Immune system review key:

Describe the system immune system?

The immune system is made up of cells, tissues, and organs that work together to protect the body against disease causing agents, pathogens (bacteria, virus, parasites), and foreign substances that enter the body (toxins) and some cancer cells that develop within the body. It must respond quickly and efficiently as many pathogens rapidly evolve and adapt to avoid detection and the defensive actions of the immune system.

To immune system includes immune cells, organs, and the lymphatic system. Immune cells include several kinds of leukocyte cells. The organis incude: adenoids, tonsils, thymus, bronchus, bone marrow, intestine, appendix, spleen, and Peyer's patches. And the Lymphatic system includes lymph fluid, lymph ducts, lymph nodes and the cardiovascular system.

Describe functions of the immune systems.

Immune Cells

Important cells leukocyte cells (some known as white blood cells) which come in two types that combine to seek out and destroy disease causing organisms or substances in two ways: immediate nonadaptive and mediated adaptive.

Leukocyte cells include lymphocytes, neutrophils, basophils, eosinophils, monocytes, and macrophages. They are created by myeloid stem cells and provide innate immunity protection (protection that is quick and doesn't adapt). Myeloid stem cells also create erythrocytes, dendritic cells, and megakaryocytes (platelets).

Leukocyte cells in the lymph nodes trap and destroy pathogens ( microorganisms that causes a disease). Leukocyte cells in the circulatory system are also part of the immune system.

Lymphocytes are one kind of Leukocyte cell created by lymphoid progenitor stem cells and provide a mediated adaptive immunity protection (protection that is slower because it takes time to adapt). They include B lymphocyte cells, T lymphocyte cells and killer cells.

T lymphocyte cells (thymus gland), B lymphocyte cells (bone marrow), and natural killer cells are part of our immune defense. They recognize antigens, produce antibodies, and destroy cells that could damage the body.

Organs

The immune system also includes organs. The adenoids, tonsils, thymus, bronchus, bone marrow, intestine, appendix, spleen, and Peyer's patches. Also included is the Lymphatic system which includes lymph fluid, lymph ducts, lymph nodes and the cardiovascular system.

Tonsils and Adenoids help prevent throat and lung infections by reducing pathogens (bacteria and viruses) that enter the body through the throat and mouth with respiration. The tonsils and adenoids trap the pathogens and kill them with antibodies (proteins) they make.

Thymus gland regualtes the immune system. While it has glandular tissue and produces some hormones, it is closely associated with the immune system as it promotes and develops white blood cells: T- cells (T-lymphocytes).

Spleen filters the blood. As part of the immune system it stores leukocyte cells and helps fight some kinds of bacteria that cause pneumonia and meningitis. It also recycles red blood cells and platelets.

Appendix protects the digestive system from infection and may serve as a reservoir for beneficial gut bacteria by stimulating growth of beneficial gut bacteria. The fetal appendix produces various biological control compounds that assist with various biological control (homeostatic) mechanisms. During early development the appendix functions as a lymphoid organ, assisting with the maturation of B lymphocytes and immunoglobulin A (IgA) antibodies.

Peyer's patches are small clumps of lymphatic tissue in the small intestine, but more concentrated in the ileum. They monitoring intestinal bacteria and preventing the growth of pathogen bacteria in the intestines.

Lymph system

Lymph fluid is in the spaces around the cells where it is deposited by the circulatory system. It contains water, protein, fat, and leukocytes. It is filtered by lymph nodes, which are small bean-shaped organs in the lymph ducts.

Lymph nodes are small structures that filter pathogens and other harmful substances. They also contain immune cells that can fight infection by attacking and destroying pathogens that are in the lymph fluid.

Lymph ducts (vessels) collect lymph fluid and return it to the heart. They are made of muscle that expand and contract to move the fluid toward the heart. When it returns to the heart, it is remixed with the blood and recirculated to the body.

Parts and functions

Match the words in the word bank to the function and label the diagram.

  1. ___ white blood cells _______ name for some leukocyte cells.
  2. ___ allergic reaction ______ an autoimmune response caused when foreign bodies (allergens) touch the skin or enter the body and cause.
  3. ___ tonsils and adenoids _____ help prevent throat and lung infections by reducing pathogens that enter the body through the throat and mouth with respiration.
  4. ___ leukocyte cells _______ seek out and destroy disease-causing organisms or substances..
  5. ___ T lymphocyte cells ______ a leukocyte cell that is a natural killer cell made in the thymus gland.
  6. ___ spleen ________ filters the blood, stores leukocyte cells, and recycles red blood cells and platelets.
  7. ___ lymph nodes _____ are small bean-shaped organs in the lymph ducts that filter lymph fluid.
  8. ___ lymph ducts _______ vessels that collect lymph fluid and expand and contract to move it to the heart.
  9. ___ B lymphocyte cells _______ a leukocyte cell that is a natural killer cell made in bone marrow.
  10. ___ appendix _____ protects the digestive system from infection and other immune functions.
  11. ___ thymus _______ gland that regualtes the immune system.
  12. ___ Peyer's patches _________ small clumps of lymphatic tissue in the small intestine.
  13. ___ bone marrow ________ makes B lymphocyte cells, red blood cells, and platelets.

Label parts on the diagram

lymph system diagram

Adapted from Bruce Blaus "Blausen gallery 2014". [CC BY 3.0], via Wikimedia Commons

Word bank

allergic reaction, appendix, B lymphocyte cells, bone marrow, hair, nails, epidermis, blood vessels, leukocyte cells, lymph ducts, lymph nodes, Peyer's patches, spleen, thymus, T lymphocyte cells, tonsils and adenoids , white blood cells,

Describe ways to care for the immune system.

  • Eat a balanced diet
  • Maintain a healthy weight
  • Avoid illegal drug use
  • Get regular medical check ups

Describe health related care issues for the immune system.

  • Allergic reactions are caused when foreign bodies (allergens) touch the skin or enter the body and cause an autoimmune response, that might not happen for most people. Symptoms, such as redness, rash, sneezing, itching, watery eyes, and a runny nose that result with the release of histamines in response to allergens.
  • Tonsillitis is when pathogens cause an infected. Treatment with antibiotics or removal with surgery.
  • Immune deficiency is when the immune system is weakened to protect the body from infection. Causes can be congenital, poor nutrition of the baby's mother, hereditary, white cell production problem, HIV, chemotherapy, drug use, toxin ingestion, and aging.
  • Hodgkin's disease or lymphoma is cancer in the lymph tissue in the lymph nodes, and spleen. Treatment can be removal of tissue, radiation, and chemotherapy.

 

Dr. Robert Sweetland's notes
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