Circ.sys.

CIRCULATORY SYSTEM

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

Structure and Function

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

Blood

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

Red Blood Cells (Erythrocytes)

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

White Blood Cells (Leukocytes)

Neutrophils Basophils Eosinophils Lymphocytes Monocytes

Five Types of White Blood Cells

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

Platelets (Thrombocytes)

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

Plasma

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

Blood Typing

Table 11-2 Blood Types

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

Lymph and Lymphatic Tissue

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

Immunity

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

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

Assessment Techniques (continued)

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

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

Disorders of the Circulatory System (continued)

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

Issues and Innovations