Term | Definition |
Lymphatic System has two major functions: | Filtration and Immunity -- transport fluids and control/destroy microorganisms |
Lymphatic System consists of: | Lymph Fluid; Lymph Vessels; Lymph Nodes; Thymus; Spleen and Tonsils |
How does the Lymphatic System differ from the Cardiovascular System? | Lymphatic System does not form a closed circuit. It originates in the intercellular spaces of the soft tissue and transport fluid in only one direction -- away from tissues towards the thoracic cavity |
Smallest Lymphatic Vessels are: | Lymphatic Capillaries that originate in tissue spaces as blind ended sacs (scoops) |
Lymphatic Capillaries | Pick up/scoop up interstitial fluid and return it to blood vessels for general circulation and help prevent edema |
What is the purpose of valves in the Lymphatic Vessels? | Prevent back-flow of fluids or lymph |
When Lymphatic Vessels merge with larger vessels they form... | Lymphatic Ducts -- Right Lymphatic Duct and Thoracic Duct |
Right Lymphatic Duct transports lymph drainage from the... | Right side of the head, neck, right upper extremities and right side of the chest. |
Thoracic Duct transports lymph drainage from the... | Remaining regions of the body. |
Where does the Right Lymphatic Duct drain into? | Right Subclavion Vein |
Where does the Thoracic Duct drain into? | Left Subclavion Vein |
What are lymph nodes? | Are a collection of lymphatic tissue; also known as lymph glands |
4 major concentrations of lymph nodes: | 1. Cervical (neck); 2. Mediastinal (space btn the lungs/sternum); 3. Axillary (armpits); 4. Inguinal (groin) |
What two processes happen as lymph passes through lymph nodes? | 1. Old dead cells and bacteria are filtered to prevent them from emptying into blood vessels; 2. Macrophages engulf and destroy bacteria which are then filtered out. |
What are Macrophages? | Phagotcytes specific to the lymphatic system to engulf and destroy bacteria and are found in the liver, spleen, lungs, brain and spinal cord |
Phagocytosis | Process for engulfing and destroying bacteria. |
What do lymph nodes produce that are important to immunity? | Antibodies and Phagocytes |
2 organs composed of lymphatic tissue are: | Spleen and Thymus |
Functions of the Spleen: | Destruction of old RBCs by marophages; filter microorganisms/foreign material from blood; activate lymphocytes as it filters antigens from blood; activate B-cell lymphocytes to produce antibodies; store blood (RBCs and platelets) |
Function of the Thymus: | Large in fetal life but becomes smaller with age; composed of nest of lymphoid cells (stroma); aids the body's ability to protect itself (especially in early life) |
Stroma | Connective tissue that provides framework of an organ -- rather than carry out a function |
Immune System | Body's special defense response against foreign organisms |
Lymphoid organs of the immune system: | Lymph nodes; Spleen; Thymus; their products -- lymphocytes, antibodies and macrophages |
Immunity | Body's ability to resist foreign organisms and toxins |
Natural immunity | Genetic predisposition present at birth; not dependent on previous contact with infectious agent; phagocytic cells for natural immunity; macrophages move in to clear out dead cells and debris; Natural Killer Cells |
Natural Killer (NK) Cells | Primitive lymphocytes that destroy tumor cells and virally infected cells. |
Acquired Immunity (Active and Passive) | Body develops powerful, specific immunity (antibodies and cells) against invading agents. |
Acquired Active Immunity | Having an infection; Vaccination; Transfer of immune cells from a donor |
Vaccination | Contains modified pathogen or toxin that stimulates lymphocytes to produce antibodies without actually having the disease. |
Acquired Passive Immunity | Antitoxins (think snake bite); Immunoglobins (injected to lessen severity and protect); Maternal antibodies (passed through placenta) |
Two major disease fighters for immune system: | 1. B-Cell Lymphocytes; 2. T-Cell Lymphocytes |
Humoral Immunity | B-Cell Lymphocytes transform into plasma cells in response to specific antigen; secrete antibodies called immunoglobins |
Immunoglobins we should know: | IgA; IgD; IgE; IgG; and IgM |
2 special Immunoglobins to know: | IgE -- important in causing allergic reactions and fighting parasitic infections; IgG -- MOST ABUNDANT and crosses placenta for immunity in newborns. |
Cell Mediated Immunity | Immune response involving T-Cell Lymphocytes; antigens are destroyed by direct action of cells as opposed to antibodies. |
T-Cell lymphocytes | Originate from stem cells in the bone marrow and are processed in the thymus gland; multiply rapidly to destroy antigens; act as supressors to inhibit B and T-cells. |
Types of T-Cells (3): | 1. Cytotoxic Cells (T8-cells); 2. Cytokines; 3. Helper Cells (T4-cells) |
Cytotoxic Cells (T-8) | Act directly on antigens to destroy them |
Cytokines (interferons and interleukins) | Aid other cells in antigen destruction |
Helper Cells (T4-cells) | Cornerstone/keystone of our immunity; Promotes antibody production by B-cells and stimulates cytotoxic T-cells. |
Afferant vs Efferant | Afferent = IN; Efferant = OUT |
Hemolysis | Destruction of blood |
Hemolytic activity in the spleen | Destruction of RBCs which liberates hemoglobin, which is then converted to bilirubin in the liver then released to the blood stream -- recycling nutrients |