Download Lymphatic System and Immunity

Idalis Laboy
Alec Wilkins
The Lymphatic System
 The lymphatic system, like the cardiovascular system,
includes a network of vessels that transport fluids.
The Lymphatic System has two jobs:
1. To carry away excess fluids from interstitial
spaces in tissues and to return it to the blood stream.
2. To protect the body against pathogens or viruses.
Lymphatic Pathways
Lymph Capillaries
Are closed ended
tubes that begin in
the interstitial
spaces of most
tissues. The walls of
lymphatic
capillaries make it
possible for tissue
fluid to enter
lymphatic
capillaries.
The fluid inside
lymphatic
capillaries is called
lymph.
Lymphatic Pathways
 Lymphatic vessels: these vessels are similar to
veins but are much thinner in size. These
eventually lead to Lymph Nodes and after will
sometimes leave to flow into larger Lymph Trunks.
 Lymphatic Nodes: The larger lymphatic vessels lead
to specialized organs called lymph nodes.
 Lymphatic trunks: drain lymph, are named for the
regions they serve. They join one of two collecting
ducts, the thoracic duct or the right lymphatic duct.
 http://www.youtube.com/watch?v=Kh-XdNnTZUo
Tissue Fluid Formation
 Tissue fluid originates from blood plasma and is composed
of water and dissolved substances that leave blood
capillaries.
 Capillary blood pressure causes filtration of water and
small molecules from the plasma.
Lymph Formation and Function
• Filtration
from the plasma normally exceeds re absorption,
leading to the net formation of tissue fluid.
• This increases the interstitial fluid hydrostatic pressure
somewhat, favoring movement of tissue fluid into lymphatic
capillaries, forming lymph.
• Lymph returns to the bloodstream most of the small proteins
that leak out of the blood capillaries.
•At the same time, lymph transports foreign particles, such as
bacteria or viruses, to lymph nodes.
Lymph Nodes and Locations
Lymph Nodes are distributed
all throughout the body and
are made up of many different
chambers.
Lymph Nodes
 Two primary functions:
1. Filtering potentially harmful particles from
lymph before returning it to the bloodstream.
2. Immune surveillance, provided by lymphocytes
ad macrophanges.
 Lymphocytes attack invading viruses, bacteria,
and other parasitic cells that lymphatic vessels
bring to the nodes.
 Macrophanges in the nodes engulf and destroy
foreign substances, damaged cells, and cellular
debris.
Major Organs involved
Thymus
Spleen
 The thymus secretes
the hormone
 The spleen is the
largest lymphatic
thymosin, which
influences the
maturation of T cells
once they leave the
thymus and provide
immunity.
organ.
 It filters the blood and
removes damage blood
cells and bacteria.
Protection through the Lymphatic
System
 One of the man functions of the lymphatic system
is to defend against pathogens. This is done
through innate defenses such as species
resistance, mechanical resistance, chemical
barriers, fever, inflammation and phagocytosis and
adaptive defenses such as antigens, lymphocytes, T
cells, B cells and antibodies.
Innate Defenses
 Species resistance is when organisms or species
develop a set of diseases that is unique to it.
 Mechanical Barriers are skin an mucus membranes
that line passages. These barriers prevent infectious
agents from entering the body. They are the first line
of defense.
 Chemical Barriers are enzymes and body fluid that
fights and locates infectious agents in the body.
 Fever is an elevated body temperature that lowers iron
throughout the body. The essentially starves bacteria.
Innate Defenses Cont.
 Inflammation is a tissue response to injury or
infection. The swelling and heating of the site allows
infection to be walled into a specific area.
 Phagocytosis is the process of removing foreign
particles through lymph as it passes through the blood
stream.
Adaptive Defenses, or Immunity
 The body’s third line of defense, immunity refers to
the response mounted by the body against specific,
recognized foreign molecules.
 Antigens: A chemical that stimulates B lymphocytes to
produce antibodies
 Lymphocytes: A type of white blood cell that provides
immunity.
1. T Cells: Lymphocyte that interacts directly with
antigens and produces cellular immunity response.
2. B Cells: Lymphocyte that secrets antibodies that
bind and destroy foreign substances.
T and B cells
activation
Types of Antibodies
 Immunoglobulin G: defends against bacterial cells, viruses, and
toxins and activates complement.
 Immunoglobulin A: defends against bacteria and viruses.
 Immunoglobulin M: activates complement and reacts with blood
cells during transfusions.
 Immunoglobulin E: is found in exocrine gland secretions and
promotes allergic reactions.
 Immunoglobulin D: is found on the surface of most B
lymphocytes and functions in B cell activation.
Immune Responses
 Primary immune response: When B or T cells become
activated the first time, after which some cells remain
as memory cells.
 Secondary immune response: If the same antigen is
encountered again, numerous memory cells can
mount a more rapid response.
Types of Immunity
 Active Immunity: Results when a person produces an
immune response. This is long lasting
 Passive Immunity: When a person receives antibodies
produced by another individual. This is short term.
 Naturally Acquired Immunity: When a person exposed
to a pathogen develops a disease.
 Artificially Acquired Immunity: When a person
receives a vaccine which is a bacteria is weakened or
killed, and produces mild symptoms but still a primary
immune response.
Immune System Errors
Allergic Reactions
Tissue Rejection
 An allergic response is
an immune attack
 When one person
receives an organ from
against a non-harmful
substance. This is
really an overreaction
to a foreign substance
that may cause tissue
damage.
another individual, the
immune system may
recognize the donor’s
organ as a foreign
substance and attempt
to destroy it.
Autoimmunity
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Auto antibodies
Autoimmunity T cells that attack and damage the
body’s tissues and organs.
In autoimmune disorders, the immune system
manufactures antibodies against some of its own
antigens.
Autoimmune disorders may result from viral
infection, faulty T cell development, or reaction to a
non self antigen that bears close resemblance to a
self antigen.
Diseases
 Lymphedema is a chronic swelling of the limbs
caused by the accumulation of lymph fluid that occurs
if the lymphatic system is damaged or not functioning
properly. While the limbs are typically involved, the
face, neck and abdomen may also be affected.
 HIV infection gradually shuts down the immune
system.
 Elephantiasis is a rare disorder of the lymphatic
system. This is when there is an abnormal
accumulation of watery fluid in tissues, causing severe
swelling.