Lymphatic System

1
Lymphatic System

• Tissues organs, vessels and a fluid called lymph
• similar to interstitial fluid
• Diffuse lymphatic tissue
• Tonsils, mucosa associated lymph tissue and red
  bone marrow
• Lymph Organs
• thymus
• spleen
• lymph nodes
• Lymphocytes for Immunity

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Functions of the Lymphatic System

• Draining excess interstitial fluid plasma
  proteins from tissue spaces
• Transport of some nutrients and hormones
• Immunity specific defense
• recognize microbes or abnormal cells responding
  by killing them directly or secreting antibodies
  that cause their destruction

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Formation Flow of Lymph

• Some fluid proteins Filtered from blood
  capillaries are collected by lymphatic
  capillaries returned to the blood
• Muscle contraction and breathing promote flow of
  lymph
• Lymphatic vessels empty into subclavian veins in
  shoulders

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Lymph Circulation

• Lymph capillaries
• Capillaries are closed-ended tubes in tissues
• Have one-way minivalves
• Pickup fluid (lymph) from Tissues (interstitial
  fluid)

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Lymph Capillaries

• Comparison of Lymph and Blood Capillaries

Minivalve
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Lymph Circulation

• Lymphatic Vessels (lymphatics)
• Lymph passes from capillaries into lymph vessels
• Resemble veins with thin walls valves
• Afferent lymphatics carry lymph to nodes
• Efferent lymphatics carry lymph from nodes

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Lymph Circulation

• Afferent, Efferent Lymphatics and Valves

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Lymph Circulation

• Lymph trunks drain lymph into ducts
• Lymph ducts - largest lymph channels
• Two ducts drain lymph into subclavian veins
• Larger thoracic duct drains most of body
• Smaller right duct drains right side head, right
  shoulder and right arm into right subclavian vein

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Lymph Ducts
Right Lymphatic Duct
Thoracic Duct
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Lymph circulation

• Drainage Pattern of Lymphatic Ducts

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Summary of Lymphatic Flow

• Interstitial fluid ? Lymph Capillaries ?
• Afferent Lymphatics ? Lymph Nodes ?
• Efferent Lymphatic ? Lymphatic Trunks
• ? Lymphatic Ducts ? Subclavian Veins of
  cardiovascular system (CVS)

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Which are the larger lymphatic structures?
Question

• (A) lymphatics
• (B) trunks
• (C) capillaries
• (D) ducts

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Lymph Tissues

• Lymphatic nodules MALT (Mucosa Associated Lymph
  Tissues)
• lymphatic nodules within the digestive and
  respiratory systems
• Small intestine
• Appendix
• Bronchi of respiratory tract

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Lymph Tissues

• Tonsils
• Located in and around throat
• Tonsilar crypts
• Functions
• Crypts Trap microbes such as bacteria
• Mount immune response against inhaled and
  ingested microbes

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Lymph Organs

• Lymph nodes
• Structure
• Location
• Throughout body but concentrated in groin, neck,
  armpit
• Functions
• Filter lymph
• Provide immunity

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Lymph Node Distribution
Cervical Nodes
Axillary Nodes
Inguinal Nodes
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Vessels that enter lymph nodes are called ______
lymphatics.
Question

• (A) efferent
• (B) afferent
• (C) enter
• (D) endo

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Lymph Organs

• Thymus
• Located in mediastinum above heart
• Large in infants atrophying with age
• Function
• Thymosin hormones for
• T-cell lymphocyte maturation

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Spleen

• Located in upper left quadrant to left of stomach
• Functions
• Filters blood
• Provides immunity
• Stores iron and platelets

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Question
Which of the following are located within the
intestinal lining?

• (A) tonsils
• (B) lymph nodes
• (C) thymus glands
• (D) MALT

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What lymphatic structure contains hormones for
T-cell lymphocyte maturation?
Question

• (A) Tonsils
• (B) Thymus gland
• (C) Spleen
• (D) MALT

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Defense

• Non-specific Defense
• First Line Defense External
• Skin
• Mucous Membranes
• Tears
• Saliva
• Stomach acid

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Non-specific Defense

• Second Line Defense Internal
• Antimicrobial proteins
• Interferons antiviral
• Complement immunity and inflammation
• Natural killer (NK) cells
• Lymphocytes
• Kill microbes and tumor cells
• Phagocytes
• Wandering phagocytes
• Fixed phagocytes

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Internal Defense

• Inflammation
• Mast cells and basophils release chemicals
  including histamine
• Arterioles vasodilate more blood to site
• Increased capillary permeability more fluid
  into tissues

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Internal Defense

• Results in
• Redness
• Heat
• Swelling (edema)
• Pain
• Healing

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Question

• Which of the following is a first-line of
  non-specific defense?
• Interferons
• mucous membranes
• NK cells
• Inflammation
• none of the above

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Specific Defense Immunity

• Study of immunity is immunology
• Immunity versus non-specific defense
• Specificity responds to specific invaders
• Destroys invaders by various means such as
  ___________________________
• Memory Second exposure to antigen causes a
  stronger response

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• Antigens
• Foreign (non-self) cells or chemicals that
  produce an immune response (stimulate antibody
  production)
• Are microbes, parts of microbes, blood cells,
  transplant tissues, and a variety of chemicals

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Immunity

• B-cell and T-cell lymphocytes responsible for
  immunity
• Two types of immune responses
• Cell mediated immunity T-cells respond to
  intracellular antigens such as virus infected
  cells and tumor cells
• Antibody mediated immunity B-cells respond to
  extracellular antigens
• Antibodies combat the antigen

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Cell Mediated Immunity

• T-cells originate in the red bone marrow and are
  processed (undergo maturation) in the thymus
  gland
• Matured T-cells then pass into other lymph
  tissues where they are ready to respond to
  antigens

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Immunity

• Two types of T-cell lymphocytes
• CD8 cells
• Activated by contact with virus infected body
  cell
• Onr type develops into killer T-cells and memory
  cells
• CD4 cells
• Activated when antigen presented by antigen
  presenting cell (APC) cell
• Develops into helper T-cells and memory cells
• Helper T-cells must activate CD8 cells before
  they can become fully activated killer Ts

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Cell Mediated Immunity continued

• Killer Ts leave lymphatic tissue to search for
  and destroy virus infected cells, tumor cells and
  tissue transplant cells on contact

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Cell Mediated Immunity Diagram
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Question

• Which of the following activate Killer
• T-cells?
• B-cells
• plasma cells
• Helper T-cells
• antibodies
• none of the above

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Antibody Mediated Immunity

• Antigen causes production of antibodies
• B-cell lymphocytes stay in lymph tissues
• Antigen enters lymph tissue and binds to B-cell
  receptors
• B-cells become activated
• B-cells divide (clone) to form identical plasma
  cells and memory cells
• Helper T-cells bind to antigen on compatible
  B-cells and help stimulate plasma cell and
  memory cell formation

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Antibody Mediated Immunity

• Plasma cells secrete various types of antibodies
• Antibodies then bind to the specific antigen that
  activated its parent B-cells
• Antibodies then cause the destruction of the
  antigen in several ways

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Antibody Mediate Immunity Diagram
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Question

• Which cells secrete most of the
• antibodies?
• Plasma cells
• T-cells
• B-cells
• NK cells
• none of the above

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Antibody Mediated Immunity

• Antibodies destroy antigens by
• Neutralizing antigens such as toxins
• Agglutinating (clumping) and precipitating
  (removing from solution) antigen bearing cells
• Activating the complement proteins that destroy
  the antigen by various means
• Enhancing phagocytosis by covering a microbe with
  antibodies

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Antibody Mediated Immunity

• There are five classes of antibodies
• IgG, IgM, IgA, IgE and IgD
• The IgG antibody is most common
• Study Table 22-1, page 807 in text and earn some
  extra credit on exam by learning the functions
  for each type.
• What does the Ig stand for?

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Summary of Immunity
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Immunological Memory

• What is meant by the terms primary response and
  secondary response?
• What causes the secondary response?

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Question

• What does the Ig in the antibody symbol
• stand for?
• Interferon globulin
• Immunoglobin
• Immunogenic
• Immunoglobulin
• none of the above

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Disorders of the Immune System

• To earn extra credit on your exam, study Immune
  Disorders on pages 815-817 in your text.