The Human Body: Lymphatic and Immune Systems Textbook Chapter 37 Review Topic 1-2

Lymphatic System Your body has two transport networks that circulate fluids: Your body has two transport networks that circulate fluids: –Circulatory system –Lymphatic system Consists of a complex network of organs, vessels, and nodes throughout the body Consists of a complex network of organs, vessels, and nodes throughout the body

Helps to: Helps to: –Distribute nutrients –Absorb excess fluids between cells –Fight disease –Remove waste products from cells

Relies on muscle contractions Relies on muscle contractions and valves to circulate the lymph From the vessels, lymph collects From the vessels, lymph collects in small rounded lymph nodes –Filter the lymph, trapping bacteria, viruses, fungi and cell fragments –Specialized immune cells ingest and destroy these wastes –Vessels carry the lymph out of the nodes, returning it to the circulatory system

Structures of the lymphatic system: Structures of the lymphatic system: –Tonsils  Lymph nodes on either side of the throat  Filter out bacteria and viruses  If a build up of pathogens occurs, it can result in swelling and infection, causing them to need to be removed

–Spleen  Largest organ in the lymphatic system  Filters and cleans the lymph  Contains white blood cells to destroy harmful bacteria and foreign organisms

–Thymus (part of endocrine system as well)  Located in chest, above the heart  Important in developing different types of white blood cells (lymphocytes)

Immune System There are different types of pathogens which enter the body in different ways There are different types of pathogens which enter the body in different ways Pathogens are disease causing agents Pathogens are disease causing agents –Bacteria –Viruses –Fungi –Protozoa –Parasites

Many body systems protect you from pathogens Many body systems protect you from pathogens –Immune system fights off infection and pathogens –Relies on physical barriers to keep pathogens out  Skin is the first line of defense –Secretes oil and sweat, creating an acidic environment which kills many pathogens on the skins surface

 Eyes, nose, ears, mouth and excretory organs are entrances to the body –Protected by mucous membranes and cilia  Once inside the body, the immune system relies on the circulatory system –Sends chemical signals to coordinate an attack –Transports specialized cells to the infection

–Cells and proteins fight the body’s infections  White blood cells –Find and kill pathogens –Types of white blood cells:  Phagocyte – cell that destroys pathogens by surrounding and engulfing them

 Lymphocytes – white blood cells that initiate the specific immune responses ~ T cells destroy body cells that ~ T cells destroy body cells that are infected with pathogens are infected with pathogens ~ B cells produce proteins that ~ B cells produce proteins that inactivate pathogens that have inactivate pathogens that have not yet infected a body cell not yet infected a body cell

 Proteins –Antibodies ~ Made by B cells ~ Made by B cells ~ Destroy pathogens ~ Destroy pathogens by making them by making them ineffective ineffective ~ Binds to the pathogen’s membrane proteins ~ Binds to the pathogen’s membrane proteins ~ Cause pathogens to clump together ~ Cause pathogens to clump together - Makes it easier to be engulfed by - Makes it easier to be engulfed by phagocytes phagocytes ~ Antibodies activate proteins which weaken the ~ Antibodies activate proteins which weaken the pathogen’s cell membrane pathogen’s cell membrane

Immunity prevents a person from getting sick from a pathogen Immunity prevents a person from getting sick from a pathogen –Passive Immunity  No immune response  Transferred between generations through DNA – From mother and child through breastfeeding or through the umbilical breastfeeding or through the umbilical chord chord

–Active Immunity  Produces a response to a specific pathogen that has infected your body  Occurs after your immune system reacts to a pathogen invasion  If exposed again, immunity is already present and illness is prevents/lessened

Your body responds to the presence of foreign particles and pathogens Your body responds to the presence of foreign particles and pathogens –Specific defenses – cellular level, specific to type of pathogen –Nonspecific responses – occur the same way to all pathogens  Inflammation  Fever

Cells of the immune system produce specific responses Cells of the immune system produce specific responses –Antigens – proteins markers on the surface of cells and viruses that help the immune system identify a foreign cell or virus –Memory cells – specialized T and B cells that provide acquired immunity The immune system rejects foreign tissues The immune system rejects foreign tissues –Tissue rejection occurs when the recipients immune system makes antibodies against the protein markers on the donor’s tissue

Many methods are used to control pathogens Many methods are used to control pathogens –Antiseptics – chemicals that kill pathogens  Ex. soap, vinegar, rubbing alcohol –Antibiotics – target on type of bacteria or fungus to prevent them from growing and reproducing  Antibiotic resistance – occurs when bacteria mutate so they are no longer affected by antibiotics

Vaccines artificially produce acquired immunity Vaccines artificially produce acquired immunity –Vaccine – substance that contains a antigen of a pathogen (weakened or dead forms) to cause your immune system to make memory cells (so it prevents you from getting sick in the future)

Allergies occur when the immune system responds to harmless antigens Allergies occur when the immune system responds to harmless antigens –Allergy – oversensitivity to a normally harmless antigen –Allergen – antigen that causes an allergic reaction  Ex. food, airborne, chemical In autoimmune diseases, white blood cells attack the body’s healthy cells In autoimmune diseases, white blood cells attack the body’s healthy cells

Autoimmune Disease Body Systems Affected The Immune System… How Many Affected Rheumatoid Arthritis Integumentary Breaks down tissues that line joints, making movement difficult 70 in 10,000 Type I Diabetes Mellitus Endocrine, Digestive Attacks the pancreas, stopping the digestion of sugars 60 in 10,000 Hashimoto’s Thyroiditis Endocrine Attacks the thyroid gland, causing it to make fewer hormones 15 in 10,000 Multiple Sclerosis (MS) Nervous Breaks down myelin sheaths, disrupting nerve communication 10 in 10,000 Graves’ Disease Endocrine Stimulates the thyroid gland, causing it to make more hormones 5 in 10,000

Leukemia is characterized by abnormal white blood cells Leukemia is characterized by abnormal white blood cells –Cancer of the bone marrow –Does not form tumors but prevents bone marrow from functioning properly  Causes bone marrow to produce white blood cells that do not develop properly and are immature  Can be treated with bone marrow transplants, radiation and chemotherapy

HIV targets the immune system HIV targets the immune system –Human immunodeficiency virus (HIV) –A retrovirus that attacks and weakens the immune system  Retrovirus contains RNA instead of DNA with 9 genes –Can only live in human blood cells  Cannot survive long outside of the body  Cannot be transferred by touching of skin or even through mosquitoes

–Transmitted when virus enters bloodstream through the mixing of blood or other bodily fluids  Sexual intercourse, umbilical chord between mother and child, sharing of needles (drugs, tattoos, piercings) –Reproduces in T cells, causing them to become ineffective to stimulate an immune response

–HIV leads to AIDS (acquired immune deficiency syndrome)  Final stages of immune system decline –HIV is a virus –AIDS is the condition of having a worn-out immune system  Results in death because a person’s immune system cannot fight off infections

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