CHAPTER 19: BLOOD

Question 1

Define blood and identify its classification as a tissue.

Answer 1

Blood is a specialized connective tissue that contains cells suspended in a fluid matrix.

Question 2

List the functions of blood.

Answer 2

• Transporting dissolved gases, nutrients, hormones, and metabolic waste
• Regulating pH, ion composition interstitial fluids
• Defending against toxins and pathogens
• Stabilizing body temperature
• Restricting fluid losses at injury sites

Question 3

Explain the characteristics of blood, including its temperature, pH, and volume.

Answer 3

The temperature of blood is 38°C (100°F), pH is slightly alkaline ranging between 7.35-7.45, and the volume of blood (litter) = 7 percent of body weight (kilograms).

Question 4

Describe the components of whole blood, including plasma and formed elements.

Answer 4

Whole blood includes plasma, which is a fluid, and formed elements, which are cells and cells fragments.

Question 5

What is fractionation and how is it related to blood?

Answer 5

Fractionation is the process of separating whole blood into plasma and formed elements.

Question 6

What is the composition of plasma, and how does it compare to interstitial fluid?

Answer 6

Plasma constitutes to approximately 55% of blood volume, with 90% being water. It also contains dissolved plasma protein and other solutes. The composition is similar to interstitial fluid, as water, ions and small solutes are exchanged across capillary walls.

Question 7

Identify the different types of plasma and their functions.

Answer 7

Albumins (60%):
- Major contributors to plasma osmolarity
- Transport fatty acids, thyroid hormones, some steroid hormones, etc.

Globulins (35%):
- Include antibodies (immunoglobulins)
- Transport globulins including hormone-binding proteins, metalloprotein, apolipoproteins (lipoprotein), and steroid binding proteins

Fibrinogen (4%)
- Soluble protein that functions im clotting
- Converted to insoluble fibrin
- Conversion of fibrinogen to fibrin leaves serum (fluid) in blood sample

Other proteins (1%):
- Varying concentrations of enzymes and hormones

Question 8

Identify the formed elements of blood and describe the process of hemopoiesis.

Answer 8

The formed elements are red and white blood cells and cell fragments (platelets). And hemopoiesis is the process of producing formed elements.

Question 9

What is another name for red blood cells?

Answer 9

Erythrocytes

Question 10

What is the function of hemoglobin in peripheral capillaries where oxygen levels are low?

Answer 10

In peripheral capillaries, where oxygen levels are low, hemoglobin releases oxygen and binds carbon dioxide, forming carbaminohemoglobin.

Question 11

Define anemia and discuss its impact on oxygen delivery to tissue.

Answer 11

Anemia results when hematocrit or Hb content of RBCs is reduced, leading to interference with oxygen delivery to peripheral tissues.

Question 12

Elaborate on the formation and turnover of red blood cells.

Answer 12

About 1% of circulating RBCs are replaced per day and 3 million new red blood cells enter the bloodstream each second.

Question 13

What is blood doping, and why is it considered a dangerous practice?

Answer 13

Blood doping is the re-infusion of packed RBCs to elevate hematocrit, considered dangerous due to potential health risks.

Question 14

Discuss the nutritional requirements for erythropoiesis, including the role of vitamins and minerals.

Answer 14

Erythropoiesis requires amino acids, iron, folic acid, and vitamins B12 and B6. Lack of vitamin B12 leads to pernicious anemia.

Question 15

Explain the process of hemoglobin recycling and the significance of bilirubin in this process.

Answer 15

Iron is removed from the heme unit, forming green biliverdin, which is converted to orange-yellow bilirubin and excreted by the liver in bile.

Jaundice is caused by bilirubin buildup.

Question 16

Define surface antigens.

Answer 16

Surface antigens are substances on plasma membrane that identify cells to the immune system. The normal cells are ignored while the foreign cells are attacked.

Question 17

Describe the four blood types and the Rh blood groups.

Answer 17

The four blood types are type A, type B, type AB, and type O. Type A has the surface antigen A, type B has the surface antigen B, type AB has the antigen A and B, and type O has neither A nor B.

The Rh blood group is based on the presence or absence of Rh antigen. Rh positive (Rh+) the Rh surface antigen is present (Type O+). The Rh negative (Rh-) the Rh antigen is absent (Type O-).

Question 18

Discuss agglutinogens and agglutinins, and their role in transfusion.

Answer 18

Agglutinogens are surface antigens on red blood cells screened by the immune system and agglutinins are antibodies in plasma that attack foreign red blood cells, causing agglutination (clumping) of foreign cells.

Question 19

What is the main function of red blood cells?

Answer 19

Red blood cells primarily function to bind and transport oxygen and carbon dioxide.

Question 20

Identify the characteristics of red blood cells.

Answer 20

Red blood cells make up 99% of formed elements and contains hemoglobin (red pigment that gives whole blood its color).

Question 21

Distinguish mature red blood cells from other types in the body.

Answer 21

Mature red blood cells lack nuclei, mitochondria, and ribosomes, making them unable to divide, synthesize proteins, or repair damage. They also have a lifespan of approximately 120 days.

Question 22

How does the structure of red blood cells contribute to their important functions, including the absorption and release of oxygen, blood flow through narrow vessels, and passage through small capillaries?

Answer 22

The large surface-area-to-volume ratio of red blood cells allows them to quickly absorb and release oxygen. The formation of stacks called rouleaux promotes smooth blood flow through narrow vessels. Additionally, their ability to bend and flex enables a 7.8-µm red blood cell to pass through a 4-µm capillary.

Question 23

What is the primary function of hemoglobin in red blood cells, and what gases does it transport?

Answer 23

Hemoglobin, a protein in red blood cells, serves as the transporter for respiratory gases. It facilitates the transport of oxygen and carbon dioxide in bloodstream.

Question 24

Describe the role of hemoglobin at the lungs where oxygen levels are high.

Answer 24

At the lungs, where oxygen levels are high, hemoglobin binds oxygen and releases carbon dioxide.

Question 25

What is the role of erythropoietin (EPO) and which organs secrete it?

Answer 25

Erythropoietin (EPO) is a hormone that stimulates erythropoiesis. It is secreted by the kidneys and liver in response to low oxygen levels (hypoxia) in peripheral tissues.

Question 26

What is blood type determined by?

Answer 26

Blood type is determined by the presence or absence of surface stufen on red blood cells: A, B, and Rh (or D).

Question 27

What antibodies are present in each blood type, and which type of blood has neither anti-A nor anti-B antibodies?

Answer 27

In type A blood there are anti-B antibodies, in type B blood there are anti-A antibodies. Type O blood has both anti-A and anti-B antibodies and type AB blood has neither anti-A nor anti-B antibodies. Only sensitized Rh-negative blood contains anti-Rh antibodies.

Question 28

What is cross-reaction in context of transfusion reactions, and when does it occur?

Answer 28

Cross-reaction in transfusion reactions happens when blood or plasma from one person is transfused to another with incompatible blood types. This occurs when the plasma antibody encounters its corresponding surface antigen, leading to agglutination and potential hemolysis of red blood cells.

Question 29

What is the purpose of compatibility testing in the context of transfusions?

Answer 29

Compatibility testing in conducted in advance of transfusions to identify ant potential cross-reactions between the donor’s red blood cells and the recipient’s plasma.

Question 30

Why is type O blood considered the universal donor in blood transfusions?

Answer 30

Type O blood is considered the universal donor because it lacks other A and B surface antigens. However, it’s essential to note that cross-reactions can still occur due to the presence of at least 48 other surface antigens besides A and B.

Question 31

What is another name for white blood cells?

Answer 31

Leukocytes

Question 32

Identify the characteristics of white blood cells.

Answer 32

White blood cells have a nuclei and other organelles but they lack hemoglobin.

Question 33

What are the functions of white blood cells?

Answer 33

White blood cells defend the body against pathogens, remove toxins and waste, and attack abnormal or damaged cells.

Question 34

Where are most white blood cells found in the body?

Answer 34

The majority of white blood cells are located in connective tissue proper, organs of the lymphatic system, and a small fraction circulates in the blood, with counts es fing from 5,000 to 10,000 per microliter.

Question 35

What are the five types of white blood cells?

Answer 35

Neutrophils, Eosinophils, Basophils, Monocytes, and Lymphocytes.

Question 36

What is another name for neutrophils?

Answer 36

Polymorphonuclear leukocytes

Question 37

What are the characteristics of neutrophils, and what is their primary function?

Answer 37

Neutrophils constitute 50%-70% of circulating white blood cells. They have pale cytoplasmic granules containing lysosomal enzymes and bactericidal compounds, emphasizing their role in killing bacteria.

Question 38

Describe the characteristics and functions of eosinophils, including their response to allergens.

Answer 38

Eosinophils comprise 2%-4% or circulating white blood cells, engulfing bacteria, protozoa, and cellular debris. They attack large parasites by releasing toxic compounds such as nitric oxide and cytotoxic enzymes. Eosinophils are sensitive to allergens and release enzymes that reduce inflammation causes by mast cells and neutrophils.

Question 39

What are the key characteristics and functions of basophils, and how do they contribute to the body’s response to tissue damage?

Answer 39

Basophils, constricting to less than 1% of circulating white blood cells, roos capillary endothelium to accumulate in damaged tissues. They release histamine, which dilates blood vessels, and heparin, which prevents blood clotting, playing a vital role in the body’s response to tissue damage.

Question 40

What are the characteristics of monocytes, and what is their role in the immune response?

Answer 40

Monocytes, large spherical cells comprising 2%-8% of circulating white blood cells, initially remain in the bloodstream for 24 hours. Afterwards, they enter peripheral tissues and transform into macrophages, aggressive phagocytes that engulf large pathogens. Monocytes also release chemicals that attract other phagocytic cells and fibroblasts to the injured area, contributing to the immune response.

Question 41

Describe the characteristics and distribution of lymphocytes, and explain their role in the body’s defense system.

Answer 41

Lymphocytes are slightly larger than red blood cells, and constitute to 20%-40% of the circulating white blood cells. They continuously migrate in and out of the bloodstream and are mostly found in the organs of the lymphatic system and connective tissues outside of the blood. Lymphocytes play a crucial role in the body’s specific defense system.

Question 42

What are the three classes of lymphocytes?

Answer 42

The three classes of lymphocytes are T cells, B cells, and natural killer (NK) cells.

Question 43

Describe T cells, B cells, and NK cells.

Answer 43

T cells (T lymphocytes) have cell-mediated immunity and attack foreign cells or control other lymphocytes.

B cells (B lymphocytes) have humoral immunity and differentiate into plasma cells, which synthesize antibodies.

Natural killer (NK) cells detect and destroy abnormal cells.