Lymphatic System
Pass
The lymphatic system is a network of tissues, vessels and organs that work together to move a
colourless, watery fluid called lymph back into your circulatory system (your bloodstream).
lymphatic system has many functions. Its key functions include:
● Maintains fluid levels in your body: As just described, the lymphatic system collects excess
fluid that drains from cells and tissue throughout your body and returns it to your
bloodstream, which is then recirculated through your body.
● Absorbs fats from the digestive tract: Lymph includes fluids from your intestines that
contain fats and proteins and transports it back to your bloodstream.
● Protects your body against foreign invaders: The lymphatic system is part of the immune
system. It produces and releases lymphocytes (white blood cells) and other immune cells
that monitor and then destroy the foreign invaders — such as bacteria, viruses, parasites
and fungi — that may enter your body.
● Transports and removes waste products and abnormal cells from the lymph.
Structure of lymphatic system
● Lymph: Lymph, also called lymphatic fluid, is a collection of the extra fluid that drains from
cells and tissues (that is not reabsorbed into the capillaries) plus other substances. The other
substances include proteins, minerals, fats, nutrients, damaged cells, cancer cells and foreign
invaders (bacteria, viruses, etc). Lymph also transports infection-fighting white blood cells
(lymphocytes).
,● Lymph nodes: Lymph nodes are bean-shaped glands that monitor and cleanse the lymph as
it filters through them. The nodes filter out the damaged cells and cancer cells. These lymph
nodes also produce and store lymphocytes and other immune system cells that attack and
destroy bacteria and other harmful substances in the fluid. You have about 600 lymph nodes
scattered throughout your body. Some exist as a single node; others are closely connected
groups called chains. A few of the more familiar locations of lymph nodes are in your armpit,
groin and neck. Lymph nodes are connected to others by the lymphatic vessels.·
● Lymphatic vessels: Lymphatic vessels are the network of capillaries (microvessels) and a
large network of tubes located throughout your body that transport lymph away from
tissues. Lymphatic vessels collect and filter lymph (at the nodes) as it continues to move
toward larger vessels called collecting ducts. These vessels operate very much like your veins
do: They work under very low pressure, have a series of valves in them to keep the fluid
moving in one direction.
● Collecting ducts: Lymphatic vessels empty the lymph into the right lymphatic duct and left
lymphatic duct (also called the thoracic duct). These ducts connect to the subclavian vein,
which returns lymph to your bloodstream. The subclavian vein runs below your collarbone.
Returning lymph to the bloodstream helps to maintain normal blood volume and pressure. It
also prevents the excess buildup of fluid around the tissues (called edema).
● Spleen: This largest lymphatic organ is located on your left side under your ribs and above
your stomach. The spleen filters and stores blood and produces white blood cells that fight
infection or disease.
● Thymus: This organ is located in the upper chest beneath the breast bone. It matures a
specific type of white blood cell that fights off foreign organisms.
,● Tonsils and adenoid: These lymphoid organs trap pathogens from the food you eat and the
air you breathe. They are your body’s first line of defense against foreign invaders.
● Bone marrow: This is the soft, spongy tissue in the center of certain bones, such as the hip
bone and breastbone. White blood cells, red blood cells, and platelets are made in the bone
marrow.
● Peyer’s patches: These are small masses of lymphatic tissue in the mucous membrane that
lines your small intestine. These lymphoid cells monitor and destroy bacteria in the
intestines.
● Appendix: Your appendix contains lymphoid tissue that can destroy bacteria before it
breaches the intestine wall during absorption. Scientists also believe the appendix plays a
role in housing “good bacteria” and repopulating our gut with good bacteria after an
infection has cleared.
, Lymph Nodes
Lymph nodes are small bean-shaped structures that are usually less than 2.5 cm in length. They are
widely distributed throughout the body along the lymphatic pathways where they filter the lymph
before it is returned to the blood. Lymph nodes are not present in the central nervous system. There
are three superficial regions on each side of the body where lymph nodes tend to cluster. These
areas are the inguinal nodes in the groin, the axillary nodes in the armpit, and the cervical nodes in
the neck.
The typical lymph node is surrounded by a connective tissue capsule and divided into compartments
called lymph nodules. The lymph nodules are dense masses of lymphocytes and macrophages and
are separated by spaces called lymph sinuses. The afferent lymphatics enter the node at different
parts of its periphery, which carry lymph into the node; entering the node on the convex side. The
Pass
The lymphatic system is a network of tissues, vessels and organs that work together to move a
colourless, watery fluid called lymph back into your circulatory system (your bloodstream).
lymphatic system has many functions. Its key functions include:
● Maintains fluid levels in your body: As just described, the lymphatic system collects excess
fluid that drains from cells and tissue throughout your body and returns it to your
bloodstream, which is then recirculated through your body.
● Absorbs fats from the digestive tract: Lymph includes fluids from your intestines that
contain fats and proteins and transports it back to your bloodstream.
● Protects your body against foreign invaders: The lymphatic system is part of the immune
system. It produces and releases lymphocytes (white blood cells) and other immune cells
that monitor and then destroy the foreign invaders — such as bacteria, viruses, parasites
and fungi — that may enter your body.
● Transports and removes waste products and abnormal cells from the lymph.
Structure of lymphatic system
● Lymph: Lymph, also called lymphatic fluid, is a collection of the extra fluid that drains from
cells and tissues (that is not reabsorbed into the capillaries) plus other substances. The other
substances include proteins, minerals, fats, nutrients, damaged cells, cancer cells and foreign
invaders (bacteria, viruses, etc). Lymph also transports infection-fighting white blood cells
(lymphocytes).
,● Lymph nodes: Lymph nodes are bean-shaped glands that monitor and cleanse the lymph as
it filters through them. The nodes filter out the damaged cells and cancer cells. These lymph
nodes also produce and store lymphocytes and other immune system cells that attack and
destroy bacteria and other harmful substances in the fluid. You have about 600 lymph nodes
scattered throughout your body. Some exist as a single node; others are closely connected
groups called chains. A few of the more familiar locations of lymph nodes are in your armpit,
groin and neck. Lymph nodes are connected to others by the lymphatic vessels.·
● Lymphatic vessels: Lymphatic vessels are the network of capillaries (microvessels) and a
large network of tubes located throughout your body that transport lymph away from
tissues. Lymphatic vessels collect and filter lymph (at the nodes) as it continues to move
toward larger vessels called collecting ducts. These vessels operate very much like your veins
do: They work under very low pressure, have a series of valves in them to keep the fluid
moving in one direction.
● Collecting ducts: Lymphatic vessels empty the lymph into the right lymphatic duct and left
lymphatic duct (also called the thoracic duct). These ducts connect to the subclavian vein,
which returns lymph to your bloodstream. The subclavian vein runs below your collarbone.
Returning lymph to the bloodstream helps to maintain normal blood volume and pressure. It
also prevents the excess buildup of fluid around the tissues (called edema).
● Spleen: This largest lymphatic organ is located on your left side under your ribs and above
your stomach. The spleen filters and stores blood and produces white blood cells that fight
infection or disease.
● Thymus: This organ is located in the upper chest beneath the breast bone. It matures a
specific type of white blood cell that fights off foreign organisms.
,● Tonsils and adenoid: These lymphoid organs trap pathogens from the food you eat and the
air you breathe. They are your body’s first line of defense against foreign invaders.
● Bone marrow: This is the soft, spongy tissue in the center of certain bones, such as the hip
bone and breastbone. White blood cells, red blood cells, and platelets are made in the bone
marrow.
● Peyer’s patches: These are small masses of lymphatic tissue in the mucous membrane that
lines your small intestine. These lymphoid cells monitor and destroy bacteria in the
intestines.
● Appendix: Your appendix contains lymphoid tissue that can destroy bacteria before it
breaches the intestine wall during absorption. Scientists also believe the appendix plays a
role in housing “good bacteria” and repopulating our gut with good bacteria after an
infection has cleared.
, Lymph Nodes
Lymph nodes are small bean-shaped structures that are usually less than 2.5 cm in length. They are
widely distributed throughout the body along the lymphatic pathways where they filter the lymph
before it is returned to the blood. Lymph nodes are not present in the central nervous system. There
are three superficial regions on each side of the body where lymph nodes tend to cluster. These
areas are the inguinal nodes in the groin, the axillary nodes in the armpit, and the cervical nodes in
the neck.
The typical lymph node is surrounded by a connective tissue capsule and divided into compartments
called lymph nodules. The lymph nodules are dense masses of lymphocytes and macrophages and
are separated by spaces called lymph sinuses. The afferent lymphatics enter the node at different
parts of its periphery, which carry lymph into the node; entering the node on the convex side. The
