Roots to Know
leuko = white
thrombo = clot
cyto = cell
COMPOSITION OF BLOOD
The cells of the human body are organized into tissues and organs.
There must be a system to transport materials between these organs and tissues.
This function is achieved by the circulation of blood and the mechanism that moves it
The cardiovascular system.
The system of vessels that connects with the veins of the cardiovascular system is the lymphatic system.
A one-way transporting network of vessels that returns excess interstitial fluid from the tissues to the bloodstream
Blood is a type of liquid connective tissue
55 % of the total volume is the fluid plasma
Plasma is a straw-color
45% consisting of the formed elements. Proteins, cells, and the like.
This fact can be easily demonstrated by placing a specimen of whole blood in a test tube with a small amount of oxalate to prevent clotting. If the sample is centrifuged or allowed to stand for a sufficient length of time, it will be found that the blood cells will settle toward the bottom of the test tube while the plasma remains on top.
The total circulating blood volume makes up about 8% of the body's weight.
a 70-kilogram (152-pound) person will have 5 to 6 liters (10.5 to 12.6 pints) of blood.
Blood is a somewhat viscous and sticky liquid.
Its viscosity is about five times that of water.
It has a characteristic odor, a salty taste'
a pH value of from approximately 7.35 to 7.45 (slightly alkaline).
The most common formed elements:
The liquid portion of the blood.
A complex solution performing many of the functions of the circulatory system.
The normal volume of plasma in a 70-kilogram adult male is about 5% of the body weight (» 3.5 liters).
Amber (straw), color.
90 - 92 % H2O
A variety of inorganic and organic substances, ions and inorganic salts.
Na+ K+ Ca++ and Mg++, and anions such as Cl -, PO44-, HC03-, and others.
albumin, globulins, fibrinogen, and lipoproteins.
And varying amounts of hormones, enzymes, pigments, and vitamins.
The composition of plasma varies with the body's activity and different physiological states.
Following a meal plasma contains an increased amount of nutrient materials.
After a period of strenuous exercise, plasma contains wastes that the blood has removed from active tissues.
Thus from one moment to the next, plasma reflects the physiological changes in the body.
PHYSIOLOGY OF THE PLASMA
The functions of the blood are closely tied to the functions of all the body's organ systems.
pH balance. Is also maintained by the balance of HCO3- and H+, buffering.
Foods that have been rendered soluble by digestion are absorbed into the plasma and are transported throughout the body.
Soluble wastes are removed from the cells and carried as disolved organics in the plasma to those organs that can either eliminate them or change them into compounds that are useful for other purposes.
Hormones manufactured in glands move directly into the blood for transportation around the body.
Maintenance of [H2O] in the tissues by drawing upon H2O reserves.
Maintenance of body temperature. Enzymes work best at body temperature. High temperatures can degrade proteins, making enzymes inactive. Thus any increase in the activity of a tissue is also accompanied by an increase in the circulatory rate, and the blood passing through it is heated. This excess heat in the blood is then eliminated through the surface of the body, the lungs, or excretions.
Fibrinogen: fiberous-like protein that forms a net for blood clots.
Plasma proteins (other than fibrinogen) are classified as either globulins or albumins.
A good example of an albumin that is not a constituent of blood is that in the white of an egg, while a globulin is present in the egg yolk.
Normally, the blood proteins do not pass through the capillary walls because of their relatively large size. However, since they are colloidal materials, they can give up, or take up, water-soluble substances.
When fibrinogen is removed, the plasma, minus its clotting proteins, is called serum.
7% of Serum
Table 19-2 Chart of Plasma Composition
Formation of Blood Cells
The erythrocytes, the leukocytes, and the thrombocytes are formed in the red marrow of many bones.
The lymphocytes and monocytes, moreover, are also formed in lymphatic tissue.
Because the formed elements of the blood are constantly being worn out, they must be replaced by the body at a corresponding rate.
Before birth, blood cells are formed in the yolk sac, liver, spleen, thymus gland, lymph nodes, and red bone marrow of the fetus.
At 7 years, red marrow becomes fatty and incapable of forming blood cells.
At 20 years, all hemopoiesis occurs in the red marrow.
Blood cells arise from mesenchymal stem cells.
Gives rise to the hemocytoblasts.
Eventually forms cellular elements of the blood
Erythroblasts form into erthrocytes.
Myeloblasts form into granulocytes.
Megakaryoblasts form into megakaryocytes.
Some stem cells migrate to the lymphatic tissue, where they form lymphoblasts.
Lymphoblasts form into monocytes.
Erthorocytes lose their nuclei, lymphocytes develop cytoplasmic structres.
Life span of 120 days.
Called reticulocytes before maturity.
0.8% of total erythrocytes in circulating blood.
Number of erythrocytes remains constant.
About 30 trillion in adult.
Using a hemocytometer to count the number of cells:
More in Men than in women.
5,450,000/mm3 erythrocytes for males,
4,750,000/mm3 erythrocytes for females.
Production of erythrocytes.
Triggered by tissues need for O2
Kidneys release erythropoietin (hormone), which activates the hematocytoblasts.
Diameter: 6.5-8 m m (adverage = 7.5 m m)
2.2 m m and the edge, and 1.1 m m in the center. (Doughnut)
Area: 140 m m2
Protein and lipids.
Permeable to water, urea, and salt.
Highly elastic to fit through small capalaries.
Main job to carry hemoglobin.
Some 280 million hemoglobin per erythrocyte.
It has 4 hemes, lobe-shapes, that has 1 Fe+3 per heme.
Each heme can carries 4 O2 molecules.
Affinity for O2 increases as the number of attached O2 decrease.
Oxyhemoglobin has 4 O2
Deoxyhemoglobin has no O2.
Fetal hemoglobin (Hbf) differs from Hb by being able to saturate with O2 under lower [O2]. Less O2 in mothers blood than in our lungs/air.
PHYSIOLOGY OF ERYTHROCYTES
The gases involved in respiration are carried by the blood.
O2 bound to Hb in the lungs ® tissues (flushed), diffused into cell, O2 released in tissues.
CO2 bound to Hb in tissues ® lungs (HC03-) released in lungs inations.
HC03- bicarbonate buffers H+.
About 25 percent of the C02 reacts with the amino groups of hemoglobin to form carbamino compounds.
White blood cells.
Less than erthrocytes.
5,000 - 9,000 per mm3 blood.
Variable size and shapes.
All are nucleated.
Life span far less than erthrocytes.
Diapedesis: ameoba-like movements that allow leukocytes to move through capillary walls.
This type of movement increases when stimlated by pathogens.
Digest bacteria through various means.
Surrounds like lysosomes, engulfs, then digest bacteria. (Phogocytosis).
Two major types, based upon the number of grauales which stains well with Writght’s stain.
Granulocytes (polymorphonuclear cells)
3000-6000 per mm3
300 per mm3
Phagocytosis of antigen-antibody complexes.
25-100 per mm3
1500-3000 per mm3
Synthesis of antibodies
500 per mm3
Very motile and phagocytic.
Forms macrophages, that attack large invaders.
250,000-500,000 per mm3
Blood clotting for small punctures and cuts, (paper cuts).
Smallest elements, cells.
Table 19-1 The Cellular Elements of the Blood
PHYSIOLOGY OF THE LEUKOCYTES
Protection against disease is another important function of the blood. This is accomplished by the white blood cells in one of two ways. First, certain granulocytes, primarily neutrophils, act as phagocytes and engulf bacteria. Second, still other types of white corpuscles have the ability to manufacture chemical substances (antibodies) to destroy bacteria or to neutralize the toxins (poisons) produced by invading organisms.
In the event of an injury involving blood loss, a number of events take place to arrest the blood flow.
+ C+2 + Vitamin K
Prothrombin ¾ ¾ ¾ ¾ ¾ ¾ ¾ ¾ ¾ ® thrombin
Fibrinogen soluble ¾ ¾ ¾ ¾ ® Fibrin insoluble
Fibrin forms a meshwork of fine protein threads. The platelets, having contractile properties, pull the fibrin fibrils together and squeeze out the remaining fluid-the serum. Once hemorrhaging is stopped, tissue repair can begin.
Physical Factors of Coagulation
The most successful method of combating excessive loss of blood is transfusing whole blood into the circulatory system of the victim. Usually, whole blood is superior to any blood substitute or component part of blood.
To transfuse blood from one individual to another, the blood types of both must be known to able to mix safely, that is, to be compatible. The mixing of unsafe, or incompatible, blood may lead to very serious or possibly fatal transfusion reactions. The problem occurs when the protein outer layer of the red corpuscles of the donor becomes "sticky" when introduced into an antagonistic plasma of the recipient. The "sticky" red blood cells clump together and block the vessels of the patient. This clumping of blood cells is called Agglutination. The plasma proteins concerned in agglutination are antibodies called agglutinins, while the proteins in the walls of the corpuscles are antigens, called agglutinogens.
The blood group of each person is designated as A, B, AB, or 0, depending on the kind of agglutinogen (antigen) present in the red blood corpuscles.
Transfusion reactions. The terms universal donor and universal recipient are frequently applied to members of groups 0 and AB, respectively.
Rh factor. There are several other proteins in the blood that may bring about agglutination under certain conditions. The most important of these is the Rh factor, which, like the blood type, is an inherited characteristic. The letters "Rh" are used since this factor was first studied in the rhesus monkey.
Blood Groups and Corresponding Antigens and Antibodies
Blood is considered a type of connective tissue composed of approximately 55 percent intercellular fluid (the plasma) and 45 percent formed elements. The contents of the blood maintain the water content of the body, protect against disease, and maintain an acid-base equilibrium in the internal environment.
Special features of blood include hemostosis (blood clotting), the control of osmotic balance by plasma proteins, the capacity of the blood to buffer acids or bases, and the ability for blood from different individuals of the some blood type to be mixed.
Disorders of the blood include different forms of anemia, clotting within vessels (thrombus) hemophilia, and hemorrhaging.