1.3 Cells and tissues of the immune system

Question 1

How do these travel through the blood?
- rbcs
- platelets
- wbcs

Answer 1

• rbcs: gaseous exchange
• platelets: clotting
• wbcs: immunity

Question 2

The bloodstream:

Answer 2

is just the motorway that WBCs use to get to the site of infection

Question 3

Macrophage function:

Answer 3

monocytes that have come from blood stream into a tissue carry on phagocytosis

Question 4

Phagocytosis of bacteria:

Answer 4

Granulocytes:
-neutrophils

Mononuclear cells:
- monocytes > macrophages

Question 5

Destruction of parasites:

Answer 5

GRANULOCYTES:
- eosinophils
- basophils (tissue mast cells)

Question 6

Immunity to viruses:

Answer 6

Mononuclear cells:
- lymphocytes

Question 7

Primary Lymphoid Organs and importance

Answer 7

Develops Lymphocyte:

Organs:
-bone marrow
-thymus

Question 8

Secondary Lymphoid Organs and function:

Answer 8

Lymphocyte response to infection:

Organs:
– Lymph nodes
– Spleen
– MALT (e.g. Peyer’s patches)

Question 9

Is the source of all lymphocytes?

Answer 9

Bone marrow

Question 10

Lymphoid precursors differentiate into?

Answer 10

B & T cells

Question 11

During lymphocyte development: B cells remain where?

Answer 11

In the bone marrow

Question 12

During lymphocyte development: T cells do what?

Answer 12

Leave bone marrow and go to the thymus

Question 13

Where in the Thymus located

Answer 13

In front of heart

Question 14

T cell development in the Thymus

Answer 14

– Each T cell must generate a unique antigen receptor (TCR).
– Each T cell must decide whether to become a CD4+ or CD8+ cell.
*initially expressed both

Question 15

T cell receptor (TCR) must engage with ?

Answer 15

MHC

Question 16

What happens to the TCRs that fail to interact with MHC molecules?

Answer 16

They are useless

Question 17

TCRs that recognize peptides from self antigens?

Answer 17

Are potentially dangerous

Question 18

The thymus screens T cells and disposed of those yay are

Answer 18

Unreactive or autoreactive

Question 19

Thymic Lymphoma (cats):

Answer 19

– Neoplasia of thymic lymphocytes
– Associated with FeLV infection
- Tumor in thymus

Clinical signs:
Anorexia, weight loss, dyspnoea

Question 20

B cells are located where in Birds?

Answer 20

Bursa of Fabricius
- Primary lymphoid organ for maturation and differentiation of B cells

Question 21

T cell location in Lymph nodes?

Answer 21

Paracortex

Question 22

B cell location in lymph nodes?

Answer 22

Follicles

Question 23

Lymph node function:

Answer 23

• Filters tissue fluid (lymph) and traps foreign organisms
• provides an environment for recognition of antigen by lymphocytes
• provides the right conditions for lymphocyte activation and differentiation

Question 24

Lymphocytes enter via

Answer 24

blood vessels to inspect the antigens present

Question 25

Superficial lymphatic drainage (5)

Answer 25

Question 26

When tissue fluid is produced

Answer 26

It is filtered by the LN and then returned to the circulation

Question 27

The efferent lymphatics join to form __ and ___

Answer 27

thoracic duct and tracheal ducts

Question 28

What 2 routes get antigen get into the lymph nodes via?

Answer 28

• Free antigen is swept into LN in afferent lymph and is trapped
• Specialist antigen presenting cells (dendritic cells) in the tissues eat antigen then migrate via the afferent lymph to the LN paracortex

Question 29

How are dendritic cells formed?

Answer 29

The differentiate from circulating monocytes

Question 30

Where are immature dendritic cells located?

Answer 30

At epithelial surfaces where they eat antigen

Question 31

How do dendritic cells migrate?

Answer 31

Via afferent lymphatics to lab during which time they process antigen

Question 32

Where do dendritic cells take up residency?

Answer 32

In the LN paracortex where they present antigen to naive T cells

Question 33

Lymphocytes enter LN via?

Answer 33

specialist blood vessels and inspect the antigens trapped there

Question 34

High Endothelial Venules (HEVs):

Answer 34

are ‘tube stops’ the T cells use to get out of the circulation and into lymph nodes
- where to exit blood in order to get into tissues

Question 35

Following activation in the lymph node…

Answer 35

Cells multiply, creating thousands of clones:

• B cells differentiate into plasma cells and migrate from follicles to medullary cords and start producing antibody
  – Activated T cells leave the LN and go off in search of infection in the tissues

Question 36

Enlarged lymph nodes (lymphadenopathy) can indicate?

Answer 36

• Infection–Reactivelymphnode
• Neoplasia-Lymphoma

Question 37

Spleen structure:

Answer 37

• Red pulp for haematological functions
• White pulp for immunological functions
  – Periarteriolar Lymphoid Sheaths (PALS)

Question 38

Spleen function:

Answer 38

• Haematopoietic organ in foetal life
• Removal of particulate material from bloodstream
  foreign organisms, old RBCs
• Immune responses to blood-borne pathogens • Store of RBCs and platelets

Question 39

Mucosal-associated lymphoid tissue (MALT)

Answer 39

• Respiratory tract – bronchial-associated
• GIT – gut-associated
• Initiate immune responses to organisms at mucosal surfaces

Question 40

What is the first point of entry for respiratory pathogens?

Answer 40

Tonsils - located in the pharynx

Question 41

Where is the Peyer’s patch located?

Answer 41

Found predominantly in the ileum and at the ileocaecal junction

Question 42

Primary lymphoid tissues __ and ___ are the source of all circulating lymphocytes

Answer 42

Bone marrow and thymus

Question 43

Lymphocytes visit ___ as part of the immune surveillance

Answer 43

Different secondary lymphoid tissues

Question 44

Lymph nodes facilitate immune response to?

Answer 44

Infection in tissue fluid

Question 45

The spleen facilitated immune response to

Answer 45

Infection in blood

Question 46

MALT facilitates immune response to

Answer 46

Infection at mucosal surfaces