Immune System

Question 1

Brief overview of what the immune system includes

Answer 1

Primary lymphoid organs

Secondary lymphatic tissues

Various cells in the innate + adaptive immune system

Question 2

What comes under the primary lymphoid organs of the immune system

Answer 2

Thymus

Bone marrow

Question 3

What comes under the secondary lymphatic tissues

Answer 3

Spleen

Tonsils

Lymph vessels

Lymph nodes

Adenoids

Skin

Liver

Question 4

What comes under innate leukocytes (WBC)

Answer 4

Phagocytes

Mast cells

Eosinophils

Basophils

Natural killer (NK) cells

Question 5

INNATE LEUKOCYTES

What comes under phagocytes?

Answer 5

Macrophages

Neutrophils

Dendritic cells

Question 6

Functions of innate leukocytes

Answer 6

Identify + eliminate pathogens

Mediators in the activation of the adaptive immune system

Question 7

What are MHC I molecules?

Answer 7

Proteins on the surfaces of all nucleated cells that help the immune system distinguish between “self” (body cells) and “non-self” (foreign cells).

Question 8

What do MHC I mol do if the cell is infected?

Answer 8

MHC I mol displays fragments of proteins from the infectious agents to T-cells.

Question 9

Do healthy cells display MHC I molecules?

Answer 9

No so are ignored by the immune system.

Question 10

What happens to cells identified as “non-self” by foreign proteins?

Answer 10

Will be attacked by the immune system.

Question 11

PRIMARY LYMPHOID ORGAN

Role of the Thymus

Answer 11

Provides an env for the development of T cells from heamatopoietic progenitor cells.

Question 12

PRIMARY LYMPHOID ORGAN

When is the Thymus its largest + most active?

Answer 12

During the neonatal + pre-adolescent period of development.

Question 13

PRIMARY LYMPHOID ORGAN

By what stage in life does the thymus begin to atrophy and what else happens?

Answer 13

Early teens

Thyme stroma is replaced by adipose tissue

Question 14

When does T-lymphopoiesis occur?

Answer 14

All through life.

Question 15

PRIMARY LYMPHOID ORGAN

Role of the bone marrow

Answer 15

RBC prod in the heads of long bones.

Red bone marrow is a key element in the lymphatic system as it generates lymphocytes from immature hematopoietic progenitor cells.

Question 16

What do the PRIMARY LYMPHOID ORGANS have to do with lymphocytes?

Answer 16

They’re involved in the prod + early selection of lymphocytes.

Question 17

What are lymphatic vessels?

Answer 17

Network carrying lymph fluid unidirectionally towards the heart.

Question 18

Functions of the lymphatic system

Answer 18

Transportation of WBC to + from lymph nodes into bones

Transportation of antigen-presenting cells to the lymph nodes where an immune response is stimulated.

Question 19

What does the spleen act as?

Answer 19

A blood filter

• Removes antibody-coated bacteria + anti-body coated blood cells through blood + lymph node circulation

Question 20

What does the spleen synthesise??

Answer 20

Antibodies

Question 21

Lymph nodes are widely distributed throughout the body, give some examples of where they can be found

Answer 21

Armpit

Stomach

Question 22

What are lymph nodes linked by?

Answer 22

Lymphatic vessels

Question 23

Purpose of lymph nodes

Answer 23

Act as filters for foreign particles

Important in the functioning of the immune system

Question 24

What are lymph nodes packed tightly of?

Answer 24

WBCs called lymphocytes + macrophages.

Question 25

What in the skin is part of the adaptive immune system?

Answer 25

Langerhans cells

Question 26

What does the reticuloendothelial system of the liver contain?

Answer 26

Immunologically active cells acting as a sieve for antigens carried to it via the portal system.

Question 27

What do leukocytes (WBCs) do?

Answer 27

Defend body vs disease + foreign material.

Question 28

List the innate leukocytes

Answer 28

Phagocytes Mast cells Eosinophils Basophils Natural killer (NK) cells

Question 29

INNATE LEUKOCYTES Name the types of phagocytes that invade pathogens

Answer 29

Neutrophils Macrophages

Question 30

INNATE LEUKOCYTES Phagocytes that invade pathogens - Neutrophils Where are neutrophils normally found?

Answer 30

In bloodstream

Question 31

INNATE LEUKOCYTES What is the most abundant type of phagocyte?

Answer 31

Neutrophils

Question 32

INNATE LEUKOCYTES - PHAGOCYTES What do neutrophils do at the acute phase of inflammation?

Answer 32

They migrate towards the site of inflammation + are the 1st cells to arrive at the scene of infection.

Question 33

INNATE LEUKOCYTES - PHAGOCYTES Where do macrophages reside?

Answer 33

In tissues + produce chemicals.

Question 34

INNATE LEUKOCYTES - PHAGOCYTES What do macrophages do?

Answer 34

Get rid of worn-out cells in the body Act as antigen-presenting cells that activate the adaptive immune system.

Question 35

What are dendritic cells?

Answer 35

Phagocytes in tissues in contact w/ the external env + are located mainly in skin, nose, lungs, stomach + intestines.

Question 36

What do dendritic cells serve as?

Answer 36

A link between bodily tissues + the innate + adaptive immune system due to presenting antigens to T-cells.

Question 37

INNATE LEUKOCYTES - MAST CELLS Where are they located?

Answer 37

Connective tissues Mucous membranes

Question 38

INNATE LEUKOCYTES - MAST CELLS Purpose

Answer 38

Regulate inflammatory response

Question 39

INNATE LEUKOCYTES - MAST CELLS What are they associated with?

Answer 39

Allergy + anaphylaxis

Question 40

INNATE LEUKOCYTES - BASOPHILS + EOSINOPHILS What do they do?

Answer 40

Secrete chemical mediators involved in defending against parasites Also play a role in allergic reactions.

Question 41

CELLS OF THE ADAPTIVE IMMUNE SYSTEM What are they?

Answer 41

Lymphocytes (special types of leukocytes)

Question 42

CELLS OF THE ADAPTIVE IMMUNE SYSTEM Major types of lymphocytes

Answer 42

B cells T cells

Question 43

CELLS OF THE ADAPTIVE IMMUNE SYSTEM Where are lymphocytes derived from?

Answer 43

Hematopoietic stem cells in the bone marrow

Question 44

CELLS OF THE ADAPTIVE IMMUNE SYSTEM - LYMPHOCYTES T cells What do they focus on?

Answer 44

Specific foreign particles rather than attacking just any antigens. They circulate until they encounter their specific antigen.

Question 45

CELLS OF THE ADAPTIVE IMMUNE SYSTEM - LYMPHOCYTES T cells What do they do?

Answer 45

Directly kill infected host cells, activating other immune cells, prod cytokines + regulate the immune response.

Question 46

CELLS OF THE ADAPTIVE IMMUNE SYSTEM - LYMPHOCYTES T cells What are the 2 major subtypes?

Answer 46

Killer T cells Helper T cells

Question 47

CELLS OF THE ADAPTIVE IMMUNE SYSTEM - LYMPHOCYTES T cells Killer T cells

Answer 47

Kill cells infected w/ the virus

Question 48

CELLS OF THE ADAPTIVE IMMUNE SYSTEM - LYMPHOCYTES T cells Helper T cells

Answer 48

Reg innate + adaptive immune responses Help determine which response the body makes according to the pathogen present.

Question 49

CELLS OF THE ADAPTIVE IMMUNE SYSTEM - LYMPHOCYTES B cells

Answer 49

Antigen-specific receptor is an antibody mol on the B cell surface which recognises whole pathogens w/out any need for antigen processing.

Question 50

What is innate immunity?

Answer 50

Natural resistance through physical, chemical + cellular approaches.

Question 51

What are natural killer cells a part of?

Answer 51

Innate immune response

Question 52

What do NK cells do as a part of the innate immune response??

Answer 52

Recognise abnormal MHC I mol on infected/tumour cells + kills them. They identify + destroy cells infected by pathogens.

Question 53

What does a NK cell do if it detects an infected or tumour cell?

Answer 53

Granules of perforin are secreted from its cytoplasm. Perforin = Destructive protein creating a pore in target cell. Granzymes are released in the immunological synapse. Granzymes = Induces a target cell to undergo apoptosis. == Phagocytic cells digest cell debris left behind.

Question 54

What are NK cells an effective mechanism for?

Answer 54

Controlling pot infections + preventing cancer progression.