Transcript Lymphatic System Notes

The Lymphatic System
http://www.faqs.org/health/Bodyby-Design-V1/The-LymphaticSystem.html
The Lymphatic System
• The body is constantly in contact with
bacteria, fungi, and viruses (all considered
pathogens)
• The body has two defense systems for
foreign materials
Types of Defense
• Non-Specific Defense
– First & Second Line of Defense
– Doesn’t care what the pathogen is – your
body will be defended!
Non-Specific Defense
• Non-Specific Defense Mechanisms
Include…
– Skin: mechanical barrier, acidic skin
secretions can also defend
– Mucous Membranes: Mucus and nasal hairs
trap microorganisms; Cilia move mucus out of
body; Gastric juice, saliva, and tears have
enzymes that destroy microorganisms
– Skin and Mucous Membranes are the first line
of defense against pathogens
– Cellular & Chemical Defense: Second line of
defense; includes…
Non-Specific Defense
• Phagocytes:
• Cell that engulfs a
foreign particle,
enclosing it in a
vacuole; destroyed
with enzymatic
contents of lysosomes
Non-Specific Defense
• Examples of
phagocytes include
macrophages (in body
tissues, developed
from monocyte WBC),
and neutrophils
(WBC)
Macrophage engulfing E-Coli
Non-Specific Defense
• Natural Killer Cells:
• Defensive cells that
can kill cancer cells
and virus-infected
body cells
• Release chemicals to
destroy invader’s cell
membrane and
nucleus
Non-Specific Defense
• Inflammatory Response:
• Non-specific response triggered whenever body
tissues are injured
Non-Specific Defense
• Benefits of inflammatory response include:
– Preventing the spread of damaging agents to
nearby tissues
– Disposes of cell debris and pathogens
– Sets the stage for repair
Non-Specific Defense
• 4 Signs of Inflammatory Response:
• Redness – due to dilation of blood vessels
in area, bringing more clotting proteins/
oxygen/nutrients to the area
• Heat – due to dilation of blood vessels in
area, helps increase metabolic rate of cells
• Swelling – due to plasma (lymph) leaking
from blood stream into tissue spaces
• Pain – pain receptors activated by plasma
leaking
Non-Specific Defense
• All of the above symptoms are due to the
inflammatory chemicals (including
histamine and kinins) that are released
when cells are damaged
Non-Specific Defense
• Fever: response to invading
pathogens
• Hypothalamus will reset internal
temperature based on presence
of pyrogens (chemicals
secreted by WBC exposed to
foreign substances)
• Fever inhibits the release of iron
and zinc from liver and spleen
needed by bacteria
• Fever also increases the speed
of tissue repair, but if fever gets
too high, it can screw up
enzymes and proteins
Specific Defense
• Specific Defense
– Third line of defense
– AKA immune system
– Plans defense based on specific type of
pathogen/antigen (The antigen is a marker on
the pathogen!)
– Must first have an initial exposure before it
can protect the body against the pathogen
– Involves the Lymph Vessels/Nodes and
Lymphoid Organs (Tonsils, Thymus, Spleen,
and Peyer’s Patches)
Specific Defense
• 2 Types of Response: Humoral and CellMediated
Specific Defense
• 3 important aspects of immune
response:
• Antigen specific – recognizes and acts
against particular foreign substances
• Systemic – not restricted to the initial
infection site
• Has memory – recognizes and mounts a
stronger attack on previously encountered
pathogens
Specific Defense
• Antigens: any substance capable of exciting our
immune system and provoking an immune
response
• A foreign signal on the outside of a pathogen!
• Examples of common pathogens/antigens
– Foreign proteins (ex: blood typing)
– Pollen grains
– Microorganisms (bacteria, fungi, virus)
• Side Note: Our immune cells do not attack our
own proteins, but our cells in another person’s
body can trigger an immune response because
they are foreign (think: organ transplants, blood
donation)
Immune System Review
– Types of cells involved
• Lymphocytes (WBC): two types…
–B Cells: help with humoral defense,
produce antibodies
–T Cells: help with cell-mediated defense,
do not produce antibodies
Specific Defense
• Both types of lymphocytes originate from
red bone marrow
• What determines if it will be a B or T cell is
where in the body it becomes
immunocompetent (capable of responding
to a specific antigen)
– T Cells: lymphocytes migrating to thymus
– B Cells: lymphocytes develop in bone marrow
Specific Defense
• Our genes determine what specific foreign
substances our immune system will be
able to recognize and resist – they only
become “activated” once exposed to the
antigen
• FYI: Because of the structure of human DNA
(deoxyribonucleic acid; the genetic material
determining the makeup of all cells), humans are
not subject to certain diseases that dogs and
other animals are, and vice-versa. For example,
humans cannot contract distemper; however,
dogs and cats can. Conversely, humans can
suffer from measles; dogs and cats cannot. The
genetic makeup of human cells (and of animal
and plant cells, also) makes it impossible for
certain pathogens to infect and reproduce in
those cells.
Specific Defense
• After becoming immunocompetent, both T
and B cells migrate to the lymph nodes
and spleen, but can be found throughout
lymphatic vessels
Specific Defenses
• Macrophages:
• Arise from monocytes (WBC) formed in
the bone marrow
• Job is to engulf foreign particles (part of
non-specific defense) and present
fragments of these antigens on their
surface (so T Cells can recognize them
and become activated, helping out specific
defense!)
Humoral Defense
• Making the Antibodies
– B Cells with specific receptors bind to a
specific antigen
– …which causes the B Cell to undergo “clonal
selection” – a whole bunch of clones are
made!
Humoral Defense
– Most of the clones will
become “plasma cells”,
which are responsible
for producing specific
antibodies!
– A few of the clones will
become “memory
cells”, which will be
ready to bind with the
antigen if it should
come around again
Humoral Defense
• Antibodies
– Soluble proteins
secreted by B cells
(plasma cells)
– Carried in blood
plasma
– Usually has a T or Y
shape formed by
amino acid chains
– Capable of binding
specifically to an
antigen
Humoral Defense
• When
antibodies
attach to
antigens, it
can have
different
effects…
Humoral Defense
– Complement Fixation:
antibody will join with a
“complement protein”
on the invader; which
will allow holes on the
invader surface; will
result in cell lysis
(bursting of cell)
Humoral Defense
– Neutralization: surrounds antigen to
mask its effects
Humoral Defense
– Agglutination: clumping of antigens;
will allow macrophages to easily catch
and engulf invaders
Cell Mediated Defense
• Begins with macrophages destroying an antigen
• Macrophage will then put fragments of the
destroyed antigen on the outside
• T Cells will recognize the antigen being
presented by the macrophage and bind with the
antigen (Antigen Presentation)
• After binding, T Cell clones form, but different
classes of cells are produced
Cell Mediated Defense
• Cytotoxic T Cell:
“killer” cells,
specialize in killing
virus-infected, cancer,
and foreign cells,
often by inserting
toxic chemicals,
causing the pathogen
cell to “blow up”
Note: basically does
the same thing as a
Natural Killer Cell,
but does it to a
specific pathogen!
http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter24/animation__cytotoxic_tcell_activity_against_target_cells__quiz_2_.html
Cell Mediated Defense
• Helper T Cell:
“regulator/conductor”
cells, encourages
cloning of B cells,
stimulates Cytotoxic T
Cells to grow and
divide, enhances
eating capabilities of
macrophages
Cell Mediated Defense
• Supressor T Cell:
helps to stop
immune response
once an antigen has
been inactivated or
destroyed
• http://highered.mcgrawhill.com/sites/0072495855/student_view0/
chapter24/animation__the_immune_respo
nse.html
Viruses
• Not considered “living”
because has no cytoplasm
or organelles
• Needs a living host cell to
survive
• Will take over host cell to
replicate
• Virus infections cannot be
treated with antibiotics
• Some can be prevented
with vaccines
Viruses
• Common Cold
• Varicella - Chicken Pox – rarely fatal
• Variola – Smallpox – often fatal – but now
eliminated thanks to vaccinations!
• Influenza – MANY different strains!
• Human Papillomavirus – HPV – can lead
to warts, cervical cancer, and some other
genital cancers
• Rotavirus – leading cause of diarrhea
among infants and young children
Smallpox
Chicken Pox
Viruses
• Mumps – swelling of salivary glands, and
testicular swelling
• Measles – can lead to diarrhea, pneumonia,
encephalitis, and eye infections
• Rubella – rash
• Poliomyelitis – in less than 1% of polio cases,
virus enters the CNS, destroying motor neurons,
leading to muscle weakness and paralysis;
highly contagious
• Rabies – causes encephalitis; extremely fatal
• HIV
Measles
Mumps
Rubella
MMR Vaccination
protects against
all three!
Vaccination
• Administration of antigenic material to
produce immunity to a disease
• Can be live but weakened, dead, or
inactivated form of pathogen (virus or
bacteria)
• Pathogens are grown in culture and
killed/weakened, but surface proteins are
intact enough to be recognized
• When injected, immune system will evoke
a response
Bacteria
• Are considered a “living” prokaryotic cell
• Does not need a living host cell to survive
• Most (99%) are good, but a few are
harmful
– Good ones help us with digestion, releasing
vitamins, eliminating body toxins, preventing
fungal growth
Bacteria
• Harmful bacterial infections can be treated
with antibiotics
• Some can live harmlessly, but develop into
an infection if immune system has had its
resistance lowered (ex: AIDS)
• A few infections can be prevented with
vaccines
Bad Bacteria
• Tuberculosis – affects lungs
• Streptococcus – affects throat (pharynx,
larynx, tonsils)
• Botulism – weakens muscles, prevents
breathing
• Bubonic Plague – spread by fleas that live
on rats; damages lymph notes
• Cholera – affects small intestine, causes
diarrhea, vomiting, and rapid dehydration
Bad Bacteria
• Salmonella – can cause digestive issues
• Escherichia Coli – aka E.Coli – some
strains are good, but the bad strains can
cause lower digestive issues or UTIs
• Syphilis – STD that causes lesions; if left
untreated, it can cause issues with the
heart and brain
• Impetigo – skin infection
Bad Bacteria
• Diphtheria – causes upper respiratory
issues
• Pertussis – whooping cough
• Tetanus – causes muscle spasms
• These last three can be quite harmful
(even deadly) that we are given the DPT
vaccination
Antibiotics
• A substance or compound that kills or
inhibits growth of bacteria
• Can either be made synthetically from
chemicals or produced by fermenting
different fungus molds
• Unfortunately, bacteria can mutate to
become resistant to antibiotics
• EX: penicillin, amoxicillin, tetracycline,
sulfa drugs, cefzil
Fungus
• Are considered a “living” eukaryotic cell
• Includes molds and yeasts
• Some are good, such as fungi used to
make antibiotics (penicillin) or baker’s
yeast
• Infections can spread very easily!
Bad Fungi
•
•
•
•
Candida – Yeast Infection
Tinea Pedis – Athlete’s Foot
Tinea Cruris – Jock Itch
Tinea Unguium – Nail Fungus
Immune System Diseases
• Allergies
– Abnormally vigorous immune responses
– Different types…
Immune System Diseases Allergies
– Acute hypersensitivity
• Pathogen & resulting antibodies
cause release of histamine…
• Which causes small blood vessels
to become dilated and leaky
• Symptoms include runny nose,
watery eyes, itching, reddened skin
(hives), bronchial constriction
(asthma)
• Antihistamine drugs can reverse
effects
Immune System Diseases Allergies
– Anaphylactic Shock
• Allergen directly enters the blood and circulates
rapidly throughout the body
• Examples: Bee stings, spider bites, drug injections
• Dilated & leaky blood vessels throughout body can
be life-threatening
• The drug Epinephrine can reverse effects
Immune System Diseases
• Immunodeficiencies
– Production or function of immune cells is
abnormal
– May be congenital or acquired
– Examples include…
Immune System Diseases Immunodeficiencies
• Severe Combined
Immunodeficiency
Syndrome (SCIDS)
– Deficit of both B and T
cells
– Have no immune
response
– “Bubble Boy” Disease
– Some success with
bone marrow
transplants
For twelve years David Vetter, born with combined
immune deficiency, lived inside this plastic bubble at
Texas Children's Hospital in Houston, Texas, waiting for
a cure to the disease that kept him prisoner.
Immune System Diseases Immunodeficiencies
• Acquired Immune Deficiency Syndrome
(AIDS)
– The virus (Human Immunodeficiency Virus, or
HIV) destroys Helper T Cells & Macrophages
– Cell-mediated immunity is reduced
– Virus then begins to multiply in lymph nodes –
which takes longer in some than in others
Immune System Diseases Immunodeficiencies
– A patient is diagnosed with AIDS when the lymph
nodes are destroyed & symptoms begin
– Symptoms include severe weight loss, night sweats,
swollen lymph nodes, and increasingly frequent
infections (gastrointestinal, pneumonia)
– Some of the drugs that are used to help act by
inhibiting the enzymes the HIV virus needs in order to
multiply, or helps to boost number of Helper T Cells
– THERE IS NO CURE OR VACCINE.
Immune System Diseases Immunodeficiencies
• Facts:
– 33.2 million worldwide have AIDS; 2.5 million are
children under age 15
– 1.9 million died of AIDS in 2010; 330,000 were
children under age 15
– Sub-Sahara Africa contains 68% of the AIDS
population
– The median survival time after infection with HIV is
estimated to be 9 to 11 years, depending on the HIV
subtype
Immune System Diseases
• Autoimmune Diseases
– The immune system does not distinguish
between self and non-self
– The body produces antibodies and T Cells
that attack its own tissues
– Examples Include…
Immune System Diseases Autoimmune Diseases
– Multiple sclerosis: myelin sheaths in the white
matter of brain & spinal cord are destroyed
– Type 1 diabetes: destroys pancreatic beta
cells that produce insulin
– Rheumatoid arthritis: destroys joints
– Lupus: affects kidney, heart, lung and skin