Transcript Lymphatic System

Chapter 35
Lymph Transport
& Immunity
Outline
The Lymphatic System
Lymph Vessels
Lymphoid Organs
Nonspecific Defenses
Barriers
Inflammatory Response
Specific Defenses
Antibodies
T Cells
Induced Immunity
Active versus Passive Immunity
Immunity Side Effects
Allergies
Blood Typing
Lymph Transport &
Immunity
2
The Lymphatic System
Lymph Transport &
Immunity
3
Consists of lymphatic vessels and the lymphoid
organs
Three main homeostatic functions:
- Lymphatic capillaries take up and return excess
fluid to the bloodstream
- Lacteals receive lipoproteins and transport them to
the bloodstream
- Helps defend body against disease
Lymphatic System
4
The Lymphatic Organs
5
Lymphatic System
Lymph Transport &
Immunity
6
One-way system that begins with lymphatic
capillaries
Take up fluid that has been diffused from, and not
reabsorbed by, blood capillaries
- Edema - Localized swelling due to accumulation of
tissue fluid
Lymph flows one way
- From a capillary to ever-larger lymphatic vessels
- Finally to a lymphatic duct, which enters a
subclavian vein
Lymphoid Organs
Lymph Transport &
Immunity
7
Lymph Nodes - Capsule surrounding two distinct
regions, cortex and medulla
Lymphocytes congregate in cortex when fighting
off a pathogen
Macrophages concentrated in medulla - cleanse
lymph
Lymph nodes named for their location
Lymphoid Organs
Lymph Transport &
Immunity
Tonsils
Patches of lymphatic tissue located around the
pharynx
First to encounter pathogens that enter via the
nose and mouth
Spleen
Located in upper left region of abdominal cavity
just beneath diaphragm
Cleanses blood
8
Lymphoid Organs
Lymph Transport &
Immunity
Thymus Gland
Located along trachea behind the sternum in
upper thoracic cavity
Produces thymic hormones
Red Bone Marrow
Origin for all types of blood cells
Area of maturation for most white blood cells
9
Immune System
Lymph Transport &
Immunity
Nonspecific Defenses
Barriers to entry serve as mechanical barriers
- Skin
- Mucous membranes lining respiratory, digestive,
and urinary tracts
10
Nonspecific Defenses
Lymph Transport &
Immunity
11
Inflammatory Reaction
Damaged cells and mast cells release histamine
and kinins
Capillaries dilate and become more permeable
Enlarged capillaries cause skin to redden
Swollen area and kinins stimulate free nerve
endings causing pain
Inflammatory Reaction
Lymph Transport &
Immunity
12
Neutrophils and monocytes migrate to the site of
injury
Neutrophils and mast cells phagocytize
pathogens
Monocytes differentiate into macrophages
Inflammatory Response
13
Complement System
Lymph Transport &
Immunity
14
A collection of plasma proteins
Activated when pathogens enter the body
Complements certain immune responses
Interferon binds to receptors of non-infected cells
Causes them to prepare for possible attack
Produce substances that interfere with viral
replication
Action of the Complement System
Against a bacterium
15
Specific Defenses
Lymph Transport &
Immunity
16
An antigen is any foreign substance that
stimulates the immune system to react
Lymphocytes capable of recognizing antigens
Have antigen receptors on plasma membrane
Protein’s shape allow it to combine with a specific
antigen
Specific Defenses
Lymph Transport &
Immunity
Immunity primarily the result of
B lymphocytes
- B cells give rise to plasma cells
- Produce antibodies
T lymphocytes
- T cells directly attack cells that bear non-self
proteins
17
Lymph Transport &
Immunity
Antibody-Mediated Immunity
Clonal selection theory:
The antigen selects which lymphocyte will
- Undergo clonal expansion, and
- Produce more lymphocytes
If the same antigen enters the system again
- Memory B cells quickly divide
- Give rise to more lymphocytes capable of quickly
producing antibodies
18
Clonal Selection Model as it Applies to B Cells19
Immunoglobins
Lymph Transport &
Immunity
20
IgG - Main antibody type in circulation
IgM - Found in circulation Largest antibody
IgA - Found in secretions
IgD - Found on surface of immature B cells
IgE - Found as antigen receptors on basophils in
blood and on mast cells in tissue
Structure of an Antibody
21
T Cells
Lymph Transport &
Immunity
22
Requirements for T cell antigen recognition:
Antigen must be presented by an antigenpresenting cell
Antigen is first linked to a major histocompatibility
complex (MHC) protein in the plasma membrane
Cytokines - signaling chemicals that stimulate
various immune cells
Clonal Selection Model
as it Applies to T cells
23
Types of T Cells
Lymph Transport &
Immunity
Cytotoxic T Cells
Destroy antigen-bearing cells
Contain Perforins
Helper T Cells
Regulate immunity by secreting cytokines
24
Cell-mediated Immunity
25
Overview of
Nonspecific and Specific Defenses
26
Induced Immunity
Lymph Transport &
Immunity
27
Active Immunity
Immunization
- Pathogens or pathogen products treated to remove
virulence
- Dependent upon memory B cells & memory T cells
capable of responding to lower doses of antigen
Active Immunity Due to Immunizations
28
Passive Immunity
Lymph Transport &
Immunity
29
Passive immunity
Occurs when an individual is given prepared
antibodies (immunoglobins) to combat a disease
- Short-lived
- Newborns are often passively immune due to
mother’s blood
Passive Immunity
30
Cytokines and Immunity
Lymph Transport &
Immunity
31
Cytokines
Signaling molecules produced by lymphocytes,
monocytes, or other cells
Both interferon and interleukins have been used
as immunotherapeutic drugs
Enhance the ability of the individual’s T cells (and
B cells) to fight cancer
Production of Monoclonal Antibodies
32
Immunity Side Effects
Lymph Transport &
Immunity
Allergies
Hypersensitivities to substances that ordinarily
would not harm the body
- Immediate Response
 IgE
antibodies
- Delayed Response
 Memory
T cells
33
Immunity Side Effects
Lymph Transport &
Immunity
34
Blood Type Reactions
ABO blood typing
- Two self antigens - A and B
- If same antigen and its antibody are present in the
blood, agglutination occurs
Rh blood typing
- People that are Rh+ have Rh factor
- People that are Rh- do not have Rh factor
- Rh- individuals may produce antibodies to Rh factor
if exposed
Blood Transfusions
35
Hemolytic Disease of the Newborn
36
Immunity Side Effects
Lymph Transport &
Immunity
37
Tissue Rejection
Antibodies and cytotoxic T cells bring about
destruction of foreign tissues in the body
Immune system is correctly distinguishing
between self and nonself
Autoimmune Diseases
Cytotoxic T cells or antibodies mistakenly attack
the body’s own cells
Review
The Lymphatic System
Lymph Vessels
Lymphoid Organs
Nonspecific Defenses
Barriers
Inflammatory Response
Specific Defenses
Antibodies
T Cells
Induced Immunity
Active versus Passive Immunity
Immunity Side Effects
Allergies
Blood Typing
Lymph Transport &
Immunity
38
Ending Slide Chapter 35
Lymph Transport
& Immunity