Immune System and Lymphoid Organs

Question 1

It provides defense or immunity against infectious agents ranging from viruses to multicellular parasites.

Answer 1

Immune System

Question 2

The Immune System consists of a large, diverse population of ________ located within every tissue of the body and ________ interconnected only by the blood and lymphatic circulation.

Answer 2

leukocytes and lymphoid organs

Question 3

Lymphoid organs are interconnected only by ______ and _______.

Answer 3

blood and lymphatic circulation

Question 4

Main function of the Immune System

Answer 4

Defense and Immunity against pathogens

Question 5

It represents the first line of defense to an intruding pathogen.

Answer 5

Innate Immunity (Non-Specific)

Question 6

An antigen-independent defense mechanism that is used by the host immediately or within hours of encountering an antigen.

Answer 6

Innate Immunity (Non-Specific)

Question 7

Why is innate immunity antigen-independent?

Answer 7

Because it does not need to be exposed to the pathogen in order to develop immunity against it.

Question 8

_____ includes physical barriers such as the skin and mucous membranes.

Answer 8

Innate Immunity (Non-Specific)

Question 9

_____ involves leukocytes (mainly granulocytes) and proteins such as defensins, lysozymes, complement, and interferons.

Answer 9

Innate Immunity (Non-Specific)

Question 10

Proteins or Anti-microbial Chemicals involved in Innate Immunity

Answer 10

1. Hydrochloric Acid
2. Defensins
3. Lysozymes
4. Complement
5. Interferons

Question 11

It lowers the pH to kill entering microorganisms directly or inhabit their growth.

Answer 11

Hydrochloric Acid

Question 12

Short cationic polypepties produced by neutrophils which disrupts the cell wall of the bacteria.

Answer 12

Defensins

Question 13

An enzyme made by neutrophils, which hydrolyzes the cell wall components, killing the bacteria.

Answer 13

Lysozymes

Question 14

A system of proteins that react with bacterial surface components to aid removal of bacteria.

Answer 14

Complement

Question 15

Paracrine factors that signal NK cells to kill such cells and adjacent cells to resist viral infections.

Answer 15

Interferons

Question 16

It is acquired gradually by exposure to microorganisms.

Answer 16

Adapative Immunity (Specific)

Question 17

A more specific and slow development defense mechanism based on antigen presentation to lymphocytes.

Answer 17

Adapative Immunity (Specific)

Question 18

Adaptive Immunity response involves ________ and _______ lymphocytes.

Answer 18

T and B Lymphocytes

Question 19

_____ involves the production of memory lymphocytes so that a similar response can be mounted very rapidly if that invader appears again.

Answer 19

Adaptive Immunity (Specific)

Question 20

These are proteins that are recognized by lymphocytes to elicit a specific immune response against them.

Answer 20

Antigens

Question 21

These are components of bacteria, protozoa, or tumor cells, etc.

Answer 21

Antigens

Question 22

These are Immunoglobulins produced by plasma cells after a progenitor B cell is activated by a specific antigen.

Answer 22

Antibodies

Question 23

It produces immunoglobulins.

Answer 23

Plasma Cells

Question 24

How are immunoglobulins produced?

Answer 24

It is produced when a specific antigen activates a progenitor B cell.

Question 25

These are **cell surface glycoproteins** whose primary function is to **present peptide fragments for recognition** by the appropriate T-cells (lymphocytes).

Answer 25

Major Histocompatibility Complexes (MHC)

Question 26

MHC are _______ that present peptide fragments to T-cells.

Answer 26

cell surface glycoproteins

Question 27

MHC are cell surface glycoproteins that present peptide fragments to ______.

Answer 27

T-cells

Question 28

These are **found on surfaces of all nucleated cells** bear fragments of their constituent proteins.

Answer 28

MHC Class I Molecules

Question 29

It involves only **antigen-presenting cells** (APCs).

Answer 29

MHC Class II Molecules

Question 30

MHC Class I and II Molecules Function

Answer 30

To present peptides to be recognized by T-cells on the cell surface.

Question 31

Humoral Immunity involved organisms

Answer 31

1. Antibodies 2. B-cell Lymphocytes

Question 32

Cell-mediated Immunity involved organisms

Answer 32

1. Mature T-cell Lymphocytes 2. Macrophages 3. Cytokines

Question 33

Two Forms of Adaptive Immune Response

Answer 33

1. Humoral Immunity 2. Cell-mediated Immunity

Question 34

A type of immune cell that **makes antibodies after detecting a specific antigen**.

Answer 34

B-cell Lymphocytes

Question 35

The stem cells for all lymphocytes are located in the ________.

Answer 35

red bone marrow

Question 36

The sites for lymphocyte origination and maturation.

Answer 36

**Primary Lymphoid Organs** (Bone Marrow and Thymus)

Question 37

The bone marrow and thymus are part of the ________.

Answer 37

Primary Lymphoid Organs

Question 38

It is the site where the **cells destined to become B-lymphocytes** are found.

Answer 38

Bone Marrow

Question 39

It is the site where **progenitors of T-lymphocytes** are found.

Answer 39

Thymus

Question 40

______ remain and further differentiate in the bone marrow.

Answer 40

B-lymphocytes

Question 41

_______ move via the circulation into the developing thymus.

Answer 41

Progenitors of T-lymphocytes

Question 42

Primary Lymphoid Organs

Answer 42

1. Bone Marrow 2. Thymus

Question 43

Secondary Lymphoid Organs

Answer 43

1. Lymph Nodes 2. MALT 3. Spleen

Question 44

The **site where lymphoid organs** are often **activated**, **proliferate**, and begin to **function**.

Answer 44

**Secondary Lymphoid Organs** (Lymph Nods, MALT, Spleen)

Question 45

Secondary lymphoid organs contain a meshwork of ______ produced by fibroblastic reticular cells.

Answer 45

Reticulin

Question 46

This is where lymphocytes are being distributed.

Answer 46

Reticulin

Question 47

Reticulin is produced by _______.

Answer 47

Fibroblastic Reticular Cells

Question 48

Thymus originated from the _______.

Answer 48

Endoderm

Question 49

The primary lymphoid organ where T-cells are produced.

Answer 49

Thymus

Question 50

A bilobed organ in the mediastinum

Answer 50

Thymus

Question 51

Thymus is (unilobed or bilobed)?

Answer 51

Bilobed

Question 52

Thymus is located in the _______.

Answer 52

mediastinum

Question 53

Thymus is most active and prominent during ________.

Answer 53

Pre-puberty (before puberty)

Question 54

Thymus undergoes ____ with less activity in adults.

Answer 54

Involution (shrink)

Question 55

An organ that undergoes involution as people get old.

Answer 55

Thymus

Question 56

The midline of the thoracic cavity, surrounded by pleural sacs.

Answer 56

Mediastinum

Question 57

Two Divisions of the Thymus

Answer 57

1. Thymic Cortex 2. Thymic Medulla

Question 58

An **outer layer** of the Thymus that is **darkly basophilic**.

Answer 58

Thymic Cortex

Question 59

**Immature T-cells** are called _______.

Answer 59

T-lymphoblasts (thymocytes)

Question 60

_______ have certain features of both epithelial and reticular cells.

Answer 60

Thymic Epithelial Cells (TEC)

Question 61

The ____ contains an **extensive population of T-lymphoblasts** and **Thymic Epithelial Cells** (TEC).

Answer 61

Thymic Cortex

Question 62

The **Thymic Cortex** contains an extensive population of __________ .

Answer 62

T-lymphoblasts and Thymic Epithelial Cells (TEC)

Question 63

Thymic Epithelial Cells (TECs) in the Thymic Cortex

Answer 63

1. Squamous Cells 2. Stellate Epithelial Cells 3. Squamous Cortical Cells

Question 64

It **forms a blood-thymus barrier** preventing unregulated exposure of thymocytes to antigens.

Answer 64

Squamous Cells

Question 65

Squamous cells form a _______.

Answer 65

blood thymus barrier

Question 66

It **prevents unregulated exposure** of thymocytes to antigens.

Answer 66

Blood-Thymus Barrier

Question 67

It **forms a cytoreticulum** that secretes numerous cytokines for T-cell development.

Answer 67

Stellate Epithelial Cells

Question 68

Stellate epithelial cells form a _______.

Answer 68

Cytoreticulum

Question 69

It **secretes numerous cytokines** for T-cell development.

Answer 69

Cytoreticulum

Question 70

It forms a **sheetlike structure** contributing to a functional **corticomedullary barrier** between cortex and medulla.

Answer 70

Squamous Cortical Cells

Question 71

Squamous cortical cells produce a ______.

Answer 71

Sheetlike structure contributing to corticomedullary barrier

Question 72

An **inner layer** of the Thymus that is **lightly stained**.

Answer 72

Thymic Medulla

Question 73

The **Thymic Medulla** contains fewer, and larger more __________ .

Answer 73

Mature Lymphocytes

Question 74

The ____ contains a fewer and larger **mature lymphocytes**.

Answer 74

Thymic Medulla

Question 75

Thymic Epithelial Cells (TECs) in the Thymic Medulla

Answer 75

1. Cytoreticulum 2. Secondary Layer 3. Hassal Corpuscles

Question 76

It **supports T-lymphocytes**, dendritic cells, and macrophages.

Answer 76

Cytoreticulum

Question 77

It **expresses many specialized proteins** specific to the cells of other organs.

Answer 77

Cytoreticulum

Question 78

It serves as the **boundary between the cortex and medulla**.

Answer 78

Secondary Layer

Question 79

These are **large aggregates of TECs**.

Answer 79

Hassall Corpuscles

Question 80

MALT stands for ________.

Answer 80

**M**ucosa-**A**ssociated **L**ymphoid **T**issue

Question 81

MALT is found in the ________.

Answer 81

Mucosa of most tracts

Question 82

MALT is concentrated in the _______.

Answer 82

* Palatine * Lingual and Pharyngeal Tonsils * Peyer Patches * Appendix

Question 83

One of the largest lymphoid organs, containing 70% of immune cells.

Answer 83

MALT

Question 84

MALT is one of the largest lymphoid organs, containing ______ of immune cells.

Answer 84

70%

Question 85

Most of the lymphocytes in MALT is _______.

Answer 85

B cells

Question 86

Among T cells in MALT _______ predominate.

Answer 86

CD4+ Helper T Cells

Question 87

These are **bean-shaped, encapsulated structures** measuring 10 mm by 2.5 cm.

Answer 87

Lymph Nodes

Question 88

It **filters lymph**, and it functions as the **site of B-cell activation and differentiation.**

Answer 88

Lymph Nodes

Question 89

Compartments of Lymph Nodes

Answer 89

1. Outer Cortex 2. Paracortex 3. Inner Medulla

Question 90

The **first point of entry** of lymphocytes to the entire Lymph Node.

Answer 90

Outer Cortex

Question 91

The site where **B cells encounter antibodies**.

Answer 91

Outer Cortex

Question 92

Lymphocytes will enter the paracortex via __________.

Answer 92

High Endothelial Venules (HEVs)

Question 93

The portal of entry for Lymphocytes to the paracortex.

Answer 93

High Endothelial Venules (HEVs)

Question 94

The Lymphocytes will enter the ______ via High Endothelial Venules (HEVs).

Answer 94

Paracortex

Question 95

It is subdivided into: Medullary cords and Medullary sinuses

Answer 95

Inner Medulla

Question 96

Inner medulla is subdivided into ________.

Answer 96

* Medullary Cords * Medullary Sinuses

Question 97

It is where the blood vessels and nerves enter.

Answer 97

Hilum

Question 98

The only lymphoid organ involved in the filtration of blood.

Answer 98

Spleen

Question 99

An important organ in defense against blood-borned antigens.

Answer 99

Spleen

Question 100

The main site of old erythrocyte destruction.

Answer 100

Spleen

Question 101

**TRUE OR FALSE.** The spleen has a cortex and medulla.

Answer 101

False

Question 102

Two Intermingled Regions of the Spleen

Answer 102

* White Pulp * Red Pulp

Question 103

It makes up 20% of the spleen.

Answer 103

White Pulp

Question 104

It is **enclosed by periarteriolar lymphoid sheaths** (PALS) of T cells.

Answer 104

White Pulp

Question 105

Region of spleen that **filter blood**.

Answer 105

Red Pulp

Question 106

Region of spleen that **removes defective erythrocytes**.

Answer 106

Red Pulp

Question 107

Region of spleen that **recycles hemoglobin iron.**

Answer 107

Red Pulp

Question 108

It contains macrophages, reticular cells and fibers, and other leukocytes.

Answer 108

Splenic Cords (Cords of Billroth)

Question 109

It is **lined by unusual endothelial cells** called ***stave cells*** that are elongated and aligned parallel to the blood flow.

Answer 109

Splenic Sinusoids

Question 110

Splenic Sinusoids are lined by unsual endothelial cells called _____.

Answer 110

Stave Cells

Question 111

PALS stands for ________.

Answer 111

Periarteriolar Lymphoid Sheaths