Chapter #12

Blood

12.1

Blood is a type of connective tissue whose cells are suspended in a liquid material.

12.2

Whole blood is:I. Slightly heavier than waterII. 3 to 4 times more viscous (resistance

to flow)Blood cells form mainly in the red bone

marrow. Blood also contains cells (RBC and WBC)

and cell fragments (platelets) called formed elements.

The average sized adult has about 5 liters of blood volume.

Men have more blood than women. Men 1.5 gallons, women 0.875 gallons.

A blood sample is usually about 45% cells (red and white) this is called the hematocrit (HCT).

A blood sample is about 55% liquid called plasma (yellow in color).

Plasma (nonliving) is a complex mixture of water (92%), amino acids, proteins, carbohydrates, lipids, vitamins, hormones, electrolytes, and cellular wastes.

In one drop of blood

RBC 5 million, live for 120 days, main job is to carry oxygen.

WBC 8,000, live for 10 days, main job is to fight infections.

Platelets 250,000, 5 days, main job is to aid in forming clots.

Red Blood Cells RBC or erythrocytes are biconcave

disks, shaped like donuts with no hole. Hemoglobin

i. is the protein that causes blood to be red.

ii. carries oxygen on the RBC. Anemia is having too few RBC or too

little hemoglobin. A person with anemia feels tired, is short of breath, and looks pale.

The production of RBC is dependent on adequate intake of iron, folic acid, vitamin B12.

RBC lack a nucleus and therefore cannot synthesize proteins or reproduce.

Sickle Cell Sickle cell anemia is a genetic disease

in which all the RBC are shaped like sickles.

i. Sickle cell is more common among African-Americas.

ii. People with sickle cell have serious health problems.

iii. Sickle cells do not carry enough oxygen and can get stuck in blood capillaries.

Destruction of RBC

Marcrophages destroy damaged RBC, primarily in the liver and spleen.

White Blood Cells

WBC or leukocytes protect against disease.

There are 5 types of WBC. They are classified according to size, the nature of their cytoplasm, nuclei shape, and how they stain.

2 Main Groups of WBC

1. Granulocytes are leukocytes with granular cytoplasm. They live only about 12 hours.

2. Agranulocytes are leukocytes without cytoplasmic granules.

5 types of WBC1. Neutrophils is the most numerous WBC.

2. Eosinophils are WBC that increase in certain parasitic infections and allergic reactions.

3. Basophils release heparin and histamine.

4. Monocytes are the largest blood cells. They are 2 or 3 times larger than RBC.

5. Lymphocytes can live for many years. They form antibodies necessary for immunity to specific diseases.

WBC combat infection by phagocytes and antibody production.

WBC diseases

Leukemia is a form of cancer characterized by uncontrolled production of WBC.

AIDS or Acquired Immune Deficiency Syndrome, is a disease of the immune system. The AIDS virus reproduces in only one kind of WBC.

Platelets

Platelets or thrombocytes are not complete cells.

Platelets lack a nucleus. Platelets help close breaks in damage

blood vessels and initiate formation of blood clots.

12.3 Blood Plasma

Plasma is the clear, straw colored, liquid portion of the blood.

Plasma is 92% water. Functions included transporting

nutrients, gases, and vitamins. Help regulate fluid and electrolyte balance and maintaining body pH.

Plasma Proteins

Plasma proteins are the most abundant of the dissolved substances in plasma.

3 Types of Plasma Proteins

1. Albumins

2. Globulins

3. Fibrinogen

Albumins are the smallest of the plasma proteins, account for 60% of these proteins by weight. Made in the liver.

Globulins make up 36% of plasma. Produce by lymphatic tissue (Lymphocytes).

Fibrinogen make up 4% of plasma. Functions in blood coagulation.

Gases and Nutrients

Blood Gases are oxygen and carbon dioxide.

Plasma nutrients include amino acids, simple sugars, nucleotides, and lipids absorbed from the digestive tract. Most nutrients found in the plasma were primarily absorbed from the small intestines.

Plasma lipids include fats, phospholipids, and cholesterol. Lipids are not soluble in water.

Lipids that connect to proteins are called lipoproteins.

Lipids are transported in plasma primarily as lipoproteins.

Cholesterol

(LDL) Low-Density lipoproteins (bad) (HDL) High-Density lipoproteins (good)

Nonprotein nitrogenous substances include amino acids, urea, and uric acid.

Plasma Electrolytes are absorbed from the intestine. Sodium, potassium, calcium, magnesium, chloride, bicarbonate, phosphate, and sulfate ions. Na and Cl are the most abundant.

12.4 Hemostasis

Is the stoppage of bleeding. Vasospasm when severed vessel close

completely only last up to 30 minutes. Serotonin release which causes smooth

muscles to contract that reduces blood loss.

Platelets adhere to any rough surface and form blood clots. Clots begin to form when platelets come in contact with a rough surface.

Blood Coagulation

Coagulation the most effective hemostatic mechanism, causes formation of blood clots.

Fibrin insoluble threads. Prothrombin produced by the liver. In the

presence of Calcium ions converts into thrombin which then forms fibrin threads.

Platelet disease

Hemophilia- genetic disease in which blood is missing the clotting factor. Blood transfusions prior to 1985 have caused 95% of the hemophiliacs to develop AIDS.

Von Willebrand- genetic disease in which a plasma protein in missing causes people to bruise and bleed easily.