The Lymphatic / Immune System Honors Biology Unit 8 Powerpoint #7

Lymphatic System: Purpose: Transports a watery fluid called lymph. This fluid distributes immune cells, and other factors throughout the body. It also interacts with the circulatory system to drain fluid from cells and tissues

Lymphatic System: Functions: Collect and return fluids, including blood plasma, to the blood, maintaining fluid homeostasis. Defends the body against disease by producing lymphocytes. Absorbs lipids from the intestine, and transports them to the blood.

Absorbs lipids from small intstine

Why do we need the Lymphatic System? Every 24 hours the circulatory system slowly leaks 3 liters of blood.

Lymphatic System: Structures: white blood cells (lymphocytes) Bone marrow Thymus Spleen Tonsils lymph nodes lymph vessels

Lymph / Lymph Vessels Lymph: fluid and protein that has been squeezed out of the blood (blood plasma). Vessels: A network of permeable capillaries and vessels that lymph drains into.

Lymph Vessels The lymph system is one- way, draining lymph from tissue, back to the blood. Lymph movement depends on smooth muscle action, and skeletal system movement.

Lymph Nodes: Filters Lymph as is travels in the lymph vessels. White blood cells are located within the lymph nodes. Bean-shaped, size ranges from 3mm to 2cm. Can become enlarged due to infection. A combination burglar alarm and West Point. They guard against intruders, but also train the ‘military’ to fight.

Lymph Nodes

White Blood Cells Bone marrow produces lymphocytes Normally in blood, but can be found at any location. Re-enter blood circulation through lymph vessels. Fight foreign invaders (microorganisms) Some last 2-5 days, others last for years.

Lymphocytes attacking cancer cell

Thymus: Location of the development of T-cell lymphocytes.

Spleen: Fist-sized mass of lymphatic tissue that destroys old or damaged red blood cells and platelets.

Elephantitis

Immune System & Disease Disease- any change that disrupts normal body functions (other than injury) Causes- Bacteria viruses fungi environmental factors (smoke, lead, pesticides) genetically inherited (hemophilia, Down's Syndrome)

Infectious diseases are caused by microorganisms Germ Theory of Disease Proposed by Louis Pasteur & Robert Koch Infectious diseases are caused by microorganisms

Agents of Disease Virus- tiny particles that invade & replicate within living cells Is not alive, only a piece of DNA or RNA bound in a protective coat

Agents of Disease Bacteria- single celled organisms (prokaryotic) Most don’t cause disease Those that cause disease attack cells directly or produce toxins that harm cells

Agents of Disease Protists- tiny single celled organisms that spread via insects, blood, food, or water Examples: Malaria, Sleeping sickness, traveler’s diarrhea

Agents of Disease Worms-- flatworms & roundworm eggs that grow inside other organisms Examples: Schistosoma Ascaris tapeworm

Agents of Disease Fungi– most are harmless Tinea attacks the skin causes athlete’s foot & ringworm

Spread of Disease Coughing, sneezing, or physical contact Contaminated food & water Animals

Fighting Infectious Disease 1. Antibiotics– compounds that kill bacteria without harming host cells Many are produced naturally by organisms (like mold creates penicillin) discovered by Alexander Fleming 2. Antiviral drugs– inhibit their ability to invade cells 3. Rest & fluids so your own immune system can work well!

The Immune System Immunity- fighting off disease before it actually makes you ill 2 categories: Specific- targeted for 1 disease Nonspecific- general line of defense against anything

Non-specific Defense 1st line of defense – Physical -Skin -Mucus -Sweat -Tears The sweat & tears contain lysozymes (enzyme that breaks down bacteria cell walls)

Non-specific Defense 2nd Line of defense Inflammatory response– Phagocytes (white blood cells) go to site of injury to engulf foreign agents 2. Fever can slow down growth or stop growth of some pathogens (also ‘s heart rate to get WBC’s to site faster) 3. Interferon proteins help cells resist viruses by slowing down their replication in cells

Specific Defense T cells B cells Attacks antigens within cells Immune response is triggered by antigens (any foreign agent) Creates B & T Lymphocytes T cells Attacks antigens within cells B cells Attacks antigens in body fluids

Antibodies Proteins created by B cells Bind to antigens to stop them from moving into cells & signals proteins (produced by liver) to destroy the antigen B memory cells store info to create antibodies quickly against another antigen attack

Antibodies Y shaped with 2 identical binding sites Shape of binding site is specific to an antigen with a complementary shape Most healthy adults can produce 100 million different types of antibodies

Cell Mediated Immunity Important in fighting infections caused by fungi & protists & viruses T-cells divide into killer, helper, suppressor, & memory cells Killer T-cells destroy the agents Helper T-cells produce memory T cells Suppressor T-cells releases substances that shut down the killer T-cells

HIV & T-cells HIV replicates inside T- cells, and then destroys them as they burst open to release more viruses When Immune cells are destroyed, other diseases & infections can weaken & kill AIDS patients

Acquired Immunity Edward Jenner created the 1st vaccine against smallpox using attenuated (heated so it won’t cause the disease) cowpox Active Immunity is the injection of a mild form of the pathogen to stimulate our immune systems to create antibodies

Passive Immunity Lasts only a short time because they are not created by the body’s own immune system Examples: 1) Mother passing antibodies through placenta or breast milk to baby 2) Vaccines with antibodies against diseases like malaria, yellow fever, rabies

Immune System Disorders Allergies- overreactions of immune system to antigens Mast cells are specialized cells that initiate the inflammatory response Histamines- chemicals released by mast cells that increase blood flow & fluids to the area This causes sneezing, watery eyes, & runny nose

Autoimmune Diseases Body attacks the body’s own cells Examples: Type I diabetes, rheumatoid arthritis, myasthenia gravis, & multiple sclerosis (MS), Lupus