lymphatic

63問 • 2年前

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-fluid that enters lymphatic capillaries composed of water and some solutes -clear or yellowish fluid derived from interstitial fluid and found in lymphatic vessels

lymph

-carries fluid in one direction from tissues to the circulatory system -Fluid moves from blood capillaries into tissue spaces.

Lymphatic System

Drains the lymph from the right arm and the right side of the head and thorax. Empties into the right subclavian vein

Right lymphatic duct

Receives lymph from the rest of the body. Empties into the left subclavian vein

Left Thoracic Duct

-form a protective ring of lymphatic tissue around -the openings between the nasal and oral cavities and the pharynx. -protect against pathogens and other potentially harmful material entering from the nose and mouth -Three groups are palatine, pharyngeal and lingual tonsils

1.Tonsils

located on each side of the posterior opening of the oral cavity the ones usually referred to as “the tonsils.” sometimes become chronically infected and must be removed.

palatine tonsils

located near the internal opening of the nasal cavity. when enlarged, it is commonly called the adenoid or adenoids. an enlarged pharyngeal tonsil can interfere with normal breathing sometimes become chronically infected and must be removed

pharyngeal tonsils

-on the posterior surface of the tongue -becomes infected less often than the other tonsils and is more difficult to remove.

lingual tonsils

-rounded structures, varying from the size of a small seed to that of a shelled almond -located along the various lymphatic vessels -filter lymph

2.Lymph nodes

conducts lymph into a lymph node

Afferent lymph vessel

conducts lymph out of each node

Efferent lymph vessel

dense aggregation or masses of lymphatic tissue; contain germinal centers

Lymphatic nodules

composed of rapidly dividing lymphocytes; sites of lymphocyte production.

Germinal centers

spaces through which lymph circulates; surround each lymph node

Lymphatic sinuses

functions as the outer boundary and support structure for each lymph node

Capsule

Extensions of the capsule; subdivide a lymph node into compartments containing lymphatic tissue and lymphatic sinuses

Trabeculae

-roughly the size of a clenched fist -located in the left, superior corner of the abdominal cavity -filters blood instead of lymph -most important function is to destroy worn- out RBC’s and return some of their breakdown products to the liver. -graveyard of RBC’s and blood reservoir -has an outer capsule of dense connective tissue and a small amount of smooth muscle.

spleen

lymphatic tissue surrounding the arteries within the spleen.

White pulp

associated with the veins; consists of a fibrous network, filled with macrophages and red blood cells, and enlarged capillaries that connect to the veins.

Red pulp

o a bilobed gland roughly triangular in shape o located in the superior mediastinum, the partition dividing the thoracic cavity into left and right parts. o stops growing at age 1 o decreases in size at age 60 o the site for the maturation of a class of lymphocytes called T cells o thymus tissue is mostly replaced with adipose tissue as we age

4.Thymus

the ability to resist damage from pathogens, such as microorganisms; harmful chemicals, such as toxins released by microorganisms; and internal threats, such as cancer cells.

Immunity

o destroy ALL types of substances that are foreign to it. o also known as nonspecific resistance o present at birth o accomplished by physical barriers, chemical mediators, white blood cells, and the inflammatory response

Innate Immunity

chemicals on the surface of cells that destroy pathogens or prevent their entry into the cells

Chemical Mediators

in tears and saliva kills certain bacteria

Lysozyme

on the mucous membranes prevents the entry of some pathogens

Mucus

promotes inflammation by causing vasodilation

Histamine

are proteins that promote inflammation and phagocytosis and can directly lyse (rupture) bacterial cells once activated

Complement

are proteins that protect the body against viral infections by stimulating those neighboring cells to produce antiviral proteins; prevent the replication of viruses.

Interferons

o Ingest and destroy microorganisms or their parts, foreign substances, or dead cells from the body. o The most important phagocytes are neutrophils and macrophages, although other white blood cells also have limited phagocytic ability.

Phagocytic cells

usually the first cells to enter infected tissues from the blood in large numbers; often die after phagocytizing a single microorganism.

Neutrophils

-derived from red bone marrow -motile WBC that can leave the blood and enter infected tissues can release histamine

Basophils

-derived from red bone marrow -found in skin, lungs, gastrointestinal tract, and urogenital tract

Mast cells

Also participate in inflammation associated with allergies and asthma

eosinophils

o involves release of chemicals and cells due to injury stimulates release of chemical mediators o Effects of Chemical Mediators

Inflammatory Response

an inflammatory response confined to a specific area of the body; produces redness, heat, swelling, pain, and loss of function.

Local inflammation

an inflammatory response generally distributed throughout the body, symptoms include an increase in neutrophil numbers, fever, and shock.

Systemic inflammation:

o supplements Innate immunity o absent @ birth o also known as specific immunity / acquired immunity

Adaptive Immunity

the ability of adaptive immunity to recognize a particular substance

Specificity

the ability of adaptive immunity to “remember” previous encounters with a particular substance.

Memory

-involves a group of lymphocytes called B cells and proteins called antibodies, which are found in the plasma. -Antibodies are produced by plasma cells, which are derived from the B cells

Antibody-mediated immunity

involves the actions of a second type of lymphocyte, called T cells.

Cell-mediated immunity

substances that stimulate adaptive immune responses e.g. bacteria, virus, pollen, food, drugs, etc.

Antigens

molecules produced by the person’s body that stimulate an immune system response

Self-antigens

-proteins produced by the body in response to antigenic stimulation -sometimes called gamma globulins, because they are found mostly in the gamma globulin part of plasma, or immunoglobulins (Ig), because they are globulin proteins involved in immunity

Antibody

cells that are responsible for immune responses.

Lymphocytes

differentiate & mature in Thymus gland. They are responsible for cell-mediated immunity.

1. T lymphocytes/T-cells

differentiate & mature in red Bone marrow. They are responsible for humoral immunity.

2. B lymphocytes/ B-cells

proteins or peptides secreted by one cell as a regulator of neighboring cells.

Cytokines

Y-shaped molecules consisting of four polypeptide chains: two identical heavy chains and two identical light chains

Antibody Structure

-V of Y -the end of each “arm” of the antibody -part of the antibody that combines with the antigen -can join only with a particular antigen, similar to the lock-and- key model of enzymes

Variable region

-stem of Y -can activate complement, or it can attach the antibody to cells, such as macrophages, basophils, and mast cells.

Constant region

site on antibody where antigen binds

Antigen-binding site

number of antigen-binding sites on antibody

valence

monomer comprising 80 - 85% of Immunoglobulins,The only antibody capable of crossing the placenta. Produced in high amounts during secondary response.

IgG

-dimer comprising 15% of Immunoglobulins, -They are predominantly found in body secretions (saliva, eyes, colostrums etc.) -Protects mucous membranes and internal cavities frominfection

IgA

o pentamer comprising 5-10% of Immunoglobulins, o Predominant antibody in primary response o Primarily destroys Gram (-) bacteria

IgM

Monomer Functions as an antigen-binding receptor on B cells found in blood and on lymphocytes

IgD

Monomer causes allergies, drug sensitivity, anaphylaxis & hypersensitivity reactions combats parasitic diseases

IgE

o a function of cytotoxic T cells and is most effective against microorganisms that live inside body cells. o also involved with some allergic reactions, the control of tumors, and graft rejection o fights viral infections by destroying virally infected cells.

CELL-MEDIATED IMMUNITY

help B cells to produce antibodies

T-helper cells (Th) (70%)

suppress B cells not to produce antibodies. Normal ratio of Th: Ts = 2 : 1

T-suppressor cells (Ts) (30%)

lyse & destroy foreign cells (cancer cells) and virus- infected cells, reject grafts & transplants.

T-cytotoxic cells (Tc)

involved in some delayed allergic reactions

T-delayed type hypersensitivity (Tdth)

chap 3 cell

MORALES, Chelsea Denise S. · 50問 · 2年前

chap 3 cell