Chapter 10Blood

• Blood transports nutrients, wastes and body heat from one part of the body to another.

Composition of Blood

• Blood is a fluid tissue (complex connective tissue). It has solid and liquid components.

Physical Characteristics of Blood

• Opaque, sticky• Metallic taste• Salty• Scarlet (lots of oxygen), Dull Red

(low oxygen)• Viscous (5 X water)• Alkaline pH 7.35-7.45

• Temperature 38 C or 100.4 F• 8% of body weight• Volume in males is 5 to 6 liters

Components of Blood

1. Plasma – non-living fluid matrix

2. Formed elements – living blood cells

Percent Composition of Blood• 45% Erythrocytes or Red Blood Cells• < 1% Leukocytes or WBC and Platelets• 55% Plasma

Plasma

• The liquid part of the blood• Straw colored fluid• 100’s of substances are dissolved

in it (nutrients, metal ions, salts, respiratory gases, hormones, plasma proteins, various wastes and products of cell metabolism)

The Three Plasma Proteins1. Albumin – contributes to the

osmotic pressure of blood, keeps water in the blood stream

2. Clotting Proteins – cut down on blood loss

3. Antibodies – protection from pathogens

- The composition of blood is kept constant by homeostatic mechanisms

Formed Elements – Three Kinds – Blood Cells

1. Erythrocytes (Red Blood Cells) or RBC’s

• Bring oxygen to all body cells• Flattened discs with depressed centers,

increases surface area• Outnumber white blood cells 1000 to 1• Make blood viscous• Contain hemoglobin – an iron containing

protein that transports oxygen

Anemia

• Occurs when there is a decrease in the oxygen carrying ability of blood

• Decrease in RBC or RBC’s with deficient hemoglobin content

Sickle Cell Anemia

• Red blood cells are sickle shaped and clog up in small blood vessels

• Decrease in oxygen delivery• Causes pain• Caused by one change in an amino acid• Offers a resistance to malaria

Polycythemia

• Abnormal increase in RBC

• Causes: bone marrow cancer, high attitudes

• Problem: blood to viscous – impairs circulation

2. Leukocytes or White Blood Cells or WBC’s

• Crucial to the bodies defense against disease

• Protective moveable army that helps defend the body against damage by bacteria, parasites, viruses and tumor cells

• Move by ameboid movement

There are two types of WBC

Groups based on visible granules or not

Granulocytes a. Neutrophils

b. Eosinophils

c. Basophils

Agranulocytesa. Lymphocytes

b. Monocytes

Leukemia

• When the bone marrow becomes cancerous and makes lots of WBC

• The WBC do not develop and do not prey on disease good

3. Platelets

• Needed for clotting

Hematopoiesis

• The process of blood cell formation occurs in: Red Bone Marrow (flat bones of skull, pelvis, ribs, sternum, humerus, femur)

• All of the formed elements arise from a common type of stem cell called a hemocytoblast, which is in the red bone marrow

Hemocytoblast

Lymphoid Stem Cell Myeloid Stem Cell

Lymphocytes (WBC) other WBC’s

RBC’s Platletes

Erythoproteins

• Control the rate of production and which types of cells are produced.

Hemostasis

• Stoppage of blood flow or clotting

Blood Clots in 3 Stages:

1. When a blood vessel is damaged platelets and RBC spill into the damaged tissues

2. Platelets increase in number and begin to attach to damaged surfaces. Strands of a protein called fibrin are formed.

3. Blood cells, platelets and strands of fibrin become enmeshed in a fibrous tangle called a clot.

Disorders of Hemostasis

1. Undesirable Clotting – forms in intact blood vessels especially the legs

Thrombus – clot that develops and persists in an unbroken blood vessel

Thrombus Types

a. Coronary thrombosis – forms in the blood vessels serving the heart muscle and a fatal heart attack

b. Embolus – thrombus that breaks away from the vessel wall and floats freely into the blood stream

2. Bleeding Disorders

a. Thrombocytopenia – insufficient number of circulating platelets – normal movements can cause spontaneous bleeding

b. Hemophilia – genetic – caused by a lack of any of the factors needed for clotting – blood does not clot

Blood Groups and Transfusions

• Loss of 15-30% leads to pallor and weakness.

• 30% or more causes severe shock and can be fatal

Human Blood Groups

• Cell membrane of a RBC has genetically determined proteins (antigens) which ID a person.

• Antigen – substances that the body recognizes as foreign – stimulates an immune response

• Antibodies – recognize antigens as foreign

Agglutination

• Binding of antibodies to antigens• Causes RBC to clump• Clogs blood vessels• RBC’s lyse and release their

hemoglobin (no oxygen)• Results – kidney failure, fever,

chills. Nausea, vomiting

• There are 30 common RBC antigens.

• The main ones: Antigens of A, B, O and Rh

ABO Blood Groups

• Table 10.2 pg 306• If you have type A blood your body

forms Anti B antibodies

• If you have type B blood your body forms Anti-A antibodies.

• If you have type O blood your body forms Anti- A and Anti-B antibodies.

• Type O – Universal donor

• If you have type AB blood your body forms no antibodies

• Type AB universal recipient

Rh Blood Groups

• People are either Rh+ and have the Rh anitgen or they are Rh- and then they do not have the Rh antigen.

• 85% of people are Rh+• Antibodies are formed when the

wrong blood is added.• Rh antibodies are produced by Rh-

people who come in contact with Rh+ blood. RBC’s that are Rh+ are attacked and destroyed.

Rh Factor and Pregnancy

• Rh- female pregnant with an Rh+ kid

• Baby is born healthy but mom begins to make Anti-Rh+ antibodies

• 2nd Rh+ kid – her antibodies will go through the placenta and destroy the babies RBC’s

Hemolytic Disease of the Newborn

• Babies RBC’s are destroyed – baby is anemic and hypoxic

• Brain damage and death results if the baby does not get transfusions.

Blood Typing

• Blood is tested by mixing it with two different types of immune serums – Anti A and Anti B.

Agglutination happens when:

• Type A is mixed with Anti-A but not Anti-B

• Type B is mixed with Anti-B but not Anti-A

• Figure 10.7 pg 308

The End