A/P 2 Chapter 18—The Circulatory System: Blood

What is the average range of hematocrit for a normal female?

38% - 48%

What is the average range of hematocrit for a normal male?

44% - 54%

Blood Volume and Composition

A blood hematocrit is normally 45% cells and 55% plasma

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A differential white blood cell count can help pinpoint the nature of an illness, indicating whether it is caused by bacteria or viruses

How can a hematocrit be used to identify anemia?

A person who has a low hematocrit is referred to as being anemic.

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Adverse reactions are due to the agglutination of red blood cells.

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Adverse transfusion reactions are avoided by preventing the mixing of blood that contains matching antigens and antibodies.

Clumping of red blood cells following transfusion is called agglutination

Agglutination is due to the interaction of proteins on the surfaces of red blood cells antigens with certain antibodies carried in the plasma

Which cell gives rise to all the formed elements?

All types of blood cells are derived from primitive cell that are pluripotent

Define plycythemia.

An increase in the hematocrit above normal

Describe the degradation of hemoglobin by the liver and the spleen.

As the red blood cells disintegrate, the hemoglobin is degraded or broken into globin, the protein part, iron conserved for latter use, and heme.

Basophils......

Basophils have fewer granules that stain blue; they account for fewer than 1% of leukocytes.

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Basophils migrate to damaged tissues and release histamine to promote inflammation and heparin to inhibit blood clotting.

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Biliverdin and bilirubin are excreted in bile as bile pigments.

Blood Coagulation

Blood coagulation is the most effective means of hemostasis

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Blood coagulation is very complex and uses clotting factors.

Blood Platelets......

Blood platelets are fragments of megakaryocytes.

Blood Vessel Spasm

Cutting a blood vessel causes the muscle in its walls to contract reflexly, or engage in vasospasm.

Describe the formation of a platelet plug.

Damaged tissues release tissue thromboplastin, which activates the first in a series of factors leading to the production of prothrombin activator.

Eosinophils....

Eosinophils have coarse granules that stain deep red, a bilobed nucleus, and make up only 1-3% of circulating leukocytes.

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Eosinophils moderate allergic reactions as well as defend against parasitic infections.

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Erythroblastosis fetalis develops in Rh-positive fetuses of Rh-negative mothers

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Five types of white blood cells are in circulating blood and are distinguished by size, granular appearance of the cytoplasm, shape of the nucleus, and stainingcharacteristics

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Following injury to a vessel, three steps occur in hemostasis: blood vessel spasm, platelet plug formation, and blood coagulation

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Heme is decomposed into iron and biliverdin

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Hemoglobin from the decomposed red blood cells is converted into heme and globin.

List three ways to achieve hemostasis.

Hemostasis refers to the stoppage of bleeding

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If the Rh factor surface protein is present on red blood cells, the blood is Rh positive; otherwise it is Rh negative.

Red Blood Cell Production and Its Control

In the embryo and fetus, red blood cell production occurs in the yolk sac, liver, and spleen; in the adult it occurs in the red bone marrow

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Iron is needed for hemoglobin synthesis

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Iron is recycled into new hemoglobin or stored in the liver.

Functions of White Blood Cells

Leukocytes can squeeze between cells lining walls of blood vessels by diapedesis and attack bacteria and debris.

Lymphocytes......

Lymphocytes are long-lived, have a large, round nucleus, and account for 25-33% of circulating leukocytes.

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Lymphocytes are the major players in specific immune reactions and some produce antibodies

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Macrophages in the liver and spleen phagocytize damaged red blood cells

Monocytes......

Monocytes are the largest blood cells, have variably-shaped nuclei, and make up 3-9% of circulating leukocytes.

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Neutrophils and monocytes are phagocytic, with monocytes engulfing the larger particles

Neutrophils....

Neutrophils have red-staining fine cytoplasmic granules and a multilobed nucleus; they comprise 54-62% of leukocytes.

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Normal counts vary from 130,000 to 360,000 platelets per mm3

White Blood Cell Counts

Normally a cubic milliliter of blood contains 5,000 to 10,000 white blood cells

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Plasma is a mixture of water, amino acids, proteins, carbohydrates, lipids, vitamins, hormones, electrolytes, and cellular wastes.

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Platelets help repair damaged blood vessels by adhering to their broken edges.

Platelet Plug Formation

Platelets stick to the exposed edges of damaged blood vessels, forming a net with spiny processes protruding from their membranes.

Explain how erythropoietin regulates the RBC count.

RBC PRODUCTION IS REGULATED BY THE HORMONE ERYTHROPOIETIN. THIS STIMULATES THE RED BONE MARROW TO PRODUCE MORE RBC'S. WHEN THE RBC LEVEL REACHES THE PROPER AMOUNT ERYTHROPOIETIN. PRODUCTION SHUTS OFF. THIS IS A GOOD EXAMPLE OF THE BODY MAINTAINING HOMEOSTASIS

Erythrocyte

RBC, ..... make up about 40% of the blood's volume.

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Red blood cells discard their nuclei during development.

Characteristics of Red Blood Cells

Red blood cells erythrocytes are biconcave disks that contain one-third oxygen-carrying hemoglobin by volume.

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Some biliverdin is converted into bilirubin.

Describe the Rh factor?

The Rh factor was named after the rhesus monkey

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The average life span of a red blood cell is 120 days.

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The bile goes through the gall bladder into the intestines where the bilirubin is changed into a variety of pigments. The most important ones are stercobilin, which is excreted in the feces, and urobilinogen,

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The heme initially breaks apart into biliverdin, a green pigment which is rapidly reduced to bilirubin, an orange-yellow pigment

Describe the components of blood?

The main components of blood include.............. Plasma............. Red blood cells.............RBC.........erythrocytes............ White blood cells.............WBC.............leukocytes....... Platelets.................

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The major event in blood clot formation is the conversion of soluble fibrinogen into insoluble fibrin.

Describe hematopoiesis.

The production of all types of blood cells including formation, development, and differentiation of blood cells.

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The total number of red blood cells remains relatively constant due to a negative feedback mechanism utilizing the hormone erythropoietin, which is released in response to low oxygen levels detected in the kidneys and liver.

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The types of white blood cells are the granular neutrophils, eosinophils, and basophils, and the agranular monocytes and lymphocytes.

Red Blood Cell Counts

The typical red blood cell count is 4,600,000-6,2000,000 cells per mm3 for males and 4,500,000-5,100,000 cells per mm3 for females

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There are no corresponding antibodies in the plasma unless a person with Rhnegative blood is transfused with Rh-positive blood; the person will then develop antibodies for the Rh factor

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These processes all occur in the reticuloendothelial cells of the liver, spleen, and bone marrow. The bilirubin is then transported to the liver where it reacts with a solubilizing sugar called glucuronic acid.

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This more soluble form of bilirubin (conjugated) is excreted into the bile.

What antigens are found on the RBCs?

Type A blood has A antigens on red blood cells and anti-B antibodies in the plasma

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Type AB blood has both A and B antigens, but no antibodies in the plasma

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Type B blood has B antigens on red blood cells and anti-A antibodies in the plasma

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Type O blood has neither antigen, but both types of antibodies in the plasma.

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Urobilinogen is finally excreted as a normal component of the urine.

List some dietary factors that promote RBC production.

Vitamins B12 and folic acid are needed for DNA synthesis, so they are necessary for the reproduction of all body cells, especially in hematopoietic tissue.

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When oxygen combines with hemoglobin, the resulting oxyhemoglobin is bright red

Types of White Blood Cells

White blood cells (leukocytes) help defend the body against disease

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With age, red blood cells become increasingly fragile and are damaged by passing through narrow capillaries.

Basophil

also participate in allergic responses.

Lymphocyte

consist of three main types: T cells (T lymphocytes) and natural killer cells, which both help protect against viral infections and can detect and destroy some cancer cells, and B cells (B lymphocytes), which develop into cells that produce antibodies

Monocyte

ingest dead or damaged cells and help defend against many infectious organisms.

Which components of hemoglobin are conserved?

iron

Eosinophil

kill parasites, destroy cancer cells, and are involved in allergic responses.

Define hematocrit.

packed cell volume; the percentage of red blood cells or blood cells in general in the total blood volume

Neutrophil

the most numerous type, help protect the body against infections by killing and ingesting bacteria and fungi and by ingesting foreign debris.

What is a normal hematocrit?

varies male or female

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which is reabsorbed back into the blood. The blood transports the urobilinogen back to the liver where it is either re-excreted into the bile or into the blood for transport to the kidneys.