthma. In addition, chemicals from eosinophils are involved in destroying certain worm parasites.

40

Each white blood cell type is named according to its appearance in stained preparations. Those containing large cytoplasmic granules are granulocytes, and those with very small granules that cannot be seen easily with the light microscope are agranulocytes. There are two types of agranulocytes. Which?

1. Lymphocytes
2. Monocytes

41

What are lymphocytes?

Lymphocytes are the smallest of the white blood cells. There are several types of lymphocytes, and they play an important role in the body's immune response.

42

What are monocytes?

Monocytes are the largest of the white blood cells. After they leave the blood and enter tissues, monocytes enlarge and become macrophages, which phagocytise bacteria, dead cells, cell fragments, and other debris within the tissues.

43

Formed elements make up about 45% of the blood. About 95% of the volume of the formed elements consists of red blood cells (RBCs), or erythrocytes. The remaining 5% of the volume of the formed elements consists of white blood cells (WBCs), or leukocytes, and cell fragments called platelets, or thrombocytes. What are platelets, where are they produced, and what is their role?

Platelets are minute fragments of cells, each consisting of a small amount of cytoplasm surrounded by a cell membrane. They are produced in the red bone marrow from megakaryocytic, which are large cells. Small fragments of these cells break off and enter the blood as platelets, which play an important role in preventing blood loss.

44

The body can tolerate a small amount of blood loss and can produce new blood to replace it. But a large amount of blood loss can lead to death. Fortunately, when a blood vessel is damaged, blood loss is minimised by three processes: ...

1. Vascular spasm
2. Platelet plug formation
3. Blood clotting

45

What is vascular spasm?

Vascular spasm is an immediate but temporary constriction of a blood vessel that results when smooth muscle within the wall of the vessel contracts.

46

What causes vascular spasm?

Ultimately blood loss. But vascular spasm can be activated through different mechanisms, such as: nervous system reflexes or release of hormones from platelets or endothelial cells in blood vessels.

47

What is a platelet plug?

A platelet plug is an accumulation of platelets that can seal up a small break in a blood vessel.

48

What happens to people who lack the normal number of platelets?

They tend to develop numerous small haemorrhages in their skin and internal organs. This is because platelet plugs are a normal function that occurs many times each day as small tears in the smaller vessels and capillaries are quite common.

49

How does platelet plug formation occur?

First, platelets stick to the collagen exposed by blood vessel damage; this phenomenon is called platelet adhesion. After platelets adhere to collagen, they become activated, change shape, and release chemicals. These chemicals activates other platelets, which causes them to release further more chemicals. One of these activates fibrinogen, which ties platelets together. The accumulating mass of platelets forms a platelet plug.

50

How is platelets connected with vascular spasm?

When platelets have adhered to collagen they release chemicals that activate other platelets, but also the hormone thromboxane. Thromboxane produce vascular spasm.

51

What is a clot?

A clot is a network of threadlike protein fibers, called fibrin, that traps blood cells, platelets, and fluid.

52

What is another word for blood clotting?

Coagulation.

53

The formation of a blood clot depends on a number of proteins found within plasma, collectively called...

clotting factors.

54

When and where can you find clotting factors within plasma?

Always and everywhere. They're usually not activated, though.

55

Clot formation is a complex process involving many chemical reactions. How does it start?

Inactive clotting factors come in contact with exposed connective tissue, resulting in their activation.

or

Chemicals, such as thromboplastin, are released from injured tissues, causing activation of clotting factors.

56

Clot formation: what happens after clotting factors have been activated?

They activate other clotting factors. This cascades until the clotting factor prothrombinase is formed.

57

Clot formation: what happens after prothrombinase has been formed?

Prothrombinase converts an inactive clotting factor called prothrombin to its active form: thrombin.

58

Clot formation: what happens after thrombin has been activated by prothrombinase?

Thrombin converts the plasma protein fibrinogen into fibrin.

59

The clotting process can be severely impaired by low levels of ...

The clotting process can be severely impaired by low levels of:
- Vitamin K
- Ca2+
- Platelets
- Clotting factors

60

Most clotting factors are manufactured in

the liver

61

Low levels of vitamin K can be caused by ...

Antibiotic use. Humans rely on two sources of vitamin K. About half comes from the diet, and the other half comes from bacteria within the large intestine. Antibiotic use can kill these bacteria and result in vitamin K deficiency.

62

A common patient group has especially low levels of vitamin K. Which?

Infants! Newborns don't have the intestinal bacteria that produce vitamin K, and must thus get this elsewhere.

63

What is an anticoagulant?

Without control, clotting would spread from the point of its initiation throughout the blood vessels. Fortunately, the blood contains several anticoagulants, which prevent clotting factors from forming clots under normal conditions.

64

Mention two anticoagulants.

1. Antithrombin
2. Heparin
They both inactivate thrombin.

65

Are the anticoagulants present at injury sites?

Yes. But at an injury site, the activation of clotting factors is very rapid. Enough clotting factors are activated that the anticoagulants can no longer prevent a clot from forming.

66

What is clot retraction?

After a clot has been formed, it begins to condense into a more compact structure through a process known as clot retraction.

67

How does clot retraction happen?

Platelets form small extensions that attach to fibrin through surface receptors. Contraction of the the extensions pulls on the fibrin and leads to clot retraction.

68

What is fibrinolysis?

Fibrinolysis is the name of the process where clots are dissolved.

69

Clots are dissolved by a process called fibrinolysis. How does it start?

An inactive plasma protein called plasminogen is converted to its active form, plasmin. Plasminogen is converted by thrombin, other clotting factors and tissue plasminogen activator.

70

Fibrinolysis: what happens after plasmin has been activated?

Plasmin slowly breaks down fibrin.

71

What is the difference between a transfusion and infusion of blood?

A transfusion is the transfer of blood or blood components from one individual to another. An infusion is the introduction of a fluid other than blood, such a saline or glucose solution, into the blood.

72

What are transfusion reactions?

Transfusion reactions are characterised by clumping or rupture of blood cells and clotting within blood vessels. They are caused by interactions between antigens and antibodies.

73

What are the blood groups based upon?

The antigens on the surface of red blood cells have been categorised into blood groups.

74

How many blood groups are there?

There are many blood groups, but the ABO and Rh blood groups are the most important when discussing transfusion reactions.

75

Where in the blood will you find antibodies?

In the plasma.

76

Where in the blood will you find the antigens?

In this case, on the surface of the blood cells.

77

You have type A blood. What antigens do you have?

Antigen A.

78

You have type A blood. What antibodies do you have?

Anti-B antibody.

79

You have type B blood. What antibodies do you have?

Anti-A antibody.

80

You have type B blood. What antigens do you have?

Antigen B.

81

You have type AB blood. What antigens do you have?

Antigens A and B.

82

You have type AB blood. What antibodies do you have?

Neither anti-A nor anti-B antibodies.

83

You have type O blood. What antibodies do you have?

Anti-A and anti-B antibodies.

84

You have type O blood. What antigens do you have?

Neither antigen A nor antigen B.

85

Among caucasians in the USA. What is the distribution of the different ABO blood types?

O, 47%; A, 41%; B, 9%; AB, 3%.

86

Type O donors have usually been called "universal donors", why?

Because type O blood has no antigens, and should not create a transfusion reaction in the recipient.

87

Donation of type O blood can cause a small transfusion reaction, that are usually not serious. Why?

Because the type O blood has both type A antigens and type B antigens.

88

Which blood group was historically called universal recipients?

type AB.

89

Another important blood group is the Rh blood group. Why is it named thus?

Because it was first studied int he rhesus monkey.

90

How many categories of Rh blood groups are there?

Just the two: Rh negative and Rh positive.

91

What does it mean to be Rh negative?

People are Rh negative if they do not have Rh antigens on the surface of their red blood cells.

92

What does it mean to be Rh positive?

People are Rh positive if they do not have Rh antigens on the surface of their red blood cells.

93

A nurse tells you you have the blood type A-positive. What does that mean?

That you have the ABO blood type A and the rhesus blood type positive.

94

What percent of caucasian americans have the Rh antigens on the surface of their red blood cells?

About 85% of caucasians are Rh-positive.

95

Do Rh-positive people have Rh-antibodies?

No. That would be incompatible with normal function.

96

Do Rh-negative people have Rh antibodies?

Not unless they've been exposed to Rh-positive blood.

97

When is Rh compatibility a major problem?

In pregnancy when the mother is Rh-negative and the foetus is Rh-positive. Blood can leak through the placenta.

98

Why is Rh incompatibility during pregnancy less severe during the first pregnancy?

Because this is probably the first time the mother is exposed to the Rh-antigens. Thus there is not sufficient time for the mother to produce enough anti-Rh antibodies to harm the foetus. In alter pregnancies, however, a problem can arise because the mother has been sensitised to the Rh antigen.

99

What is a crossmatch?

In a crossmatch, the donor's blood cells are mixed with the recipient's serum, and the donor's serum is mixed with the recipient's cells. The donor's blood is considered safe for transfusion only if no agglutination occurs in either match.

100

What is a complete blood count (CBC)?

A complete blood count is an analysis of blood that provides much useful information. A CBC consists of a red blood cell count, hemoglobin and hematocrits measurements, and a white blood cell count.

101

An overabundance of red blood cells is called..

Erythrocytosis.

102

An abnormally low hemoglobin measurement is an indication of ...

Anemia

103

A lower than normal white blood cell count could indicate ...

Leukopenia, which results from decreased production or destruction of the red bone marrow.

104

An abnormally high which blood cell count is called...

Leukocytosis.

105

What can cause leukocytosis?

Bacterial infections often cause leukocytosis by stimulating neutrophils to increase in number. Also leukaemia.

106

High altitudes contain less oxygen. This can cause ...

Erythocytosis. The decrease in oxygen due to the altitude stimulates erythropoietin secretion and red blood cell production.

107

What is blood doping?

Blood doping is an intentional process that serves to increase the number of circulating red blood cells. Blood doping can be accomplished in several ways, including the use of transfusions or by taking drugs that stimulate the process of red blood cell production.