Chapter 8: The Immune System Flashcards

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1
Q

Two divisions of the immune system

A

Innate immunity (non-specific immunity)

Adaptive immunity (specific immunity)

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2
Q

Innate immunity (non specific immunity)

A

Composed of defenses that are always active against infection, but lack the ability to target specific invaders. Also called non-specific immunity. Mount a faster attack than adaptive immunity. All Granulocytes are part of the innate immunity. Complement system.

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3
Q

Adaptive immunity (specific immunity)

A

Refers to the defenses that target specific pathogens. Also called specific immunity. Slower to act than innate immunity, but can maintain immunological memory of an infection to mount a faster attack and subsequent infections.

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4
Q

Structures and components of the immune system

A

Bone marrow, thymus, spleen, lymph nodes, tonsils, appendix, Peyer’s patches (located in small intestine).

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5
Q

Spleen

A

Storage area for white blood cells and platelets, recycle red blood cells, filter blood and lymph.

Activation of B – cells (B-cells are a part of the adaptive immunity. B-cells turn into plasma cells to produce antibodies as part of the adaptive immune system).

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6
Q

Bone marrow

A

Produces all of the leukocytes (white blood cells) and erythrocytes (red blood cells). Leukocytes participate in the immune system through the process of hematopoiesis.

Remember: lueko means white.

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7
Q

B-cell (stored and activated by what organ? what do they turn into?)

A

B cells are stored in and activated by the spleen, also activated by lymph nodes. B cells can turn into plasma cells (plasma or effector B cells). B cells create antibodies. B cells are a part of the adaptive immunity.

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8
Q

Plasma cells

A

Produce antibodies as part of adaptive immunity. Preceded by B cells. Plasma cells (and B cells) are a part of humoral immunity.

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9
Q

Mature but naive B cells

A

When B cells leave the bone marrow, they are considered mature (capable of functioning) but naive because they have not yet been exposed to an antigen and created antibodies.

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10
Q

Humoral immunity

A

Humoral immunity produces antigen-specific antibodies and is primarily driven by B cells. B cells dissolve and act in the blood (as opposed to cell mediated immunity)

Think B cells (mature in the Bone) - adaptive immunity - humoral (fluid) immunity

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11
Q

T cells

A

Adaptive (specific) immunity, develop in the bone marrow, mature in the Thymus, cell mediated immunity.

Directly kill VIRALLY INFECTED cells, et al.

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12
Q

B cells v T cells (superficial)

A

B cells create antibodies

T cells kill infected cells

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13
Q

Thymus

A

Small gland just in front of the pericardium (sac around heart). Location of maturation of T cells.

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14
Q

Cell mediated immunity

A

Cell-mediated immunity is an immune response that does not rely on the production of antibodies.

Think T cells - made in bone marrow - mature in thymus - cell mediated immunity.

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15
Q

Lymph nodes

A

Provide a place for immune cells to communicate and mount an attack. Filter lymph.

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16
Q

Gut associated lymphoid tissue (GALT)

A

Immune tissue found in close proximity to the digestive system (including the mouth), as this these are sites of potential invasion by pathogens.

Include tonsils, adenoids (in the head), Peyer’s patches in the small intestine, lymphoid aggregates in the appendix.

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17
Q

Leukocytes

A

White blood cells. Arise from hematopoiesis in the bone marrow. Separated by granulocytes and agranulocytes.

Types include: neutrophil, eosinophils, basophils, monocytes- macrophages, dendritic cells, lymphocytes - B cell, T cell, natural killer cell

Granulocytes: neutrophils, eosinophils, basophils

Agranulocytes: T cell, B cell, monocyte (which turn into macrophages when they get to tissues)

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18
Q

Granulocytes and the four types

A

Contain granules in their cell membrane that exocytose that contain toxic enzymes and chemicals that are effective against bacterial, fungal, and parasitic pathogens.

Eosinophils (come from eosinophil progenitor)

Neutrophils (come from neutrophil progenitor)

Basophils and Mast cells (come from the same progenitor - the basophil progenitor)

Also Megakaryocytes (which make platelets) as they have some granules.

All arise from myeloid (bone marrow) stem cells, which arise from hematopoietic stem cells.

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19
Q

Leukocytes v lymphocytes

A

All lymphocytes are leukocytes but all leukocytes are not lymphocytes.

It goes leukocyte then lymphocyte.

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20
Q

Leuko meaning

A

White

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21
Q

Agranulocytes

A

A type of luekocyte. There are only two types: lymphocytes and monocytes.

Lymphocytes produce antibodies, monocytes phagocytose pathogens.

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22
Q

Monocytes

A

A type of granular lymphocyte that phagocytize pathogens. They become macrophages in tissues. Part of the INNATE IMMUNE SYSTEM

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23
Q

Three example of macrophages in text

A

Langerhan (skin)
Microglia (CNS)
Osteoclast (bone)

These are all leukocytes, agranulocytes, monocytes.

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24
Q

Non specific immune response

A

Also known as innate immunity. Cells can carry out their functions without learning.

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25
Q

Specific immune response

A

Also known as the adaptive immune response. Immune cells that learn to recognize and respond to particular antigens.

Split into humoral and cell mediated immunity.

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26
Q

Humoral and cell mediated immunity is a type of what immunity?

A

Specific immune response, or adaptive immunity.

Remember: specific or adaptive immunity requires cells to learn from specific pathogens.

Humoral- B cells

Cell mediated - T cells

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27
Q

Notes on the structure of the immune system (8.1)

A
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28
Q

Notes regarding the innate immune system 8.2

A
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29
Q

The innate immune system

A

Non specific first line of defense against pathogens. Consist of non-cellular non-specific defenses (skin, the respiratory system, oral cavity), the gastrointestinal tract, complement, interferons, macrophages, natural killer cells, granulocytes.

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30
Q

Non-cellular non-specific defenses

A

Think of this is the first line of defense. Our skin (integument), sweat also has antimicrobial properties. The respiratory system also has mechanisms to prevent pathogens from entering the body such as mucus membranes lined with cilia, the eyes and the oral cavity.

Include interferons, complement, GI tract, skin.

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31
Q

Defensins

A

Defensins are members of a large family of cationic antimicrobial peptides that form an essential element of INNATE immunity.
Defensins are Cationic Antimicrobial Peptides (CAP), a broad spectrum antimicrobial defense of the innate immune system.

Important to remember that these are antibacterial enzymes and can be found all over the body: skin, gut, lungs, kidneys.

A part of the non-cellular nonspecific defenses.

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32
Q

Lysozyme

A

Nonspecific enzyme important to the innate immune system. Effective in protecting against bacterial, viral, and fungal infections.

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33
Q

The gastrointestinal tract, regarding immunity

A

Plays a role in non-specific immunity. The stomach secretes acid which can eliminate most pathogens. Also colonized by bacteria that provide competition for potential invaders.

A part of the non-cellular nonspecific defenses.

Interesting: many antibiotics reduce the population of gut flora, providing an opportunity for the growth of pathogens resistant to that antibiotic.

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34
Q

Breast milk, regarding the immune system and newborns

A

The GI tract of newborn baby is particularly susceptible to infection because the newborns immune system is underdeveloped and the GI tract is not colonized. Breastmilk contains a family of antibodies that are particularly effective on mucosal surfaces and help to defend newborn babies against gastrointestinal infections.

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35
Q

The complement system

A

Broken down into the classical pathway and the alternative pathway.

The complement system consist of a number of proteins in the blood that act as a non-specific defense against bacteria. Complement proteins punch holes in the cell walls of bacteria, making them osmotically unstable. Despite the association with antibodies, complement is considered a non-specific defense because it cannot be modified to target a specific organism over others.

A part of the non-cellular nonspecific defenses.

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36
Q

Classical pathway of the complement system

A

Requires the binding of an antibody to a pathogen, activated by antigen – antibody complexes.

Note that even though the classical pathway of the complement system requires antibodies, it is still considered a part of the non specific innate immune system and can be activated by natural antibodies like natural IgM, which are present in the body even without prior exposure to a specific pathogen, allowing for an immediate response against certain invaders; essentially bridging the gap between innate and adaptive immunity.

A part of the non-cellular nonspecific defenses.

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37
Q

Alternative pathway of the complement system

A

Does not require antibodies. Mark pathogens for destruction, process called opsonization.

A part of the non-cellular nonspecific defenses.

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38
Q

Interferons

A

Proteins that prevent viral replication and dispersion, produced by cells that have been infected with viruses. Interferons cause nearby cells to decrease production of both viral and cellular proteins.

A part of the non-cellular nonspecific defenses.

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39
Q

Cells of the innate immune system

A

The cells of the innate immune system are nonspecific and form the first line of defense against pathogens.

Macrophages, granulocytes, dendritic cells, natural killer cells, and mast cells.

B and T cells are NOT a part of the innate immune system.

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40
Q

Macrophages

A

Macrophages are a type of a granulocyte and reside within the tissues. Derived from monocytes. Macrophages become activated when a bacterial invader enters the tissue. They will do three things:
1: phagocytize the invader
2: Digest the invader using enzymes
3: presents little pieces of the invader to other cells using major histocompatibility complex (MHC).

Examples include:

Langerhan cells in the skin
Microglia in the central nervous system
Osteoclasts in the bone

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41
Q

Resident population regarding macrophages

A

Macrophages can set up resident populations within a tissue becoming a permanent, rather than transient, cell group and a tissue.

Glial, Langerhans, osteoclast

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42
Q

Major histocompatibility complex MHC

A

Bind to pathogenic peptide (also called an antigen) and carries it to the surface, where it can be recognized by cells of the adaptive immune system, most notably T cells. There are MHC class one and MHC class two molecules.

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43
Q

Major histocompatibility complex Class 1

MHC-I (endogenous pathway)

A

All nucleated cells in the body display MHC class one molecules. Any protein produced within a cell can be loaded onto major histocompatibility complex class one and presented on the surface of the cell. The MHC allow the immune system to monitor the health of cells and a detect if the cells have been infected with a virus or another infected cellular pathogen. Only cells that are infected would be expected to present an unfamiliar (or non-self) protein on their surfaces.

44
Q

Cytokines

A

Chemical substances that stimulate inflammation and recruit additional immune cells to the area. Macrophages release cytokines.

45
Q

Major histocompatibility complex class two

MHC-II (exogenous pathway)

A

Mainly displayed by professional antigen – presenting cells like macrophages. Recall that such phagocytic cells pick up pathogens from the environment, process them, and then present them on MHC-II. This presentation of an antigen by MHC–II may result in the activation of both the innate and adaptive immune systems.

46
Q

Pattern recognition receptors (PRR)

A

INNATE IMMUNITY. PRRs are able to recognize the category of invaders (bacteria, virus, fungus, or parasite). This allows for the production of appropriate cytokines to recruit the right type of immune cells.

Pattern recognition receptor (PRR) are a class of receptors that can directly recognize the specific molecular structures on the surface of pathogens, apoptotic host cells, and damaged senescent cells.

Defensins are considered to be a type of PRR.

47
Q

Toll – like receptors (TLR)

A

The best described variety of pattern recognition receptors (PRR). Toll-like receptors (TLRs) are proteins that help the immune system identify and respond to microbes and other threats.

48
Q

Natural killer cells (NK cells)

A

A type of non-specific lymphocyte able to detect the down regulation of MHC and induce apoptosis in these virally infected cells. NK cells are known to offer protection from growth of cancer cells. NK cells are innate lymphocytes.

49
Q

Granulocytes

A

Part of the innate immune system, also known as the non-specific immunity, including neutrophils, eosinophils, basophils, and mast cells.

Contain granules in the cell membrane that once released are toxic to pathogens.

50
Q

Neutrophil

A

Most populous leukocyte in the blood and are very short-lived. These cells are phagocytic and target bacteria. Detect bacteria through chemotaxis and also follow bacteria once they have been opsonized (marked with an antibody from a B-cell). Dead neutrophil collections are responsible for the formation of pus during an infection.

51
Q

Opsonized

A

Cell or pathogen marked with an antibody from a B-cell.

52
Q

Pus

A

Collections of dead neutrophil during an infection.

53
Q

Eosinophils

A

Primarily involved in allergic reactions and invasive parasite infections. Release large amounts of histamine. Trigger the response of macrophages and neutrophil to move out of the bloodstream and into the tissue.

54
Q

Histamine

A

An inflammatory mediator which causes inflammation by inducing vassal dilation, and the movement of fluid and cells from the bloodstream into tissues.

Histamine is not a cytokine, but it does affect cytokine production and release.

55
Q

Basophil

A

Involved in allergic responses, they are the least populous leukocyte in the bloodstream under normal conditions. Release large amounts of histamine in response to allergens, leading to inflammatory responses.

56
Q

Mast cells

A

Closely related to basophils and serve largely the same purpose. Smaller granules, existing in tissues, mucosa, and epithelium. For the purpose of this study mast cells and basophils are analogues. Release histamine and cause inflammation. Innate immunity.

57
Q

The adaptive immune system notes 8.3

A
58
Q

The adaptive immune system (also known as specific immune system) general

A

Called specific immunity for a reason as they identify specific invaders and mount an attack against those pathogens. Divided into two divisions: humoral immunity and cell mediated (cytotoxic) immunity. Can mainly have two types of lymphocytes, B cells (humoral) and T cells (cytotoxic or cell mediated).

59
Q

Humoral immunity

A

Involves the production of antibodies, produced by B cells, may take as long as a week to become fully effective after initial infection.

Named after the humors, or body fluids. Refers to the liquid portion of the blood.

60
Q

Immunoglobulin [Ig]

A

Fancy word for antibodies.

61
Q

Three main possibilities for when antibodies are secreted into body fluids

A

First. Once bound to a specific antigen, antibodies may attract other leukocytes to phagocytize those antigens immediately.

Second. Antibodies may cause pathogens to clump together, or agglutinate, forming large soluble complexes that can be phagocytized.

Third. Antibodies can block the ability of a pathogen to invade tissues, essentially neutralizing them.

62
Q

Opsonization

A

An immune process that helps the body identify and destroy pathogens and old cells.

63
Q

Degranulation

A

Exocytosis of granule contents of granulocytes.

64
Q

Molecular shape of antibodies

A

Antibodies are Y shaped molecules made up of two identical, heavy chains and two identical light chains.

65
Q

Antigen – binding region of an antibody

A

Also known as the variable region (domain). Highly specific polypeptide sequences that will bind with one, and only one, specific antigen sequence. Part of the reason it takes so long to initiate the antibody responses that the B cell undergoes hypermutation of its antigen binding region, trying to find the best match for the antigen.

66
Q

Clonal selection

A

Mechanism for generating clones of the B cells and T cells that bind a specific antigen with high affinity.

67
Q

Constant region (domain) of an antibody

A

The stem part of the Y shape of antibodies. This is the region that cells such as natural killer cells, macrophages, monocytes, and eosinophils have receptors for, and that can initiate the complement cascade.

68
Q

Five different isotopes of antibodies

A

MEGAD

IgM, IgE, IgG, IgA, IgD

Don’t need to know the specific purposes of each antibody isotope, just know that the different types can be used at different times during the adaptive immune response for different types of pathogens or in different locations of the body.

IgG - long term (grandma), crosses placenta
IgM - first response (first thing in the morning)

69
Q

Naive B cells

A

B cells that have not yet been exposed to an antigen. They wait in the lymph nodes for their particular antigen to come along. Upon exposure to the correct antigen, a B cell will proliferate and create plasma cells, and memory B cells.

70
Q

Plasma cells (humoral immunity)

A

Daughter cell of naïve B cells. Produce large amounts of antibodies.

71
Q

Memory B cells

A

Daughter cell of naïve B cells stay in the lymph node and await re-exposure to the same antigen. If the same microbe is ever encountered again, the memory sells rapidly proliferate and differentiate into plasma cells to produce antibodies specific to that pathogen.

72
Q

Primary response of humoral immunity

A

Initial activation of naïve B cells that creates proliferation of the B cells, plasma cells, and memory B cells.

73
Q

Secondary response of humoral immunity

A

The secondary response happens if the same microbe is ever encountered after the primary response, memory B cells rapidly proliferate, and differentiate into plasma cells to produce antibodies specific to that pathogen.

74
Q

Cytotoxic immunity (also called cell mediated immunity)

A

Part of the adaptive immune system (also known as specific immunity) That involves T cells. Divided into positive and negative selection.

In cytotoxic immunity, “positive selection” refers to the process where developing cytotoxic T cells (CD8+) in the thymus are chosen to mature if they weakly bind to self Major Histocompatibility Complex (MHC) molecules, ensuring they can recognize and interact with healthy cells, while “negative selection” eliminates those that bind too strongly to self-antigens, preventing autoimmune reactions by removing potentially harmful T cells that could attack the body’s own tissues.

75
Q

Positive selection of cytotoxic immunity

A

Positive selection refers to allowing only the maturation of cells that can respond to the presentation of antigen on MHC (major histocompatibility complex). Cells that cannot respond to MHC undergo apoptosis because they will not be able to respond in the periphery. Part of the adaptive immune system.

76
Q

Negative selection of cytotoxic immunity

A

Refers to causing apoptosis of cells that are self reactive (activated proteins produced by the organism itself). This is an important selection process in the body’s attempt to mitigate autoimmunity. Part of the adaptive or selective immune system.

77
Q

Thymosin

A

A peptide hormone secreted by thymic cells in the thymus responsible for maturation of naïve T cells as a part of adaptive cytotoxic immunity.

78
Q

Four major types of T cells (specific cytotoxic immunity)

A

Helper T cells (Th) (CD4+ cells)
Cytotoxic T cells or killer (Tc) (CD8+)
Suppressor T cells or regulatory (Treg)
Memory T cells

79
Q

CD4+ cells

A

Specific cytotoxic immunity. Also known as helper T cells (Th). Respond to antigens presented on MHC – II molecules (EXOGENOUS PATHWAY), therefore most effective against bacterial, fungal, and parasitic infections.

Coordinate the immune response by secreting chemicals known as lymphokines. Capable of recruiting other immune cells, such as plasma cells, cytotoxic, T cells, and macrophages.

80
Q

CD8+

A

Adaptive cytotoxic immunity. Also known as cytotoxic T cells or killer T cells (Tc). MHC-I (ENDOGENOUS PATHWAY) and therefor effective against viruses.

Capable of directly killing virally infected cells by injecting toxic chemicals that promote apoptosis into the infected cell.

81
Q

Lymphokines

A

Lymphokines are a polypeptide produced by activated lymphocytes that help regulate the immune system. They can enhance or suppress immune functions, as well as many other functions including regulating cell functions and cell growth.

Majority of lymphokines are secreted by CD4+ cell (helper T cells) that coordinate immune responses from plasma cells, cytotoxic T cells, and macrophages.

Recall: -kines suffix is derived from -kinesia meaning motion or movement.

82
Q

Suppressor or Regularory T cells (Treg)

A

Expresses FOXP3 and CD4+. Tone down immune response once the infection has been adequately contained. Called suppressor also because they suppress self reactive lymphocytes to help prevent autoimmune diseases, a process called self tolerance.

83
Q

Self Tolerance (adaptive cytotoxic immunity)

A

Self tolerance is when suppressor or regulatory T cells (Treg) turn off self reactive lymphocytes to help prevent auto immune diseases.

84
Q

Memory T cells

A

Memory T cells lie in wait until the next exposure to the same antigen.

85
Q

Flow cytometry

A

A lab technique used to analyzes cells or particles by passing them through a flow cytometer machine. Uses fluorescent antibody dies and detects light scattering and fluorescence patterns.

86
Q

Lymphocytes of specific immunity diagram

A
87
Q

Five types of infectious pathogens

A

Virus, bacteria, fungus, parasite, prion

There are no known immune defense for prions.

88
Q

Two types of CD4+ T cells (helper T cells)

A

Th1 and Th2 (adaptive cytotoxic immunity)

Th1 activates macrophages and increase their ability to kill bacteria

Th2 help activate B cells

89
Q

Viral infection. What happens?

A

Infected cell will begin to produce interferons which reduced the permeability of nearby cells, reduce the rate of transcription and translation in these cells, and cause systemic symptoms.

Present inter cellular proteins on their surface in conjunction with MCH – I.

CD8+ T cells (MHC-I EXOGENOUS PATH) Will recognize the antigen complex as foreign and will inject toxins into the cell to promote apoptosis. Natural killer cells will recognize the absence of MCH – I and will accordingly cause apoptosis of infected cells.

Memory T cells will be generated.

90
Q

Self antigens

A

Self antigens are the proteins and carbohydrates present on the surface of every cell of the body.

91
Q

Autoimmunity

A

Auto immunity is when the immune system fails to make the distinction between self and foreign and may attack cells expressing particular self antigens.

92
Q

Allergic reaction

A

A problem when the immune system misidentifies a foreign antigen as dangerous when, in fact, it is not. Pet dander, pollen, and peanuts, for example.

93
Q

Active immunity v passive immunity

A

Active immunity is when the immune system is stimulated to produce antibodies against a specific pathogen.

Passive immunity results from the transfer of antibodies to an individual, such as through a mother nursing an infant or a vaccine.

94
Q

The lymphatic system notes 8.4

A
95
Q

The lymphatic system

A

The lymphatic system is a secondary circulatory system. Made up of one-way vessels that become larger as they move toward the center of the body. Vessels carry lymph and most join to form a large thoracic duct in the posterior chest, which then delivers the fluid into the left subclavian vein near the heart.

The lymphatic system drains excess fluid from tissues and subsequently return the fluid to the bloodstream.

Transports fats from the digestive system into the bloodstream. Lymphatic fluid carrying many chylomicrons Is milky white and is called chyle.

The lymph nodes in the lymphatic system are a place for antigen presenting cells and lymphocytes to interact.

B cells proliferate and mature in the lymph nodes in collections called germinal centers.

96
Q

Lymph

A

The name for lymphatic fluid

97
Q

Thoracic duct

A

The thoracic duct is the body’s largest lymphatic vessel located in the posterior chest. Transports lymph from the bodies tissues back into the circulatory system into the left subclavian vein near the heart.

98
Q

Lymph node

A

Lymph nodes are small, bean shaped structures along the lymphatic vessels. Contain a lymphatic channel as well as an artery and a vein. The lymph nodes provide a space for the cells of the immune system to be exposed to possible pathogens. Recall that B cells proliferate and mature in lymph nodes in collections called germinal centers.

99
Q

Edema

A

Edema occurs when the lymphatics are overwhelmed and is a swelling due to fluid collecting in tissue.

100
Q

Lacteals

A

Small lymphatic vessel located at the center of each villus in the small intestine which absorb fats via chylomicrons.

101
Q

Chylomicrons

A

Chylomicrons are lipoproteins in the intestines that transport dietary fats and cholesterol from the small intestine into lymphatic system.

102
Q

Chyle

A

Lymphatic fluid carrying many chylomicrons takes on a milky white appearance and it’s called chyle.

103
Q

Germinal centers of lymph nodes

A

Centers are collections in the lymph nodes where B cells proliferate and mature.

104
Q

Immunity conclusion

A
105
Q

What are Cationic Antimicrobial Peptides?

A

Cationic Antimicrobial Peptides (CAP) are a broad spectrum antimicrobial defense of the innate immune system. Defensins are CAPs.