Essay about Blood: White Blood Cells

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Dr. Charu Taneja

Fluids of the Body
 Cells of the body are serviced by 2 fluids
 blood

composed of plasma and a variety of cells transports nutrients and wastes

 interstitial fluid
 bathes the cells of the body

 Nutrients and oxygen diffuse from the blood into the

interstitial fluid & then into the cells
 Wastes move in the reverse direction
 Hematology is study of blood and blood disorders

Essential Terms plasma  liquid portion of blood formed elements
 cells and cell fragments of blood
 red blood cell
 white blood cells or leukocytes hemopoiesis  blood cell production pluripotent stem cell
 cells with capacity to develop into several types of cells Introduction
Cardiovascular system consists of three interrelated components 1. BLOOD
Blood is connective tissue with liquid portion (plasma) and cell and cell fragments portion (formed elements)
RBCs carry oxygen
WBCs function in immunity

Anatomy and Physiology of



Functions of Blood


oxygen from lungs to body tissues metabolic wastes from tissues to lungs, kidneys, and liver nutrients from GI tract to body cells hormones •



pH via buffers body temperature

coolant properties of water vasodilatation of surface vessels dump heat

helps regulate water content of cells by interactions with dissolved ions and proteins



immunity and immune responses

Physical Characteristics of Blood
 Thicker (more viscous) than water and flows more

slowly than water
 Temperature of 100.4 degrees F
 pH 7.4
 8 % of total body weight
 Blood volume
 5 to 6 liters in average male
 4 to 5 liters in average female
 hormonal negative feedback systems maintain constant blood volume and osmotic pressure

Protection from disease

Components of Blood
 45% formed elements
99% are RBCs
 1% WBCs and platelets

 55% blood plasma

Blood Plasma
 0ver 90% water
 7% plasma proteins

created in liver confined to bloodstream

 albumin
 maintain blood osmotic pressure
 globulins (immunoglobulins)
 antibodies bind to foreign substances called antigens
 form antigen-antibody complexes
 fibrinogen
 for clotting

 2% other substances
 electrolytes, nutrients, hormones, gases, waste products


Figure 18.1a

 process by which formed elements develop  before birth occurs in liver, spleen, thymus, lymph nodes of fetus
 last trimester and beyond occurs in red bone marrow

red bone marrow found in spaces between trabeculae of spongy bone
0.05-0.1% of red bone marrow are pluripotent stem cells



Formed Elements of Blood
 Red blood cells ( erythrocytes )
 White blood cells ( leukocytes )
 granular leukocytes
 neutrophils
 eosinophils
 basophils
 agranular leukocytes
 lymphocytes = T cells, B cells, and natural killer cells
 monocytes

 Platelets (special cell fragments)

 Percentage of blood occupied by cells
 female normal range
 42%

Formation of Blood Cells
 Most blood cells types need to be continually replaced  die within hours, days or weeks

 male normal range
 46%

 Anemia
 not enough RBCs or not enough hemoglobin

 process of blood cells formation is hematopoiesis or


 In the embryo
 occurs in yolk sac, liver, spleen, thymus, lymph

 Polycythemia
 too many RBCs (over 65%)

nodes & red bone marrow

 In adult
 occurs only in red marrow of flat bones like sternum,

ribs, skull & pelvis and ends of long bones

Stages of stem cells Cell Formation
 Pluripotent
 .1% of red marrow cells
 replenish themselves as they differentiate into either myeloid or

lymphoid stem cells

 Myeloid stem cell line of development continues: