Blood Cells in the body are fixed within tissues and must have nutrients and oxygen brought to them...

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Blood Cells in the body are fixed within tissues and must have nutrients and oxygen brought to them and waste removed. The blood is classified as a fluid matrix connective tissue – The cells and cell fragments are the formed elements and the matrix of the blood is fluid (plasma). – Formed elements make up about 45% and plasma 55% of the total blood volume. – Blood volume: 4-5 L in females, 5-6 L in males.

Transcript of Blood Cells in the body are fixed within tissues and must have nutrients and oxygen brought to them...

Blood• Cells in the body are fixed within tissues and

must have nutrients and oxygen brought to them and waste removed.

• The blood is classified as a fluid matrix connective tissue– The cells and cell fragments are the formed

elements and the matrix of the blood is fluid (plasma).

– Formed elements make up about 45% and plasma 55% of the total blood volume.

– Blood volume: 4-5 L in females, 5-6 L in males.

Blood Functions• Distribution and transportation

– Respiration

– Nutritive

– Excretory

– Negative Aspects

• Regulation and Maintenance

– Hormonal regulation

– Thermoregulation

– pH / acid-base balance

– Fluid volume

• Protection

– Clotting

– Immunity

Major Components of the Circulatory System

• Two divisions: Cardiovascular and lymphatic systems.– Cardiovascular: Heart, blood vessels

• Heart• Vessels

– Lymphatic: lymphatic vessels and lymphoid tissues in spleen, thymus, tonsils, and lymph nodes.

• The fluid portion of the blood (plasma) passes through the capillary walls under hydrostatic pressure (interstitial fluid).

• Some interstitial fluid returns to the blood and some enters the lymphatic system

– Lymphatic vessels carry interstitial fluid now called lymph back to the venous blood.

– Lymph nodes along the way filter and cleanse the blood before it is returned.

Erythrocytes• Structure

– Biconcave, anucleate– 4.8 million/mm3 in

women. – 5.4 million/mm3 in men.– 7.5 um in diameter

• Components– Hemoglobin– Lipids, ATP, carbonic

anhydrase• Function

– Transport oxygen from lungs to tissues and carbon dioxide from tissues to lungs

Hemoglobin

• Consists of: – 4 globin molecules: 2 alpha and 2 beta chains

• 280 million per RBC.• Transport carbon dioxide (carbonic anhydrase involved), nitric

oxide.

– 4 heme molecules: Transport oxygen• Iron is required for oxygen transport

Erythropoiesis

• Production of red blood cells

– Stem cells proerythroblasts early erythroblasts intermediate late reticulocytes

• Erythropoietin: Hormone to stimulate RBC production

Hemolytic Anemia

Anemias • Result of either a decrease in hemoglobin / RBC or in the

number of RBCs.

• Symptoms: pale, lethargic, shortness of breath, tired.

• Aplastic anemia: inability of red bone marrow to produce RBCs

• caused by: damage to Red bone marrow, Iron of Folate deficiency

• Pernicious anemia - Vitman B12 deficiency

• Hemorhagic anemia - results from loss of blood

• Hemolytic anemia - erythrocytes rupture or are destroyed at an increased rate.

• Thalasemia - defective hemoglobin production

Malaria

Sickle cell anemia

Formed Elements• Red blood cells (erythrocytes)• White blood cells (leukocytes)

– Granulocytes• Neutrophils

• Eosinophils

• Basophils

– Agranulocytes • Lymphocytes

• Monocytes

• Platelets (thrombocytes)

Production of Formed Elements

• Hematopoiesis or hemopoiesis: Process of blood cell production

• Stem cells: All formed elements derived from single population– Proerythroblasts: Develop into red blood cells– Myeloblasts: Develop into basophils,

neutrophils, eosinophils– Lymphoblasts: Develop into lymphocytes– Monoblasts: Develop into monocytes– Megakaryoblasts: Develop into platelets

Hematopoiesis

Neutrophil

• Appearance– 2-5 lobes – 10-12 um– 54-62% of white cells

• Characteristics– Fights bacterial and

fungal infections– Contains peroxidases and

defensins– Numbers increase with

meningitis and appendicitis

Eosinophil

• Appearance– Bilobed nucleus– Red granules– 11-14 um– 1-3% of white blood cells

• Characteristics– Fights parasitic infections.– Releases anti-

inflammatory chemicals.– Secretes enzymes that

break down clots.

Basophils

• Appearance– Two indistinct lobes– Blue-purple granules– 10-12 um– Less than 1% of WBC

• Characteristics– Release histamine– Chemoattractant for other

WBCs– Releases heparin to

prevent clots.Basophil Eosinophil

Monocyte

• Apearance

– Nucleus round, kidney or horseshoe shaped

– 12-20 um

– 3-9 % of WBC

• Characteristics

– Transforms into macrophages

Lymphocyte

• Appearance– Round nucleus– 6-14 um– 25-33% of WBC

• Characteristics– Found in lymphoid tissue– Provides specific immune

response• T - lymphocytes

• B - lymphocytes

Leukocytes

Hemostasis

• Arrest of bleeding• Events preventing excessive blood loss

– Vascular spasm: Vasoconstriction of damaged blood vessels

– Platelet plug formation – Coagulation or blood clotting

Thrombocytes

• Cell fragments pinched off from megakaryocytes in red bone marrow

• Important in preventing blood loss

– Platelet plugs

– Promoting formation and contraction of clots

Platelet Plug Formation

Coagulation

• Stages

– Activation of prothrombinase

– Conversion of prothrombin to thrombin

– Conversion of fibrinogen to fibrin

• Pathways

– Extrinsic

– Intrinsic

Clot Formation

Fibrinolysis

• Clot dissolved by activity of plasmin, an enzyme which hydrolyzes fibrin

Blood Grouping

• Determined by antigens (agglutinogens) on surface of RBCs

• Antibodies (agglutinins) can bind to RBC antigens, resulting in agglutination (clumping) or hemolysis (rupture) of RBCs

• Groups– ABO and Rh

ABO Blood Groups

Agglutination Reaction

Rh Blood Group

• First studied in rhesus monkeys• Types

– Rh positive: Have these antigens present on surface of RBCs

– Rh negative: Do not have these antigens present

• Hemolytic disease of the newborn (HDN)– Mother produces anti-Rh antibodies that cross

placenta and cause agglutination and hemolysis of fetal RBCs

Erythroblastosis Fetalis

Diagnostic Blood Tests

• Type and crossmatch

• Complete blood count

– Red blood count

– Hemoglobin measurement

– Hematocrit measurement

• White blood count

• Differential white blood count

• Clotting

Blood Disorders

• Erythrocytosis: RBC overabundance

• Anemia: Deficiency of hemoglobin

– Iron-deficiency

– Pernicious

– Hemorrhagic

– Hemolytic

– Sickle-cell

• Hemophilia

• Thrombocytopenia

• Leukemia

• Septicemia

• Malaria

• Infectious mononucleosis

• Hepatitis