AP II exam 2 Lymphatics and endocrine

What is the function of the thymus?

Produces thymosins (hormones) which stimulate lymphocyte stem cell division and T cell maturation

Functions of the spleen

Same job for blood that lymph nodes do for lymph

Removes abnormal red blood cells and other blood components by phagocytosis

Stores iron from recycled blood cells

Initiates immune response by B and T cells in response to antigens in blood

Which WBCs are Agranulocytes?

Lymphocytes and Monocytes

Which WBCs are granulocytes?

Neutrophils, Basophils, and Eosinophils

Organize the WBC in order of prevalence

Neutrophils(50-70%), Lymphocytes(20-40%), Monocytes(2-8%), Eosinophils (2-4%), Basophils (<1%)

Main functions of Eosinophils

Attack large parasites & antigen coated pathogens

Sensitive to allergens

Control inflammation

Main function of basophils

Accumulate in damaged tissues

Release Histamine -> dilates blood vessels

Release Heparin -> prevents blood clotting

Main functions of Neutrophils

First to attack -> phagocytize pathogens & form pus

Granules contain lysosomal enzymes and bactericides (Hydrogen peroxide & superoxide)

Main functions of Lymphocytes

Migrate in and out of blood (mostly in connective tissues and lymphoid organs)

Specific defense system -> T cells: Cell mediated immunity, B cells: hormonal immunity & synthesize antibodies, NK cels: detect and destroy abnormal tissues (cancers etc.)

Main functions of monocytes

Enter peripheral tissues and become macrophages

Engulf large particles and pathogens

Secrete substances that affect immune system cells and fibroblasts to injured area

What WBCs are phagocytes

Neutrophils and monocytes

What are the 3 functions of the lymphatic system?

1-      Immunity

2-      Return fluids and solutes to blood

3-      Distribute hormones, nutrients, and waste produces from their tissues of origin to the general circulation

What are the two main branches of immunity?

1-      Innate (nonspecific) immunity (present at birth and does not distinguish)

2-      Adaptive (specific immunity

What are the 7 non specific immunity categories

physical barriers, phagocytes, immune surveillance by NK cells, Interferons, complement, inflammation, fever

Steps of how NK cells target and exert their immune effect

1)       NK cell adheres to target cell

2)       Golgi apparatus realigns near target cell & perforins (proteins) are produced

3)       Perforins are released from NK cell to target cell

4)       Perforins create pores in target cells membrane (target cell death)

Explain classical pathway of complement action

most rapid and effective complement activation method

-            Antibodies bind to bacterial cell wall

-            C1 (complement) must attach to two antibodies for its activation

-            C3a diffuses away and activates an inflammatory response

-            Activation and cascade

-            C3b attachment: C3b binds to bacterial surface and enhances phagocytosis

-            Membrane attack complex (MAC) destroys integrity of target cell

Explain alternative pathway of complement action

slower and less effective, occurs in absence of antibody molecules

-            Complement proteins interact in plasma (properdin, factor B, factor D)

-            C3a activates an inflammatory response

-            C3b binds to bacterial surface and enhances phagocytosis

-            Membrane attack complex (MAC) destroys integrity of target cell

What are the three results of complement activation

1-      Milling of pathogen by cell lysis (MAC)

2-      Enhanced phagocytosis (opsonization)

3-      Inflammation (histamine release)

What kind of immunity is achieved by vaccines

Artificially induced active immunity

Active immunity

Exposure to antigen

Naturally acquired (antigens in environment)

Artificially acquired (exposure in clinical setting)

Passive Immunity

receiving antibodies

Naturally acquired (maternal antibody transfer to fetus or baby)

Artificially induced (administration of antibodies to a patient)

What are the Four properties of adaptive immunity

Specificity, Versatility, Memory, Tolerance

Explain specificity

B and T cells only have receptors for one specific antigen

Explain Versatility

Millions of lymphocytes, each sensitive to a different antigen and able to produce clones

Explain Memory

Activated lymphocytes produce two groups of cells, one that attack immediately, and memory cells that remain inactive unless exposed to same antigen later

Explain tolerance

ignores self and targets non self (abnormal or foreign cells/toxins). Can develop over time

List the four types of T cells

Cytotoxic T cells, Helper T cells, Memory T cells, Regulatory T cells

What do cytotoxic T cells do

attack foreign cells or body cells infected by viruses commonly by direct contact. Primary cells involved in production of cell-mediated immunity (cellular immunity)

What do helper T cells do

stimulate activation and function of T and B cells. Activated B cells before B cells can produce antibodies  

What do regulatory T cells do

AKA suppressor T cells. Moderate immunity by inhibiting T and B cell activity, establish and control sensitivity of immune response

What do memory T cells do?

Respond to antigens they have already encountered. “remember” invaders to fight them off in future

Explain how helper T cells assist with the immune response

· Activating B cells to produce antibodies.

· Stimulating cytotoxic T cells to kill infected cells.

· Enhancing macrophage activity to clear pathogens.

· Coordinating the overall immune response by releasing cytokines.

· Establishing immune memory for faster responses in future infections

Class I Major histocompatibility complex proteins (MHC)

Present in membranes of all nucleated cells, Triggered by viral or bacterial infection of a body cell. “hey im an abnormal cell please destroy me”

Class II MHC proteins

Present in membranes of antigen- presenting cells (APCs). Phagocytic cells engulfs pathogenic material and processes the antigens for presentation; antigen processing. “This is a dangerous antigen floating around, get rid of it”

Process of Class I MHC antigen presentation

1-      Viral or bacterial infection of a cell triggers antigen presentation by Class 1 MHC proteins

2-      The infection results in the appearance of abnormal peptides in the cytoplasm

3-      The endoplasmic reticulum produces Class 1 MHC proteins to which the abnormal peptides are attached

4-      After export to the Golgi apparatus, The MCH proteins with their bound abnormal peptides are transported to the plasma membrane

The abnormal peptides are displayed by class 1 MHC proteins on the plasma membrane

Process of antigen presentation by APCs (class II MHC)

1-      Phagocytic APCs engulf the extracellular pathogens

2-      Lysosomal action produces antigenic fragments

3-      The endoplasmic reticulum produces class II MCH proteins

4-      Antigenic fragments are bound to class II MHC proteins

5-      Antigenic fragments are displayed by class II MHC proteins on the plasma membrane

Explain how B cells become fully activated

-            Full activation requires helper T cell

·       This prevents inappropriate activation

·       Helper T cell must have been activated by exposure to the same antigen

·       Helper T cell binds to MHC (Class II) complex of sensitized B cell

·       Secretes cytokines to promote B cell activation

Basic configuration of IGs

2 parallel pairs of polypeptide chains, one light and one heavy, each pair contains consistent segments and variable segments

List all 5 Igs

IgG, IgE, IgD, IgA, IgM

what does IgG do

responsible for resistance against many viruses, bacteria, and bacterial toxins

What does IgE do

attaches to basophil and mast cell surface (accelerates inflammation in presence of antigens)

What does IgD do?

on B cell surface, where it binds antigens in extracellular fluid, also plays a role in B cell sensitization

what does IgM do?

first class of antibody secreted after antigen encountered (production declines as IgG production increases)

What does IgA do?

attack primarily before pathogens gain internal access ( found primarily in glandular secretions, such as mucus, tears, saliva, and semen

What is antigenic determination site?

Formed when a specific antibody molecule binds to its corresponding antigen molecule. Binds to specific portions of the exposed surface called antigenic determinant sites on an antigen

List the 7 functions of antigen- antibody complexes

Neutralization of antigen-binding sites

Precipitation and agglutination: formation of immune complex

Activation of complement

Attraction of phagocytes

Opsonization: increasing phagocyte efficiency

Stimulation of inflammation

Prevention of bacterial and viral adhesion.

What do lymphocytes respond to?

Antigens

The attraction or repulsion of certain cells to chemicals in their environment is called

Chemotaxis

Lymphatic vessels are located everywhere but

CNS

Compared to blood capillaries, lymph capillaries

Have no basement membrane

are larger in diameter

have walls of endothelial cells that overlap

are frequently irregular in shape

What do beta cells of the pancreatic islets produce?

Insulin which lowers Blood sugar

What hormone promotes glucose formation in the liver

Cortisol

what are Eicosanoids synthesized from?

Arachidonic acid

Results of thyroid hormones

Thyroid hormones are responsible for increasing cellular metabolism. Therefore, they elevate rates of oxygen consumption and energy consumption, increase heat generation, and assist in the normal development of the skeletal, muscular, and nervous systems in children.

Amino Acid derivatives

Thyroid hormones, Catecholamines, Tryptophan derivatives

Lipid derivative

Eicosanoids, steroid hormones