Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

RESP > The Immune system > Flashcards

The Immune system Flashcards

1
Q

What are the main cells of the immune system?

A

-WBC or leukocytes

there are myeloid cells or lymphoid cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are myeloid cells?

A

Neutrophils, basophils, eosinophils, monocytes

-(ability to secrete inflammatory mediators and function as phagocytes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are lymphoid cells?

A

B lymphocytes, T lymphocytes, natural killer cells, plasma cells
-lymphocytes serve as recognition cells in adaptive immune responses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the major function of plasma cells?

A

Synthesize and secrete antibodies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are macrophages derived from and what is their function?

A

macrophages are derived from monocytes that pass through the walls of blood vessels to enter cells and transform into macrophages, they engulf particles and pathogens via phagocytosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is phagocytosis?

A

The form of endocytosis whereby a cell engulfs and usually destroys particulate matter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Where are macrophages mostly found?

A
  • in the skin
  • internal surfaces of respiratory and digestive system tubes
  • in several organs they line the vessels through which blood or lymph flows
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are dendritic cells?

A
  • they are high motile
  • found scattered in almost all tissues, particularly where internal and external environments meet eg digestive tract
  • upon activation dendritic cells process phagocytosed pathogens and migrate through the lymphatic vessels to secondary lymphoid organs where they activate T cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are mast cells and where are they found?

A

Mast cells are derived from the differentiation of a unique set of bone marrow cells that have entered the blood and then left the blood vessels to enter connective tissue, where they differentiate and undergo cell division (so mature mast cells are not normally found in the blood)

  • found throughout connective tissues, particularly beneath epithelial surfaces of the body
  • contain large cytosolic vesicles (these secrete hormones eg histamine)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are cytokines?

A

-multitude of protein messengers that regulate host cell division and function in both innate and adaptive immune responses
-produced by a variety of individual cells
-variety of functions (not all immune related)
(often acts as a autocrine or paracrine substance, sometimes however it does enter the blood stream to exert hormonal effects on distant organs and tissues) ‘cross talk’ allows different immune system cells to talk to each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Innate immune responses

A

Innate immune responses defend against foreign cells or matter without having to recognize specific identities

  • they recognise general molecular property marking the invader as foreign
  • these are often carbohydrates or lipids on microbial cell walls
  • plasma cell receptors and circulating proteins bind to these foreign carb or lipids
  • the innate immune response includes defences at the body surface
  • the response to an injury or infection known as inflammation
  • and interferons (family of antiviral proteins)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are neutrophils? Where are they produced and what is their function?

A
  • Leukocytes (WBC)
  • prodcued in bone marrow
    1. Phagocytosis
    2. Release chemicals involved in inflammation (vasodilators, chemotaxins, etc)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are basophils? Where are they produced and what is their function?

A

-Leukocytes (WBC)
-prodcued in bone marrow
Release chemicals involved inflammation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are eosinophils? Where are they produced and what is their function?

A
  • Leukocytes (WBC)
  • produced in bone marrow
    1. Destroys multicellular parasites
    2. Participates in immediate hypersensitivity reactions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are monocytes Where are they produced and what is their function?

A
  • Leukocytes (WBC)
  • produced in bone marrow
    1. carries out functions similar to those of macrophages in tissues
    2. enters tissues and transforms into macrophages
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are lymphocytes? Where are they produced and what is their function?

A
  • Leukocytes (WBC)
  • mature in the bone marrow (B cells and NK cells) and thymus (T cells); activated in peripheral lymphoid organs
    1. serves as recognition cells in specific immune responses and are essential for all aspects of these responses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are B cells? Where are they produced and what is their function?

A
  • Leukocytes (WBC)
    1. Initiate antibody-mediated immune responses by binding specific antigens to the B cell’s plasma membrane receptors, which are immunoglobins
    2. Upon activation, are transformed into plasma cells, which secrete antibodies
    3. Present antigen to helper T cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are cytotoxic T cells (CD8)? Where are they produced and what is their function?

A
  • Leukocytes (WBC)
    1. Bind to antigens on plasma membrane of target cells (virus infected cells, cancer cells, and tissue transplants) and directly destroy the cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are helper T cells (CD4)? Where are they produced and what is their function?

A
  • Leukocytes (WBC)

1. Secrete cytokines that help to activate B cells, cytotoxic T cells, NK cells and macrophages

20
Q

What are NK cells? Where are they produced and what is their function?

A
  • Leukocytes (WBC)
    1. Bind directly and nonspecifically to virus-infected cells and cancer cells and kill them
    2. Function as killer cells in antibody-dependent cellular cytotoxicity (ADCC)
21
Q

What are plasma cells? Where are they produced and what is their function?

A
  • produced in peripheral lymphoid organs, differentiate from B cells during innate response
    1. secrete antibodies
22
Q

What are macrophages? Where are they produced and what is their function?

A

produced in the bone marrow, reside in almost all tissues and organs, differentiate from monocytes

  1. Phagocytosis
  2. Extracellular killing via secretion of toxic chemicals
  3. Process and present antigens to helper T cells
  4. Secrete cytokines involved in inflammation, activation and differentiation of helper T cells and systemic responses to infection or injury (acute phase response)
23
Q

What are dendritic cells? Where are they produced and what is their function?

A

Produced in almost all tissues and organs; microglia in the CNS

  1. Phagocytosis
  2. Antigen presentation
24
Q

What are mast cells? Where are they produced and what is their function?

A

Produced in the bone marrow; reside in almost all tissues and organs, differentiate from bone marrow cells
1. Release histamine and other chemicals involved in inflammation

25
Q

What are the first defences against the body?

A

-Intact skin
-various skin glands, salivary glands, lacrimal (tear) glands all secrete antimicrobial chemicals, these may include antibodies, enzymes
(lysozyme destroys bacterial cell walls)
(lactoferrin prevents bacteria from obtaining the iron they require to function properly)
-mucus secreted by the epithelial lining of the resp and upper GI tract also contains antimicrobal chemicals, it is also sticky
-particles stuck in the mucus cannot enter the blood and are then swallowed or phagocytosed by macrophages
-HCl acid secretion of the stomach can also kill pathogens

26
Q

What is inflammation

A

Local response to infection or injury

  • destroys or inactivates foreign invaders and sets the stage for tissue repair
  • phagocytes
27
Q

Describe the process of inflammation beginning with a wound

A
  1. Bacteria are introduced into a wound
  2. Chemical mediators cause vasodilation and capillary permeability: chemoattractants recruit neutrophils to area
    (endothelial cells contract, opening spaces so proteins can move through)
    -increased blood flow increases delivery of proteins and leukocytes
    -increased permeability to proteins ensures that plasma proteins that participate in inflammation can gain entry to the interstitial fluid
  3. Diapedesis results in neutrophils entering tissue where they engulf bacteria
  4. Capillaries return to normal as neutrophils continue to clear the infection
28
Q

Name 4 signs of tissue injury and inflammation

A

Local redness, swelling, heat and pain

29
Q

Name some important local inflammatory mediators that are generated from enzymatic action on plasma protein

A
  • Kinins
  • Complement
  • Products of blood clotting
30
Q

Name an mportant local inflammatory mediator that is secreted by mast cells and/or injured cells

A

-Histamine

31
Q

Name some important local inflammatory mediators that are secreted by many different cell types

A
  • Eicosanoids
  • Platelet activating factor
  • Cytokines, including chemokines
32
Q

Name some important local inflammatory mediators that are secreted by injured cells, neutrophils, and macrophages

A

-Lysosomal enzymes, nitric oxide, and other oxygen-derived substances

33
Q

What is chemotaxis?

A

This is when circulating neutrophils begin to move out of the blood across the endothelium of capillaries and venules to enter the inflamed area

  • multistaged
  • involves a variety of protein and carbohydrate adhesion molecules on both the endothelial cell and the neutrophil
  • regulated by messenger molecules released by the cells in the injured area, including endothelial cells (these are called chemoattractants/chemotaxins or chemotactic factors)
34
Q

Describe the stages of chemotaxis?

A
  1. Margination - the neutrophil is loosely tethered to endothelial cells by adhesion molecules, the neutrophil rolls along the blood vessel wall
    - the exposes the neutrophil to chemoattractants being released in the injured area
    - these chemoattractants act on the neutrophil to induce the rapid appearance of another class of adhesion molecules in its plasma membrane
    - molecules that bind tightly to their matching molecules on the surface of endothelial cells. as a result the neutrophils collect along the site of injury rather than being washed away with the flowing blood
  2. Diapedesis
    A narrow projection of the neutrophil is inserted into the space between two endothelial cells, and the entire neutrophil squeezes through the endothelial wall and into the interstitial fluid; huge numbers of neutrophils migrate into the interstitial fluid this way.
    Once in the fluid neutrophils follow a chemotatic gradient and flow towards to site of tissue damage
    -this occurs because pathogen-stimulated innate immune cells release chemoattractants.
    -monocytes follow later, once in the tissue they differientiate into macrophages
    (lymphocytes undergo chemotaxis in adaptive immune responses, as do basophils and eosinophils under certain conditions)
    (various chemokines have different chemoattractant actions and therefore attack different cells at different times)
35
Q

Phagocytosis

A
  1. Contact between phagocyte and microbe. phagocyte receptors bind with carbohydrates or lipids on microbial cell walls (small bacteria have a thick capsule)
  2. Chemical factors are produced which bind the phagocyte tightly to the microbe enhancing phagocytosis (any substance that does this is called an opsonin)
  3. As the phagocyte engulfs the microbe the internal, microbe-containing sac formed in this step is called a phagosome. A layer of plasma membrane separates the microbe from the cytosol of the phagocyte.
  4. The phagocyte membrane then makes contact with one of the phagocyte’s lyzosomes (this is filled with hydrolytic enzymes)
  5. The membranes of the phagosome and the lysosome fuse and the combined vesicles are now called a phagolysome
  6. Inside the phagolysome the lysosomal enzymes breakdown the microbe’s macromolecules
  7. Also other enzymes in the phagolysosome membrane produce nitric oxide, hydrogen peroxide and other oxygen derivatives. These are all highly destructive to the microbe’s macromolecules.
  8. Phagocytes also release antimicrobial substances into the ECF where the chemicals can destroy microbes. Some of these substances also act as inflammatory mediators. When phagocytes enter the area and encounter pathogens, +ve feedback mechanisms cause inflammatory mediators, including chemokines, to be released that bring in more phagocytes.
36
Q

What is a complement protein?

A
  • A family of plasma proteins
  • Provides another means for extracellular killing of pathogens without prior phagocytosis
  • Certain components are always circulating in the blood in an inactive state
  • Upon activation of a complement protein in response to infection or damage, a cascade occurs so that this active protein activates a second complement protein, (this activates a third, and so on.)
  • This means multiple active complement proteins are generated in the extracellular fluid of the infected area from inactive complement molecules that have entered from the blood.
37
Q

What is the central protein in the complement cascade? Describe the series of events it intitates

A

C3

  • activation of C3 initiates a series of events
    1. deposition of C3b on the microbial surface.
    2. C3b then acts as an opsonin that is recognised by phagocytes for destruction
    3. C3b also acts as part of a proteolytic enzyme that amplifies the complement cascade and leads to the downstream development of a multiunit protein called the membrane attack complex (MAC)
    4. The MAC embeds itself in the bacterial plasma membrane and forms pore like channels in the membrane making it leaky
    5. Water, ions, and small molecules enter the microbe, this disrupts the intracellular environment and kills the microbe
38
Q

What are the functions of complement proteins?

A
  1. Direct destruction of invading microbes by membrane attack complexes
  2. Vasodilation and increased permeability of capillaries and venules to proteins
  3. Chemotaxis
  4. Enhancement of phagocytosis (opsonization)
39
Q

What is the alternative complement pathway

A
  • An alternative initiation bypassing antibodies during non-specific inflammation
  • It is activated as a result of interactions between carbohydrates on the surface of the microbes and inactive complement molecules beyond C1
  • leads to formation of active C3b
40
Q

What other plasma proteins can facilitate opsonization

A
  • C-reactive protein (produced in the liver, always found in the plasma - however concs are greatly increased during inflammation)
41
Q

Tissue repair

A
  • The final stage of inflammation is tissue repair
  • may involve multiplication of organ-specific cells
  • fibroblasts divide rapidly and begin to secrete large quantities of collagen, and blood vessel cells proliferate in the process of angiogenesis
  • All these events are brought about by chemical mediators, particularly locally produced growth factors
  • remodelling
  • may be imperfect final repair, leaving a scar
42
Q

What are type I interferons

A
  • include several proteins that nonspecifically inhibit viral replication inside host cells
  • in response to infection by a virus, most cell types produces these interferons and secrete them to the extracellular fluid
  • interferons then bind to plasma membrane receptors on the secreting cell and on other cells, whether they are infected on not
  • binding triggers the synthesis of antiviral proteins by the cell
  • these interfere with the virus’ ability to replicate

Type I interferons also have a role in the killing of tumour cells and generating a fever during infection
-not specific

43
Q

What are type II interferons

A

-interferon gamma is produced by immune cells, this interferon potentiates some of the actions of type I interferons, enhancing bacteria-killing activity of macrophages and acts as a chemokine in the inflammatory process

44
Q

What are Toll-Like receptors?

A

Toll-like receptors (TLRs) are a class of proteins that play a key role in the innate immune system. They are single, membrane-spanning, non-catalytic receptors usually expressed in sentinel cells such as macrophages and dendritic cells, that recognize structurally conserved molecules derived from microbes.

45
Q

Pathogen-associated molecular patterns (PAMPs)

A

Pathogen-associated molecular patterns, or PAMPs, are molecules associated with groups of pathogens, that are recognized by cells of the innate immune system. These molecules can be referred to as small molecular motifs conserved within a class of microbes. They are recognized by Toll-like receptors (TLRs) and other pattern recognition receptors (PRRs) in both plants and animals.

RESP (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions