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Biomed P2 > Week 11 > Flashcards

Week 11 Flashcards

1
Q

What percentage of deaths worldwide are estimated by WHO to be due to infectious diseases?

A

23%

This statistic highlights the significant impact of infectious diseases on global mortality.

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2
Q

What is the primary role of the lymphatic system?

A

Captures lost fluid from the blood, transports dietary lipids, transports foreign substances & immune cells

The lymphatic system plays a crucial role in maintaining fluid balance and supporting the immune system.

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3
Q

What fluid is referred to as lymph when in the lymphatic system?

A

Interstitial fluid

Interstitial fluid becomes lymph once it enters the lymphatic vessels.

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4
Q

What are the two main divisions of the immune system?

A
  • Innate
  • Adaptive

These divisions work together to protect the body from pathogens.

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5
Q

What characterizes the innate immune system?

A

Present at birth, provides immediate protection, is general

The innate immune system offers non-specific defense mechanisms against a wide range of pathogens.

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6
Q

What is a key feature of the adaptive immune system?

A

Develops in response to pathogens, has memory, responds more rapidly and tailored on second exposure

The adaptive immune system is highly specific and improves its response upon subsequent encounters with the same pathogen.

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7
Q

List the main types of cells involved in the immune system.

A
  • Neutrophils
  • Eosinophils
  • Basophils
  • Mast cells
  • Lymphocytes (B cells & T cells)
  • Macrophages
  • Dendritic cells
  • Natural Killer cells

Each of these cell types has unique functions in immune response.

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8
Q

What is the role of neutrophils in the immune system?

A

Most abundant phagocytes, first cell at site of infection, major defense against bacteria

Neutrophils are critical for the initial response to infection.

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9
Q

True or False: Eosinophils play a major role in inflammation.

A

True

Eosinophils are involved in the immune response to parasites and also contribute to inflammatory processes.

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10
Q

Fill in the blank: The lymphatic vessels collect lymph and empty into the _______.

A

venous system

This drainage is essential for returning fluid to the bloodstream.

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11
Q

What attracts neutrophils to the site of infection?

A

Chemical gradients (chemotactic)

This process helps ensure that immune cells are directed to where they are needed most.

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12
Q

What do the granules of basophils contain?

A
  • Histamine
  • Digestive enzymes
  • Heparin

These substances are important in inflammatory responses and allergic reactions.

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13
Q

What are macrophages?

A

Large agranular cells derived from monocytes that are actively phagocytic

Macrophages deploy a variety of weapons including lysozymes and play a large role in both innate and adaptive immunity.

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14
Q

What is the primary function of dendritic cells?

A

To present antigens to T cells in lymph nodes after migrating from epithelium and organs

Dendritic cells are a major link between innate and adaptive immunity.

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15
Q

What are natural killer (NK) cells?

A

Small population of large granular lymphocytes that are cytotoxic against cancer and virally-infected cells

NK cells lack specific antigen receptors and release perforins and granzymes to initiate cell death via apoptosis.

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16
Q

Where do lymphocytes of adaptive immunity mature?

A

In the bone marrow and thymus

They are able to recognize specific antigens.

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17
Q

What are the two classes of T cells?

A
  • Helper T cells (CD4)
  • Killer T cells (CD8)

Each class performs different roles in the immune response.

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18
Q

What is the role of B cells in the immune response?

A

Produce immunoglobulin and are responsible for the humoral response

B cells differentiate into plasma cells that produce large amounts of antibodies.

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19
Q

What is unique about T cell receptors?

A

Each T cell expresses a unique antigen-specific receptor

T cells perform effector and regulatory roles in the immune response.

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20
Q

What is lymphoid tissue composed of?

A

Elements containing vast numbers of immune cells, mostly made of reticular connective tissue

The passage of lymph carries foreign particles to immune cells.

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21
Q

What are the primary lymphatic organs?

A
  • Bone marrow
  • Thymus
  • Secondary lymph nodes
  • Spleen
  • Mucosa-associated lymphoid tissue (MALT)

These organs are where lymphocytes mature and activate.

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22
Q

What happens to the thymus after puberty?

A

It atrophies

The thymus is essential for T cell maturation during early development.

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23
Q

Fill in the blank: Macrophages are a component of _______ immunity but play a large role in _______ immunity.

A

innate; adaptive

This highlights the dual role of macrophages in the immune system.

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24
Q

What are the two major functions of lymph nodes?

A

Filtration and immune activation

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25
Where do lymphocytes encounter B cells and dendritic cells in the lymph node?
Cortex
26
What is contained in the inner cortex of lymph nodes?
Circulating T cells
27
What are the two main components of the spleen?
Red pulp and white pulp
28
What is the function of the red pulp in the spleen?
Contains vascular sinuses filled with WBC and macrophages
29
What is the role of white pulp in the spleen?
Site of lymphatic proliferation and immune surveillance
30
What are the functions of lymphoid tissue in MALT?
Found in mucous membranes throughout the body
31
Name three types of tonsils.
* Palatine * Lingual * Pharyngeal
32
Where are Peyer's patches located?
Wall of the small intestine
33
What is the first line of defense in the innate immune system?
Physical barriers, cellular constituents, and chemical constituents
34
List four examples of physical barriers in the innate immune system.
* Skin * Mucous membranes * Peristalsis * Normal microbiota
35
What is the role of mucous in the immune system?
Secretion of mucous and various antibacterial substances
36
What are the components of cellular defense in the immune system?
* Phagocytosis * Neutrophils * Macrophages * Natural killer cells
37
What are the three main stages of inflammation?
* Vasodilation and increased permeability * Accumulation of phagocytes and antimicrobial proteins * Clearance of pathogens and accelerated tissue repair
38
What are examples of chemical defenses in the immune system?
* Inflammation * Antimicrobial proteins (interferons, complement) * Fever
39
True or False: Normal microbiota can inhibit pathogen colonization.
True
40
How does normal microbiota inhibit pathogens?
* Formation of bacterial layer * Competing for nutrients and space * Production of bactericides
41
What are the symptoms of inflammation?
* Pain * Redness * Heat * Swelling
42
Fill in the blank: The epidermis acts as a _______ barrier.
Renewable mechanical
43
What are the components of the dermis and hypodermis in terms of immune function?
* Sweat glands * Secretions of various antibacterial chemicals
44
What is leukocytosis?
An increase in the number of white blood cells (WBCs) due to factors released by injured cells. ## Footnote Leukocytosis is a response to injury or infection, indicating an immune response.
45
Define margination in the context of phagocytes.
The expression of cell adhesion molecules that enables phagocytes to adhere to capillary walls. ## Footnote This process is crucial for the migration of phagocytes to sites of injury.
46
What is diapedesis?
The process by which phagocytes pass through capillary walls into injured tissue. ## Footnote Diapedesis allows immune cells to reach and infiltrate areas of infection or injury.
47
What does chemotaxis refer to?
The attraction of cells to the site of injury along chemical gradients. ## Footnote This process guides immune cells to areas where they are needed most.
48
List the types of chemical mediators involved in the immune response.
* Proteins/enzyme cascades (Kinins, complements) * Lipid-derived mediators (prostaglandins, leukotrienes) * Vasoactive amines (histamine released by mast cells/basophils) * Cytokines (signaling proteins) ## Footnote These mediators play significant roles in inflammation and immune responses.
49
What are antimicrobial proteins?
A collection of cellular and plasma proteins that enhance immunity. ## Footnote They include key components like interferons and complement proteins.
50
What are the types of interferons and their main property?
Types: * Type I → IFNα * Type II → IFNγ * Type III → IFNλ Main property: Anti-viral properties and ability to protect neighboring cells. ## Footnote Interferons also help regulate inflammation and activate natural killer (NK) cells.
51
Describe the complement system.
A collection of 20 plasma proteins present in inactive states that enhance inflammation, phagocytosis, and directly kill bacteria when activated. ## Footnote The complement system is vital for both innate and adaptive immunity.
52
What are the three pathways of complement activation?
* Classical * Mannose-binding lectin (MBL) * Alternative ## Footnote All pathways lead to the cleavage of C3 into C3a and C3b, which are essential for complement functions.
53
What initiates the classical pathway of complement activation?
The binding of antibody to antigen and activation of C1. ## Footnote This pathway is part of the adaptive immune response.
54
How is the MBL pathway activated?
By lectin binding to mannose on the surface of microbial organisms. ## Footnote This pathway is crucial for recognizing and responding to certain pathogens.
55
What is the role of C3a and C5a in the complement system?
* C3a enhances inflammation * C5a enhances inflammation and promotes phagocytosis ## Footnote These components are key mediators of the inflammatory response.
56
What complex is formed by C5b and other proteins in the complement system?
Membrane attack complex (MAC) with C6, C7, C8, and C9. ## Footnote The MAC is essential for directly killing bacteria by creating pores in their membranes.
57
What is the function of Lysozyme?
Degrades peptidoglycan in bacterial cell walls ## Footnote Lysozyme is an antimicrobial protein that plays a role in the innate immune system.
58
What do various peptides do in the context of antimicrobial activity?
Disrupt microbial membranes and inhibit protein synthesis ## Footnote These peptides serve as a defense mechanism against microbial infections.
59
What are the two divisions of adaptive immunity?
* Humoral immunity * Cellular immunity ## Footnote Humoral immunity involves antibodies, while cellular immunity involves T cells.
60
What is the main function of humoral immunity?
Immune function performed by the release of immunoglobulin ## Footnote It primarily blocks the entry of pathogens for destruction.
61
What is cellular immunity responsible for?
Causes death of infected cells and pathogens within ## Footnote This is achieved through the action of T cells.
62
Define 'antigen'.
Toxin or foreign substance which induces an immune response ## Footnote Antigens are crucial for the activation of the adaptive immune system.
63
What does specificity refer to in the context of antigens?
Ability to bind one but not another member of a family of related substances ## Footnote This property is essential for the immune system's precision in targeting pathogens.
64
Where can antigens be found?
* On foreign cells * On our own cells ## Footnote Antigens can be present on both pathogens and the body’s own cells, which is vital for immune recognition.
65
What characterizes large, complex proteins as antigens?
Possess numerous antigenic determinants ## Footnote These determinants enhance the likelihood of inducing a strong immune response.
66
Why are smaller antigens often not very effective at inducing an immune response?
They have a single or very few determinants ## Footnote Limited antigenic determinants reduce their ability to activate the immune system.
67
What type of antigens do T cells recognize?
Peptide sequences ## Footnote This specificity is crucial for T cell activation and subsequent immune response.
68
How many receptors does each individual cell have for a specific antigen?
Thousands of receptors ## Footnote All receptors on a single cell are the same, allowing it to recognize only one antigen.
69
True or False: Each individual cell can recognize multiple antigens.
False ## Footnote Each individual cell recognizes only one specific antigen due to its unique receptors.
70
What is immunocompetence?
The ability of lymphocytes to recognize and respond to a large number of foreign antigens while not responding to normal self antigens. ## Footnote The body can respond to 10^6 - 10^10 different foreign antigens.
71
Where do lymphocytes develop immunocompetence?
In the primary lymphoid organs: bone marrow for B cells and thymus for T cells. ## Footnote After development, they circulate in secondary lymphoid organs.
72
What is the role of MHC molecules?
MHC molecules incorporate and present antigens to T cells as peptide complexes. ## Footnote There are two distinct types: MHC Class I and MHC Class II.
73
What types of cells display MHC Class I molecules?
All nucleated cells. ## Footnote MHC Class I incorporates foreign peptides generated within the cell and presents them to CD8+ T cells.
74
What are professional antigen presenting cells (APCs)?
Cells that display MHC Class II molecules, including dendritic cells, macrophages, and B cells. ## Footnote They engulf and break down antigens into peptides.
75
What is the function of CD4+ T helper cells?
They perform a variety of functions in the immune response. ## Footnote They interact with antigens presented by MHC Class II molecules.
76
What are B cell receptors?
Membrane-bound immunoglobulin (antibodies) on B cells. ## Footnote They are crucial for antigen binding and activation of B cells.
77
What is the activation process of B cells?
A three-step process: 1) Antigen binds to B cell receptor, 2) Activation, 3) Proliferation and differentiation. ## Footnote Activated B cells divide into clones.
78
What are the two distinct types of cells B cells differentiate into after activation?
* Plasma cells * Memory B cells
79
What do plasma cells do?
They secrete large quantities of immunoglobulin (antibodies). ## Footnote Plasma cells secrete about 2000 antibodies per second and live for approximately 4-5 days.
80
What is the role of memory B cells?
They remember the antigen for future activation. ## Footnote This allows for a tailored antibody response to the pathogen upon re-exposure.
81
What are antibodies also known as?
Immunoglobulins. ## Footnote They consist of two identical light chains and two heavy chains.
82
What determines the class (isotype) of an antibody?
Heavy chains ## Footnote Heavy chains are linked to each other and a light chain by disulphide bonds.
83
What are the two regions of an antibody?
Variable region and constant region ## Footnote The variable region binds to the antigen and is specific for one antigen, while the constant region dictates the characteristics of the antibody.
84
What is the function of the variable region in antibodies?
Binds to antigen ## Footnote There are two variable regions on each antibody, specific for one antigen.
85
What process do T cells undergo to recognize antigens?
Clonal selection ## Footnote T cells recognize antigens via the T cell receptor (TCR).
86
What do T cells recognize that is bound to MHC molecules?
Peptide ## Footnote T cells utilize their T cell receptors to recognize peptides presented on MHC molecules.
87
Which T cells recognize MHC Class II molecules?
CD4 T cells ## Footnote CD4 T cells help activate other T cells.
88
What type of T cells recognize MHC Class I molecules?
CD8+ T cells ## Footnote CD8+ T cells are also known as cytotoxic T cells.
89
What is the primary function of cytotoxic T cells?
Attack and destroy infected cells ## Footnote Their main targets are virally-infected cells.
90
What do cytotoxic T cells release to induce cell death?
Perforin and granzymes ## Footnote These substances help induce apoptosis in infected cells.
91
What accessory molecules do helper T cells express?
CD3 ## Footnote CD3 is involved in intracellular signaling.
92
Fill in the blank: T cells recognize _______ presented on MHC Class I.
peptide ## Footnote This recognition is crucial for the activation and function of cytotoxic T cells.

Biomed P2 (11 decks)

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