Immune System and Lymphatic Organs

Question 1

Two general function of the lymphoid system(NONE)

Answer 1

General: facilitate immunity by:
Production of lymphocytes
Activation of lymphocytes

Question 2

‘Self’ (NONE)

Answer 2

an organism’s own mecums (literally itself)

Question 3

Non-self (NONE)

Answer 3

foreign molecules

Question 4

Network and function of lymphatic vessels

Answer 4

➔ Lymphatic tubules travel alongside the blood vessels and collect extra fluid at the capillaries
➔ This fluid carries proteins, WBC’s, some RBC’s
➔ Connects chains of lymph nodes
➔ Tubules converge to form lymphatic ducts that carry the fluid to the lymph nodes for filtration & phagocytosis
➔ Eventually dumps the filtered fluid back into the venous system at the subclavian veins
➔ Right upper body drains to lymphatic trunkà right subclavian vein
➔ Rest of body drains to thoracic ductà left subclavian vein

Question 5

Major network of lymph nodes

Answer 5

◆	Neck (cervical, occipital)
◆	Clavicular
◆	Axillary
◆	Bronchial
◆	Mediastinal
◆	Mesentery
◆	 Iliac
◆	Inguinal

Question 6

Immunocompetent cell

Answer 6

A cell that is able to recognize antigens and act against them

Question 7

Immune response

Answer 7

How your body recognizes and defends itself against bacteria viruses, and substances that appear to be foreign and harmful

Question 8

Humoral immunity

Answer 8

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

Question 9

Cellular immunity

Answer 9

Mediated by T cells that either:

• Secrete cytokines that act on B lymphocytes, on other T cells, and on inflammatory cells (macrophages & neutrophils
• Attack foreign cells

Question 10

Memory cells

Answer 10

cell derived from B or T cells that can quickly recognize a foreign antigen to which the body has been previously exposed

Question 11

Antigen-presenting cell (APC)

Answer 11

Immunocompetent cels that mediate the cellular immune response by processing and presenting antigens to T cells. Examples: macrophages, dendritic cells, B lymphocytes

Question 12

Central lymphoid organs

Answer 12

Primary, sites of antigen independent lymphocyte generation. The bone marrow for B cells and thymus for T cells

Question 13

Peripheral lymphoid organs

Answer 13

Secondary, where adaptive immune responses are initiated and include MALT, GALT, BALT, CALT

Question 14

Waldeyer’s ring

Answer 14

composed of pharyngeal, palatine, and lingual tonsils which form a circle at the entrance of the gut and airway and monitors what comes into mouth and nose before it gets into the gut and lungs. The tonsils are an aggregate of partially encapsulated, confluent lymphoid follicles

Question 15

Peyers patches

Answer 15

a group of lymphoid nodules in the mucosa of the ileum that response to foreign antigens in the GI tract

Question 16

Immunoglobulin (Ig) antibody

Answer 16

a protein produced by B cells in response to one unique antigen. Combines with that specific antigen to destroy it

Question 17

Antigen

Answer 17

any substance that causes your immune system to produce antibodies against it

Question 18

Innate immunity (natural)

Answer 18

Most primitive immune response, fast. Specificity to pathogens is very broad and is programmed in germline DNA. Key players of this system who are directly involved in killing pathogens include macrophages, neutrophils, eosinophils, and NK cells. Dysfunctional activatio can lead to autoimmune diseases.

Question 19

Adaptive immunity

Answer 19

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

Question 20

Immunodeficiency

Answer 20

decreased or compromised ability to respond to antigenic stimuli with an appropriate immune response, as the result of one or more disorders in B-cell mediated immunity, T cell mediated immunity, compliment, or phagocytic cells. Some causes include genetics, aquired infections, drug abuse, immunosuppressive therapy (chemo), or malnutrition. Treated based on underlying cause with transplants, antibiotics, infusions of immune globulin.

Question 21

Development and maturation sites for B lymphocytes and T lymphocytes

Answer 21

B: develop and mature in bone marrow
T: develop in bone marrow, mature in thymus

Question 22

Plasma cells

Answer 22

Some B cells will differentiate into plasma cells. Their primary function is to create and secrete antibodies. However, each plasma cell can only create one type of antibody in the five classes (IgG, IgA, etc.). Most live for 2-5 days.

Question 23

Types of peripheral lymph tissue (NONE)

Answer 23

Diffuse: scattered T and B cells
Confluent: aggregates of many lymph nodules
Tonsils, lymph nodes, spleen, peyer patches

Question 24

Tonsils

Answer 24

confluent - called Waldeyer’s ring, composed of pharyngeal, palatine, and lingual tonsils.

Question 25

Lymph nodes

Answer 25

filters fluid before entering blood stream. Remove foreign substances, etc. This is where antigens and antigen-specific lymphocytes cross paths and do battle. B cells located in the cortex, T cells in the parafollicular (deep) cortex, macrophages and plasma cells in the medullary cords.

Question 26

Spleen

Answer 26

filters blood but activates immune responses to substances found in the blood. Red pulp filters blood cells, white pulp is lymphatic tissue.

Question 27

Peyer patches

Answer 27

confluent areas of the small intestine

Question 28

Three sets of tonsils and function

Answer 28

Palatine: principally composed of lymph tissue, they are organized as follicles and crypts covered by mucous membranes Pharyngeal (adenoids) and lingual: provide defensive responses to inhaled and intranasal antigens

Question 29

Afferent lymphatic vessels

Answer 29

carry fluid/lymph/stuff into lymph nodes

Question 30

Efferent lymphatic vessels

Answer 30

E for Exit! Carry exiting fluid/lymph/stuff

Question 31

Follicular cortex

Answer 31

Outer cortex, B cell zone

Question 32

Parafollicular cortex

Answer 32

deep cortex, T cell zone

Question 33

Medulla

Answer 33

macrophages and plasma cells chill here

Question 34

Cortical sinuses

Answer 34

lymph sinuses in the cortex (lymph flows through these)

Question 35

Medullary sinuses

Answer 35

Collect lymph that has filtered through the cortex

Question 36

Medullary cords

Answer 36

Cords of lymphatic tissue where the macrophages and plasma cells chill

Question 37

T and B cell rich zones

Answer 37

T: parafollicular cortex B: outer cortex

Question 38

Spleen

Answer 38

- Largest secondary lymphoid organ - Filters blood to get rid of damaged and old cells - Activates immune responses and microbes in blood - Blood flow: Splenic artery-->trabecular arteries--->central arteries and arterioles in white pulp-->red pulp-->marginal zone sinuses or arterioles and macrophage sheathed capilaries and sinusoids

Question 39

Red pulp

Answer 39

Main filtration function of spleen. Contains sinusoids and cords

Question 40

White pulp

Answer 40

Lymphoid tissue Pariarterial lymphatic sheath (PALS)-T cells around central artery Follicles that are B-cell rich, interspersed in PALS Marginal zone and sinus, has a lot of antigen-presenting cells Lymphocytes leave via lymphatics that originate in white pulp

Question 41

Splenic cords

Answer 41

Rich in macrophages that eat old cells and foreign particles. Contain plasma cells and all blood cells

Question 42

Splenic sinusoids

Answer 42

Barrel-like, lined by endothelial cells, reticular fibers circle sinusoids like bands around a barrel. Has a discontinuous wall that allows blood to fill cords as well as sinusoids

Question 43

Two function of the thymus

Answer 43

The thymus is the central lymphoid organ for development of T lymphocytes. It produces the lymphocytes and also regulates immune function by secretion of hormones that promote T-lymphocyte differentiation.

Question 44

Blood thymus barrier

Answer 44

Impermeable epithelium vessel walls-complete tight junctions and thickened basement membrane Macrophage in perivascular space Epithelial reticular cells Basically keeps foreign materials out

Question 45

Cortex of thymus

Answer 45

Immature T-cells (thymocytes) No B cells, no follicles Macrophages that act as phagocytes to T cells that aren’t up to par CFU-L cells leave bone marrow, migrate to cortex where they undergo DNA rearrangements to generate antigen recognition diversity

Question 46

Medulla of thymus

Answer 46

T cells Epithelial reticular cell stroma Hassall’s corpuscles

Question 47

Hassal's corpuscle

Answer 47

Concentric, flattened epithelial reticular cells Can calficy May secrete factors (interleukins 4 & 7) needed for thymic function