Histo Test 3: Lymphatic Organs

Front 1

Tonsil general features

Back 1

ring of lymphoid tissue in pharynx
Incompletely Encapsulated
Efferent Lymphatic vessels present, NO Afferent

Front 2

Tonsil Fxn

Back 2

removal of Ags

Front 3

Pharyngeal Tonsils

Back 3

Single tonsil in roof of pharynx
Ciliated pseudostratified epithelium
NO Crypts

Front 4

Adenoid

Back 4

Inflamed Pharyngeal Tonsil

Front 5

Palatine Tonsil

Back 5

2 at junction of oral cavity and pharynx
Stratified Squamous wet Epi
crypts, which contain debris

Front 6

Lingual Tonsils

Back 6

base of tongue
smaller and more numerous
SINGLE crypt

Front 7

Encapsulated Lymph Organs

Back 7

Lymph Nodes, Thymus and Spleen

Front 8

Lymph Node Morphology

Back 8

bean shaped organ located along Lymphatic vessel pathway
Lymph must cross node before entering circulation

Front 9

Lymph Node Fxn

Back 9

filter lymph and fight infection
maintain B and T Cells and contain memory cells

Front 10

Lymph node vessels:
Afferent

Back 10

located on convex surface
carries lymph toward

Front 11

Lymph node vessels:
Efferent

Back 11

carries lymph away from node
located at Hilum

Front 12

what do reticular cells secrete?

Back 12

type 3 collagen

Front 13

Dendritic Cells

Back 13

APCs found only in Bone Marrow
use both MHC 1 and 2 to present foreign antigens

Front 14

3 regions of the Lymph Node

Back 14

Cortex
Paracortex (deep cortex)
Medulla

Front 15

Lymph Nodes:
Cortex

Back 15

outer portion containing nodules
B cells found here
covered by CT Capsule

Front 16

Lymph Nodes:
Paracortex

Back 16

T cells present here
contains High Endothelial Veins

Front 17

Thymus Dependent Region

Back 17

paracortex of Lymph Node
will not develop well w/o Thymus

Front 18

High Endothelial Veins

Back 18

site of entry/exit lymphocytes from circulation
lined w/ cuboidal-columnar endothelial cells

Front 19

Lymph Nodes:
Medulla

Back 19

contain lymphatic cords and Medullary Sinuses
all converge near hilum and drain into Efferent

Front 20

Lymph Node Sinuses

Back 20

Subscapular
Trabecular
Medullary

Front 21

Lymph Node Sinus:
Subscapular

Back 21

b/t CT capsule and cortical lymphocytes
contains Afferent Lymph

Front 22

Lymph Node Sinus:
Trabecular

Back 22

contain lymph
drains into medullary sinus

Front 23

Lymph Node Sinus:
Medullary Sinus

Back 23

contain Lymph AND blood
converge at Hilum
drain into Efferent Lymphatic Vessels

Front 24

Characteristics of Lymphatic Sinuses

Back 24

macrophages present for lymph monitoring
NOT OPEN SPACES
contains reticular fibers

Front 25

Phagocytosis and immune response in Lymph Node

Back 25

MO are phagocysitized
activation and differentiation of B cells
memory cells proliferate and spread in response to specific Ag

Front 26

Thymus Morphology

Back 26

Bilobed, encapsulated
ONLY LOBULATED Lymphoid Organ
functional at birth
grows until puberty
NO AFFERENT vessels

Front 27

Thymus germ cell derivation?

Back 27

3rd pharyngeal pouch
Endoderm and Mesoderm

Front 28

Thymus Trabeculae

Back 28

continuous w/ capsule, Efferent Lymphatic

Front 29

Thymus Cortex

Back 29

outer Parenchyma, Basophilic
Developing T cells found here
Education and transfer of T cells

Front 30

Thymus Medulla

Back 30

inner region of Parenchyma
Eosinophilic
Large Lymphocytes
THYMIC CORPUSCLES
T cell education complete here

Front 31

Epitherlioreticular Cells

Back 31

characteristics of reticular and epithelial cells
3 in cortex
3 in medulla

Front 32

are there reticulocytes in Thymus?

Back 32

NO

Front 33

Epitherlioreticular Cells:
Type 1

Back 33

boundary of cortex and CT Capsule
Occluding Jxns b/t cells
DO NOT express MHC 1 or 2

Front 34

Epitherlioreticular Cells:
Type 2

Back 34

involved in T Cell education
Expresses both MHC 1 and 2

Front 35

Epitherlioreticular Cells:
Type 3

Back 35

Involved in T Cell education
boundary b/t cortex and medulla
create barrier b/t cortex and medulla
expresses MHC 1 and 2

Front 36

Macrophages in the Cortex of Thymus?

Back 36

remove T cells that fail thymic education

Front 37

Crosstalk in Thymus

Back 37

T Cells control architecture of Thymic Epithelioreticular cells
both influence each other

Front 38

Epitherlioreticular Cells:
Type 4

Back 38

b/t cortex and medulla in medulla
Occluding Jxns
Function as Barrier

Front 39

Epitherlioreticular Cells:
Type 5

Back 39

medulla
Desmosomes b/t cells
compartmentalize and framework medulla

Front 40

Epitherlioreticular Cells:
Type 6

Back 40

Forms Thymic Corpuscles

Front 41

Thymic Corpuscles

Back 41

produce IL-4 and IL-7
fxn in T cell education
produce thymosin and thymopoietin

Front 42

T Cell Education

Back 42

expression and deletion of specific Antigens
Education in cortex and medulla is seperate

Front 43

T Cell education in Cortex

Back 43

positive selection for cells expressing MHC and any Ag

Front 44

T Cell education in Cortex:
Double negative stage

Back 44

CD2 and CD7 expressed

Front 45

T Cell education in Cortex:
Middle Stage

Back 45

CD1

Front 46

T Cell education in Cortex:
Double Positive Stage (3rd)

Back 46

TCR, CD3 and CD4 and CD8 expressed

Front 47

T Cell education in Cortex:
Positive Selection Process

Back 47

If a cell expresses Self MHC and any Ag, it survives
if not, undergoes apoptosis

Front 48

T Cell education in Medulla:

Back 48

Negative Selection for self Ag displayed by self MHC

Front 49

T Cell education in Medulla:
Single positive Stage

Back 49

surviving cells lose one CD marker-either CD4 CTL or CD8 CTL

Front 50

Hormones required for T Cell Maturation

Back 50

Thymosin
Thymopoietin
Thymulin
Somatotropin
Thymic Humoral Factor
Thyroxin
Adrenocorticosterioids

Front 51

Hormones required for T Cell Maturation:
Thymosin

Back 51

produced by epithelioreticular cells

Front 52

Hormones required for T Cell Maturation:
Thymopoietin

Back 52

produced by epithelioreticular cells

Front 53

Hormones required for T Cell Maturation:
Thymulin

Back 53

produced by epithelioreticular cells

Front 54

Hormones required for T Cell Maturation:
Somatotropin

Back 54

Produced by Pituitary

Front 55

Hormones required for T Cell Maturation:
Thymic Humoral Factor

Back 55

produced by epithelioreticular cells

Front 56

Hormones required for T Cell Maturation:
Thyroxin

Back 56

from thyroid
induces thymulin production from epithelioreticular cells

Front 57

Hormones required for T Cell Maturation:
Adrenocorticosteriods

Back 57

from adrenal gland
depresses T cell formation in Thymus

Front 58

Blood-Thymus Barrier importance

Back 58

protects immature T cells from Ag contact

Front 59

Components of Blood-Thymus Barrier:
Endothelium of Capillary Wall

Back 59

impermeable to macromolecules
major structural component

Front 60

Components of Blood-Thymus Barrier:
Macrophages

Back 60

phagocytose Ag that escape from capillary

Front 61

Components of Blood-Thymus Barrier:
Type 1 Epithelioreticular Cells

Back 61

Occluding Jxns
isolate developing T Cells

Front 62

Effects of absence of Thymus

Back 62

abnormal development of 3rd and 4th pharyngeal pouches
abnormal Cell-Mediated immunity
Normal Humoral Immunity
patients die of tetany or infection

Front 63

Thymus Involution

Back 63

expands as aging
T Cell differentiation and proliferation decrease
does not become totally nonfunctional

Front 64

Spleen General Features

Back 64

lacks a cortex and medulla
reticular fibers present

Front 65

Immune Fxns of Spleen

Back 65

Ag presentation by APCs
Activation and Proliferation of B an T Cells
Production of Abs
Removal of Macromolecular Ags from blood
Production of Abs by plasma cells

Front 66

Hemopoietic Function of Spleen (red pulp)

Back 66

formation RBC
Filter Blood
Phagocytose damaged RBC
retrieve Iron from RBC Hgb

Front 67

Where is Heme broken down into Bilirubin?

Back 67

Red Pulp of Spleen

Front 68

Is the spleen essential for life?

Back 68

no, Bone marrow and liver can take over fxn

Front 69

Spleen Histology

Back 69

Covered by Visceral Peritoneum (simple squamous)
capsule of dense irregular CT
Trabeculae CT extensions
Hilum on concave surface

Front 70

what is found in the hilum of the spleen?

Back 70

Splenic Artery and Vein
nerves and Lymphatic vessels

Front 71

Red Pulp of Spleen

Back 71

red due to RBC
Splenic Sinuses and cords present, filled w/ blood

Front 72

Red Pulp Sinuses:
lining endothelial cells

Back 72

few contact points b/t cells
allows easy passage of cell in and out of sinus

Front 73

Red Pulp Sinuses:
Macrophages

Back 73

extend b/t endothelial cells into lumen
monitors passing blood for foreign Ags

Front 74

Red Pulp Sinuses:
Basil Lamina

Back 74

NO continuous basal lamina present
strands present and wrap outside of sinus

Front 75

Red Pulp Sinuses:
Reticular Cells

Back 75

processes extend to basal side of endothelium

Front 76

How do Macrophages ID abnormal RBC?

Back 76

RBC morphologic and biochemical change
coated w/ specific Abs
causes phagocytosis

Front 77

Breakdown of Hgb from RBC

Back 77

macrophages and lysozomes
Iron is transported to Bone Marrow
Heme is changed to Bilirubin, sent to liver

Front 78

Spleen White Pulp General Features

Back 78

mostly lymphocytes
Basophilic

Front 79

What artery is found in white pulp of spleen?

Back 79

Central Artery

Front 80

What is the Lymphocytic aggregation around the central artery in white pulp of spleen?

Back 80

Periarterial Lymphatic Sheath (PALS)

Front 81

Splenic Circulation

Back 81

Splenic Artery--> white pulp trabeculae-->red pulp trabeculae-->pulp arteriole-->terminal capillaries-->empty in splenic cords

Front 82

how does blood in the spleen return to circulation?

Back 82

through the walls of the splenic sinuses (Open Circulation)

Front 83

what is the only route of blood to return to circulation from the Spleen?

Back 83

Open Circulation Only