The Lymphatic System Study Guide

Primary Function of the Lymphatic System
production, maintenance, and distribution of lymphocytes to provide defense against pathogens and other environmental hazards, carried out by lymphoid tissue such as tonsils, spleen, and thymus gland
Secondary Function of the Lymphatic System
returns excess fluid from body tissues to the blood stream because capillaries deliver more fluid to peripheral tissues than they carry away and also helps transport lymphocytes and other defense cells from one organ to another
Non-Specific Defense
anatomical barriers that slow the entry of infectious agents, like the skin and mucus membranes
Specific Defense
lymphocytes attack a specific type of bacterium, an immune response
T Cells
thymus dependent, 80% of circulating lymphocytes, destroy viruses using cell-mediated immunity
Cytotoxic T Cells
attack cells infected by viruses involving direct contact, involved in cell-mediated immunity
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Helper T Cells
stimulate activation and function of both T and B cells
Suppressor T Cells (Regulatory T Cells)
inhibit activation and function of both T and B cells
B Cells
bone marrow derived, 10-15% of circulating lymphocytes, associated with bacteria and antibodies, targets antigens like bacteria and allergens
Plasma Cells
produce and secrete antibodies or immunoglobulins
Antigens
specific chemical targeted by B cells, mostly consisting of proteins
NK Cells (Natural Killers)
large, granular lymphocytes that recognize and destroy abnormal cells when they appear in peripheral tissue but are not as specific in their attack
Lymph Tissue
connective tissue dominated by lymphocytes
MALT
collection of lymphoid tissues linked with digestive system
Lymph Nodes
small lymphoid organs ranging in diameter from 1mm to 25mm, purify lymph before it reaches the venous circulation
Swollen Glands
enlargement of lymph nodes, natural inflammatory response due to an increased number of lymphocytes and phagocytes in response to a minor localized infection
Lymphadenopathy
chronic or excessive enlargement of lymph node, a response to a bacterial or viral infection, endocrine disorder, or cancer
Thymus
located in the mediastinum just posterior to sternum, produces several key immune system hormones
Thymosin
hormone involved in the development of lymphocytes
Spleen
located along the left lateral border of the stomach, removes abnormal blood cells and other blood components, stores iron recycled from red blood cells, initiates immune responses by B and T cells, and contracts to push out blood, not able to be repaired as it is too fragile
Tonsils
large lymphoid nodules in the walls of the pharynx
Inflammation
localized tissue response to injury
4 Cardinal Signs of Non-Specific Defense
local swelling, redness, heat, and pain
Causes of Non-Specific Defense
impact, abrasion, distortion, chemical irritation, infection by pathogens, and extreme temperatures (hot or cold)
Necrosis
the death of cells or tissues from disease or injury
Pus
an accumulation of debris, fluid, dead, and dying cells, and necrotic tissue
Abscess
a localized collection of pus within a damaged tissue
3 Benefits of a Fever
high body temperature may inhibit some viruses and bacteria, body metabolism speeds up, and cell movement and enzymes reactions occur faster
Cell-Mediated Immunity
defends against abnormal cells and pathogens inside cells using phagocytosis and T cells, the primary defense against viruses
Antibody-Mediated Immunity
B cells defend against antigens and pathogens in body fluids, the primary defense against bacteria
Innate Immunity
genetically determined and is present at birth, no previous exposure to antigen required
Acquired Immunity
acquire immunity when exposed to antigen, not present at birth
Vaccination/Immunization
antigen from pathogen put in “shot” form, forces B cells to make antibodies to target antigen, antigen is neutralized and memory cells are made
Naturally Acquired Active Immunity
develops after birth as you encounter each “new” pathogen
Induced Active Immunity
develops after administration of antigen to prevent disease
Naturally Acquired Passive Immunity
from mother to child during gestation or breast feeding
Induced Passive Immunity
antibodies are administered to fight an infection or prevent a disease
Autoimmune Diseases
occurs when immune response inappropriately targets normal body cells and tissues – psoriasis, vitiligo, rheumatoid arthritis, lupus, Grave’s disease
Immunodeficiency
the immune system fails to develop normally or immune response is blocked in some way, results from problems with embryological development of lymphoid organs and tissues, infection with a virus like HIV which suppresses immune function, or treatment with or exposure to immunosuppressive agents such as radiation or drugs
Allergies
an inappropriate or excessive immune response to an antigen
Histamine
a chemical released by mast cells to initiate an inflammatory response
Antihistamine
chemical that stops body from producing histamine
Anaphylaxis
a circulating allergen affects mast cells in your body
Anaphylactic Shock
severe reaction to allergen that includes rapid decrease in blood pressure and vasodilation, can lead to circulatory system collapsing or even death
Mast Cells
release histamines, located in the immune system in lymph
Lymph Vessels vs. Blood Capillaries
lymph originate as pockets rather than forming continuous tubes, have larger diameters, thinner walls, and have valves and are pale green in color
Superficial Lymphatics
located in the subcutaneous layer deep to skin, found in mucus membranes lining digestive, respiratory, urinary, and reproductive tracts
Deep Lymphatics
larger lymphatic vessels that accompany deep arteries and veins, supply skeletal muscles and other organs of neck, limbs, and the trunk
Lymphatic Trunks
larger than superficial and deep lymphatics and empty into thoracic and right lymphatic ducts
Thoracic Duct
collects lymph from right side below diaphragm and entire left side
Right Lymphatic Duct
smaller than thoracic duct, collects lymph from right side superior to diaphragm
Lymphedema
blockage of lymphatic drainage from a limb, causes swelling and grossly distended parts, can be permanent if left untreated
Lupus
a chronic inflammatory autoimmune disease that can affect many parts of your body, including your skin, joints, kidneys, blood cells, heart and lungs, episodes tend to come and go throughout your life, and they may make you feel tired and achy
Crohn’s Disease
inflammation of the lining of the digestive tract, can cause severe bouts of watery diarrhea and abdominal pain
Autoimmune Hepatitis
a disorder in which the immune system attacks the liver, causing chronic inflammation of the liver
Type 1 Diabetes
develops when your pancreas makes little or no insulin, insulin acts like a key to unlock microscopic doors that allow glucose into your cells, instead of being transported into your cells, glucose accumulates in your bloodstream and eventually is excreted in your urine
Scleroderma
a rare, progressive disease that involves hardening and thickening of the skin and may damage internal organs as well
Rheumatic Fever
a serious inflammatory condition that can affect many parts of your body – heart, joints, nervous system and skin, symptoms generally appear within five weeks after an untreated streptococcal throat infection
Rheumatoid Arthritis
the synovial membrane that protects and lubricates your joints becomes inflamed, causing pain and swelling, joint erosion may follow
Glomerulonephriitis
a type of kidney disease that affects your kidneys’ filtering function, complications include high blood pressure and kidney failure
Sarcoidosis
starts in your lungs but can cause inflammation in any part of your body, it can last a lifetime – or disappear in a few years
Myasthenia Gravis
a condition of muscle weakness caused by a breakdown in communication between nerves and muscles
Multiple Sclerosis
a chronic, potentially debilitating disease that affects the brain and spinal cord
Physical Barriers
prevent approach of and deny access to pathogens
Phagocytosis
remove debris and pathogens
Inflammatory Response
blood flow increased, phagocytes activated, capillary permeability increased, complement activated, clotting reaction walls off region, regional temperature increased, specific defenses activated
Fever
mobilizes defenses, accelerates repairs, inhibits pathogens
Pathogens
disease causing agent, like viruses, bacteria, fungi, and parasites
HIV
original diagnosis that progresses into AIDS, a virus
AIDS
has progressed from HIV because it has a secondary disease associated with it