Question | Answer |
What are the three main functions of the Lymphatic System? | Maintenance of fluid balance, absorption of fats, & immunity |
What is fluid balance in the lymphatic system? | Lymph fluid is formed from tissue left behind after capillary exchange; absorbs fluid not reabsorbed by the capillaries & returns it to the bloodstream |
Define lymph? | A clear, colorless fluid similar to plasma but with a lower protein content |
What direction does lymph flow in? | Flows in only one direction; away from the tissues |
Describe the lymphatic vessels | Filled with lymph, have thin walls & valves to prevent back flow. Formed by a thin layer of epithelial cells |
How does the fluid move in the lymphatic system? | Fluid moves passively, aided by the rhythmic contraction of skeletal muscles (respiration causes pressure changes that help propel lymph from the abdomen to the thoracic cavity |
What are the two collecting ducts in the Lypmhatic system? | Right Lymphatic duct & Thoracic duct |
Where does the right lymphatic duct drain from and to? | Drains from the URQ of the body into the right subclavian vein |
Where does the thoracic duct drain from and to? | Drains from the rest of the body into the subclavian vein |
What are the lymphatic nodules that reside in the small intestines called? | Peyer's patches |
What are the primary lymphatic organs? | Red bone marrow & thymus; these provide a location for B and T lymphocytes to mature |
What are the secondary lymphatic organs? | Lymphnodes, tonsils, spleen; these contain lymphocytes that have matured in red bone marrow or the thymus |
What are the lymphatic tissues that exist in masses called? | Lymphatic nodules |
What are examples of passages that open to the outside of the body that contain a covering of lymphocytes in there mucosa linings? | Respiratory, digestive, urinary, & reproductive tracts |
What are the functions of the lymph nodes? | Remove pathogens from the lymph |
What forms and releases lymphocytes when an infection is present? | Germinal centers |
What is the pharyngeal tonsil? (be able to locate) | Single tonsil that sits on the wall of the pharynx, just behind the nasal cavity |
What is another term for pharyngeal tonsil? | Adenoid |
Describe the spleen and its location | It's approximately the size of a fist, it is the largest lymphatic organ and is located in the ULQ (inferior to the diaphragm) |
What protects the spleen? | Lower ribs |
What are the spleens functions? | Immunity, destruction of RBC's, & blood storage |
What happens with immunity in the spleen? | Screen blood for foreign antigen; ingest & destroy and microorgansisms |
What happens with destruction of RBC's in the spleen? | Digest worn out RBCs and imperfect platelets, recycle hemoglobin, salvaging iron & globin - returning it to the bone marrow and liver for later use |
What happens with blood storage in the spleen? | Helps stabilize blood volume by rapidly adding blood back into general circulation; stores 20%-30% of the body's platelets |
What are the immune systems three lines of defense? | External barriers; Nonspecific immunity, and specific immunity |
What are the external barriers? | Skin & mucous membranes |
What is non-specific immunity? | Mechanisms present at birth |
What is specific immunity? | Body retains a memory of a pathogen after defeating it |
What does non-specific immunity do? | Protects against a broad range of pathogens using a variety of mechanisms such as, external barriers, phagocytosis, and anti microbial proteins |
Define external barriers in non-specific immunity | Mucus membranes lining the digestive, respiratory, urinary, & reproductive tracts produce mucus that physically traps pathogens; mucus, tears, and saliva contain an enzyme called lysozyme which destroys bacteria |
What is phagocytosis? | Sole job is to ingest & destroy microorgansisms & other small particles |
What are the most important phagocytes? | Neurtophils & macrophages |
What are the two types of proteins that help provide non-specific immunity against bacterial & viral invasion? | Interferons & complement system |
What is a neutrophil? | Phagocyte that travel to sites of infection after being summoned by a chemical released from inflamed cells |
What are interferons? | Protein that binds to surface receptors on neighboring cells triggering production of enzymes within the cells that prevent a virus from replicating |
What is the first step in the complement system? | More that 20 different types off proteins (called complement) circulate in the blood steam in an inactive form |
What is the second step in the complement system? | Bacteria or antibodies against the bacteria, activate the compliment |
What is the third step in the complement system? | Complement reaction continues a cascade of chemical reactions; with one complement protein activating the next |
What is the fourth step in the complement system? | Eventually holes are punched in the bacterium and it swells and burst |
Define natural killer cells? | Unique group of lymphocytes; roam the body; most involve the secretion of chemicals that causes the cell to die and break apart |
What are the classic signs of inflammation? | Swelling, redness, heat & pain |
What is another term for fever? | Pyrexia |
What does a fever do? | Inhibits the reproduction of bacteria & viruses |
What is a fever? | Abnormal elevation of the body's temperature |
Define specific immunity | Directed against a specific pathogen |
Describe cellular (cell-mediated) immunity | Has T cells, aims to destroy foreign cells or host cells that have become infected with a pathogen |
Describe humoral (antiboy-mediated) immunity | Has B cells, focuses on pathogens outside the host cells; it sends out antibodies to "mark" a pathogen for later destruction |
Which specific immunity system uses lymphocytes and antibodies? | Both - Cellular immunity & Humoral immunity |
What are the two weapons used in the specific immunity process? | T-cells & B-cells |
What are the three classes of lymphocytes? | Natural killer cells, T lymphocytes, & B lymphocytes |
What are T lymphocytes? | Develop in bone marrow & mature in the thymus |
What are B lymphocytes? | Develop in bone marrow & remain there until fully developed |
What happens when a lymphocyte is mature? | It migrates to lymphatic organs & tissues throughout the body |
What is another name for antibodies? | Immunoglobulins |
What is the most abundant of all the immunoglobulins? | IgG (makes up 80% of all circulating antibodies) |
Describe cellular immunity | Destroys pathogen within a cell |
What are the three classes of T cells? | Cytotoxic T cells, Memory T cells & Helper T Cells |
What do the Helper T cells do? | Play a supportive role; secrete chemicals that summon neutrophils and natural killer cells |
What is Humoral Immunity? | Focuses on pathogens outside the cell |
How does humoral immunity work? | Uses antibodies to mark antigen for later destruction |
What range of tactics to antibodies use to defeat antigens? | Prevent the antigen from attaching to a human cell; triggers agglutination; triggers the complement cascade of chemical reactions |
What is anaphylaxis? | A severe, immediate allergic reaction that affects the whole body |
What happens when someone is exposed to an allergen? | First exposure, body produces IgE, which makes the person sensitized
Mast cells release histamine |
What are the two different types of immunity? | Active - permanent or at least long lasting
Passive - Immunity last only a few months |
Receive rabies serum after being bitten by stray dog | Artificial passive immunity |
Person receives immunization | Artifical active immunity |
Person develops immunity after having disease | Natural active immunity |
From mother to newborn | Natural passive immunity |
What is hypersensitivity? | Inappropriate or excessive response of the immune system (allergic reaction) |