IMMUNE AND LYMPHATIC SYSTEM

Naya, Shannon, Alina, Jowell’la, Jordanna, Satin, Kelsey, and Kenysia

Functions of Lymphatic System

• Responsible for returning tissue fluid to the blood and for protecting the body against foreign material

• Drains fluid from around cells• Absorbs fat from intestines• Circulates and Filters lymph• Immunity

Lymphatic Vessels• Structures of the lymphatic system that

transport fluid away from tissues• The vessels transport a clear fluid called lymph• Lymph is returned to the circulatory system at

either the right or left subclavian veins.

Lymphatic Ducts

• Large vessels that drain the lymph into the blood in veins (subclavian) in the neck area

Lymphatic Nodes

• Clusters of small encapsulated masses of lymphatic tissue located at strategic spots in the lymph system.

• Size of a pin head or lima bean • Lymph enters the node through afferent

vessels and leaves through a single efferent vessel.

• Function: filter

Lymphatic Glands/ Structures

• Thymus – Located inferiorly to the thyroid gland in the mediastinum.

Produces T-lymphocytes (T-cells) and secretes thymosin and other hormones

• Spleen – Largest lymphoid organ in the body located in the upper

left quadrant of the abdomen, lateral to the stomach, just below the diaphragm

• Tonsils – Located in the pharynx form a protective ring under the

mucous membranes in the mouth and back of throat.

Lymph• A clear fluid that comes from blood plasma

that exits blood vessels at capillary beds.

White Blood Cells • also called leukocytes, they are essential for good

health and protection against illness and disease• account for only about 1 percent of your blood• they flow through your bloodstream to battle

viruses, bacteria, and other foreign invaders that threaten your health.

Lymphocytes

• The most numerous cells of the immune system responsible for antibody production

• Type of white blood cell • B Lymphocytes (B cells)– Some lymphocytes remain in the bone marrow, where in

humans they develop into B cells.• T Lymphocytes (T cells) – Some lymphocytes move to the thymus, where they mature

into T cells

Antibodies/Antigens

• Antigens – Chemical markers that identify cells – Each cells has its own set of markers

• Antibodies– Proteins produced by plasma cells in response to

foreign antigens; each one is specific for a certain antigen

Cytokines • cell signaling molecules that aid cell to cell

communication in immune responses and stimulate the movement of cells towards sites of inflammation, infection and trauma.

• Examples include the agents interleukin and the interferon

Phagocytosis• Neutrophils, monocytes, and macrophages,

derived from none marrow, carry out ingestion and digestion of foreign cells or particles

• Monocytes develop into macrophages • Macrophages-some wander and some are

fixed

Adaptive Immunity• called into action against pathogens

that are able to evade or overcome innate immune defenses

• components “adapt” to the presence of infectious agents by activating, proliferating, and creating potent mechanisms for neutralizing or eliminating the microbes.

Acquired Immunity • When the immune system encounters foreign substances (antigens),

the components of acquired immunity learn the best way to attack each antigen and begin to develop a memory for that antigen.

Specific and Nonspecific responses

• Specific– innate immunity– the human body protects itself against foreign

material that is perceived to be harmful• Nonspecific – a complement to the function of phagocytes and

other elements of the innate immune system– allows for a targeted response against a specific

pathogen

Structure of Epithelium & Connective Tissue

• Epithelium– 1) It protects us from the outside world - skin– 2) Absorbs – stomach and intestinal lining (gut)– 3) Filters – the kidney– 4) Secretes – forms glands

• Connective– 1) Wraps around and cushions and protects organs– 2) Stores nutrients– 3) Internal support for organs– 4) As tendon and ligaments protects joints and attached muscles to

bone and each other– 5) Runs through organ capsules and in deep layers of skin giving

strength

How the body responds to invasion of bacteria and viruses

• Fixed plasma cells produce antibodies in response to foreign material and these antibodies then circulate in the blood stream.

How the body responds to transplants

• the immune system recognizes it as foreign material and therefore attempts to attack and destroy it.

• immunosuppressive drugs must be administered to prevent the body from attacking it, in an attempt to introduce tolerance of the transplanted organ.

Autoimmune Disease

• An autoimmune disease develops when your immune system decides your healthy cells are foreign.

• As a result, your immune system attacks healthy body cells.

• Depending on the type, an autoimmune disease can affect one or many different types of body tissue.

• It can also cause abnormal organ growth and changes in organ function.