Lect 2 - -Lymphatic organs Flashcards

1
Q

What is the function of The Immune System

A

distinguishing between self or non-self, dangerous or non-dangerous and responding to those with tolerance or elimination.

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2
Q

What is Immunohomeostasis?

A

maintenance of the genomic permanency

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3
Q

What is Antigen?

A

every structure (cells, molecules, microbes) that the immune system recognizes and responds to it

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4
Q

Steps of Innate immune system?

A

Cells → cellular immune response
(Monocytes - macrophages
Granulocytes
Dendritic cells
Mast cells)

Soluble molecules → humoral immune response
Complement proteins (glycoproteins, enzymes, receptors)

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5
Q

Steps of adaptive immune system

A

Cells → cellular immune response
(B lymphocytes
T lymphocytes)

Soluble molecules → humoral immune response (Antibodies)

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6
Q

Activation of the Innate System
-> What are some recognized structures?

A

Pathogen Associated Molecular Pattern (PAMP), or Damage-Associated Molecular Patterns (DAMP)

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7
Q

What are Receptors in Activation of the Innate System?

A

Pattern Recognizing Receptors (PRR).
(They are not clonal. They are the same on different cell types. )

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8
Q

Function of Major Histocompatibility Complex:MHC-I

A

MHC I displays endogenous antigens, or antigens from within the cell
- a diverse set of cell surface receptors expressed on all nucleated cells in the body, as well as platelets.

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9
Q

Function of Major Histocompatibility Complex: MHC-II

A

MHC II displays exogenous antigens, or antigens from outside the cell
- MHC class II molecules thereby are critical for the initiation of the antigen-specific immune response.

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10
Q

Origin of Antigens

A

originated from lipids join to CD1, peptide antigens join to MHC-I or MHC-II.

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11
Q

Antigen presentation
-> Antigen processing of endogenous proteins (the host cell synthesizes foreign proteins with tumour cell like characteristics in viral or bacterial infected cells).

A

proteasome (enzymes)
→ ER (peptide fragments join to MHC-I
→ Golgi
→ vesicular transport
→ appearance on the cell surface

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12
Q

Antigen presentation
-> Antigen processing of Exogenous proteins (the host cell synthesizes foreign proteins with tumour cell like characteristics in viral or bacterial infected cells).

A

endo- and lysosome system
→ protected MHC II - formed in the ER join to vesicular system
→ protein binds to MHC-II
→ appearance on the cell surface

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13
Q

The role of NK cells

A

NK cells express „Killer Activating Receptor (KAR) „ and „Killer Inhibitory Receptor” (KIR).

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14
Q

Steps of activation of NK cells

A
  1. Binding „self” MHC-I molecules to the KIRs inhibits the KARs.
  2. NK cell does not destroy self. Virus infected and tumour cells decrease the MHC-I expression to hide themselves from cytotoxic T-cells.
    => Therefore there is no enough MHC-I to activate the KIR so the NK cells attack.

(NK cells express „Killer Activating Receptor (KAR) „ and „Killer Inhibitory Receptor” (KIR). )

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15
Q

Does NK cells destroy itself? Why?

A

NK cell does not destroy self.
=> Virus infected and tumour cells decrease the MHC-I expression to hide themselves from cytotoxic T-cells.
=> Therefore there is no enough MHC-I to activate the KIR so the NK cells attack.

(NK cells express „Killer Activating Receptor (KAR) „ and „Killer Inhibitory Receptor” (KIR). )

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16
Q

Virus infected and tumour cells decrease the MHC-I expression to hide themselves from ____ (which type of cells?)

A

cytotoxic T-cells

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17
Q

What is CD (Clusters of Differentiation)?

A

The cell surface molecules that determine the type of the cell, the stage of the differentiation or activation.

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18
Q

Example of Cell line markers

A

1/ Hemopoietic stem cell CD34+
2/ T-helper cell - CD4+
3/ T-citotoxic-CD8+

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19
Q

2 types of cell line markers

A
  1. Maturation markers
  2. Activation markers
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20
Q

Examples of maturation markers

A

Tymocytes in the thymus CD1+, mature T lymphocyte does not express this

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21
Q

What are Cytokines?

A

small peptides or glycoproteins that regulate the cell functions in the immune system through receptor mediated pathways.

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22
Q

What are Lymphokines?

A

cytokines produced by lymphoid cells.

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23
Q

5 types of Antibodies – Immunoglobulins (Ig)

A

1/ IgM
2/ IgD
3/ IgG
4/ IgA
5/ IgE

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24
Q

Identify the 5 types of antibodies

A
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25
Q

What is IgM?

A

naive B cell antigen binding receptor

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26
Q

What is IgD?

A

naive B cell antigen binding receptor

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27
Q

What is IgG?

A

„switched” B cell antigen binding receptor (opsonisation, complement activation, maternal immunity)

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28
Q

What is IgA?

A

„switched” B cell antigen binding receptor (mucosa immunity)

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29
Q

What is IgE?

A

„switched” B cell antigen binding receptor (immediate hypersensitivity)

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30
Q

What does it mean when it comes to Diversity of the Antigen Binding Receptors?

A

Genetic mechanism that results in diversity and specificity is the somatic recombination of genes that code the antigen binding site of the immunoglobulins and T-cell receptors.

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31
Q

What is B-cell Receptor (BCR)?

A

membrane bound immunoglobulin molecule with signal transduction chains

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32
Q

BCR: membrane bound immunoglobulin molecule with signal transduction chains.
-> BCR reacts with _____

A

soluble or corpuscular antigens

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33
Q

Antigen-activated B-cells may follow two pathways which are ____ and ____

A

1/ T-dependent activation
2/T-independent activation

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34
Q

How does T-dependent activation occur?

A

T-cell-independent antigen, B cells will proliferate and differentiate into short-living (SL) plasma cells and release low-affinity antibodies (first-line defence)

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35
Q

How does T-independent activation occur?

A

(2) T-cell-dependent antigen, B cells proliferate, undergo somatic hypermutations and isotype class switch, and differentiate into either long-living (LL) plasma cells releasing high-affinity antibodies and memory B cells.

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36
Q

T-cell Receptor (TCR) coded by ___

A

genes belonging to the Ig super-family

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37
Q

T-cell Receptor (TCR) recognize only ___

A

linear sequence of peptide fragments that join to MHC molecules!!!

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38
Q

Is TCR-MHC-antigen binding enough for T-cell activation? Why?

A

TCR-MHC-antigen binding is not enough for T-cell activation.
-> Co-stimulatory molecules are necessary!!!

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39
Q

What are included in cellular immune response?

A
  1. Production of cytokines (lymphokines) – activation of macrophages
  2. Regulation of inflammatory and cytotoxic processes
  3. Defense against intracellular pathogens
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40
Q

What are the 2 responses relating to T-cell classes?

A
  1. Cellular immune response
  2. Humoral immune response
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41
Q

What are included in humoral immune response?

A
  1. Production of lymphokines – activation of B cells
  2. Differentiation into plasma cells
  3. Defense against extracellular pathogens
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42
Q

What is included in regulation of immune response?

A

Production of lymphokines

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43
Q

The role of T-cell classes

A

Destroys virus or intracellular pathogen infected or tumour cells (perforin, granular enzymes.)

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44
Q

3 Organization Levels of the Immune System

A
  1. Cells: cells of the innate and adaptive immune system
  2. Tissues: blood and lymphatic tissues
  3. Organs: lymphatic organs
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45
Q

Organization of Lymphatic Organs
-> What are the 2 Primary (central) lymphatic organs?

A
  1. Bone marrow
  2. Thymus
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46
Q

Organization of Lymphatic Organs
-> Primary (central) lymphatic organs
-> The role of Bone marrow

A

formation of T and B lymphocyte and maturation of B-cells

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47
Q

Organization of Lymphatic Organs
-> Primary (central) lymphatic organs
-> The role of Thymus (thymus gland)

A

maturation of T-cells

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48
Q

Organization of Lymphatic Organs
-> What are the 5 Secondary (peripheral) lymphatic organs?

A
  1. Mucosa Associated Lymphatic Tissue (MALT: antigen in the mucosa)
  2. Skin Associated lymphatic Tissue (SALT), antigen in the skin)
  3. Lymph and lymph node (antigen in tissues)
  4. Spleen (antigen in the blood)
  5. Gastriontestinal tract (digestive tract) GALT
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49
Q

Organization of Lymphatic Organs
-> The role of Secondary (peripheral) lymphatic organs

A

„meeting with the antigens”
→ activation of B and T cells

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50
Q

Different Forms of Lymphatic Tissue
-> Identify this form of lymphatic tissue

A

Diffuse lymphoid elements (lymphocytes)

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51
Q

Different Forms of Lymphatic Tissue
-> Identify this form of lymphatic tissue

A

Aggregated lymph nodules (pl. Payer’s plaque)

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52
Q

Different Forms of Lymphatic Tissue
-> Identify this form of lymphatic tissue

A

Lymph node

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53
Q

Different Forms of Lymphatic Tissue
-> Identify this form of lymphatic tissue

A

Solitary lymph nodule or follicle

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54
Q

Different Forms of Lymphatic Tissue
-> Identify this form of lymphatic tissue

A

Epithelium related lymphatic tissue : tonsils

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55
Q

Different Forms of Lymphatic Tissue
-> Identify this form of lymphatic tissue

A

spleen

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56
Q

Different Forms of Lymphatic Tissue
-> Identify this form of lymphatic tissue

A

Thymus

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57
Q

Types of lymphatic organs

A

Capsulated lymphatic organs

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58
Q

Primary Lymphatic Organ: Thymus
-> What is the arterial supply?

A

a. thoracica interna, a. pericardiophrenica, a. thyroidea sup. et. inf.

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59
Q

Primary Lymphatic Organ: Thymus
-> What is the venous supply?

A

v. brachiocephalica

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60
Q

Primary Lymphatic Organ: Thymus
-> What are the included lymph vessels?

A

only efferents!!!
-> Anterior mediastinal lymph nodes

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61
Q

Primary Lymphatic Organ: Thymus
-> What is the Vegetative innervation?

A

n. vagus, sympathetic innervation

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62
Q

Histology of the Thymus
-> Identify

A

Pseudo-lobules

63
Q

Thymus, foetal H&E
-> Connective tissue trabeculae (interlobular septum) divide the lobes into ______

A

(pseudo)lobules.

64
Q

Histology of the Thymus
-> Each lobule has a peripheral darkly stained region called (1)___ and a central light area called the (2)____

A
  1. cortex
  2. medulla
65
Q

Histology of the Thymus
-> Each lobule has a peripheral darkly stained region called (1)___ and a central light area called the (2)____

A
  1. cortex
  2. medulla
66
Q

Cells of the Thymus
-> Which thymus cells are included cortex?

A

(5) cortical epithelial reticular cells secreting thymoxatin, thymosin, thymopoietin
(2) nurse cells (expressing MHC-II and T lymphocytes called thymocytes develope among their processes)
(9) macrophage

67
Q

Cells of the Thymus
-> Which thymus cells are included in Cortico-medullary junction?

A

(6) medullary epithelial reticular cells (larger than the cortical ones, PTH, CRP, insulin)
(7) dendritic cells (APC from the bone marrow), macrophages, eosinophils

68
Q

Cells of the Thymus
-> Which thymus cells are included in Cortico-medullary junction?

A

(6) medullary epithelial reticular cells (larger than the cortical ones, PTH, CRP, insulin)
(7) dendritic cells (APC from the bone marrow), macrophages, eosinophils

69
Q

Cells of the Thymus
-> Which thymus cells are included in medulla?

A

(6) medullary epithelial reticular cells, Hassal- body (keratinized epithelial cells type VI), macrophage, dendritic cells, Hammar myoid cell

70
Q

Type VI Epithelial Reticular Cells, Hassal body
-> Identify

A
71
Q

Type VI Epithelial Reticular Cells, Hassal body
-> Identify

A
72
Q

Type VI Epithelial Reticular Cells, Hassal body
-> Identify

A
73
Q

What is Hassel body?

A

concentrically located flattened, eosinophilic, epithelial reticular cells connected with desmosomes.

74
Q

What are accumulated in the centre of Hassal body?

A

Keratohyalin and cytokeratin

75
Q

Dendritic Cells (DC)
-> Identify

A

1/ Lymphocyte
2/ Dendritic cell

76
Q

Where do Dendritic Cells (DC) originate from?

A

the bone marrow

77
Q

Identify this cell

A

Dendritic Cell (DC)

78
Q

Maturation of T cells
-> T progenitor (pro-T) cells from the bone marrow enter the Thymus through ____

A

the venules of the cortico-medullary junction

79
Q

Maturation of T cells
-> T progenitor (pro-T) cells from the bone marrow enter the Thymus through the venules of the cortico-medullary junction
→ They move into the ____ region and intensively proliferate.

A

subcapsular

80
Q

Maturation of T cells
-> T progenitor (pro-T) cells from the bone marrow enter the Thymus through the venules of the cortico-medullary junction
→ They move into the subcapsular region and intensively proliferate.
-> Do they express CD8 or CD4?

A

They do not express neither CD8 nor CD4 receptor, double negative T cells (DN)

81
Q

Maturation of T cells
-> T progenitor (pro-T) cells move into the subcapsular region and intensively proliferate
-> They do not express neither CD8 nor CD4 receptor, double negative T cells (DN)
-> What will make them expressing CD8 and CD4?

A

Environmental signal molecules induce the expression of TCR-s (genetic recombination) and CD4 and CD8, double positive T cells (DP)

82
Q

Maturation of T cells
-> T progenitor (pro-T) cells move into the subcapsular region and intensively proliferate
-> They do not express neither CD8 nor CD4 receptor, double negative T cells (DN)
→ They migrate toward ____

A

the medulla

83
Q

Maturation of T cells
-> T progenitor (pro-T) cells move into the subcapsular region and intensively proliferate
-> They do not express neither CD8 nor CD4 receptor, double negative T cells (DN)
→ They migrate toward the medulla and meet with their own ____

A

MHC molecules presented by nurse cells, epithelial reticular cells, dendritic cells, macrophages).

84
Q

Maturation of T cells
-> T progenitor (pro-T) cells move into the subcapsular region and intensively proliferate
-> They do not express neither CD8 nor CD4 receptor, double negative T cells (DN)
→ They migrate toward the medulla and meet with their own ____

A

the venules of the cortico-medullary junction

85
Q

Maturation of T cells
-> T progenitor (pro-T) cells move into the subcapsular region and intensively proliferate
-> They do not express neither CD8 nor CD4 receptor, double negative T cells (DN)
→ They migrate toward the medulla and meet with their own MHC molecules presented by nurse cells, epithelial reticular cells, dendritic cells, macrophages).
-> Those thymocytes that recognize at least one of the MHC-s (MHC restriction) will survive.
-> Others (90%) die by apoptosis.
-> This process is called ___

A

Positive selection

86
Q

Barriers in the Thymus
-> Identify

A
87
Q

Barriers in the Thymus
-> Tightly arranged _____ form a closed sheath under the capsule, around the trabeculae and vessels to form an inpermeable barrier to macromolecules to protect the thymocytes from contact with foreign antigens.

A

subcapsular epithelial cells (3)

88
Q

Barriers in the Thymus
-> Tightly arranged subcapsular epithelial cells (3) form a closed sheath under the capsule, around the trabeculae and vessels to form an inpermeable barrier to macromolecules to protect ____ from contact with foreign antigens.

A

the thymocytes

89
Q

Barriers in the Thymus
-> Tightly arranged _____ form a closed sheath under the capsule, around the trabeculae and vessels to form an inpermeable barrier to macromolecules to protect the thymocytes from contact with foreign antigens.

A

subcapsular epithelial cells (3)

90
Q

Barriers in the Thymus
-> Tightly arranged sub-capsular epithelial cells (3) form a closed sheath under the capsule, around ___ and ____ to form an impermeable barrier to macromolecules to protect the thymocytes from contact with foreign antigens.

A

the trabeculae and vessels

91
Q

What are the 5 Layers of blood-thymus barrier?

A
  1. Epithelial reticular cells (contacted with each other by desmosomes and tight junctions, type I)
  2. Basal lamina of the epithelial reticular cells
  3. Perivascular connective tissue septa with macrophages
  4. Basal lamina of the endothels
  5. Capillary endothels
92
Q

General Features of Peripheral Lymphatic Organs
-> Name of lymphoid cells

A

B and T lymphocytes, plasma cells, NK cells,

93
Q

General Features of Peripheral Lymphatic Organs
-> Name of accessory cells

A

Macrophages and dendritic cells

94
Q

The role of of follicular dendritic cells (FDC)

A
  • bind native antigens
  • help the differentiation of B-cells in the germinal center of the lymphatic nodule (B- dependent area)
95
Q

The role of dendritic cells (interdigitating dendritic cell)

A

It present MHC-II joined antigens to the Th cells in the T- dependent area of lymphatic organs, (eg. Langerhans cells of the skin, interstitial dendritic cells in the connective tissue)

96
Q

What are some Vessels characterize peripheral lymphatic organs?

A
  1. blood vessels (with high endothelial venules, HEV)
  2. lymph capillaries
97
Q

Special formations of of Peripheral Lymphatic Organs?

A

lymphatic nodules (follicles)

98
Q

Reticular cell
-> Identify

A
99
Q

What does primary follicles contain?

A

reticulum cells, resting naive B-lymphocytes (antigen free environment, e.g. intrauterine life)

100
Q

What do secondary follicles contain?

A
  1. Cap (like the primer follicle).
  2. Germinal centre (centrum germinativum): dark zone - B lymphoblasts (centroblasts), dividing forms light zone-smaller centrocytes , follicular dendritic cells, macrophages
101
Q

Which reaction occur in germinal center?

A

B-cell activation

102
Q

Germinal Centre - Reaction: B-cell activation
-> Identify

A
103
Q

Germinal Centre - Reaction: B-cell activation
-> Identify (red squares)

A

tingible body macrophage

104
Q

Why are there two types of dendritic cell ???

A
105
Q

Naive B-cells, macrophages, follicular dendritic cells are the main cell types in the ____

A

Follicle

106
Q

naive T cells, dendritic cells, macrophages are located in the ____

A

interfollicular areas.

107
Q

Identify

A
108
Q

General Features of Tonsils
-> What does MALT – Mucosa Associated Lymphatic Tissue contain?

A
  1. Lymphoepithelial tissue
  2. Lymphoreticular tissue
  3. Crypts
109
Q

What is Lymphoepithelial tissue?

A

the epithelium is infiltrated with lymphatic cells

110
Q

What are the characteristics of Lymphoreticular connective tissue with lymphatic nodules?

A
  1. The follicles are B-dependent areas.
  2. Among the follicles, T-dependent areas are with blood vessels (HEV), and lymph capillaries.
111
Q

What are crypts (fossula, lacuna)?

A

epithelial invaginations (increasing the surface for immune response)

112
Q

Histology of Lingual Tonsil
-> Identify

A
  1. Crypt lined with stratified squamous non-keratinized epithelium
  2. Mucosa-associated lymphoid tissue (MALT)
  3. Germinal center
  4. Skeletal muscle fibers
  5. Seromucous accessory salivary glands (lingual salivary glands)
113
Q

Histology of Palatine Tonsil
-> Type of epithelium

A

stratified squamous non-keratinizing epithelium infiltrated with lymphoid cells.

114
Q

Histology of Palatine Tonsil
-> are the crypts deep?

A

Crypts are deep and branched
(during bacterial infection (strepto- or staphylococcus) the crypts are filled with neutrophils → pus

115
Q

Histology of Palatine Tonsil
-> What is Hemicapsule?

A

a band of dense connective tissue acting as a capsule separating the lymphoid tissue from the subjacent structure

116
Q

Histology of Palatine Tonsil
-> Function of hemicapsule

A

barrier against to spread infections (area for tonsillectomy)

117
Q

Histology of Palatine Tonsil
-> Embryology
-> Palatine tonsil is a derivative of ____

A

The 2nd pharyngeal pouch

118
Q

Histology of Palatine Tonsil
-> Identify E and F

A

E - Epithelium: stratified squamous non-keratinizing epithelium infiltrated with lymphoid cells.
F - Follicles (Lymphoreticular connective tissue with follicles)

119
Q

Histology of Pharyngeal Tonsil
-> Describe the epithelium

A

ciliated pseudostratified columnar epithelium (with islands of stratified squamous non-keratinizing epithelium on the top of the folds and in the pits) infiltrated with lymphoid cells.

120
Q

Identify

A

MALT: Peyer’s Patches

121
Q

What is lymph?

A

: interstitial (extracellular) fluid with some red blood cells and lymphoid cells.

122
Q

What is Lymph capillary?

A

thin endothelial cells formed tubes covered by basal lamina and connective tissue fibers

123
Q

Does lymph capillary contain valves? Why?

A

It contains valves that determine the direction of the lymph flow

124
Q

What are lymphatic ducts?

A

the largest lymph vessels (intima: endothel, elastic fibers, media: circular smooth muscle cells, adventitia: spiralry organized smooth muscle cells mixed with connective tissue fibers

125
Q

Lymphokinetic motion and pressure gradient

A

Capillary →extracellular fluid→lymph capillary→ vasa lymphatica→ lymphatic duct →large vein

126
Q

Lymph and Blood Circulation
-> How can fluid go from lymph capillary to large veins?

A

Lymph capillary → vasa lymphatica → lymphatic duct → large veins

127
Q

Lymph node
-> Identify

A
128
Q

Lymph node
-> What does the cortex contain?

A

dense parenchyma with follicles and less sinusoids

129
Q

Lymph node
-> What does the paracortex contain?

A

dense parenchyma less sinuses, no follicles

130
Q

Lymph node
-> What does the medulla contain?

A

lymph sinusoids, with parenchyma (medullary cords) extending from the cortex

131
Q

Identify

A

Reticular cells

132
Q

Lymph node
-> identify

A

1 - medulla
2 - cortex

133
Q

Lymph node
-> Identify

A

1/ medullary cord
2/ medullary sinus
3/ trabecule
4/ follicle

134
Q

Identify 1 -> 3

A
135
Q

What does cortex contain?

A

follicles (B dependent area) with follicular dendritic cells and follicular macrophages, interfollicular zone (T-dependent area as the paracortex),

136
Q

What does paracortex contain?

A

T lymphocytes , dendritic cells, macrophages, HEV

137
Q

Identify MS and MC

A

MC - medullary cord
MS - medullary sinus

138
Q

Identify MS and MC

A

MC - medullary cord
MS - medullary sinus

139
Q

Medulla
-> What does medullary cord have?

A

B cells
Few T cells
Plasma cells

140
Q

Medulla
-> What does medullary sinus have?

A

flat reticular cells (sinusendothel) covered vessels in which lymph and cells are located (lymphocytes, plasma cells, macrophages)

141
Q

Write down Lymph route

A

vasa afferentia
-> marginal sinus (subcapsular)
-> trabecular sinus
-> medullary sinus
-> vasa efferentia

142
Q

Write down blood circulation

A

Blood circulation: (enter through the hilus) artery → capillary → postcapillary venule (HEV) → hilar vein

143
Q

Where are High Endothelial Venule located?

A

Mainly in paracortex

144
Q

Describe endothelium of High Endothelial Venule

A

The cuboidal or low columnar endothelial cells with large lightly stained nucleus.
-> Circulating lymphocytes leave the blood circulation (homing, 15-20 thousand cells/second!)

145
Q

Structure of the spleen

A
  1. Peritoneum (mesothel)
  2. Capsule: dense connective tissue (collagen, elastic fibres, myofibroblasts, smooth muscle cells)
  3. Trabeculae: similar to the capsule (but more elastic fibre among collagen) blood and lymph vessels, nerves
  4. Red pulp
  5. White pulp
146
Q

Spleen
-> Identify

A
  1. Red pulp
  2. White pulp with splenic nodules
147
Q

What does Red Pulp Sinusoid contain?

A
  1. Blood cell
  2. Hoop fibers
  3. Stave cells
148
Q

What does storm of red pulp contain?

A

reticular connective tissue (reticular fibres with reticulum cells)

149
Q

Spleen - Red pulp
-> Sinuses are separated by ____

A

splenic Cords of Billroth

150
Q

What do splenic Cords of Billroth have?

A

(The Cords of Billroth (also known as splenic cords or red pulp cords) are found in the red pulp of the spleen between the sinusoids)

  1. reticular fibres
  2. reticulum cells
  3. macrophages, plasma cells
  4. granulocytes
  5. thrombocytes
  6. red blood cells (red colour of the pulp).
151
Q

Red pulp of spleen
-> identify

A

1 - cell in transit
2 - sinusoids
3 - endothelium
4 - cell in transit

152
Q

Spleen
-> Where can you find white pulp?

A

White pulp (lymphoreticular connective tissue) around the central artery

153
Q

What does white pulp (lymphoreticular connective tissue) contain?

A
  1. PALS: periarterial lymphoid sheath.
  2. Follicles (splenic nodule, Malpighian follicle)
  3. Marginal zone