Hematopoiesis - Immune System and Lymphoid Organs

Question 1

Describe general functions of lymphoid system

Answer 1

Facilitate immunity. This is done by production and activation of lymphocytes.

Question 2

Define self and non-self

Answer 2

Self: Organism’s own molecules/cells.

Non-self: Extrinsic molecules/cells.

Question 3

Function of lymphatic vessels

Answer 3

Travel alongside blood vessels and collect extra fluid at capillaries. Fluid carries proteins, WBCs and some RBCs. Connects chains of lymph nodes.

Question 4

Desribe network of lymphatic vessels

Answer 4

Tubule converge to form lymphatic ducts that carry lymph to lymph nodes for filtration and phagocytosis. Eventually dumps back into venous system at sublavian veins.

Question 5

Immunocompetent cell

Answer 5

Cell able to recognize antigens and act against them.

Question 6

Immune response

Answer 6

How body recognizes and defends itself against foreign, harmful invaders

Question 7

Humoral immunity

Answer 7

B cells differentiate into plasma cells which end up secreting antibodies that bind to specific antigens.

Question 8

Cellular immunity

Answer 8

Mediated by T cells. Either secrete cytokines that act on B lymphocytes, other T cells, and inflammatory cells (macrophages, neutrophils) or attack foreign cells.

Question 9

Memory cells

Answer 9

Cell derived from B or T cells that can quickly recognize a foreign antigen which body has been previously exposed.

Question 10

Antigen presenting cell (APC)

Answer 10

Immunocompetent cells that mediate cellular response by processing and presenting antigens to T cells. Common APCs include macrophages, dendritic cells, B cells.

Question 11

Waldeyer ring

Answer 11

Composed of pharyngeal, palatine, and lingual tonsils which form a circle at entrance of gut/airway and monitors what comes into mouth/nose before it gets to guts/lungs. Tonsils are an aggregate of confluent lymphoid follicles.

Question 12

Peyer patches

Answer 12

Group of lymphoid nodules in mucosa of ileum that resopnd to foreign antigen in GI tract.

Question 13

Immunoglobulin (Ig)/antibody

Answer 13

Protein produced by B cells in response to one unique antigen. Combines with antigen to destory it.

Question 14

Antigen

Answer 14

Any substance that causes your immune system to produce antibodies against it.

Question 15

Innate immunity

Answer 15

Primitive and fast immune response. Specificity to pathogens is broan and programmed into DNA. Includes macrophages, neutrophils, eosinophils, and NK cells. Dysfunctional activation can lead to autoimmune disease.

Question 16

Adaptive immunity

Answer 16

Antigen specific immune response that is more complex. Antigen is recognized, adaptive immune system creates specific immune cells to attack antigen. Also involves creation of memory cells which will make subsequent responses to antigen faster and more efficient. Two types: humoral- and cell-mediated.

Question 17

Immunodeficiency

Answer 17

Decreased or compromised ability to respond to antigenic stimuli. Result of disorders in B cell mediated immunity, T cell mediated immunity, compliment, or phagocytic cells. Caused by genetics, acquired infections, drug abuse, chemotherapy, malnutrition. Treated based on underlying etiology: transplants, antibiotics, infusions, or immune globulin.

Question 18

Describe plasma cells

Answer 18

Naive B cells proliferate and differentiate into plasma cells (or memory B cells). Stay in organ of origin or migrate to medullary cords, GI mucosa, or bone marrow.
Generally live for 2-4 days; some live for months to years and secrete antibodies without antigen presence.

Question 19

Plasma cell function

Answer 19

Secrete antibodies that bind specific antigens. Block actions of antigens, mark antigens for phagocytosis, activate complement system.

Question 20

Compare/contrast each type of peripheral lymphoid tissue.

Answer 20

Mucosae: Vaginal, urinary (scattered T/B cells).
Gut: Diffuse lymphoid tissue (scattered T/B cells). Contains Peyer patches.
Bronchus: Diffuse lymphoid tissue (scattered T/B cells).
Conjunctiva: Associated w/eye.
Lymphoid follicles: Predominantly B cells (but also helper T cells). Aggregate form known as Peyer patches.

Question 21

Pharyngeal

Answer 21

Respiratory. Catches pathogens as they are inhaled through nose.

Question 22

Palatine

Answer 22

Non-keratinized stratified squamous. Local immunity. Contain all 5 antibodies and fight infection.

Question 23

Lingual

Answer 23

Non-keratinized stratified squamous. Have on signle tonsillar crypt. Local immunity. Contain all 5 antibodies and fight infection.

Question 24

Afferent lymphatic vessels

Answer 24

Point of entry for lymph fluid and soluble substances (self or non-self). Vessels penetrate capsule.

Question 25

Efferent lymphatic vessels

Answer 25

Point of exit of lymph after it has gone through filtration.

Question 26

Follicular cortex

Answer 26

Rich capillary network; B cell zone.

Question 27

Parafollicular cortex

Answer 27

Deep cortex with rich capillary network; T cell zone.

Question 28

Medulla

Answer 28

Rich with cells (macrophages, dendritic cells, plasma cells, B cells). Highly branched network of thin reticular fibers that provide physical support and network for movement of lymphocytes and dendritic cells.

Question 29

Cortical sinuses

Answer 29

Receives fluid from affent vessels. Made up of trabechular, cortical, and intermediate sinuses. Contains macrophages and dendritic cells for phagocytosis.

Question 30

Medullary sinuses

Answer 30

Collect lymph after filtration in cortex. Contains macrophages and antibodies.

Question 31

Medullary cords

Answer 31

Contains plasma cells that secrete antibodies into sinuses.

Question 32

Identify T and B cell rich zones in lymph node cortex.

Answer 32

B cells: Follicular cortex.

T cells: parafollicular cortex.