Transcript Lymphatic System - SCF Faculty Site Homepage

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
Functions of the Lymphatic System
Draining excess interstitial fluid & plasma
proteins from tissue spaces
 Transport of some nutrients and
hormones
 Immunity –specific defense
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
recognize microbes or abnormal cells &
responding by killing them directly or
secreting antibodies that cause their
destruction
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
Lymph Circulation
 Lymph
capillaries
 Capillaries
are closed-ended tubes in
tissues
 Have one-way minivalves
 Pickup fluid (lymph) from Tissues
(interstitial fluid)
Lymph Capillaries

Comparison of Lymph and Blood Capillaries
Minivalve
Lymph Circulation
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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
Lymph Circulation

Afferent, Efferent Lymphatics and Valves
Lymph Circulation
Lymph trunks drain lymph into ducts
 Lymph ducts - largest lymph channels
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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

Lymph Ducts
Right Lymphatic Duct
Thoracic Duct
Lymph circulation

Drainage Pattern of Lymphatic Ducts
Summary of Lymphatic Flow
Interstitial fluid  Lymph Capillaries 
Afferent Lymphatics  Lymph Nodes 
Efferent Lymphatic  Lymphatic Trunks
 Lymphatic Ducts  Subclavian Veins
of cardiovascular system (CVS)
Question
Which are the larger lymphatic structures?
(A) lymphatics
(B) trunks
(C) capillaries
(D) ducts
Lymph Tissues

Lymphatic nodules – MALT (Mucosa
Associated Lymph Tissues)
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lymphatic nodules within the digestive and
respiratory systems
Small intestine
 Appendix
 Bronchi of respiratory tract
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Lymph Tissues

Tonsils
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Located in and around throat
Tonsilar crypts
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Functions

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Crypts Trap microbes such as bacteria
Mount immune response against inhaled and ingested
microbes
Lymph Organs
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Lymph nodes

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Structure
Location
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Throughout body
but concentrated in
groin, neck, armpit
Functions

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Filter lymph
Provide immunity
Lymph Node Distribution
Cervical Nodes
Axillary Nodes
Inguinal Nodes
Question
Vessels that enter lymph nodes are called
______ lymphatics.
(A) efferent
(B) afferent
(C) enter
(D) endo
Lymph Organs

Thymus
Located in mediastinum
above heart
 Large in infants atrophying
with age
 Function

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Thymosin hormones for
T-cell lymphocyte
maturation
Spleen

Located in upper
left quadrant to
left of stomach

Functions

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Filters blood
Provides
immunity
Stores iron and
platelets
Question
Which of the following are located within the
intestinal lining?
(A) tonsils
(B) lymph nodes
(C) thymus glands
(D) MALT
Question
What lymphatic structure contains hormones for
T-cell lymphocyte maturation?
(A)
(B)
(C)
(D)
Tonsils
Thymus gland
Spleen
MALT
Defense

Non-specific Defense
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First Line Defense: External
Skin
 Mucous Membranes
 Tears
 Saliva
 Stomach acid

Non-specific Defense
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Second Line Defense: Internal
 Antimicrobial
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Interferons – antiviral
Complement – immunity and inflammation
 Natural
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proteins
killer (NK) cells
Lymphocytes
Kill microbes and tumor cells
 Phagocytes
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Wandering phagocytes
Fixed phagocytes
Internal Defense
 Inflammation
 Mast cells and basophils release chemicals
including histamine
 Arterioles vasodilate – more blood to site
 Increased capillary permeability – more fluid
into tissues
Internal Defense
 Results
in
 Redness
 Heat
 Swelling
 Pain
 Healing
(edema)
Question
Which of the following is a first-line of nonspecific defense?
(A) Interferons
(B) mucous membranes
(C) NK cells
(D) Inflammation
(E) none of the above
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

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
Immunity
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Two types of T-cell lymphocytes
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CD8 cells
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Activated by contact with virus infected body cell
Onr type develops into killer T-cells and memory cells
CD4 cells
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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 T’s
Cell Mediated Immunity continued
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Killer T’s leave lymphatic tissue to
search for and destroy virus infected
cells, tumor cells and tissue transplant
cells on contact
Cell Mediated Immunity Diagram
Question
Which of the following activate Killer
T-cells?
(A) B-cells
(B) plasma cells
(C) Helper T-cells
(D) antibodies
(E) none of the above
Antibody Mediated Immunity

Antigen causes production of antibodies
 B-cell lymphocytes stay in lymph tissues
 Antigen enters lymph tissue and binds to Bcell receptors
 B-cells become activated
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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
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
Question
Which cells secrete most of the
antibodies?
(A) Plasma cells
(B) T-cells
(C) B-cells
(D) NK cells
(E) none of the above
Antibody Mediated Immunity
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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
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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.
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What does the Ig stand for?
Summary of Immunity
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?
(A) Interferon globulin
(B) Immunoglobin
(C) Immunogenic
(D) Immunoglobulin
(E) none of the above
Disorders of the Immune System
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To earn extra credit on your exam, study
“Immune Disorders” on pages 815-817 in
your text.