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67 Cards in this Set
- Front
- Back
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What are the three functions of the lymphatic system?
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Production
Maintenance and Distribution of Lympohcytes for defense |
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What does the lymphatic system consist of?
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Lymphatic Vessles
Lymphatic Organs Lymphatic Tissues (there needs to be a fourth here I think) |
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Where are the lymphatic vessels
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In all tissues with blood supply EXCEPT bone marrow and central nervous system
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Why would there be no lympatic vessels in the marrow and CNS?
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Foreign bodies exist in lymph and infection of the CNS or Marrow can provide for huge infection and problems.
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What is the function of lympahtic vessels?
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To carry lymph from peripheral tissues to the veins.
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What are the transporters of lymph to the veins? (3)
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Lymphatic vessels
Small Lymphatic Vessels Major Lymph collecting vessels |
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Three major characteristics of "Lymphatic Capillaries"
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The originate as pocket - opposed to blood capillaries which branch off arteries. They have their own origination.
They have a large diameter and thinner walls than blood capillaries. They have a flattened or irregular outline on a cross section (Not round) |
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Features of "Small Lymphatic Vessels"
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Structure is similar to veins with endothelial cells.
---- endothelial cells overlap allowing things in but not out - like a one way valve. Have valves to prevent backflow (like leg veins) Commonly occur in association with blood vessels They are pale and golden in color. |
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What are the two sets of "Lymphatic Vessels?"
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Superficial
and Deep Lymphatic |
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What are the characteristics of the "Superficial Lymphatic"
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Subcutaneous including mucous membranes and serous membranes
Found on the skin |
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Describe the Deep Lymphatics
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Accompany deep arteries and veins
They converge to form lymphatic trunks They empty into the Thoracic Duct & Right Lymphatic Duct |
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Four characteristics of the "lymphocytes"
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The main element of the lymph system
Thymus dependent (as per T cells) 80% circulating cells Cell mediated |
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What are the types of T cells?
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Cytotoxic T cells (attack virus infected cells)
Regulatory T Cells (two types - helper and suppressor) - see later slide for explanation Natural Killer Cells - Attack virus infected cells |
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Explain the two types of regulatory T cells
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Helper - they instigate all systems to get it all going
Suppresor - They are the "enough is enough" cells and stop the T cell production |
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Explain the roles of the Bone Marrow derived B cells -
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Account for 10-15% of circulating cells
Humeral (fluid) mediated Responsible for the production of antibodies |
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What is the life span of lymphocytes
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Some last 20+ years
80% last 4 years |
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How do T cells circulate?
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T cells move relatively quickly
Most T cells stay in place for only hours B cells stay in lymph nodes for a minimum of 10 hours |
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Where do lymphocytes come from?
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Original blast cell in the bone marrow
AKA the stem cells in the bone marrow. |
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Where do B cells and NK cells mature?
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In the bone marrow
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How do lymphoid cells migrate?
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they migrate to the thymus to mature into T cells
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Where is lymphocyte production?
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Out of the bone marrow
lymphocytes can divide and reproduce |
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What are the characteristics of lymphoid tissues?
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Connective tissues dominated by lymphocytes
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characteristic of a lymphoid tissue
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densely packed ina n area of areolar tissue
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What are germinal centers
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They contain dividing lymphocytes
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MALT stands for:
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Mucosa Associate Lymphoid Tissue
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MALT means:
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They are clusters of lympoid nodules deep to the mucosal epithelial linign in various sites of the body
Abundant in gastrointestinal epithelium Mostly found in the intestines |
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What are tonsils?
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Large Lymphoid nodiles in teh walls of the pharynx.
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Three types of tonsils and their descriptor:
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Palatine Tonsils : Visible tonsils
Pharyngeal Tonsil : IN the middle (the adenoids - also visible but not immediately) Near the nasal cavity Lingual Tonsils : AT the base of the tongue and not normally visible |
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What are the three lymphoid organs?
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Lymph nodes
Thymus Spleen |
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Four characteristics of lymph nodes:
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Up to an inch in diameter
Covered by dense connective tissues Fibroid connective tissue is extended into interior of the node (called trabeculae) Afferent lymphatics (toward) and efferent lympatics (away) |
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List the histology of a lymph node
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Lymph enters the subscapular sinus (dendritic cells initiate an immune response)
It then flows through the outer cortex (B cells present in germinal center) Flows through the deep cortex then into the medulla (efferent lymphatics) |
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What is the function of a lymph node?
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Filters lymph before it enters a vein removing 99% of the antigens
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Where are lymph glands located?
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Groin, axillae & base of neck
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Swollen glands are really what?
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enlarged lymph nodes - usually from injury
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What are lymph glands?
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Large lymph nodes located where the peripheral lymphatics connect with the trunk.
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Where is the thymus?
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Posterior to the sternum
Covering the aorta and the superior vena cava |
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What is the life cycle of the thymus?
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It grows to it's maximum size (approx 40 g) by puberty and eventually diminishes (involutes)
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Describe the structure of the thymus.
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Two lobes
Has fibrous partitions (septa) separating the lobes Has a densely packed outer cortex |
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What occurs within the thymus?
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Cytotoxic T cells mature
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What are thymosins
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A group of hormones produced by the thymus to help T cells mature.
It is important to the development and maintenance of normal immunological defenses. |
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What is made of the largest collection of lymphoid tissue?
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Spleen
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What are three functions of the spleen?
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Same function as lymph but for blood - removes abnormal blood cells
Stores recycled Iron Initiates immune responses by B cells and T cells. |
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What is the texture of the spleen?
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Extremely soft - like liver - but softer
Does not hold sutures well Must be repaired with topical coagulants (like those used in boxing) |
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Three characteristics of a splenechtomy...
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Not performed unless absolutely necessary (Used to happen regularly)
Increases the risk of bacterial infection by pneumococcal bacteria Patients with a splenechtomy require the pneumovax vaccinne. |
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Describe the histology of the spleen.
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The red pulp contains large quantities of red blood cells
The white pulp resembles lymphoid nodules Capillaries discharge blood into red pulp Blood flows through the mesh structure with phagocytes Empties into the venous system |
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What are specific defenses?
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Protects against particular threats
Dependent on lymphocytes Lymphocytes produce immunity |
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What are non-specific defenses?
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Physical barriers (ie skin)
Prevents the approach of and denies access to pathogens |
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How do phagocytes act as a defense?
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They remove debris and pathogens
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How does interferon act as a defense?
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Increases resistance of cells to viral infection and slows the spread of disease.
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How is fever a defense?
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mobilizes defenses
accelerates repairs inhibits pathogens |
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What is the complement system?
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attacks and breaks down cell walls
attracts phagocytes stimulates inflammation |
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What are the properties of immunity? (4)
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Specificity - activated by a specific antigen and response to that particular antigen.
Versatility - responds to millions of antigens Memory - ready to combat second round Tolerance - will not attack the antigens in own body (Lack of tolerance is found in auto immune disorders) |
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Antigens bind to what on the cell membrane in order to trigger an immune response?
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glycoproteins
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Glycoproteins originate from what?
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DNA
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What gene controls the synthesis of MHC protein on chromosome 6?
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Major Histocompatability Complex gene. (this is the glycoprotein)
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What are the two types of MHC proteins?
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Class I - self-identification (found on all cells)
Class II - defense against intruders |
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What are the MHA II cells?
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Major Histocompatability proteins on membranes of antigen presenting cells (apc's) ie phagocytic cells and lymphocytes
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What are cytotoxic t cells & function?
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seek out and destroy abnormal and infected cells. It's how a virus is killed.
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Memory T cells
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set aside for secondary response. They watch from the sidelines.
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Suppressor T cells
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they are the "off timer" and tell the t cells when enough is enough to keep the body from attacking its own cells.
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Helper T cells
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the messengers that secrete cytokines to stimulate other defense cells.
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What is the definition of an auto-immune disorder?
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The body's immune system attacks it's own normal tissues.
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Hashimoto's Thyroiditis
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Body has antibodies against it's own thyroglobulin
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Rheumatoid Arthritis
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auto-antibodies form immune complexes in the joints
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Insulin dependent diabetes mellitus
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auto-antibodies attack cells in the pancreas that make insulin
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A bubble boy results from what?
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Severe combined immunodeficiency disease
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What are allergies?
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Inappropriate or excessive immune responses
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