Chapter 6: The Lymphatic and Immune Systems

- MED TERM

lacteals

specialized structures of the lymphatic system that absorb those fats that cannot be transported by the bloodstream.

interstitial fluid

Also known as intercellular or tissue fluid. This is plasma from arterial blood that flows out of the arterioles and into the capillaries, and then flows into the spaces between the cells of the tissues. This fluid delivers nutrients, oxygen, and hormones to the cells. 90% of this fluid returns to the bloodstream

lymph

The Remaining 10% of interstitial fluid. a clear, watery fluid containing electrolytes and proteins. It Enters very small capillaries within the tissues and then flows into progressively larger vessels and ducts

lymphatic circulatory system

Works closely with the blood circulatory system and is often referred to as the secondary circulatory system. It Depends on pumping motion of muscles to move fluid upward. It Flows in only one direction (upward to the circulatory system at the base of the neck). Vessels are not visible, since lymph is a clear fluid.

lymphatic capillaries

Microscopic, blind-ended tubes near the surface of the body with capillary walls that are only one cell in thickness.

lymphatic vessels

located deeper within the tissues, and have valves. Like veins, they prevent the backward flow of lymph.

right lymphatic duct

collects lymph from the right side of the head and neck, the upper right quadrant of the body, and the right arm. It empties into the right subclavian vein.

thoracic duct

it is the largest lymphatic vessel in the body, collects lymph from the left side of the head and neck, the upper left quadrant of the trunk, the left arm, the entire portion of the trunk, and both legs. It empties into the left subclavian vein.

lymph nodes

These are small, and bean-shaped and contain specialized lymphocytes that are capable of destroying pathogens.

cervical lymph nodes

located along the sides of the neck

axillary lymph nodes

located under the arms in the area known as the armpits.

inguinal lymph nodes

located in the inguinal (groin) area of the lower abdomen.

lymphocytes

also known as lymphoid cells, are leukocytes that are formed in bone marrow as stem cells. They work together with the body’s organs to defend the body against antigens.

antigen

any substance that the body regard as being foreign. This includes viruses, bacteria, toxins, and transplanted tissues.

natural killer cells

(NK cells) play an important role in the killing of cancer cells and cells infected by viruses.

B cells

also known as B lymphocytes, are specialized lymphocytes that produce antibodies. They are most effective against viruses and bacteria that are circulating in the blood.

plasma cells

develop from B cells and secrete a large volume of antibodies coded to destroy specific antigens.

T cells

also known as T lymphocytes, and have their origin in the thymus. These lymphocytes play a central role in cell-mediated immunity.

cytokines

a group of proteins such as interferons and interleukins released primarily by the T cells. They act as intracellular signals to begin the immune response.

interferons

(IFNs) are produced in response to the presence of antigens, particularly viruses or tumor cells. They activate the immune system, fight viruses by slowing or stopping their multiplication, and signal other cells to increase their defenses.

interleukins

play multiple roles in the immune system, including directing B and T cells to divide and proliferate.

tonsils

three masses of lymphoid tissue that form a protective ring around the back of the nose and upper throat. They play an important role in the immune system by preventing pathogens from entering the respiratory system when breathing through the nose and mouth.

adenoids

also known as the nasopharyngeal tonsils, are located in the nasopharynx, which is the upper part of the pharynx.

palatine tonsils

located on the left and right sides of the throat in the area that is visible at the back of the mouth.

lingual tonsils

located at the base of the tongue; however, they are not readily visible.

thymus

is a mass of lymphoid tissue located above the heart, reaches its greatest size at puberty and becomes smaller with age.

vermiform appendix

commonly referred to as the appendix, hangs from the lower portion of the cecum, which is the first section of the large intestine.

spleen

sac-like mass of lymphoid tissue located in the left upper quadrant of the abdomen, just inferior to (below) the diaphragm and posterior to (behind) the stomach.

hemolytic

function of destroying worn-out erythrocytes (red blood cells) and releasing their hemoglobin for reuse

Intact skin

wraps the body in a physical barrier to prevent invading organisms from entering the body.

respiratory system

traps breathed-in foreign matter with nose hairs and the moist mucous membrane lining of the respiratory system.

digestive system

uses the acids and enzymes produced by the stomach to destroy invaders that are swallowed or consumed with food.

lymphatic system

specialized leukocytes (white blood cells) work together in specific ways to attack and destroy pathogens that have succeeded in entering the body.

antigen-antibody reaction

also known as the immune reaction, involves binding antigens to antibodies. This reaction labels a potentially dangerous antigen so it can be recognized and destroyed by other cells of the immune system. The immune system immediately responds to the presence of any antigen

Tolerance

refers to an acquired unresponsiveness to a specific antigen. The term is also used to describe a decline in the effective response to a drug, usually due to repeated use.

antibody

is a disease-fighting protein created by the immune system in response to the presence of a specific antigen

Immunoglobulins

bind with specific antigens in the antigen-antibody response. The five primary types of immunoglobulins, which are secreted by plasma cells, are also known as antibodies

Phagocytes

are specialized leukocytes that act as part of the antigen-antibody reaction by destroying substances such as cell debris, dust, pollen, and pathogens by the process of phagocytosis

Monocytes

are leukocytes that provide immunological defenses against many infectious organisms. When they leave the bloodstream and enter into the tissue, they become macrophages and dendritic cells.

macrophage

is a type of leukocyte that surrounds and kills invading cells. They also remove dead cells and stimulate the action of other immune cells.

Dendritic cells

are specialized leukocytes that patrol the body searching for antigens that produce infections. When such a cell is found, the___ cell grabs it, swallows it, and alerts B and T cells to act against this specific antigen.

complement system

is a group of proteins that normally circulate in the blood in an inactive form. When needed, these cells complement the ability of antibodies to ward off pathogens by combining with them to dissolve and remove pathogenic bacteria and other foreign cells.

Immunity

the state of being resistant to a specific disease. This resistance can be present naturally, or it can be acquired.

Natural immunity

known as passive immunity, is resistance to a disease present without the administration of an antigen or exposure to a disease. is present at birth, and can be augmented when breast milk passes from a nursing mother to her baby.

Acquired immunity

is obtained by having had a contagious disease. Being vaccinated against a contagious disease provides protection against that disease, such as measles or polio, without having been exposed to the risk of actually having the disease.

allergist

specializes in diagnosing and treating conditions of altered immunologic reactivity, such as allergic reactions.

infectious disease specialist

a physician who specializes in diagnosing and treating diseases caused by microorganisms such as viruses, bacteria, and parasites.

immunologist

specializes in diagnosing and treating disorders of the immune system

lymphologist

is a physician who specializes in diagnosing and treating disorders of the lymphatic system

oncologist

is a physician who specializes in diagnosing and treating malignant disorders such as tumors and cancer

Lymphadenitis

commonly known as swollen glands, is an inflammation of the lymph nodes

Lymphadenopathy

is any disease process affecting a lymph node or nodes

lymphangioma

is a benign tumor formed by an abnormal collection of lymphatic vessels due to a congenital malformation of the