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Flashcards in Lymphoid Organs Deck (54):
1

What does the immune system of humans lack

An immunological memory

2

What are the components of the innate immune system

Barriers against invasion, phagocytes, a cascade of plasma proteins that form an enzyme system and defends against bacteria and extracellular killers

3

Examples of extracellular killers

Lymphocytes and eosinophils

4

What is the major role high specificity adaptive immune system

Destruction

5

What must the immune system have the ability to do

Distinguish from self and non-self

6

What occurs when the immune system fails to distinguish between self and non-self

An autoimmune disease occurs

7

Characteristics of the adaptive immune system

Slower to react, highly flexible, very specific, based on lymphocytes and a vast array of genetically determined cell surface receptors

8

What is the major role of the adaptive immune system

Destruction

9

What happens when the tolerance of lymphocytes breaks down

The immune system fails to distinguish between self and non-self

10

What are organs of the immune system known as

Lymphoid organs

11

How are lymph organs linked

By the blood vascular and lymphatic vascular systems

12

What are the primary lymphoid organs

Bone marrow and thymus

13

What do the primary lymphoid organs do

Sites of lymphocyte production and maturation

14

What are the secondary lymph organs

Spleen, lymph nodes and lymph nodules

15

What occurs within the secondary lymph organs

The lymphocytes migrate to these organs and aggregate in large numbers

16

What are the three types of lymphocytes

B cells, T cells and natural killer cells

17

What do B cells produce

Antibodies

18

What do T cells participate in

Cellular immunity

19

What are the three forms of T cells

Helper T cells, cytotoxic T cells and suppressor T cells

20

Function of natural killer cells

Kill virus infected cells and some tumour cells

21

How are cells of the immune system identified

Using immunohistochemistry

22

Where are B and T cells produced

In the bone marrow

23

Where is the thymus located

In the mediastinum

24

What subdivides the thymus

Septa

25

Structure of the lobules of the thymus

Highly cellular outer cortex and a less cellular inner medulla

26

What is contained within the cortex of the thymus

Large number of T cells, epithelioreticular cells and macrophages

27

What does the medulla of the thymus contain

Fewer T cells that are less tightly packed and larger and epithelioreticular cells

28

What part of the thymus are the immature T cells found

Cortex

29

What process do the immature T cells go through

Proliferation, maturation and a selection process

30

What occurs to the T cells that fail the processes

They undergo apoptosis and are phagocytosed by macrophages

31

What happens to T cells that survive

They enter the medulla and interact with the epithelioreticular cells and present self antigens

32

What are the whorls of epithelial cells found in the medulla of the thymus called and what else do they contain

Hassall's corpsucles and keratin

33

What does the system of lymphatic vessels and accociated lymph nodes allow

The drainage of lymph into the vascular system, surveillance of tissue for signs of antigens and the delivery of absorbed fats from the small intestine

34

Structure of lymphatic vessels

Thin walled, lined by endothelium and anchored to the tissue by filaments

35

Areas of clusters of lymph nodes

Neck, axilla and groin

36

How do lymphocytes enter the lymph node

Via the incoming lymph or the blood stream

37

What are the circular aggregations with the lymph node known as and what do they contain

Follicles and B cells

38

What are the densely pack follicles of the lymph node called

Primary follicles

39

What is the centre of active lymph node follicles called

The germinal centre

40

What does the germinal centre of lymph follicles contain

Actively dividing B calls

41

What surrounds the germinal centre of the lymph follicle

Mantle zone

42

What is within the mantle zone

Resting B cells

43

What is within the paracortical region of the lymph node

T cells and high endothelial venules

44

What lines the high endothelial venules

Cuboidal epithelium

45

What is within the medulla of the lymph node

Medullary sinuses and medullary cords that contain plasma cells and macrophages

46

What areas do the developing B cells go through in the lymph node

Form a follicle in the superficial cortex, to the paracortex and finally into the medulla

47

What are aggregations of lymph in the gut known as

GALT

48

What is aggregations of lymph in the respiratory tract and gastrointestinal tract known as

MALT

49

Examples of aggregations of lymphoid tissue

Waldeyer's ring and payer's patches

50

Functions of the spleen

Immune response against blood-borne antigens, removes particulate matter and aged blood cells and produces blood cells during foetal life

51

Structure of the spleen

Composed of white pulp nodules surrounded by red pulp

52

What makes up the white pulp

Either T or B cells

53

What is contained within the red pulp

Blood filled capillaries with discontinuous endothelium and sinuses

54

What happens to old RBCs within the spleen

They lyse and become phagocytosed by macrophages associated with the sinuses