Chapter 14

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Includes:
 Network of vessels that transports fluids
 Similar to cardiovascular
 Organs, etc:
 Lymph nodes/vessels/fluid, capillaries, veins/arteries, thymus, spleen, bone marrow
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Functions:
 Drain interstitial fluid back to the circulatory system
 Dietary lipid absorption/transport
 Initiate & regulate immune responses

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Lymphatic capillaries →
Lymphatic vessels →
Lymphatic Trunks →
Collecting Ducts →
Veins
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The lymph will also pass through lymph nodes found along vessels

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Closed-ended tubes
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Form network with blood capillaries
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Thin-walled
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Fluid inside is called lymph

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Lymphatic vessels
 Structure is very similar to veins
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Lymphatic Trunks
 Larger vessels than lymphatic vessels; drain into collecting ducts

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Two Main Ducts
 1) Thoracic Duct- collects lymph drained from the lower limbs, abdomen, left upper limb, and left side of the thorax, head, and neck
 2) Right Lymphatic Ductcollects lymph drained from right upper limb and right side of the thorax, neck, and head

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Interstitial fluid surrounding capillaries
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Constant movement in and out of capillaries
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Generally same composition as plasma (except doesn’t contain plasma proteins)
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Some excess fluid stays in tissue and is not recollected by capillaries

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Volume pressure of interstitial fluid causes some of the fluid to enter lymphatic capillaries
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Lymph will return to the bloodstream but will be filtered along the way
 Removing: Wastes, pathogens, carbon dioxide

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Controlled by:
 Skeletal muscle movement
 Pressure changes
(due to breathing)
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Valves keep the movement going in one direction

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Filter foreign particles from blood before returning the lymph to the blood stream
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Immune surveillance

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Usually small and bean shaped
Afferent lymphatic vessels:
 Carry lymph into lymph node
 Come in at various points along convex surface
Efferent Lymphatic vessels:
 Carry lymph out of lymph node
 Come out at hilum (area on the concave side)
Blood vessels and nerves enter at hilum

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Connective tissue encloses lymph node and creates sub-compartments inside
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Compartments are lymph nodules
 Lymph sinus: space inside the nodule
 Sinuses are filled with lymphocytes and macrophages

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Bilobed structure found in the chest region
Largest during childhood
Creates T-cells
Also an endocrine gland
 Releases thymosins
(make T-cells mature after leaving the thymus)

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Largest lymphatic organ
Found near stomach
Similar structure to lymph nodes
 Sinuses contain blood instead of lymph
White pulp
 High in lymphocytes
Red pulp
 High in red blood cells, lymphocytes, and macrophages
Filters Blood

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Protection against pathogens

Pathogens include:
 Viruses
 Bacteria
 Fungi
 Protozoans

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Innate vs Adaptive

Natural vs Artificial

Active vs Passive

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Species specific
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First line of defense:
 Skin and mucous layers
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Second line of defense:
 Chemical barriers
 Tears, gastric juices, and sweat
 Interferons
 Fever
 Inflammation
 Phagocytosis

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Third line of defense

Lymphocytes are responsible
 Lymphocytes: WBCs specific for adaptive immunity
 Types of lymphocytes: B and T cells
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Responds to specific antigen on the invading pathogen

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Undifferentiated lymphocytes made by fetal bone marrow
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T cells
 Lymphocytes travel to thymus and become T cells
 T cells either circulate in blood or are found in lymph system
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B cells
 Made in marrow
 B cells either circulate in blood or found in the lymph system

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1) Cellular Immune response
 Attack up close
 Performed by T cells
 soldiers, destroying the invaders that the intelligence system has identified (hand to hand combat)
 Signal other cells if needed for additional help
2) Humoral immune response
 Attack from afar (produce antibodies)
 Can’t destroy without T cells help
 Performed by B cells
 body's military intelligence system, seeking out their targets and sending defenses to lock onto them

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Antigen-presenting cells processes and displays antigen of pathogen
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Displayed antigen must be matched with a circulating helper T cells antibody receptor
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Helper T cell is activated

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Known as T c
Function:
 Attack cells infected virus or cancerous cells
 Release destructive enzymes into pathogen
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Must be activated by a matching antigen

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Sequence of events:
1.
B cell must match with an antigen
2.
3.
4.
Activated Helper T cell secrete cytokines
Cytokines make B cell proliferate to form plasma cells and memory cells
Plasma cell secrete antibodies

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Globular proteins; all immunoglobulins
 Contain heavy and light protein chains
 Contain variable region (area that is specific to antigen – foreign body- attachment)

IgA
IgM
IgD
IgE
IgG
Type Found
Plasma and tissue fluid
(passed down to fetus)
Function/s
Activates complement system, effective against bacteria, viruses and toxins
Control homeostasis Breast milk (passed down to infant), tears, nasal fluid, gastric juice, intestinal juice, bile, urine
Plasma (in response to food or bacteria)
Surface of B cells (esp. infants)
Exocrine secretions (with
IgA)
Activates complement system
Activate B cells
Allergic reactions/response



1) Attack directly
 Allows antibody to more easily phagocytize cells, eliminate them
 Types of Direct Attack:
1.
2.
3.
Agglutinate (Clump pathogens together)
Precipitate (Make pathogen insoluble)
Neutralize (Cover or destroy toxic part of antigen)

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2) Complement
 Bind antigens
 Starts a series of rxns that activate the complements circulating in the plasma
 Complement Function:
 Opsonization- coating antigen-antibody complex
 Chemotaxis- bringing macrophages to the area
 Lysis- rupturing membranes
 Agglutination
 Neutralization


Get out a piece of paper:
 Did you know about the AIDS struggles illustrated in the movie BEFORE watching it?
 Did you find yourself angry at anytime during movie?
When?
 Did you find yourself sympathetic at anytime? When?
 Did you find yourself sad? When?
 Overall view of movie…

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Memory T and B cells
 Circulate after primary immune response
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Body will be able to respond quickly during secondary immune response

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Natural:
 Through exposure to pathogen
 Resistance is the result of primary immune response
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Artificial:
 Through vaccine injection
 Vaccine: bacteria or virus that has been killed or weakened
 Contains antigens that stimulate primary immune response
 Don’t produce severe symptoms of disease
 Ex: Measles, mumps, flu, rubella

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Naturally Acquired Active:
 Occurs during pregnancy
 Certain antibodies (IgG) pass from maternal blood to fetal blood
 Fetus acquires limited immunity against pathogens
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Artificially Acquired Passive:
 Through injection of antiserum (ready-made antibodies)
 Obtain from globulin proteins from people who have already developed immunity against a certain disease

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Immune response to everyday, non-harmful antigens (allergens)
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Types: Delayed and Immediate
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Delayed-reaction allergy:
 Exposure to allergen on skin
 Collects T cells and macrophages in the area
 Causes dermatitis


Immediate-reaction allergy:
 Occurs within minutes
 First exposure- B cells become sensitized; IgE is attached to basophils and mast cells
 Subsequent exposures- mast cells and basophils secrete several substances including histamine
 These substances produce the reactions seen in allergy reactions

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Transplant tissue or organ
 Ex: Organ – liver, kidney, heart; Tissue – skin, bone

New transplant tissue/organ has its own antigens
 Recognized as foreign
 Starts immune response (which can often reject the new transplant tissue/organ)

Tissue matching helps minimize reaction
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Immunosuppressive drugs
 Suppress immune reaction, avoid rejection (usually)

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Cytotoxic T cells cannot correctly identify self cells and attacks self cells
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Why?
 Pathogen borrows self antigens during attack
 Pathogen antigen is very similar to a self antigen

Disorder
Lupus
Description
Occurs in 1 out of 2,000 Americans
Symptoms profound fatigue, rashes, and joint pains, severe cases: immune system attacks organs (kidney, brain, lung)
Crohn’s result from intestinal inflammation diarrhea, nausea, vomiting, abdominal cramps, and pain that difficult to control
Psoriasis
Diabetes
(Type 1)
Rheumatoid arthritis
Multiple
Sclerosis common , affects more than 2% of Americans, often runs in families destruction of the insulinproducing cells of the pancreas immune system targets the lining
(synovium) that covers various joints immune system targets nerve tissues of the CNS skin or body covered with buildup of red scales, skin rash
See chapter 11 pain, swelling, and stiffness of the joints possible blindness, paralysis, and premature death
Grave’s disease immune system destruction or stimulation of thyroid tissue fatigue, nervousness, cold or heat intolerance, weakness, changes in hair texture/amount, and weight gain/loss