Blood Flashcards
Functions of Blood
transportation, regulation, protection
Characteristics of Blood
- heavier, thicker, and more viscous than water, also flows slower than water
- temperature is higher than normal body temp
- slightly alkaline pH of about 7.4
Components of Blood
blood plasma, formed elements, and leukocytes
Blood Plasma
- straw colored liquid
- mostly water
- contains plasma proteins, and small amount of other solutes
Plasma Proteins
- play a role in maintaining proper blood osmotic pressure, and act as buffer system
- most synthesized by hepatocytes
- albumins, globulins, fibrinogen
Albumin
- about 55% of plasma proteins
- major contributors to the osmotic pressure of plasma
- important in the transport of fatty acids
Globulin
- about 38% of plasma proteins
- transport globulins and immunoglobulins
- immunoglobulins produced by lymphocytes
Fibrinogen
- about 7% of plasma proteins
- function in blood clotting
Hemopoiesis
definition
the production of blood cells from hemopoietic stem cells in red bone marrow
Myeloid stem cells develop into what under the influence of erythropoiten?
develop into reticulocytes and then erythrocytes (RBCs)
Myeloid stem cells develop into what under the influence of thrombopoietin?
develop into megakaryocytes and then platelets
Myeloid stem cells develop into what under the influence of colony stimulating factors?
develop into white blood cells: basophils, eosinophils, neutrophils, and monocyes
Erythropoiten (EPO)
low-oxygen stimulates the release of EPO from the kidneys, which travels to the bone marrow and stimulates erythropoiesis
- increases rate of division
- increases maturation of RBCs
Hematocrit
definition
the percent of red blood cells in the blood
- so a hematocrit of 40 means that 40% of the volume of blood is RBCs
Anemia
general definition
refers to a reduction, below normal, in the O2-carrying capacity of the blood
- characterized by a low hematocrit
Causes of Anemia
- a decreased rate of erythropoiesis
- excessive loss of erythrocytes
- deficiency in the hemoglobin content of erythrocytes
Polycythemia
general definition
an excess of circulating red blood cells and an elevated hematocrit
- primary and secondary types
Primary Polycythemia
- caused by tumor-like condition of bone marrow in which erythropoiesus proceeds in an excessive, uncontrolled rate
- increases viscosity of blood leading to sluggish blood flow and pressure overload
Secondary Polycythemia
- an EPO-induced adaptive mechanism to improve the O2 carrying capacity of the blood in response to a prolonged reduction of O2 delivery to tissues
- hematocrit is lower than that of primary
Nutritional Anemia
- caused by a dietary deficiency of a factor needed for erythropoiesis
- ex. iron, folic acid
Pernicious Anemia
- caused by inability to absorb adequate amounts of vitamin B12 from digestive tract
- need intrinsic factors to absorb B12
Aplastic Anemia
- caused by failure of the bone marrow to produce adequate numbers of RBCs
Renal Anemia
- inadequate EPO as a result from kidney disease causes insufficient red blood cell production
Hemorrhagic Anemia
- caused by loss of substantial quantities of blood
Hemolytic Anemia
- caused by rupture of excessive numbers of circulating erythrocytes
