Download 9.3 Allergies and Lymphatic System

Do Now 4/3/15
1. What did Nagler and her team conclude could be a possible
cause of food allergies?
2. How were food allergies treated in the experiment
conducted by Nagler and her team?
3. Why was administration of Clostridia effective in eliminating
symptoms of food allergies?
4. What are the implications of this study on humans?
Upcoming Dates
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Tuesday, 4/7: Blood Quiz Corrections due
Thursday, 4/9: Blood, Immune/Lymphatic Quiz
Friday, 4/17: Digestive Quiz
Thursday, 4/23: Digestive Project due
Monday, 4/27: Urinary Quiz; Urinary Project due
Friday, 5/1: Urinary & Reproductive Test
Thursday, 5/7: Semester 2 Final Exam
Allergies
• Disorder of the immune system
• When the immune system responds to a “false alarm”
• When typically harmless substances are encountered by a
person who is allergic, the immune system produces
antibodies that “attack” the allergen
• Can result in itching, wheezing, runny nose, watery or itchy eyes,
etc.
• Potential allergens include dust, mold, pollen, some food
proteins, etc.
• Just like with other pathogens, no one is born with these
antibodies (no one is born allergic), but after a first exposure,
antibodies can develop causing allergic reactions in the future
Allergic Reactions
• Allergic reactions occur when IgE antibodies are produced in
response to a harmless antigen, or allergen
• Exposure to an allergen causes activation of IgE and mast cells
• Mast cells = specialized cells found in tissues all over the body
that store histamine (the chemical that causes symptoms like
runny nose or sneezing)
• Considered to be an “acute hypersensitivity”
• Almost ½ the populations of North America and Europe have
allergies to one or more common environmental allergens
• Usually not life-threatening but can cause much distress and lost
time away from school and work
Food Allergies
• Often caused by proteins that resist heat of cooking, acid in
stomach, AND digestive enzymes in the intestines
• Allergens survive and cross from the intestines into the
bloodstream and cause allergic reactions throughout the body
• Typically has an inherited component (most people with food
allergies come from families in which allergies are common)
Pet Allergies
• 15% of Americans are allergic to animals
• Allergies can develop at any age
• Caused by pet dander from the skin, not the fur! Even saliva or
urine can cause a reaction.
• Most allergies commonly caused by cats
• Because they are the worst.
For a more detailed look at the
physiology of allergies…
• Read and take notes on page 877 in the textbook
• Read and take notes on 21.1-2
Introduction
• Immune system
• Protects the body
against
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Bacteria
Viruses
Fungi
Toxins
Parasites
Cancer
• Lymphatic system
• Works with immune
system to remove
disease-causing agents
• Organs
• Thymus
• Spleen
• Lymph nodes
The Lymphatic System
• Network of connecting vessels
• Collects fluid (lymph) between cells and returns it to bloodstream
• Picks up lipids from digestive organs and transports them to
blood stream
• Functions to defend the body against pathogens
Lymphatic System: Pathways
• Lymphatic capillaries
• Extend into interstitial spaces
• Permeable, thin walls pick up fluid, now lymph
• Delivers lymph to lymphatic vessels
• Lymphatic vessels
• Deliver lymph to lymph nodes
• Cells in nodes can remove pathogens from lymph and start an
immune response
• Leaves nodes through efferent lymphatic vessels
Lymphatic System: Pathways (cont.)
• Lymphatic trunks
• Receive lymph from efferent lymphatic vessels
• Deliver it to ducts
• Lymphatic collecting ducts
• Thoracic duct
• Left side of head and neck, left arm, left side of thorax, entire
abdominopelvic area, and both legs
• Right lymphatic duct
• Right side of head and neck, right arm, and right side of chest
Lymphatic System:
Tissue Fluid and Lymph
• Interstitial fluid
• Fluid in spaces between cells that has leaked from blood
capillaries and has not been picked up by body cells
• High in nutrients, oxygen, and small proteins
• Becomes lymph
• Pushed through lymphatic vessels by squeezing action of
neighboring skeletal muscles and breathing movement
Back
Lymphatic System: Nodes
• Small, glandular
structures
• Located along paths of
larger lymphatic vessels
• Afferent lymphatic vessels –
Lymph to node
• Efferent lymphatic vessels –
Lymph away from node
Lymphatic System: Nodes (cont.)
• More lymph enters than can
leave at one time
• Cells in nodes
• Macrophages – digest unwanted
pathogens
• Lymphocytes – start an immune
response against pathogen
• Nodes can generate some
lymphocytes
Apply Your Knowledge
What are the lymphatic collecting ducts and what
area do they drain?
ANSWER: The collecting ducts are:
Thoracic duct, which drains the left side of the head and
neck, left arm, left side of thorax, entire abdominopelvic
area, and both legs; and the right lymphatic duct, which
drains the right side of the head and neck, right arm,
and right side of the chest.
Lymphatic System:
The Thymus and Spleen
• Thymus
• Soft, bi-lobed organ
• Located just above the heart in the mediastinum
• Large in children, shrinks as we age
• Functions
• Same as lymph nodes
• Also produces lymphocytes
• Produces thymosin – stimulates production of lymphocytes
Thymus Gland
Lymphatic System:
The Thymus and Spleen (cont.)
• Spleen
• Largest lymphatic organ
• Located in the upper left quadrant of abdominal cavity
• Functions
• Filters blood similarly to lymph nodes
• Removes worn-out red cells
• If removed (splenectomy), liver takes over most of its
function
Spleen
Tonsils
• Multiple groups of large lymphatic nodules
• Location – mucous membrane of the oral and pharyngeal cavities
• Palatine tonsils
• Posterior-lateral walls of the oropharynx
• Pharyngeal tonsil
• Posterior wall of nasopharynx
• Lingual tonsils
• Base of tongue
Tonsils
Defenses Against Disease (cont.)
Two major types of lymphocytes
B Cells and T Cells
Response
Recognize antigens in the body
B cells
Respond to antigens by
becoming plasma cells
 Plasma cells make antibodies
 Memory B cells produce
stronger response with next
exposure to antigen

T Cells
Cell-mediated response
 Bind to antigens on cells
and attack them directly
 Secrete lymphokines that
increase T cell production and
directly kill cells with antigens

Back
Defenses Against Disease (cont.)
• T cell activation
• Begins when macrophage ingests and digests pathogen with
antigen on it
• Antigens are placed on cell membrane of macrophage
• T cell recognizes and binds to antigen and the major
histocompatibility complex (MHC) on the surface of the
macrophage
• Now can divide to form other types of T cells
Defenses Against Disease (cont.)
• Types
• Cytotoxic T cells
• Protect body against viruses and cancer cells
• Helper T cells
• Increase antibody formation, memory cell formation,
B cell formation, and phagocytosis
• Memory T cells
• Remember the pathogen that activated original T cell
• Later exposures trigger an immune response more
effective than initial response
Defenses Against Disease (cont.)
• Natural killer (NK) cells
• Type of lymphocyte
• Primarily target cancer cells
• Kill on contact
• Do not recognize a specific
antigen
Apply Your Knowledge
ANSWER:
Identify whether each item refers to T cells, B cells, or NK cells:
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NK Primarily target cancer cells
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B Respond to antigens by becoming plasma cells
T Must be activated to respond to an antigen
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T Bind to antigens on cells and attack them directly
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NK Kill on contact
T Need macrophages and MHC for activation
___
B Make antibodies against specific antigen
___
Major Immune System
Disorders
• Cancer
• Uncontrolled growth of abnormal cells form malignant
tumors
• 200 known types
• Treatment based on stage
0 – very early; cancer cells localized
I – spread to deeper layers or some in surrounding tissues
II – spread to surrounding tissues but contained in primary site
III – spread beyond primary site into nearby areas
IV – spread to other organs
Recurrent – reappeared after treatment
Common Immune System
Disorders
• Autoimmune disease
• Body attacks its own antigens
• Examples
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Psoriasis
Rheumatoid arthritis
Graves’ disease
Myasthenia gravis
Multiple sclerosis
Type I diabetes (mellitus)
HIV
• Read article about potential ‘cure’ for HIV
http://www.cnn.com/2014/03/06/health/hiv-babycured/
• Research and write a summary of the mechanism of HIV and
how antiretroviral treatment is used to combat it