Microanatomy 2-4 Immune System

Front 1

Innate Immunity

Back 1

Barriers to primary infection:
Phagocytosis, Inflammation and
Complement System

Front 2

Adaptive Immunity

Back 2

Self vs. non-self; Clonal lymphocyte response,
Antigen recognition molecules,
Memory

Front 3

Immune cells develop in______

Back 3

bone marrow

Front 4

______ cells take infections to lymph nodes and stimulate adaptive immunity

Back 4

dendritic

Front 5

Antigen recognition induces expression of effector molecules by __ cells which activate __ cells.

Back 5

T, B

Front 6

Proliferating B cells differentiate to resting ____ cells and antibody secreting _____ cells.

Back 6

memory, plasma

Front 7

Primary Organs

Back 7

Bone Marrow, Thymus; sites of lymphocyte production and development.

Front 8

Secondary Organs

Back 8

Lymph Nodes, Spleen, Mucosal Lymphoid Tissue; sites where lymphocytes encounter and respond to antigens.

Front 9

T cells

Back 9

include several functionally distinct subtypes and are responsible for cell-mediated responses. They assist B cells in developing antibody responses

Front 10

B cells

Back 10

develop into antibody-secreting plasma cells. Each plasma cell secretes only one class of immunoglobulin that binds only one antigen. The memory cells can react to the same antigen in subsequent encounters.

Front 11

thymus

Back 11

no significant filtering function, but supports the proliferation and programming of T lymphocyte precursors.

Front 12

Where is the thymus?

Back 12

lies in the mediastinum anterior to the large vessels emerging from the heart. It is divided into two lobes and covered by a thin connective tissue capsule that penetrates the lobes as septa, dividing each lobe into lobules.

Front 13

Each thymic lobule has an outer, dark-staining _____ and an inner, lighter-staining _____.

Back 13

cortex, medulla

Front 14

Part of the maturation process for T-cells is the elimination of self-reactive cells, to limit ______ disease.

Back 14

autoimmune

Front 15

What goes down w/in the thymic cortex and medulla?

Back 15

The densely-packed cortex contains the rapidly proliferating more immature thymocytes. As they mature they move towards the medulla. As many as 95% of the thymocytes fail to develop or display inappropriate self-reactivity, and die by apoptosis.

Front 16

Describe the blood supply of the Thymus.

Back 16

Enters through the capsule and connective tissue septa. Branches of arteries and then capillaries go into the cortex. The continuous capillaries are sheathed by processes of epithelial reticular cells.

Front 17

What makes up the blood-thymus barrier?

Back 17

The epithelial reticular cells, thick basal lamina, and continuous capillaries

Front 18

There are no ____ lymphatic vessels coming into the thymus.

Back 18

afferent; it's job is not to filter lymph, but grow T cells.

Front 19

What primarily constitutes the thymic cortex?

Back 19

thymocytes, along with epithelial reticular cells (large pale cells), and macrophages

Front 20

cortical epithelial reticular cells

Back 20

program which thymocytes (T cells) will die and which ones will live and progress to the thymic medulla.

Front 21

The medulla contains ____ epithelial reticular cells and ____ T lymphocytes than the cortex

Back 21

more, fewer

Front 22

Does the medulla or cortex have more mature T lymphocytes?

Back 22

medulla

Front 23

Hassall's Corpuscles

Back 23

-concentric layers of flattened epithelial reticular cells that have died and calcified with age. They are found only in the thymic medulla and their function is unknown.

Front 24

Compared to a young thymus, an aged thymus looks______.

Back 24

moth eaten

Front 25

T/F: Babies are born with a fully fnx thymus gland.

Back 25

true; w/ aging, thymic tissue is replaced with adipose.

Front 26

Digeorge's Syndrome

Back 26

congenital thymus abnormality- chromosome 22 defect. Complete Digeorge means there is no thymus present.

Front 27

Lymphatic System

Back 27

vast complex network of capillaries, thin vessels, valves, ducts, nodes, and organs. It helps to protect and maintain the fluid environment of the body by producing, filtering, and conveying lymph

Front 28

Lymph is roughly __% of the tissue fluid that surrounds cells; usually 1-2 quarts makes up___% of the body weight

Back 28

10%, 1-3%

Front 29

What do Lymph Node concave and convex surfaces do/contain?

Back 29

Convex surface = receives afferent lymphatic vessels

Concave surface = contains arterioles and efferent lymphatic vessels

Front 30

The lymph node stroma contains_____.

Back 30

reticular fibers

Front 31

What's in the cortex and paracortex of lymph nodes?

Back 31

cortex= . Lymphoid follicles (B cells with some T cells & other cell types)
paracortex= mostly T cells

Front 32

germinal centers

Back 32

light staining regions containing activated B cells undergoing transformations that yield memory cells and plasma cells

Front 33

the paracortex is ____ staining because it's full of T cells.

Back 33

dark

Front 34

lymph node medulla

Back 34

contains cords with reticular cells and plasma cells present; stains lighter than cortex

Front 35

Lymphadenopathy

Back 35

When antigen-specific T and B cells are stimulated, they rapidly proliferate in the follicles (B-cells) and paracortex (T-cells) to produce effector clones and memory cells. This cellular expansion can result in the lymph node enlarging

Front 36

high endothelial venule-HEV

Back 36

paracortex of lymph node; lymphocyte point of entry from blood

Front 37

largest lymphoid organ

Back 37

spleen; filters blood

Front 38

in the spleen, connective tissue _____ pass from capsule to interior.

Back 38

trabeculae; trabecular artery→ central artery (w/ sheath full of T-cells)→ penicillar arterioles→ sheathed capillaries

Front 39

white pulp

Back 39

spleen; a thick accumulation of lymphocytes surrounding the central arterioles; thickens to form splenic nodules

Front 40

red pulp

Back 40

occurs in irregular masses - splenic cords, and splenic sinuses

Front 41

What separates red and white pulp?

Back 41

marginal zone

Front 42

What makes up PALS in white pulp?

Back 42

T cells

Front 43

Where are the B cells in white pulp?

Back 43

splenic nodules

Front 44

cords of billroth

Back 44

red pulp; The regions between sinusoids are occupied by pulp cords, rich in macrophages, reticular cells, and plasma cells

Front 45

Does the spleen have afferent lymphatics? Lymph sinuses?

Back 45

no, no.

Front 46

Where is most of the spleen's lymphoid tissue located?

Back 46

white pulp (i.e. B cell nodules and PALS)

Front 47

MALT

Back 47

mucosa-associated lymphatic tissue, found on mucus membranes lining the respiratory, gastrointestinal, and urogenital systems; secondary lymphoid tissue

Front 48

non-encapsulated lymphoid nodules

Back 48

inactive= primary, active=secondary; B cells in the germinal center's center surrounded by marginal zone of memory cells

Front 49

peyer's patches

Back 49

Large aggregates of lymphoid follicles/nodules in the *ileum.* Nodules originate in the lamina propria and extend into the submucosa.

Front 50

microfold (M) cells

Back 50

specialized epithelial cells over follicles that endocytose microorganisms from the lumen, and pass them intact to the antigen-presenting cells in the Peyer’s patches.

Front 51

Pharyngeal Tonsils (Adenoids)

Back 51

nasopharynx posterior wall; covered with ciliated pseudostratified columnar epithelium- some portions may be stratified squamous epithelium (especially in older individuals).

Front 52

Tonsillectomy

Back 52

surgical excision of the palatine tonsils

Front 53

Waldeyer’s ring

Back 53

composed of the tonsils and form a ring of lymphoid tissue around the entrance to the GI and respiratory tracts.

Front 54

Lingual Tonsils

Back 54

diffuse infiltration of lymphocytes or multiple small nodules below epithelium of the posterior third of the tongue.