11 circulatory system

Copyright 2003 by Mosby, Inc. All rights reserved.

CHAPTER 11

CIRCULATORY SYSTEM


Structure and Function

• Structure of the circulatory system– Includes the blood and lymph that move

through the body • Function of the circulatory system

– Both blood and lymph are tissues that maintain homeostasis and give the body immunity


Blood

• Body contains approximately 4 to 5 liters of blood, making up about 8% of the body’s weight

• Functions include:– Transporting nutrients, oxygen, and hormones– Removing metabolic wastes and carbon dioxide– Providing immunity through antibodies– Maintaining body temperature and electrolyte

balance– Clotting to prevent bleeding from a wound


Red Blood Cells (Erythrocytes)• Erythrocytes contain a protein called

hemoglobin that carries oxygen to all cells and removes carbon dioxide

• Each red blood cell lives only 90 to 120 days• New cells are manufactured by the red

marrow or myeloid tissue in bones• The liver and spleen remove dead red blood

cells


White Blood Cells (Leukocytes)• White blood cells remove foreign particles,

fight infection, and help prevent disease• There are fewer white blood cells than red• White blood cells are larger than red• Leukocytes live about 9 days• Pus consists of white blood cells mixed with

bacteria


Five Types of White Blood Cells• Neutrophils• Basophils• Eosinophils• Lymphocytes• Monocytes


Platelets (Thrombocytes)

• Smallest blood cells • Platelets promote clotting to prevent

blood loss• Platelets can form a plug to seal small

vessels by themselves or start the clotting process

• Produced in red bone marrow• Live about 5 to 9 days


Plasma

• A pale yellow liquid that remains when elements are removed from blood

• Whole blood is 55% plasma• Plasma is 90% water and approximately 10%

proteins• It contains nutrients, electrolytes, oxygen,

enzymes, hormones, and wastes• Helps fight infection and assists in the clotting

(coagulation) of blood


Blood Typing

• A person’s blood type is an inherited characteristic of the blood

• A blood type is determined by the antigens located on the surface of the red blood cell

• Clumping of incompatible cells blocks blood vessels and may cause death


Table 11-2 Blood Types


Lymph and Lymphatic Tissue• Two important functions

– The process of immunity – Maintaining the body’s fluid balance

• Lymph is a watery substance formed from fluid that filters into the body tissue or interstitially

• Lymphatic tissues consist of the tonsils, thymus, spleen, nodes, and the lymph vessels


Immunity• Immune response takes on two forms

– As a barrier of the skin, mucous membranes, tears, and the leukocytes

– In leukocytes antibodies are formed in response to antigens or foreign materials that enter the body

• May be a localized or systemic reaction• Acquired and/or inherited immunity


Assessment Techniques

• Hemoglobin (Hgb) test measures the amount of oxygen-carrying ability of the blood

• Hematocrit (Hct) measures the volume of erythrocytes in the blood

• Sedimentation rates measure how long it takes for erythrocytes in the blood to settle to the bottom of a container

• Reticulocyte studies measure the number of immature red blood cells


Assessment Techniques (continued)• Red blood cell (RBC) counts determine the

number of circulating red blood cells in 1 mm3 of blood

• Platelet or thrombocyte counts measure the number of platelets in 1 mm3 of blood to determine clotting ability

• Aspiration biopsy cytology (ABC) studies examine bone marrow from the iliac crest of the hip


Disorders of the Circulatory System • Acquired immunodeficiency syndrome

– Dysfunction of the immune system caused by a virus

• Allergy– Hypersensitive response by the immune system to

an outside substance• Anemia

– The blood has an inadequate amount of hemoglobin, red blood cells, or both


Disorders of the Circulatory System (continued)• Autoimmune

– Conditions in which the immune system of the body turns against itself

• Elephantiasis– A massive accumulation of lymphatic fluid in body

tissues, causing an abnormally large growth of tissue or hypertrophy

• Erythroblastosis fetalis – A condition in an unborn baby in which the mother

forms antibodies against the antigens in the baby’s blood


Disorders of the Circulatory System (continued)

• Hemophilia – A rare sex-linked genetic blood disease in which

the blood is missing a clotting factor • Hepatitis

– A viral infection of the blood • Hodgkin’s disease

– A malignant cancer of the lymph system


Disorders of the Circulatory System (continued)• Leukemia

– Also called blood cancer, is an abnormal malignant increase in the number and longevity of white blood cells

• Lymphosarcoma – Is a group of malignant cancers of lymph tissues

other than Hodgkin's disease • Polycythemia

– An abnormal increase in the number of blood cells, making the blood thicker and slower flowing


Disorders of the Circulatory System (continued)• Septicemia

– Called blood poisoning, is an infection that occurs when pathogens enter the blood

• Sickle cell anemia – A genetic condition that results in malformed red

blood cells • Splenomegaly

– An enlargement of the spleen caused by an acute infection such as mononucleosis or anemia


Disorders of the Circulatory System (continued)• Thalassemia

– One of the most common genetic blood disorders • Thrombocytopenia

– A decrease in the number of platelets in the blood • Thrombosis

– A condition in which a blood clot, called a thrombus, forms in the blood vessels


Issues and Innovations• Transfusion

– Risks– Autologous transfusions– Platelet donations

• Interferon– Prevention of viral diseases

• Monoclonal antibodies– Used in organ transplants, against autoimmune disease, and to diagnose certain diseases

11 circulatory system

Science

blood body

blood vessels

blood lossplatelets

bloodwhole blood

blood typescopyright

liters of blood

redwhite blood cells

fewer white blood cells