CH 16 The Blood

List 8 functions of the blood:

1. Delivery of oxygen and nutrients to body cells 2. Transports metabolic waste to lungs and kidneys 3. Transport hormones 4. Maintains body temperature 5. Maintains pH 6. Maintains adequate fluid volume in blood 7. Prevents blood loss 8. Prevents infection

Describe fluids used to replace blood volume and the circumstances for their use:

BV is replaced with normal saline or multiple-electrolyte solution that mimics plasma; used when the situation is an emergency and there is not time for blood typing

Describe the composition and physical characteristics of whole blood. Explain why it is classified and a connective tissue:

Blood is composed of RBCs, WBCs, Plasma, and platelets. It is sticky, opaque liquid, metallic taste, pH 7.35-7.45. Considered a connective tissue because it connects all of the body systems together.

List the classes, structural characteristics, and functions of leukocytes :

Function in defense against disease. Classes: Granulocytes & Agranulocytes Granulocytes: (visible cytoplasmic granules) Neutrophils- most numerous WBC, contain hydrolytic enzymes, 3-6 lobes in nucleus, twice the size of a RBC, actively phagocytic Eosinophils- bilobed nucleus, aid to digest parasitic worms, role in allergies or asthma Basophils- rarest WBC, deep purple nucleus, acts as a vasodilator, purplish-back granules Agranulocytes: (no visible granules) Lymphocytes- T-Cells (virus infected cells and tumor cells) and B-Cells (give rise to plasma cells which produce antibodies) Monocytes- largest WBC, U-shaped nucleus, leave circulation and enter tissues, differentiate into macrophages. Actively phagocytic cells crucial against viruses, intracellular bacterial parasites, and chronic infections

Describe the chemical composition of hemoglobin:

Heme: iron containing, highly modified amino acid, that cannot be reused and is eventually degraded to bilirubin pigment Globin: Starts out as a protein that binds to a heme group, will eventually metabolize and be recycled as amino acids and released into cirulation

Describe the process of hemostasis. List factors that limit clot formation and prevent undesirable clotting.

Hemostasis: fast series of reactions for stoppage of bleeding (vascular spasm, platelet plug formation, coagulation) 2 mechanisms limit clot size: swift removal and dilution of clotting factors and inhibition of activated clotting factors Undesirable clotting is prevented by : smooth endothelium of blood vessels, nitric oxide and prostacyclin secreted by endothelial cells, and vitamin E quinone acts as an anticoagulant

Explain the diagnostic importance of blood testing:

Importance of blood testing is that the tests give info that can be used to evaluate a patient's current state of health

Describe how leukocytes are produced:

Leukopoiesis (production of WBCs) is stimulated by interleukins and colony-stimulating factors; all leukocytes originate from hemocytoblasts

Discuss the composition and functions of plasma:

Plasma is 90% water, it's a universal solvent, and is made up of many proteins such as albumin, globulins, and fibrinogen. Albumin helps maintain osmotic pressure, carry substances, and acts as a blood buffer. Globulins are mainly antibodies. Fibrinogen helps form blood clots.

Describe the structure and function of platelets:

Platelets are cytoplasmic fragments of megakaryocytes. They form temporary plugs in broken blood vessels but are inactive until used to help clotting in broken blood vessels.

Describe the structure, function, and production of erythrocytes.

RBCs have a biconcave disc shape, are anucleate, and have no organelles. Their diameter is larger than some blood vessels and their dedicated to gas transport. Hematopoiesis (formation of RBCs) happens in stages: stem cell > committed cell > basophilic erythroblast > polychromatic erythroblast > reticulocyte > erythrocyte(RBC). And it originates in the red bone marrow.

Describe the ABO and RH blood groups. Explain the basis of transfusion reactions.

Types A, B, AB, and O: based on presence or absence of two agglutinogens. Rh+ indicates presence of D antigen (85% of americans are Rh+) Transfusion reactions can occur when the wrong blood is given because the antigens on the RBCs will cause the transfused blood to coagulate.