Pearson's Comprehensive Medical Assistingftc-drthorson.weebly.com/uploads/5/5/4/4/55444029/beaman_ch28_l… · Administrative and Clinical Competencies, 3/e Beaman | Routh | Papazian-Boyce

Pearson's ComprehensiveMedical Assisting

Administrative and Clinical Competencies

CHAPTER

THIRD EDITION

Pearson's Comprehensive Medical Assisting:Administrative and Clinical Competencies, 3/eBeaman | Routh | Papazian-Boyce | Sesser | Mills | Maly

Copyright © 2015, 2011 by Pearson Education, Inc.All Rights Reserved

The Immune SystemLesson 1:The Immune System

28



Lesson Objectives

Upon completion of this lesson, students should be able to:

1. Define and spell the terms to learn for this chapter.

2. Identify and discuss the anatomy of the immune system.

3. Discuss the functions of the immune system.

4. Explain the immune system and its response.



Immune System

• Immune system consists of:

Tissues

Organs

Physiological processes that identify abnormal cells

Foreign substances

Foreign tissues, such as transplants



Anatomy of the Immune System

• The Lymphatic System

Network of vessels, nodes, ducts more or less parallel, but separate from, blood vessels of the circulatory system

Conductive structures are vessels and ducts that help maintain fluid balance by removing excess fluid from spaces between body cells





Fluid (lymph) comes from blood plasma that has leaked out from capillaries and system collects lymph and returns it to bloodstream





Lymphoid tissues function as part of immune system helping to defend body against harmful substances

Central lymphatic tissue: composed of bone marrow and thymus

Peripheral lymphoid tissue: consists of lymphatic pathways, lymph nodes, spleen, and tonsils




• Bone Marrow

Central lymphatic tissue

Contains stem cells that develop into all cells of the body in a process called hematopoiesis

Immune system cells either become mature cells of immune system or precursors of cells that will mature in a part of body other than bone marrow




• Thymus Gland

Central lymphatic tissue

Located posterior to sternum in anterior mediastinum

Endocrine gland that secretes substances into bloodstream

Divided into two distinct compartments:

• Outer cortex

• Internal medulla




• Thymus Gland

Immature lymphoid cells created in bone marrow enter cortex of thymus, reproduce and mature, then move to medulla from which they reenter the circulation of the body

Manufactures infection-fighting T cells and helps distinguish normal T cells from those that attack the body's own tissues



FIGURE 28-1 Components of the lymphatic system.



Critical Thinking Questions

1. What is so critical about the immune system to one's overall health?

2. If one has a compromised immune system would that shorten the person's life?





Peripheral lymphatic tissue

Lymphatic pathways: structures that collect and circulate lymph

Intricate system of vessels

• Capillaries

• Vessels

• Trunks

• Ducts



FIGURE 28-2 Structures of the lymphatic pathway from smallest to largest.





Lymph nodes: many different sizes and shapes; most bean shaped and about 1 inch long covered with thick fibrous capsule

Each node has two parts: outer cortex and inner medulla





Cortex populated mainly with lymphocytes

Germinal centers in cortex primary locations where B lymphocytes reproduce



FIGURE 28-3 A cross section of a lymph node.





B lymphocytes (B cells) responsible for production of antibodies, specialized proteins that lock onto specific antigens

Each unique type of B cell produces only one type of antibody

Antibody-mediated response or humoral immunity





Lymph node cortex contains T lymphocytes (T cells) that circulate through lymph nodes, lymphatic ducts, bloodstream to seek out any infection

T lymphocytes promote immunity through a cell-mediated response

Medulla of lymph node primarily made up of macrophages




• Spleen

Located in upper left quadrant of abdomen

Largest lymphatic organ

Blood passes through intricate meshwork of tiny blood vessels in spleen and continues on to the liver

Spleen's blood vessels lined with macrophages




• Tonsils

Located in depressions of mucous membranes of the throat and pharynx

Function is to filter bacteria and aid in formation of white blood cells

When tonsils unable to properly filter bacteria and pathogens, they can become enlarged and infected



FIGURE 28-4 Tonsils—normal and enlarged.



The Immune System and the Body's Defenses

• Immune system

Body's defense against infectious organisms and pathogenic invaders

• Immune response

Cells, tissues, and organs that make up immune system work together to attack organisms and substances that invade body systems and cause illness and disease




• Leukocytes, or white blood cells (WBCs), seek out and destroy harmful organisms.




• Two types

Lymphocytes

• Allow the body to remember and recognize previous invading organisms

Phagocytes

• Attack and ingest (engulf, or eat) the invading organism




• Antigens Versus Antibodies

When an antigen is detected, proteins—antibodies/immunoglobulins—work together to recognize and respond to it.

Terms antibody and immunoglobulinoften used interchangeably





Immunoglobulins are glycoproteins that function as antibodies

Vaccine

• Fragments of a disease organism or small amounts of weakened disease





Although antibodies can recognize an antigen and lock onto it, they are not capable of destroying it alone; that is job of T cells

Antibodies can neutralize toxins produced by different organisms





Antibodies can activate proteins called complement that are part of immune system

Complement assists in destroying bacteria, viruses, or infected cells




• Immunosuppressants and Immunity

Immunosuppressants

• Medications that suppress immune system

Usually given after organ transplant to prevent rejection of the organ




• Immunosuppressants and Immunity

Can help prevent organ rejection

These medications render patient very vulnerable to illness

Extreme stress can also suppress immune system




• Innate Immunity

Everyone born with innate (natural) immunity

Passed down from parents to children

Provided in part by external barriers of body (skin, mucous membranes, tears)




• Innate Immunity

First line of defense against harmful pathogens

Renders many viruses and bacteria that affect other species incapable of harming human beings




• Active Immunity

Unlike innate immunity, is not inborn

Develops after birth

Permanent and gives individual lifelong protection against the disease

Acquired active immunity: person exposed to a live pathogen, develops the disease, and becomes immune as a result of the primary immune response




• Active Immunity

Artificially acquired active immunity: induced by a vaccine, a substance that contains the antigen and stimulates a primary response against the antigen without causing symptoms of the disease




• Passive Immunity

Not permanent form of immunity

It only lasts for a little while

• For example, antibodies passed to an infant through breast milk

• This temporary form of immunity helps protect infant against infection during early years of childhood



Questions?

Documents

Pearson's Comprehensive Medical Assistingftc-drthorson.weebly.com/uploads/5/5/4/4/55444029/beaman_ch28_l… · Administrative and Clinical Competencies, 3/e Beaman | Routh | Papazian-Boyce