Histology- Immune System

Front 1

What do immune cells form?

Back 1

Immune cells form parenchyma. (Immunocytes)

Front 2

What are the 3 types of Immunocytes?

Back 2

Lymphocytes
Neutrophils
Macrophages

Front 3

What are the 3 types of Stromal cells?

Back 3

Reticular cells
Epithelial reticular cells
Dendritic cells

Front 4

What are reticular cells and what is their function?

Back 4

Mesenchymal origin; form a reticulum in lymphatic organs
Funct: formation of reticular fibers.

Front 5

Where do Epithelial reticular cells originate?

Back 5

Epithelial origin (endoderm)

Front 6

Thymyus and cloacal bursa have stellate ___________ cells which form the stroma.

Back 6

epithelial reticular cells

Front 7

Do Epithelial reticular cells produce reticular fibers?

Back 7

No, they only produce reticular cells.

Front 8

Where do dendritic cells develop and what is their function?

Back 8

They develop from bone marrow
Major function is to capture and present antigens to lymphocytes.

Front 9

What are the 4 types of dendritic cells?

Back 9

Follicular
Interdigitating
Intraepidermal macrophage (Langerhans cell)
Veiled cells

Front 10

What is the function of primary or central lymphoid organs?

Back 10

Produce lymphocyte precursors (Training academy of lymphocytes)

Front 11

What are the primary or central lymphoid organs?

Back 11

Embryonic yolk sac
Thymus
GALT (Gut associated lymphatic tissue)
Cloacal Bursa (birds)
Bone marrow

Front 12

What are the secondary or peripheral lymphoid organs?

Back 12

Lymph Nodes
Spleen
MALT (Mucosa associated lymphatic tissue)

Front 13

What is the function of secondary or peripheral lymphoid organs?

Back 13

House mature immunocytes and site of immune responsiveness (Battle field of lymphocytes)

Front 14

What is Diffuse Lymphatic Tissue composed of and whats its function?

Back 14

lymphocytes and macrophages in stroma of dendritic cells and connective tissue

Front 15

Where do you find Diffuse Lymphatic Tissue?

Back 15

Scattered throughout the loose CT of GIT, Respiratory tract, Urogenital tract and skin.

Front 16

Where are lymphnodes situated and what are their function?

Back 16

Situated along the lymph vessels, filters the lymph before returning it to the blood stream.

Front 17

What type of vessels do lymphnodes have?

Back 17

Have both afferent and efferent vessels.

Front 18

What surrounds the lymphnode?

Back 18

Surrounded by a capsule composed of dense irregular C.T.

Front 19

The trabeculae of the lymph node extends from the capsule into the parenchyma as ________ _______.

Back 19

Irregular septa

Front 20

What are the sinuses of the Lymph Node? What do they do?

Back 20

Subcapsular
trabecular
medullary
They circulate lymph.

Front 21

The lumen of the sinuses of a lymph node is traversed by what?

Back 21

dense network of reticular cells and numerous processes.

Front 22

What lines the sinuses of the lymph node?

Back 22

reticular cells

Front 23

What is in the sinus lumen of a lymph node?

Back 23

lymphocytes and macrophages

Front 24

Younger animals have more ________ lymph nodes and older animals have _________.

Back 24

Primary and secondary

Front 25

What are the parts of the cortex of the lymph node?

Back 25

Outer cortex
Primary lymphatic nodules
Secondary lymphatic nodules
deep cortex

Front 26

Outer cortex of lymph node consists of what?

Back 26

primary and secondary lymphatic nodules seperated by diffuse lymphatic tissue.

Front 27

Primary lymphatic nodules of a lymph node consists of what?

Back 27

reticular CT w/ small tightly packed lymphocytes.

Front 28

What do secondary lymphatic nodules contain?

Back 28

germinal centers which have a dark and light zone

Front 29

What is in a dark zone of the germinal center of a lymph node?

Back 29

large lymphocytes with intense mitotic activity

Front 30

What is in a light zone of the germinal center of a lymph node?

Back 30

small lymphocytes with few mitotic cells).

Front 31

What is in the deep cortex of the lymph node?

Back 31

diffuse lymphatic tissue.

Front 32

How is the medulla portion of the lymph node arranged?

Back 32

using medullary cords

Front 33

What are the medullary cords of the medulla of a lymph node composed of?

Back 33

lymphocytes,plasma cells and macrophages

Front 34

How are the medullary cords of the medulla of a lymph node seperated?

Back 34

by a network of endothelial-lined sinuses and CT.

Front 35

In the medulla of a lymph node in a pig, cortical and medullary tissues are _______.

Back 35

reversed

Front 36

Where are the post capillary venules of lymph nodes located and what type of epithelium are they composed of?

Back 36

Located in the deep cortex and characterized by cuboidal epithelium

Front 37

The thymus has a connective tissue _________ that penetrates the parenchyma and divides it into _________.

Back 37

capsule, lobules

Front 38

Where do you find epithelial reticular cell?

Back 38

They are found in the thymus and function to support the thymus.

Front 39

Large and medium sized lymphocytes are found where?

Back 39

Thymus

Front 40

Macrophages that delete "self" recognizing Tcells are found where?

Back 40

Thymus

Front 41

The medulla of the thymus contain _________, these are concentrically arranged, flattened, keratinized epithelial cells.

Back 41

Hassal's or thymic corpuscles

Front 42

The capillary network of the thymus drains into the _______ in the medulla which join veins in the CT septa.

Back 42

Post capillary venules

Front 43

The _________ of the thymus prevents circulating antigen from reaching thymic cortex where T-lymphocytes are being formed.

Back 43

blood thymic barrier

Front 44

What forms the blood thymic barrier?

Back 44

capillary endothelium, perivascular space and epithelial reticular cells

Front 45

Thymus has ________ lymphatic vessels.

Back 45

no afferent

Front 46

The thymus functions in what type of animal?

Back 46

young

Front 47

What organ makes and pumps out T-cells?

Back 47

Thymus

Front 48

The _______ drains lymph but doesn't allow it in, exits only.

Back 48

Spleen

Front 49

What is the function of the spleen?

Back 49

Filter's out damaged & dead RBC's
Store RBC's & platelets
Erythropoiesis in fetus

Front 50

Which is the only lymph organ that has smooth muscle in its capsule?

Back 50

Spleen

Front 51

Which organ has lymphatic tissue involved in immune responses against blood-borne antigens.

Back 51

spleen

Front 52

The spleen is surrounded by a ________ composed of connective tissue and smooth muscle.

Back 52

capsule

Front 53

The capsule of the spleen sends out__________ that contain arteries,veins,lymph vessels and nerves.

Back 53

trabeculae

Front 54

What supports the splenic parenchyma?

Back 54

capsule, trabeculae and reticular fibers

Front 55

The splenic parenchyma is composed of _____ & ______.

Back 55

Red & white pulp

Front 56

What do the reticular fibers of the spleen form?

Back 56

Stroma

Front 57

What is the red pulp of the spleen composed of?

Back 57

splenic cords and or splenic or venous sinuses

Front 58

What are splenic cords of the red pulp in the spleen composed of?

Back 58

reticular fiber with reticular cells, enmeshed with erythrocytes, macrophages, lymphocytes, plasma cells and other leucocytes.

Front 59

What are splenic sinuses?

Back 59

wide vascular channels between the splenic cords

Front 60

What is the function of splenic sinuses?

Back 60

allows erythrocytes to pass between the splenic cords and splenic sinuses

Front 61

What do splenic cords do?

Back 61

They store RBCs

Front 62

What makes up the white pulp of the spleen?

Back 62

lymphatic nodules and periarterial lymphatic sheaths (PALS).

Front 63

lymphatic nodules in the white pulp of the spleen may or may not have _________ depending on their functional state.

Back 63

germinal centers

Front 64

What do you find in the PALS of the spleen?

Back 64

lymphatic sheath of t-cells.

Front 65

Where do you find the marginal zone of the spleen?

Back 65

Between the red and white pulp

Front 66

The periphery of the white pulp in the marginal zone of the spleen is bounded by _________.

Back 66

circumferiential reticular network

Front 67

The reticular network of the marginal zone in the spleen receives capillaries from where?

Back 67

the red and white pulp

Front 68

The marginal zone of the spleen plays an important role in the ________ of the blood.

Back 68

filtration

Front 69

In the spleen, a _______ artery enters the capsule and extends into the trabeculae as _________ arteries.

Back 69

splenic,trabecular

Front 70

As the trabecular artery leaves the trabeculae, it is called the __________ and fills w/ lymphocytes (PALS).

Back 70

artery of the white pulp

Front 71

________ feeds capillary beds in the nodule and terminate in the marginal zone or enter the red pulp as __________.

Back 71

branches of the white pulp artery
pulp arterioles

Front 72

The pulp arterioles of the spleen become ________.

Back 72

sheathed capillaries or ellipsoids

Front 73

Describe the blood flow of the spleen.

Back 73

splenic artery-trabecular artery-artery of white pulp-pulp arterioles-splenic capillaries-post capillary venules-veins

Front 74

What are the 3 theories of the terminal capillaries of the spleen?

Back 74

open, closed, third

Front 75

The ______ theory of the terminal capillaries of the spleen open directly into the splenic sinuses or venules.

Back 75

closed

Front 76

The ______ theory of the terminal capillaries of the spleen open into spaces bt. reticular cells of the red pulp

Back 76

open

Front 77

The ______ theory of the terminal capillaries of the spleen proposes the existence of both forms.

Back 77

third
open-distended
closed-contracted

Front 78

Lymph vessels of the spleen have no _______ lymph vessels.

Back 78

afferent

Front 79

Sinusual spleen is abundant where?

Back 79

venous sinuses in dogs

Front 80

Nonsinusal spleen is found where?

Back 80

poorly developed sinuses in cat,horses,pigs and ruminants

Front 81

What is MALT and where is it found?

Back 81

(Mucosa Associated Lymphoid Tissue)
submucosa of Digestive and Respiratory system organs

Front 82

BALT stands for what? and where is it found?

Back 82

Bronchus Associated Lymphoid Tissue, found in diffuse lymphatic tissue along the length of the organ

Front 83

What is GALT and where is it found?

Back 83

Gut Associated Lymphoid Tissue-(Ileal Peyer’s patch)

Front 84

Where is GALT found?

Back 84

jejunum / ileum in young ruminants, pigs and carnivores.
lymph nodules in the colon and rectum.

Front 85

Describe the different surfaces of the tonsil.

Back 85

It can be smooth or have deep invaginations (tonsillar fossulae)

Front 86

What is the function of tonsillar fossulae?

Back 86

It allows a high concentration of lymphatic tissue.

Front 87

The epithelium of tonsils are usually infiltrated with ________, _______, & _______.

Back 87

lymphocytes, neutrophils and macrophages

Front 88

Beneath the epithelium of the tonsil, diffuse lymphatic tissue with plasma cells surrounds___________ , which frequently possess a _________ center.

Back 88

lymphatic nodules
germinal

Front 89

The tonsil is surrounded by a distinct C.T.________.

Back 89

capsule

Front 90

What are hemal nodes and what species can you find them in?

Back 90

nodes that filter blood, present only in ruminants

Front 91

Are the cortex and medulla of hemal nodes distinct?

Back 91

No

Front 92

Do hemal nodes have lymph vessels?

Back 92

No, they receive all their antigens from the blood and respond to blood borne antigens

Front 93

What are in hemal nodes of young animals?

Back 93

diffuse lymphatic tissue and a few lymph nodules

Front 94

What are in hemal nodes of adult animals?

Back 94

filled w/ erythrocytes