Card Set Information
What are the 2 "parts" of the lymphatic system?
Lymphatic Tissues and Organs
What does the lymphatic system do?
Transport fluids back to the blood
Body defense and resistance to disease
What is lymph?
Excess fluid carried by lymphatic vessels
What are the properties of lymphatic vessels?
One way system towards the heart
Moves fluid by milking action of the skeletal muscles and rhythmic contraction of smooth muscle in vessel walls
How do lymph capillaries work?
Walls overlap to make flap like mini valves
High pressure on the inside closes valves
Fluid leak into lymph capillaries
What are lymph collecting vessels?
Vessels that collect lymph from capillaries
Carry lymph away from lymph nodes
Returns fluids to circulatory veins near the heart
What are the 2 lymph ducts?
Right lymphatic duct
What materials are returned to the blood?
What harmful materials enter the lymph vessels?
What do the lymph nodes do, and how?
Filter lymph before its returned to the blood
Macrophages engulf and destroy foreign substances
Lymphocytes provide immune response to antigens
What is the structure of a lymph node?
Cortex - outer part containing follicles (collection of lymphocytes)
Medulla - Inner part containg phagocytic macrophages
Less than 1 inch long
How does lymph flow through nodes?
Enters afferent lymphatic vessels
Flows through sinuses
Exits efferent lymphatic vessels
Fewer efferent than afferent causes back-up
What are the "other" lymphoid organs?
What does the spleen do?
Destroys worn out blood cells
Forms blood cells in the fetus
Acts as a blood reservoir
What does the thymus do?
Produces hormones to program lymphocytes
Functions at peak levels during childhood
What do the tonsils do?
Trap and remove bacteria and other foreign materials
Tonsillitus is caused by bacterial congestion
What do Peyer's Patches do?
Capture and destroy bacteria in the small intestine
What are Mucosa-Associated Lymphatic Tissues (MALT)?
Protects respiratory and digestive tracts
Other small lymphoid accumulations
What is the body's 2 systems for defense against foriegn materials?
Nonspecific defense system - protects against a variety of invaders, responds immediately
Specific defense system - immune system, specific defense required for each type of invader
What are nonspecific body defenses?
Surface coverings - skin, mucous membranes
Specialized human cells
Chemicals produced by the body
What is the skin?
Physical barrier to foreign materials
pH of skin is acidic to inhibit bacterial growth
Sebum is toxic to bacteria
Vaginal secretions are very acidic
What does the stomach mucosa do?
First line of defense
Secretes hydrochloric acid
Has protien digesting enzymes
What are the defensive cells of the lymphatic system?
Phagocytes - neutrophils and macrophages
Engulfs foriegn material into vacuoles
Enzymes from lysozyme digest material
What do phagocytes do?
Lyse and kill cancer cells
Destroy virus-infected cells
What is the lymphatic systems second line of defense?
Triggered when body tissues are injured
What are the functions of inflammatory response?
Prevents spread of damaging agents
Disposes of cell debris and pathogens
Sets the stage for repair
What is fever?
High body temperature
Increases speed of tissue repair
Inhibit release of iron and zinc from liver that bacteria need
Hypothalmus reset by pyrogens
What is the immune system?
Antigen specific defense
Systemic - not limited to infection site
Has memory - recognized and mounts stronger attack the next time there is infection
What are the types of immunity?
Humoral - antibody mediated, cells produce chemicals for defense
Cellular - cell mediated, cells target virus infected cells
What are antigens (nonself)?
Substance capable of igniting an immune response
Large carbohydrates, and some lipids
What are self-antigens?
Human cells have many surface protiens
Body usually doesn't attack itself
Our cells in another persons body could cause an immune response
Limits donors for transplants
What are allergies?
Small molecules that bind with our own cells
The immune system is harmful due the body attacking its own cells
What are the cells of the immune system?
Lymphocytes - B lymphocytes bone morrow, T lymphocytes thymus
Macrophages - arise from monocytes, widely distributed in lymph organs
Characteristics of humoral immune response:
B lymphocytes bind to specific antigens
Large number of clones are produced
Most B cells become plasma
Produce antibody's to destroy antigens
What is a secondary response?
Memory cells are long lived
Secondary response is stronger and longer lasting
What is active immunity?
B cells enounter antigens and produce antibodies
Naturally or artifically acquired
What is passive immunity?
Antibodies obtained from someone else
Naturally from mother to child
Artifically from immune serum or gamma globulin
What are monoclonal antibodies?
Antibodies prepared for clinical testing, produced from a single cell line
Diagnose pregnancy and treatment for hepatitis and rabies
What are antibodies?
Soluable protiens secreted by B cells
Carried in blood plasma
Binds specifically to an antigen
What is the structure of an antibody?
Four amino acid chains linked by disulfide bonds
Two identical amino acid chains are linked to form a heavy chain
Two identical chains are light chains
Specific antigen binding sites are present
5 antibody classes:
IgM - fix complement
IgA - mainly in mucus
IgD - activation of B cells
IgG - can cross placental barrier
IgE - involved in allergies
How do antibodies inactivate antigens?
How does cell mediated immune response work?
Antigens must be presented by macrophages to an immnocompetent T Cell
T cells must recognize nonself and self
After antigen binding, different classes of cells are produced
3 types of T-Cell clones
Cytotoxic T cells - kill infected cells, insert toxic chemical
Helper T cells - Recruit other cells to fight, interact with B cells
Supressor T cells - keeps immune response from overacting
4 types of grafts:
Autografts - tissue transplant on same person
Isograts - tissue transplant from identical twin
Allografts - tissue taken from unrelated person
Xenografts - tissue taken from different animal species
Types of hypersensitivities:
Immediate hypersensitivity - IgE, reacts in seconds, anaphalactic shock
Delayed hypersensitivity - T cells, reacts within 1 - 3 days
Congenitcal or acquired
Immune system does not distinguish "self"
T lymphocytes attack own tissues