Lymphatic & Immune SystemsChapter 6Functions & Structures

Absorb fats & fat soluble vitamins from the digestive system and transport them to the cells

Return cellular waste products and excess fluid from the tissues to the circulatory system

Serve as an important part of the immune system

Lymphatic system functions

Lymph fluid Lymph vessels

◦ Lymph capillaries◦ Lymphatic ducts◦ Valves◦ Lacteals

Specialized lymph capillaries located in the villi of the small intestine. There fats and fat-soluble vitamins are absorbed and carried into the bloodstream

Structures of the Lymphatic system

Structures of the Lymphatic system Lymph Nodes

◦ Produce lymphocytes and filter harmful substances from lymph as it flows through the nodes

Tonsils◦ Adenoids, Palatine

tonsils, & Lingual tonsils◦ Study the chart on page

108 about the different locations of the tonsils

Vermiform Appendix◦ Lymphatic tissue that hangs from the lower

portion of the cecum of the large intestine Peyer’s patches

◦ Small bundles of lymphatic tissue located on the walls of the ileum of the small intestine

◦ Where lymphocytes form and undergo further maturation and differentiation

Structures of the Lymphatic system

Structures of the Lymphatic system Cont.

Spleen◦ Filters microorganisms and

foreign material from blood◦ Forms specialized WBCs◦ Hemolytic function◦ Stores extra erythrocytes

Thymus – plays a role in endocrine & immune systems

Protects the body from harmful substances◦ Pathogens◦ Allergens◦ Toxins◦ Malignant cells

Functions of the Immune System

First line of defense◦ Intact skin – physical barrier◦ Respiratory system◦ Digestive system◦ Lymphatic system

Structures of the Immune System

Structures of the Immune System Immune response

◦ Antigen? Any substance the

body regards as foreign

◦ Antibody – disease fighting protein created by the immune system in response to the presence of that specific antigen

◦ Antigen-antibody reaction

Specialized cells◦ Lymphocytes-

White Blood cells that specialize so they can attack specific microorganisms.

Mature in the lymphatic tissue◦ B cells

Immunoglobulin – synonym for antibody, different types eg. M, G, A, E, D

Plasma cells – B cells turn into these when exposed to their antigen. They then make and secrete antibodies coded to match the antigen.

Structures of the Immune System

T cells Regulatory T cells coordinate immune defenses.

Cytotoxic T cells kill infected cells on contact. Interferon

Produced by T cells. A family of proteins released by cells when invaded by a virus. Causes noninfected cells to form an antiviral protein that slows or stops viral multiplication. Grouped into 3 categories: alpha, beta, and gamma

Lymphokines Phagocyte – eat invading antigens

Macrophage

Structures of the Immune System

Immunity◦ Natural

Passed from mother to fetus before birth. After birth additional immunity is passed through breast milk

◦ Acquired Obtained by the development of antibodies during

an attack of an infectious disease. As an example, after having chickenpox antibodies are present against it.

◦ Artificial Acquired through vaccination. Also known as

immunization.

Structures of the Immune System

Immune system response factors◦ Health◦ Age◦ Heredity◦ Opportunistic infection

Structures of the Immune System

Bacteria – one celled microscopic organisms◦ Bacilli – rod-shaped, spore forming◦ Rickettsia – live in lice, fleas, ticks, and

mites. Rocky Mountain spotted fever transmitted by infected tick bites

◦ Spirochete – spiral-shaped, have flexible walls and are capable of movement. Lyme disease transmitted by deer tick bites.

◦ Staphylococci – form irregular groups or clusters. Bacterial pneumonia is this type of bacteria

◦ Streptococci – form a chain

Pathogenic organisms

Fungus - Simple parasitic plant◦ Aspergillosis caused by Aspergillus

Yeast - Type of fungus◦ Moniliasis – infection of the skin or mucous

membranes. Usually localized in the mouth or the vagina

Parasites – plant or animal that lives on or within another living organism at the expense of that organism◦ Malaria – transmitted by the bite of an

infected mosquito

Pathogenic organisms

Viruses – very small infectious agents that live only by invading cells◦ Cytomegalovirus (CMV) ◦ Mononucleosis◦ Mumps◦ Rubella◦ Herpes zoster – Shingles. Caused by the chickenpox virus

that remains dormant in a nerve and is reactivated later◦ Varicella – VZV – Chickenpox. Caused by a herpes virus◦ Measles – Koplik’s spots, small red spots with blue-

white centers that appear on the lining of the mouth.

◦ Rabies

Pathogenic organisms

Antibiotics- useless on viruses◦ Bactericide – kills the bacteria, ◦ Bacteriostatic – inhibits, or slows down, the

growth of bacteria antivirals

Medications to Control Infection