Practical 2, Lymphatic System

infectious agents

One of the main functions of the lymphatic system is to help the immune system defend the body against ________

lymphocytes and other immune cells

One of the main functions of the lymphatic system is to transport and house _____________________

return; fluid balance

One of the main functions of the lymphatic system is to _____ excess fluid to blood to maintain _______________

Lymphocytes

are produced and stored in lymphoid tissues and lymphoid organs.

Lymphocytes

They are also produced in red bone marrow.

Lymphocytes

They circulate in the blood, enter the interstitial fluid through capillar-ies, and return to the bloodstream through lymphatic vessels.

Macrophages, microphages

The circulation of fluids from blood plasma to lymph and back to the venous system also transports other immune system cells (such as ___________ and ___________) as well as hormones, nutrients, and waste products.

T-Lymphocytes

(T cells)

T-Lymphocytes

Make up approximately 80% of circulating lymphocytes.

T-Lymphocytes

Matures in the thymus; responsible for attacking and destroying foreign cells (direct cellular immunity).

Helper T Cells

Special type of T cell that stimulates the functions of both T cells and B cells.

B-Lymphocytes

(B cells)

B-Lymphocytes

Make up approximately 10-15% of circulating lymphocytes.

B-Lymphocytes

Produced in the bone marrow

B-Lymphocytes

differentiate into plasma cells after exposure to specific antigens.

Plasma Cells

Produce antibodies which target specific antigens (antibody-mediated immunity, “humoral immunity”)

Natural Killer Cells

Make up/5-10% of circulating lymphocytes.

Natural Killer Cells

NK cells are responsible for immunologiçal surveillance and attacking foreign cells, virus-infected cells, and cancer cells.

Macrophages

Phagocytizes bacteria and helps activate T cells.

Reticular Cells

Forms the stroma in most lymph organs.

Stroma

structural network that supports other immune cells (in reticular cells)

Dendritic Cells

Binds to antigens and presents them to other immune cells.

Dendritic Cells

in skin and mucous membranes

titer (titre)

how much antibodies you have

Three main parts of lymphatic system

lymph, lymphatic vessels (lymphatics), and lymphoid tissues and organs

Lymph

A fluid similar to plasma, but without the plasma proteins.

Lymphatic vessels (lymphatics)

The network that carries lymph from peripheral tissues to the venous system.

Lymphoid tissues and lymphoid organs

Found throughout the body.

Lymphatic vessels begin at the lymphatic capillaries, which are positioned near the cardiovascular capill-laries.

Lymphatic capillaries

drain excess interstitial fluid from the tissue and pass them on to the larger lymphatic collecting vessels. Have an endothelium surrounded by smooth muscle.

Lymphatic collecting vessels

are similar in structure to the blood vessels reviewed earlier. Have an endothelium surrounded by smooth muscle.

lymphatic collecting vessels

Similar to the medium-sized veins, _____________________ also have valves that assist in the propulsion of fluid through the vessels.

subclavian veins

Several lymphatic collecting vessels join to form the larger lymphatic trunks before forming two large ducts that return the lymph to the cardiovascular system at the junction of the internal jugular and _______________ on each side of the body.

Lymphatic Trunks

jugular, subclavian, bronchomediastinal, intestinal, lumbar, and cisterna chyli

Jugular Trunks

Head and neck.

Subclavian Trunks

Upper limbs.

Bronchomediastinal Trunks

Thoracic cavity.

Intestinal Trunks

Abdominal cavity, intestines

Lumbar Trunks

Lower limbs.

Cisterna Chyli

Lumbar trunks and intestinal trunk; begins the thoracic duct.

Lymphatic Ducts

Right & Thoracic

Right Lymphatic Duct

Right side of the head and neck, right upper limb, and right thoracic cavity.

Thoracic Duct

Left side of the head and neck, left upper limb, left thoracic cavity, abdominal and pelvic cavities, and lower limbs.

Lymph nodes

the principal lymphoid organs of the body

Lymph nodes

found embedded in connective tissue, in clusters along lymphatic vessels near the bodies surfaces

Inguinal, axillary, cervical

lymph nodes are found near the surface in what areas

Capsule

Outer connective tissue covering.

Trabeculae

Bundles of connective tissue extending from the capsule inward.

Afferent Lymphatic Vessel

Carries lymph from the peripheral tissues into the lymph node.

Cortex

Outer region of the lymph node, divided into two regions

Medulla

Inner region; contains B cells and plasma cells organized into medullary cords.

Medullary Cords

Organized groups of cells extending inward from the cortex; contains B cells, T cells, and plasma cells.

Sinuses

Drains the afferent lymphatic vessels; contains macrophages.

Efferent Lymphatic Vessel

Carries lymph away from the sinuses and into larger lymphatic collecting vessels.

Hilum

Location where the efferent lymphatic vessel exits.

Spleen

The ______ contains the largest collection of lymphoid tissue.

Spleen

It lies along the lateral curvature of the stomach and is attached to the lateral border of the stomach by the gastrosplenic ligament.

Removal

one function of the spleen: ______ of abnormal blood cells and other blood components

iron

one function of the spleen: Storage of _______ from recycled RBCs

B cells and T cells

one function of the spleen initiation of immune responses by ____________ responding to antigens in the blood

Capsule

outer connective tissue covering of the spleen

White Pulp

Located around the central arteries. Dominated by lymphocytes on reticular fibers and involved in immune functions.

Central Artery

Supplies the blood for the white and red pulp.

Red Pulp

Rich in macrophages for disposal of worn-out RBCs and blood-borne pathogens.

thymus

lies posterior to the sternum in the anterior mediastinum.

Thymus

It reaches maximum size in the first year after birth, and then it gradually decreases in size.

Thymus

By adulthood, it has atrophied into a fatty organ with a reduced role in immune system function.

Thymus

differs from other lymphoid organs in that it functions strictly in T lymphocyte maturation and it does not directly fight antigens.

Cortex

Outer region of the thymic lobules. Lymphocytes in the cortex are surrounded by reticular epithelial cells, which release hormones that cause the lymphocytes to divide. Lymphocytes differentiate into I cells that migrate into the medulla.

Medulla

Inner region of the thymic lobules. Mature T cells leave the thymus through medullary blood vessels.

Hassall's Corpuscle

Concentric layers of reticular epithelial cells found in the medulla. Function is unknown.

Mucosa-associated lymphatic tissue

MALT aka ___________

MALT

can be found in the gastrointestinal, respiratory, genital, and urinary tracts.

MALT

It is located in lamina propria of the mucosa and helps defend the body against foreign substances in those locations.

Tonsils

are large nodules of lymphatic tissue located in the walls of the pharynx.

a pharyngeal tonsil (adenoids), a pair of palatine tonsils, and a pair of lingual tonsils

Most people have five tonsils, _______

Peyer's patches

are clusters of lymphoid nodules found in the submucosa of the ileum, the last part of the small intestine (ileum).

Peyer's patches

collectively protect against potential pathogens that might enter the body through the intestinal mucosa.

vermiform appendix

is a diverticulum branching from the first part of the large intestine that contains lymph aggregations of lymph tissue in its walls.

vermiform appendix

It protects against potential pathogens that may enter the body through the cecum.

Human Immunodeficiency Virus (HIV)

Disease that targets the helper T cells.

Human Immunodeficiency Virus (HIV)

With progression to acquired immune deficiency syndrome (AIDS), the lack of helper T cells suppresses the immune system and compromises an individual's ability to fight off secondary infections.

Lymphadenopathy

Enlargement or swelling of the lymph nodes caused by a number of diseases.

Edema (lymphedema)

Blockage of normal lymph drainage leading to swelling associated with the accumulation of fluid.

Edema (lymphedema)

Can be temporarily caused by tight fitting clothing or sleeping incorrectly.

Filariasis

Edema (lymphedema) can also be _________, a disease caused by a parasitic roundworm belonging to the family filaride.

Elephantiasis

Extreme tissue swelling of the limbs and genitalia caused by these parasitic roundworms (filariasis) worms is called _______.

Autoimmune disease

Malfunction in the immune system where an autoimmune response is triggered and the immune system begins to create antibodies against the body's own tissue.

Buboes

Swelling of the lymph nodes in response to infections such as bubonic plague, gonorrhea, tuberculosis, or syphilis.

Tonsillitis

Inflammation of the tonsils caused by either viral or bacterial infection. If the condition becomes chronic, a tonsillectomy can be performed to remove the tonsils completely or partially.

Rheumatoid arthritis, Lupus, Multiple Sclerosis, Vitiligo, Type 1 diabetes mellitus, and scleroderma

types of autoimmune diseases