Chapter 11 : Blood

Question 1

Describe the functions of blood.

Answer 1

Transport of gases, nutrients, waste products.

Transport of processed molecules.

Transport of regulatory molecules

regulation of pH in osmosis
maintenance of body temperature

protection against foreign substances

Clot formation

Question 2

Define plasma.

Answer 2

Plasma is a pale yellow liquid that consists of 91% water: 7% proteins and 2% of other substances.

Question 3

List the functions of plasma.

Answer 3

Water acts as a solvent and suspending medium for blood components

Proteins maintain osmotic pressure, destroy foreign substances, transport molecules and form clots.

Ions are involved in osmotic pressure, membrane potential and acid-base balance.

Nutrients are a source of energy in building blocks of complex molecules

Gases are involved in aerobic respiration

Waste products are the breakdown products of protein metabolism, erythrocytes and anaerobic respiration

Regulatory substances catalyze chemical reactions and stimulate or inhibit many body functions

Question 4

Define the formed elements, and name the different types of formed elements.

Answer 4

The formed elements are cells such as red blood cells and white blood cells and cell fragments such as platelets.

Question 5

Explain how and where the formed elements arise through haematopoiesis.

Answer 5

The process of blood cell production is called hematopoiesis.
and the fetus, Haematopoiesis occurs in several tissues such as the liver, thymus gland, spleen, lymph nodes and red bone marrow. Afterbirth haematopoiesis is confined to red bone marrow and some white blood cells are produced in lymphatic tissues.

Question 6

Describe the two basic parts of a hemoglobin molecule. Which part is associated with iron? What gases are transported by each part?

Answer 6

Globin and heme: oxygen is transported by hemoglobin, consists of 4 protein groups and 4 heme groups which bounds to each other
Globin: the protein part 
Heme: the red-pigmented molecule 
Contains iron which transports oxygen 
Heme: oxygen 
Globin: carbon dioxide

Question 7

What is the role of Carbonic anhydrase in gas transport?

Answer 7

It is an enzyme found primarily inside red blood cells and it catalyzes the reaction that converts carbon dioxide and water into a hydrogen ion and the bicarbonate ion. 70% of carbon dioxide in blood is transported in the form of bicarbonate ions.

Question 8

Why are the vitamins folate and b12 important in red blood cell production?

Answer 8

Vitamins folate and b12 are important in red blood cell production because itIs required in the process of cell division. Cell division produces more red blood cells. Every second 2.5 million red blood cells are destroyed and therefore we need new production of red blood cells. Stem cells form proerythroblast which give rise to the red blood cell line and the red blood cells are the final cells produced formed from a series of cell divisions.

Question 9

Explain how low blood oxygen levels result in increased red blood cell production.

Answer 9

Red blood cell production is stimulated by low blood oxygen levels.

• caused by a decrease in red blood cells, decrease or defective hemoglobin, disease of the lung, high altitude, inability of the cardiovascular system to deliver blood to tissues, increased tissue demands for oxygen such as endurance exercises.
• Low blood oxygen levels increased blood red blood cell production by increasing the formation of a glycoprotein erythropoietin. This protein stimulates red bone marrow to produce more red blood cells.Therefore when oxygen levels in blood decrease, the production of erythropoietin increases which increases red blood cell production.

Question 10

Where are red blood cells broken down? What happens to the breakdown products?

Answer 10

Red blood cells are broken down by macrophages located in spleen and liver.

• Within the macrophage the globin part of the molecule is broken down into amino acids that are reused to produce proteins.
• The iron released from heme is transported in the blood to red bone marrow and is used to produce new hemoglobin. Small amounts of iron are required in the daily diet. The molecules are converted into bilirubin which is taken up by the liver and released into the small intestine as part of the bile.
• Then once it enters the intestine bilirubin is converted by bacteria into other pigments and excreted in the form of urine.

Question 11

Give two functions of white blood cells.

Answer 11

1. To protect the body against invading microorganisms

2. To remove dead cells and debris from the tissues by phagocytosis

Question 12

What is the function of monocytes?

Answer 12

Monocytes. They have a longer lifespan than many white blood cells and help to break down bacteria.

Question 13

What is the function of lymphocytes?

Answer 13

Lymphocytes. They create antibodies to fight against bacteria, viruses, and other potentially harmful invaders.

Question 14

What is the function of neutrophils?

Answer 14

Neutrophils. They kill and digest bacteria and fungi. They are the most numerous type of white blood cell and your first line of defense when infection strikes.

Question 15

What is the function of basophils?

Answer 15

Basophils. These small cells seem to sound an alarm when infectious agents invade your blood. They secrete chemicals such as histamine, a marker of allergic disease, that help control the body’s immune response.

Question 16

What is the function of eosinophils?

Answer 16

Eosinophils. They attack and kill parasites and cancer cells, and help with allergic responses.

Question 17

What are platelets?

Answer 17

Platelets or thrombocytes are fragments of cells each consisting of a small amount of cytoplasm surrounded by a cell membrane.

Question 18

How are platelets formed?

Answer 18

They are produced in the red bone marrow from megakaryocytes which are large cells. Small fragments of the cells break off and enter the blood is platelets and these play an important role in preventing blood loss.

Question 19

Describe the role of blood vessel constriction and platelet plugs in preventing bleeding.

Answer 19

Blood vessel constriction and platelet plugs play a role in Stopping blood loss from the body while new blood is being produced.

Question 20

Describe the three steps of platelet plug formation.

Answer 20

Platelet plug formation:
Platelet adhesion occurs when Von Willebrand factor connects collagen and platelet.

The platelet release reaction is the release of ADP, thromboxanes and other chemicals that activate other platelets.

Platelet aggregation occurs when fibrinogen receptors on activated platelets Bind to fibriogen, connecting the platelets to one another. The platelet plug is formed by the accumulating mass of platelets.

Question 21

What are clotting factors?

Answer 21

The formation of a blood clot depends on a number of proteins found within plasma called clotting factors. Usually clotting factors are inactive and do not cause clotting until an injury has occurred.

Question 22

Describe the three steps of activation that result in the formation of a clot.

Answer 22

1. Chemical reactions can be started in two ways. The first way is the contact of inactive clotting factors exposed to connective tissues. The second way is chemicals released from injured tissues that can cause activation of clotting factors. Once they’re activated they activate other clotting factors and a series of reactions which results in each clotting Factor activating the next until the clotting Factor prothrombinase is formed.
2. Prothrombinase acts on an inactive clotting Factor called prothrombin and converts it to its active form called thrombin.
3. Thrombin converts the inactive clotting Fibrinogen into its active form fibrin and forms a network of fibrin that traps blood cells, platelets and fluid which is also known as a clot.

Question 23

Explain the function of anticoagulants in the blood, and give an example of an anticoagulant.

Answer 23

Anticoagulants prevent clotting factors from forming clots. Antithrombin and heparin are examples of anticoagulants. For example, without dropping, fibrinogen is not converted to fibrin and no clot forms.

Question 24

What is clot retraction, and what does it accomplish?

Answer 24

Clot retraction is a process which condenses to clot, pulling the edges of damaged tissue closer together.
It helps to stop the flow of blood, reducing the probability of infection and enhancing healing.

Question 25

Define fibrinolysis, and name the chemical is responsible for this process.

Answer 25

Fibrinolysis is the process in which clots are dissolved. An inactive plasma protein called plasminogen is converted to its active form plasmin.

Question 26

What are blood groups, and how do they cause transfusion reactions?

Answer 26

Blood groups are categories which categorize antigens on the surface of red blood cells.

They cause transfusion reactions because antibodies are very specific to each antigen. When the antibodies in the plasma bind to the antigens on the surface of red blood cells, they form molecular bridges that connect the red blood cells that form agglutination. The combination of the antibodies with the antigens can initiate reactions that cause hemolysis.

Question 27

List the four ABO blood types. Why is type O blood considered universal?

Answer 27

Type A, type B, type A B, Type O.
Type O blood is considered universal because it contains neither A nor B antigens which means that they can donate both type A blood and type B blood.

Question 28

What is meant by the term RH positive?

Answer 28

RH positive means that they have Rh antigens on the surface of their red blood cells.

Question 29

How can RH incompatibility affect the pregnancy?

Answer 29

Antibodies Against the RH antigens do not develop until an rh-negative person is exposed to RH positive red blood cells through transfusion or body transfer of blood across the placenta to a mother from her fetus. When this occurs the mom becomes sensitized to the RH antigens and produces anti-rh antibodies. The anti-rh antibodies from the mother cross the placenta and cause agglutination and hemolysis of fetal red blood cells in hemolytic disease of the newborn.

Question 30

Define Type and cross-match.

Answer 30

This test prevents transfusion reactions. Blood typing determines the ABO and Rh blood groups of a blood sample. A cross-match test for agglutination reactions between donor and recipient blood.

Question 31

Define Red blood cell count

Answer 31

Red blood cell count provides information about the number of red blood cells per microliter of blood. Erythrocytosis.

Question 32

Define Hemoglobin measurement

Answer 32

Determines the amount of hemoglobin in a given volume of blood. Anemia.

Question 33

Define Hematocrit measurement

Answer 33

Percentage of total blood volume composed of red blood cells.

Question 34

Define White blood cell count:

Answer 34

Measures the total number of white blood cells in the blood. Leukopenia.

Question 35

Define White blood cell differential count

Answer 35

Determines the percentage of each of the five kinds of white blood cells in the white blood cell count. For example in bacterial infections, neutrophil count is greatly increased while allergic reactions that eosinophil and basophil counts are elevated.

Question 36

Define Platelet count:

Answer 36

A measurement of the number of platelets per microliter of blood. Thrombocytopenia.

Question 37

Define Prothrombin time

Answer 37

A measure of how long it takes for the blood to start clotting.

Question 38

Define Blood chemistry test

Answer 38

The composition of materials dissolved or suspended in plasma which can be used to assess the functioning and status of the body’s systems.