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Blood
Composition & Functions of Blood
30
Physiology
12th Grade
05/01/2012

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Term

What is the function of Blood?

 

Definition
Blood transports everything that must be carried from one place to another within the body – nutrients, hormones, wastes, respiratory gases (oxygen & carbon dioxide), and body heat through blood vessels
Term

True or False?

Blood is the only fluid tissue in the body

Definition
True
Term

 

What is plasma?

 

Definition
It is the nonliving fluid portion of the blood. It functions as a solvent for carrying other substances, absorbs heat, clotting blood, and defense of anitbodies.
Term
Which body organ plays the main role in producing plasma proteins?
Definition
The liver
Term

 

List the cell types making up the formed elements, and describe the major functions of each type.

 

Definition
Erythrocytes are the red blood cells that function in carrying oxygen. They differ from other blood cells that they are anucleate (lack a nucleus). Leukocytes are the white blood cells that function in protecting the body against infection and disease. Platelets are cell fragments that help stop bleeding and clotting process.
Term

 

What determines whether blood is bright red(scarlet) or dull red?

 

Definition
The amount of oxygen it is carrying
Term

 

Describe erythrocytes.

 

Definition
They differ from other blood cells because they are anucleate (lack a nucleus). RBCs are “bags” of hemoglobin molecules (an iron-bearing protein) that transports the bulk of oxygen that is carried in the blood. It also binds with a small amount of carbon dioxide. When the number of RBCs increase, blood viscosity increases & when RBCs decrease, blood thins and flows more rapidly. The more hemoglobin molecules the RBCs contain, the more oxygen they will be able to carry.
Term

 

What is polycythemia?

 

Definition
It is an excessive or abnormal increase in the number or erythrocytes. It may result from bone marrow cancer or a normal physiologic(homeostatic) response to living at high altitudes, where the air is thinner and less oxygen is available. The major problem that results from excessive numbers of RBCs is increased blood viscosity, which causes blood to flow sluggishly in the body and impairs circulation.
Term

 

What is anemia?

 

Definition
A decrease in the oxygen-carrying ability of the blood.
Term

 

What is hemorrhagic anemia?

 

Definition
It is caused by a decrease in RBC number ; results from sudden hemorrhage(losing blood)
Term

 

What is hemolytic anemia?

 

Definition
It is caused by decrease in RBC number ; results from lysis of RBCS – due to bacterial infections
Term

 

What is pernicious anemia?

 

Definition
It is caused by decrease in RBC number ; results from lack of vitamin B12(Usually due to lack of intrinsic factor required for absorption of vitamin. Intrinsic factor is formed by stomach mucosa cells) ; reliable food sources of B12 are shellfish, meat, fish, poultry, milk and dairy foods, & fortified cereals.
Term

 

What is aplastic anemia?

 

Definition
It is caused by decrease in RBC number ; results from depression/destruction of bone marrow by cancer, radiation, or certain medications
Term

 

What is iron-deficiency anemia?

 

Definition
It is caused by inadequate hemoglobin content in RBCs ; results from lack of iron in diet or slow/prolonged bleeding(such as results from heavy menstrual flow or bleeding ulcer) which depletes iron reserves needed to make hemoglobin; RBCs are small and pale because they lack hemoglobin; common in females
Term
What is sickle-cell anemia?
Definition
It is caused by abnormal hemoglobin in RBCs ; results from genetic defect which leads to abnormal hemoglobin, which becomes sharp and sickle shaped under conditions of increased oxygen use by body; occurs mainly in people of African descent.
Term

 

What is leukemia?

 

Definition
Leukemia means “white blood” and is where the bone marrow becomes cancerous, and huge numbers of WBCs are turned out rapidly. The WBCs are immature and incapable of carrying out their normal protective functions. Consequently, the body becomes susceptibleto disease and infection. Severe anemia and bleeding problems may result.
Term
Describe Hematopoiesis (Blood Cell Formation)
Definition
It occurs in the red bone marrow, or myeloid tissue, which is found in the flat bones of the skull, pelvis, ribs, sternum, femur, and humerus. The formed elements arise from a common type of stem called called the hemocytoblast, which resides in the red bone marrow. The hemocytoblast forms types cells - the lymphoid stem cell which produces lymphocytes, and the myeloid stem cell which produces erythocytes, basophils, eosinophils, neutrophils, monocytes, and platelets.
Term
Describe the formation of red blood cells
Definition
RBCs are anucleate so they are unable to synthesize proteins, grow, or divide. They only transport oxygen. They live for 3-4 months and are disposed of by the spleen and liver. It's hormone controlled by erythropoietin which is produced by the kidneys. When blood levels of oxygen decline, the kidney releases erythropoietin.
Term
Formation of White Blood Cells and Platelets
Definition
The formation of leukocytes and platelets is stimulated by hormones called thrombopoietin.
Term
What is hemostatis?
Definition

(hem = blood , statis = standing still ) It is the stoppage of bleeding. It involves three major phases: vascular spasms, platelet plug formation, and coagulation. Vascular spasms occur and the response is vasoconstriction, which causes that blood vessel to go into spasms which decreases blood loss until clotting can occur. Then  platelets become "sticky" and cling to the damaged site. As more platelets pile up, a small mass called a platelet plug, or white thrombus, forms. An enzyme called thrombin joins fibrinogen proteins into fibrin. Fibrin forms a meshwork that traps the RBCs and forms the basis of the clot.

 

Term
What are the two major disorders of hemostasis?
Definition
Undesirable clotting and bleeding disorders
Term

What is undesirable clotting in hemostatis?

 

Definition
A clot that develops and persists in an unbroken blood vessel is called a thrombus. If it is large enough, it can prevent blood from flowing to the cells beyond the blockage. If a thrombus breaks away from the vessel wall and floats freely, it becomes an embolus. An embolus isn't usually a problem unless is lodges in a blood vessel too narrow for it to pass through. Undesirable clotting may be caused by severe burns, physical blows, or an accumulation of fatty material. Blood pooling, or slowly flowing blood is another risk factor. Anticoagulants are aspirin, heparin, and dicumarol.
Term
What bleeding disorders occur from hemostasis?
Definition
Thrombocytopenia and Hemophilia
Term
What is thrombocytopenia?
Definition
The most common causes of abnormal bleeding are platelet deficiency, thrombocytopenia, which results from an insufficient number of circulating platelets from an impaired liver function or certain genetic conditions. It is treated with vitamin K supplements (kale, spinach, brussel sprouts) or if the liver function is severely impaired, transfusions of concentrated platelets are needed which provides temporary relief from bleeding.
Term
What is hemophilia?
Definition
Hemophilia occurs from hereditary bleeding disorders that result from a lack of any of the factors needed for clotting. Hemophiliacs are given a transfusion of plasma or injections of the clotting factor they lack. Some hemophiliacs have become the victims of hepatitis and AIDS because of these therapies.
Term
What are antigens?
Definition
Antigens are substances foreign to the body which activates and is attacked by the immune system.
Term
What are antibodies?
Definition
They are proteins released by immune cells that binds with a specific antigen and inactivates it in some way.
Term
ABO Blood Groups
Definition

They are based on which antigen A or type B, a person inherits. Absence of both = type O, presence of both = type AB, the presence of A or B yield type A or B blood. During infancy, antibodies from against the antigens not present on your own RBCs.

Type O is most common, least common is AB.

Term
Rh Blood Groups
Definition
Most Americans are Rh+ meaning that their RBCs carry the Rh antigen. Rh- people do not have preformed antibodies to Rh+ RBCs but form them once exposed to Rh+ blood. Incompatibility occurs in pregnant Rh- women who are carrying Rh+ babies. Her anti-Rh+ antibodies unless treated with RhoGAM, will destroy the baby's RBCs which will cause the baby to anemic and becomes hypoxic and cyanotic.
Term
Desccribe the production process of RBCs when there is oxygen depletion.
Definition
The RBCs are produced quicker and in more abundance. Since there is low oxygen, the kidney will produce more erythopoietin.
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