Chapter 17 - Blood

Transport

Oxygen, Carbon dioxide, Nutrients, Hormones, Metabolic wastes, Heat

Protection

White blood cells, Antibodies, Clotting mechanisms

Regulation

Body temp, pH, Fluid balance, Osmotic pressure, Electrolyte concentrations

Functions of Blood

Transport, protection, regulation

Composition of Blood

Plasma 55%

Erythrocytes, Leukocytes, Thrombocytes 45%

Blood Volume

Male: 5-6 L

Female: 4-5 L

Blood pH

7.35 - 7.45

Blood Temperature

38^oC

Blood Salinity

0.9% NaCl

Hematocrit

Percentage of blood volume occupied by erythrocytes

Hematocrit Count

Male: 47% +_ 5%

Female: 42% +_ 5%

Increased Hematocrit Causes

Polycythemia, dehydration, high altitude

Decreased Hematocrit Causes

Anemia & blood loss

Osmolarity

Total concentration of dissolved particles

280-296 (~300) mOsm/L

Viscosity

Resistance of a fluid to flow

Whole blood: 4.5 - 5.5x of water

Plasma: 2.0x

Increased Viscosity Causes

Polycythemia & dehydration

Plasma Composition

90 - 92% water

Nutrients, glucose, amino acids, vitamins, hormones, electrolytes, oxygen, carbon dioxide

Nitrogenous Wastes

Ammonia, Urea, Uric acid, Creatinine, Bilirubin

Ammonia

Produced from amino acid metabolism

Converted to UREA

Urea

Most abundant

Product of amino acid catabolism

Uric Acid

Product of nucleotide catabolism

Creatinine

Product of creatine metabolism

Bilirubin

Product of hemoglobin metabolism

Plasma Proteins

Albumin 60-80%

Globulin 36%

Fibrinogen 4%

Albumin

Most abundant

Maintains blood volume & COP

Creates colloid osmotic pressure that pulls water into capillaries

Globulin

Carries lipids

Alpha: Haptoglobin, Ceruloplasmin, Prothrombin

Beta: Transferrin, Complement proteins

Gamma: Antibodies

Fibrinogen

Inactive clotting protein

Converted to fibrin during coagulation

Kwashiorkor

Protein defficiency

Low albumin, COP, water reabsorption,

High fluid accumulation in tissues

Results in edema

Serum vs Plasma

Plasma: Clotting factors, fibrinogen

Serum: Plasma after clotting, lacks clotting proteins

Hematopoiesis

Blood cell formation

Myeloid Tissue: Bone marrow

Lymphoid Tissue: Lymphatic organs

Erythropoiesis

Formation of RBCs

Stimulated by Erythropoietin (EPO)

Produced in kidneys

Hemoglobin Structure

Globin: 2 alpha 2 beta

Heme: Contains Fe²⁺

Oxygen Carrying Capacity

Each heme binds 1 O₂

Each hemoglobin binds 4 O₂

Each RBC contains 280 million hemoglobin molecules

Oxyhemoglobin

Ruby red

O₂ loading in the lungs

Deoxyhemoglobin

Dark red

O₂ unloading in the tissues

Carbaminohemoglobin

CO₂ loading in the tissues

Iron Metabolism

Iron is essential for hemoglobin synthesis

Storage: Ferritin, hemosiderin

Transport: Transferrin

Erythrocyte Life Cycle

Lifespan: 100-120 days

Destruction: Spleen, liver

Hemoglobin Fate

Globin: Broken into amino acids

Iron: Recycled & Reused

Heme: Converted to bilirubin

Jaundice

Yellow discoloration caused by excess bilirubin

Liver disease, bile obstruction, excessive RBC destruction

Anemia

Reduced oxygen-carrying capacity of blood

Symptoms: Fatigue, pallor, chills, shortness of breath

Hemorrhagic Anemia

Chronic loss of blood

Hemolytic Anemia

Premature RBC destruction

Aplastic Anemia

Bone marrow damage

Pernicious Anemia

Vitamin B12 deficiency

Low levels of intrinsic factor, produced in stomach

Thalassemias Anemia

Defective globin chains

Sickle-Cell Anemia

Low-oxygen situations causes RBCs to form abnormally

Polycthemia

Excess erythrocyte production

Increased hematocrit, viscosity, risk of clotting

Polycythemia Causes

Polycythemia Vera: Bone marrow cancer

Secondary Polycythemia: High altitude

Blood Doping: Artificial increase in RBC count

Transfusion Reactions

Incompatible blood is transfused together

Agglutination, kidney damage, jaundice, vessel blockage, death

Agglutinogen

Antigen on red blood cell

Agglutinin

Antibody in plasma

Hemagglutination

Clumping of red blood cells

Not clotting

Rh⁺

D antigen present

Rh^-

D antigen absent

Erythroblastosis Fetalis

Rh⁻ mother & Rh⁺ fetus

Mother develops anti-Rh antibodies.

During later pregnancies antibodies cross placenta and destroy fetal RBCs

Leukocytes

Defense, immunity, destruction of pathogens

Granulocytes

Neutrophils, eosinophils, basophils

Agranulocytes

Monocytes, lymphocytes

Neutrophils

Primary bacterial phagocytes

Eosinophils

Attack parasites & reduce allergic responses

Basophils

Release histamine

Promote inflammation

Monocytes

Becomes macrophages

Lymphocytes

B cells: Produced antibodies

T cells: Kill infected tumor cells

Leukopenia

Low white blood cell count

Leukemia

Cancer of WBC-producing tissues

Platelets

Produced form megakaryocytes

Regulated by thrombopoietin

Contains serotonin & thromboxane A2

Hemostasis

Stopping of bleeding

Vascular spasm, platelet plug formation, coagulation

Coagulation Cascade

Formation of prothrombin activator

Prothrombin → thrombin

Fibrinogen → fibrin

Requirements For Clotting

Vitamin K: Required for activation of clotting proteins

Calcium Ca²⁺: Required for several clotting factors

Natural Anticlotting Factors (Vasodilators)

Prostacyclin (PGI₂)

Nitric Oxide (NO)

Vasodilation, prevent platelet activation, prevent unnecessary clotting

Fibrinolysis

Dissolution of clot after repair

Thromboembolism

Embolism caused by a traveling blood clot

Embolism

Object from one part of the body migrates and causes blockage of blood vessels

Anticoagulants

Heparin, Coumarin, Aspirin

Heparin

Activates antithrombin III, blocking thrombin

Coumarin

Inhibits activation of Vitamin K

Aspirin

Suppresses formation of thromboxane A₂

Hemophilia

Bleeding disorder

A - VIII

B - IX

C - XI

Red Blood Cell Count

Male: 4.7 - 6.1 million/uL

Female: 4.2 - 5.4 million/uL

White Blood Cell Count

4,500 - 10,000u/L

Platelet Count

150,000 - 400,000/uL

Hemoglobin Count

Male: 14 - 18 g/dL

Female: 12 - 16 g/dL