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MCAT Bio > Bio #8 > Flashcards

Bio #8 Flashcards

1
Q

innate immunity

A

also known as non-specific immunity. Defenses that are always active against infection, but lack the ability to target specific invaders.

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2
Q

what are the players in innate immunity

A

o Consists of antimicrobial molecules and various phagocytes (cells that ingest and destroy pathogens). Some phagocytes include dendritic cells and macrophages. These cells activate an immune response by releasing cytokines. The cytokines trigger an immune response and recruit more immune cells from the blood which include more phagocytes: monocytes (mature into macrophages) and neutrophils.
o Without learning

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3
Q

cytokines

A

The cytokines trigger an immune response and recruit more immune cells from the blood which include more phagocytes

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4
Q

adaptive immunity

A

also known as specific immunity. Defenses that target a specific pathogen. Slower to act, but can have immunological memory to an infection so a faster response can be mounted next time to similar infections.

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5
Q

what are the players in adaptive immunity?

A

o Consists of B and T cells. B cells release antibodies that bind to antigens of the invader and destroy the invader or mark them to get destroyed by something else. T-cells recognize antigens presented by cells and can attack these cells, signal to B cells, or signal to other T cells. T and B cells can also spawn memory cells.
o Immune cells learn to recognize and respond to particular antigens

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6
Q

B cells

A

B cells release antibodies that bind to antigens of the invader and destroy the invader or mark them to get destroyed by something else.

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7
Q

T cells

A

T-cells recognize antigens presented by cells and can attack these cells, signal to B cells, or signal to other T cells. T and B cells can also spawn memory cells.

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8
Q

Does innate or adaptive immunity occur faster?

A

innate

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9
Q

Does innate or adaptive immunity have memory?

A

adaptive

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10
Q

what is the process that leukocytes are produced?

A

hematopoiesis

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11
Q

what is another name for white blood cells?

A

leukocytes

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12
Q

what produces all of the white blood cells?

A

bone marrow

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13
Q

where are B cells activated?

A

the spleen and lymph nodes

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14
Q

When B cells are activated what are they called?

A

plasma cells

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15
Q

compare humoral immunity and cell-mediated immunity

A
  • Humoral immunity (B cell mediated): antibody response, present in the blood (rather than within cells).
  • T cells mature in the thymus, a small gland just in front of the pericardium, the sac that protects the heart.
  • Cell-mediated immunity (T-cell mediated): consists of T cells that coordinate the immune system and directly kill virally infected cells.
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16
Q

humoral immunity

A

antibody response, present in the blood (rather than within cells).

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17
Q

cell mediated immunity

A

(T-cell mediated): consists of T cells that coordinate the immune system and directly kill virally infected cells.

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18
Q

where do T cells mature?

A

thymus

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19
Q

lymph nodes

A

where immune cells communicate and mount an attack. B cells can also be activated here.

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20
Q

gut associated lymphoid tissue

A

(GALT): located near the digestive system. This includes the adenoids and tonsils in the head, Peyer’s patches in the small intestine, and lymphoid aggregates in the appendix.

the largest mass of lymphoid tissue in the body. It consists of immune cells such as B and T lymphocytes, macrophages, antigen-presenting cells, including dendritic cells, and specific epithelial and intra-epithelial lymphocytes.

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21
Q

Leukocytes are divided into two types of cells: (both come from hematopoietic stem cells) ______

A

granulocytess and agranulocytes

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22
Q

granulocytes

A

granules in the cytoplasm (these granules contain toxic enzymes and can be released)
 Ex: Neutrophils, eosinophils, and basophils.

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23
Q

agranulocytes

A

do not contain granules in cytoplasm
 Lymphocytes (B and T cells): responsible for antibody production, immune system modulation, and targeted killing of infected cells.
 Monocytes: phagocytic cells in the bloodstream
• Become macrophages in tissues
o Microglia: Central nervous system
o Langerhans cells: skin
o Osteoclasts: bone

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24
Q

name of macrophages in the central nervous system

A

microglia

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25
Q

name of macrophages in the skin

A

langerhans cells

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26
Q

name of macrophages in the bone

A

osteoclasts

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27
Q

neutrophils are _____ while dendritic cells are good for______

A

fast and abundant

triggering the adaptive/specific immune system

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28
Q

humoral response is for when pathogens are ______ while the cell-mediated response is for when pathogens are _____

A

outside of cells

inside of cells

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29
Q

opsonization

A

is the molecular mechanism whereby molecules, microbes, or apoptotic cells are chemically modified to have a stronger attraction to the cell surface receptors on phagocytes and NK cells. With the antigen coated in opsonins, binding to immune cells is greatly enhanced.

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30
Q

Professional Antigen Professional Cells

A 
B cells and macrophages
MHC class II
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31
Q

naive T cell or B cell

A

non memory and non effector ==> never been activated (hasn’t had anything bound to it yet)

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32
Q

effector T cell

A

raises the alarm, releases cytokines

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33
Q

effector T cell

A

raises the alarm, releases cytokines, bind to other immune cells and tells them to get in gear (activated B cell producing antibodies and cytotoxic T cells)

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34
Q

what are examples of noncellular nonspecific defenses?

A 
skin
lysozyme
gastrointestinal tract 
complement system
interferons
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35
Q

skin

A

noncellular nonspecific defense

integument

the first line of defense
o Provides a barrier between the inside of our body and outside world, cuts are bad.
o Defensins: can be found on skin, antibacterial enzymes
o Sweat also has antimicrobial properties

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36
Q

lysozyme

A

noncellular nonspecific defense

nonspecific bacterial enzyme secreted in tears and saliva.

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37
Q

complement system

A

o Consists of a number of proteins in the blood that act as a nonspecific defense against bacteria. Punch holes in the bacterial wall.
o Classical pathway: requires binding of an antibody to a pathogen and then it acts.
o Alternative pathway: does not require binding of an antibody before it acts.

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38
Q

defensins

A

noncellular nonspecific defense

can be found on skin, antibacterial enzymes

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39
Q

the gastrointestinal tract as noncellular nonspecific defense

A

o Stomach secretes acid which kills off a lot of bacteria. The gut is already colonized with a lot of bacteria that are harmless and potential invaders cannot compete. Antibiotics reduce the gut flora which provides opportunity for growth of pathogens resistant to the antibiotic.

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40
Q

complement system classical pathway

A

requires binding of an antibody to a pathogen and then it acts.

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41
Q

complement system alternative pathway

A

does not require binding of an antibody before it acts.

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42
Q

interferons

A

o Proteins that are released by cells that have been infected by a virus to reduce viral replication and dispersion.
o These proteins do the following to nearby cells:
 Decrease production of viral and cellular proteins
 Decrease permeability of cells
 Upregulate MHC Class I and MHC Class II  increased antigen presentation and better detection of infected cells.
o Cause flu-like symptoms.

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43
Q

what do interferons do to nearby cells?

A

 Decrease production of viral and cellular proteins
 Decrease permeability of cells
 Upregulate MHC Class I and MHC Class II  increased antigen presentation and better detection of infected cells.

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44
Q

macrophages

A

MHC II
o reside in tissues where they become a resident population (permanent cell population)
o derived from blood-borne monocytes.

Two functions

  • phagocytosis, enzyme breaks down invader, presents it via MHC
  • releases cytokines
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45
Q

macrophage phagocytosis

A

 1. Phagocytizes invading bacteria through endocytosis, enzymes break it down, presents a pathogenic peptide (antigen) at its cell surface via a protein called a major histocompatibility complex (MHC). This antigen is recognized by cells of the adaptive immune system.

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46
Q

protein that helps present antigen on cell surface

A

major histocompatibility complex

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47
Q

MHC I vs. MHC II

A

• MHC Class I: all nucleated cells have these proteins. Any protein in the cell can be presented by this protein. Endogenous pathway because it binds antigens from inside the cell. Only infected cells would present an unfamiliar protein.
• MHC Class II: displayed by professional antigen-presenting cells such as macrophages. These cells pick up pathogens from the environment. Also known as the exogenous pathway because the antigens it presents come from outside the cell.
o Macrophages, dendritic cells in the skin, some B cells, and certain activated epithelial cells.

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48
Q

MHC I: antigens presented that come from ______

A

inside the cell, so the cell was infected

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49
Q

MHC II: antigens presented that come from _____

A

pathogens in the environment that were phagocytosed

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50
Q

cytokines

A

chemical substances that stimulate inflammation and recruit additional immune cells.

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51
Q

cytokines

A

chemical substances that stimulate inflammation and recruit additional immune cells.

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52
Q

antigen

A

substance (usually pathogenic protein) that can be targeted by an antibody.

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53
Q

pattern recognition receptors

A

macrophages and dendritic cells have them. Recognize the category of invader (virus, bacteria, fungus, parasite) and allows for the production of specific cytokines to recruit the right immune cells with right weapons.

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54
Q

natural killer cells (NK)

A

o Sense downregulation of MHC molecules that is caused by viruses and induce apoptosis in these virally infected cells.
o So, it destroys the body’s own cells that have been infected.
o It also goes after cancer cells because they can also downregulate MHC production.

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55
Q

what are the different types of granulocyes

A

neutrophils, basophil, eosinophil, mast cell, macrophage, dendritic cell

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56
Q

neutrophils

A

 most populous leukocyte, short lived, phagocytic
 they target bacteria via chemotaxis  the movement of an organism according to chemical stimuli  Specifically opsonized bacteria
 Pus: dead neutrophil collections
 Can also detect bacteria once they have been opsonized: marked with an antibody from a B cell (NK cells, macrophages, monocytes, and eosinophils can also attack opsonized bacteria by sensing antibodies.

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57
Q

pus

A

collected of dead neutrophils

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58
Q

chemotaxis

A

the movement of an organism according to chemical stimuli  Specifically opsonized bacteria

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59
Q

neutrophils

A

phagocytose bacteria and kill them
 most populous leukocyte, short lived, phagocytic
 they target bacteria via chemotaxis  the movement of an organism according to chemical stimuli  Specifically opsonized bacteria
 Pus: dead neutrophil collections
 Can also detect bacteria once they have been opsonized: marked with an antibody from a B cell (NK cells, macrophages, monocytes, and eosinophils can also attack opsonized bacteria by sensing antibodies.

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60
Q

basophils

A

 Involved in allergic reactions
 Usually the least populous leukocyte in the blood stream
 Release histamine in response to allergens

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61
Q

mast cells

A

 Release histamine in response to allergens and promote inflammation
 Exist in tissues, mucosa, and epithelium.

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62
Q

dendritic cells

A

 Type of antigen presenting cell.

MHC II

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63
Q

inflammation

A

result of the cells moving into the tissue, useful against extracellular pathogens.

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64
Q

mast cells

A

 Release histamine in response to allergens
 Exist in tissues, mucosa, and epithelium.

Mast cells mediate inflammatory responses such as hypersensitivity and allergic reactions. … Upon stimulation by an allergen, the mast cells release the contents of their granules (a process called degranulation) into the surrounding tissues.

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65
Q

B cells mature in the ______ and T cells mature in the ______

A

bone marrow

thymus

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66
Q

what are the responses of antibodies when they are in body fluids?

A

 1. Once bound, may attract other leukocytes to phagocytize the antigen immediately (opsonization)
 2. Cause pathogens to clump together, agglutinate, and then the clumps are phagocytized.
 3. Neutralize the pathogen and restrict it from invading tissues.

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67
Q

what are the responses of antibodies when they are cell-surface antibodies?

A

 The binding of antigen to a B cell results in the proliferation of the B cell and the formation of the plasma cells and memory B cells.
 When antigen binds to the cell surface of the mast cell, it causes degranulation which releases histamine and causes an inflammatory allergic reaction.

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68
Q

what happens when antigen binds to the cell surface of a mast cell?

A

 When antigen binds to the cell surface of the mast cell, it causes degranulation which releases histamine and causes an inflammatory allergic reaction.
• Antibody structure

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69
Q

describe antibody structure

A

o Y-shaped made up of two identical heavy chains and two identical light chains held together by disulfide linkages and non-covalent interactions.
o Antigen binding region at the tips of the Y which is known as the variable region (domain).
 Binds one specific antigen sequence.
 Hypermutation: the antigen binding region goes through this to find the best match for the antigen  why the response takes awhile.
 Clonal selection: only the B cells that can bind the antigen with high affinity survive.
o Constant region (domain): remaining part of the antibody.
 Part of the antibody that fells bind to.
o Antibodies come in 5 different isotypes  specific to certain things.
 Isotype switching: cells can change which isotype of antibody they produce when stimulated by specific cytokines.

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70
Q

which part of the antibody is the variable region?

A

2 tips

71
Q

hypermutation of antibody

A

the antigen binding region goes through this to find the best match for the antigen  why the adaptive/humoral response takes awhile.

mutate the genes used to produce antinbodies to find one with highest affinity and then select this B cell to make plasma cells and memory B cells from.

72
Q

clonal selection of antibody

A

only the B cells that can bind the antigen with high affinity survive.

Clonal selection is a process proposed to explain how a single B or T cell that recognizes an antigen that enters the body is selected from the pre-existing cell pool of differing antigen specificities and then reproduced to generate a clonal cell population that eliminates the antigen.

73
Q

which part of the antibody is the constant region?

A

1 tip

74
Q

isotype switching

A

cells can change which isotype of antibody they produce when stimulated by specific cytokines.

75
Q

antibody production is ____ expensive

A

energetically

76
Q

process of naive B cells

A

• Naïve B cells wait in lymph nodes for their antigen to come along. Upon exposure to the right antigen, the B cell will proliferate producing two types of daughter cells:
 Plasma cells: produce large amounts of antibodies
 Memory B cells: stay in the lymph node and wait for exposure to the same antigen.

77
Q

process of naive B cells

A

• Naïve B cells wait in lymph nodes for their antigen to come along. Upon exposure to the right antigen, the B cell will proliferate producing two types of daughter cells:
 Plasma cells: produce large amounts of antibodies
 Memory B cells: stay in the lymph node and wait for exposure to the same antigen.

78
Q

what is the primary and secondary response?

A

primary: initial activation, takes 7-10 days.
secondary: plasma cells die but the memory B cells remain. So, if the same microbe comes again, the memory B cells can jump into action. This response is more rapid and robust.

79
Q

vaccination utilizes the idea of the _____

A

secondary response

plasma cells die but the memory B cells remain. So, if the same microbe comes again, the memory B cells can jump into action. This response is more rapid and robust.

80
Q

Cytotoxic or Cell Mediated Immunity (T cells) is important for ____

A

intracellular pathogens

81
Q

positive selection

A

select for T cells that can respond to the presentation of MHC

82
Q

negative selection

A

cause apoptosis in cells that are self-reactive and will be activated by the body’s own proteins.

83
Q

both positive and negative selection of T cells occurs in the ____

A

thymus

84
Q

thymosin

A

responsible for the maturation of T cells and is secreted by thymic cells.

85
Q

what are the 3 types of T cells?

A

helper T cells
suppressor T cells
killer (cytotoxic) T cells

86
Q

helper T cells

A

o Helper T cells: also called CD4+ T cells coordinate the immune response by secreting lymphokines.
 Recruit other immune cells
 HIV: human immunodeficiency virus: loss of CD4+ cells, body cannot mount an immune response. Untreated leads to AIDS (acquired immunodeficiency syndrome): allows opportunistic infections to have devastating effects.
 Respond to antigens presented by MHC Class II
 Th1 cells secrete interferon gamma, which activates macrophages. Th2 cells activate B cells, primarily in parasitic infections,

87
Q

helper T cells = _______

A

CD4+ cells

88
Q

helper T cells respond to antigens presented on ______

A

MHC II

89
Q

Helper 1 T cells vs. Helper 2 T cells

A

1: cells secrete interferon gamma, which activates macrophages
2: activate B cells, primarily in parasitic infections,

90
Q

suppressor T cells

A

also known as regulatory T cells, also express CD4 but are differentiated from helper T-cells due to Foxp3 expression. Stop the immune response when the pathogen is taken care of. Also prevent against autoimmune diseases (immune system attacks itself) via self-tolerance.

91
Q

memory T cells

A

lie and wait for next exposure to the same pathogen and produce rapid and robust response.

92
Q

memory T cells produce a _______response

A

rapid and robust

93
Q

what are the steps for bacterial extracellular pathogen response?

A

o 1. Macrophages engulf bacteria, release inflammatory mediators and present antigen
o 2. Cytokines attract inflammatory cells including neutrophils and macrophages. Mast cells are activated and release histamine, opening capillaries.
o 3. Immune cells come to site
o 4. Dendritic cells take antigen and present it to B cells in the lymph node
o 5. B cells create plasma cells which release antibodies and also create memory B cells.
o 6. CD4+ T cells are also activated, releasing interferon to activate macrophages and activate B cells.
o 7. After pathogen is taken care of, memory cells remain.

94
Q

what are the steps for viral intracellular response?

A

o 1. Virally infected cell releases interferons
o 2. Present viral antigens on their surface via MHC Class I
o 3. CD8+ cells recognize it and secrete toxins in these cells to produce apoptosis.
o 4. Natural killer cells recognize if MHC Class I is downregulated and attacks these cells.
o 5. Memory B and T cells remain.

95
Q

self-antigens

A

the proteins and carbohydrates present on the surface of every cell in the body.
o Typically signal that the cell is not infected and to not attack it.

96
Q

autoimmunity

A

can’t tell self from foreign antigen
 Human body tries to prevent cells that do this via maturation early on.
 Glucocorticoids: used to treat autoimmune diseases with their immunosuppressive qualities.

97
Q

hypersensitivity reactions

A

allergies and autoimmunity.

98
Q

active immunity

A

the immune system is stimulated to produce antibodies against a specific pathogen. Exposed to pathogen naturally or via artificial vaccination.
o Vaccine: individual never receives full pathogen, maybe just parts of its protein structure or a weakened pathogen.

99
Q

passive immunity

A

transfer of antibodies to an individual.
o Immunity is transient.
o Ex: mother to fetus during pregnancy, mother to infant during breastfeeding, intravenous immunoglobin for rabies virus or tetanus.

100
Q

passive immunity

A

: transfer of antibodies to an individual.
o Immunity is transient.
o Ex: mother to fetus during pregnancy, mother to infant during breastfeeding, intravenous immunoglobin for rabies virus or tetanus.

101
Q

what is the lymphatic system

A

• It is a type of circulatory system which contains one-way vessels that become larger as they move toward the center of the body. Contain lymph fluid (watery fluid that flows through the lymphatic system) and most join to form the thoracic duct in the posterior chest which delivers the fluid to the left subclavian vein near the heart.

102
Q

where do most lymphatic vessels join up

A

thoracic duct

103
Q

edema

A

swelling due to fluid collecting in tissue.
o If a key plasma protein is low in concentration somewhere, oncotic pressure can change so that less fluid is put back into the bloodstream and it instead stays in a particular tissue.

104
Q

hydrostatic pressure

A

: pressure of the blood on the membrane of the capillary. When it increases, more fluid leaves the capillary.
 Bigger proteins stay in blood so need some fluid to stay in capillary

105
Q

oncotic pressure

A

pulling fluid back into the capillaries or preventing the fluid from leaving the capillaries.

106
Q

transport and the lymphatic system

A

o The lymphatic system also transports fats from the digestive system into the bloodstream.
o Lacteals: small lymphatic vessels located at the center of each villus in the small intestine transport fats in chylomicrons. Lymph fluid carrying lots of chylomicrons is called chyle.

107
Q

germinal cells

A

location where B cells proliferate and mature.

108
Q

germinal cells

A

location where B cells proliferate and mature.

109
Q

what cells have MHC I

A

any cells in the human body that have a nucleus have them

presented by cells that have been infected (or reduced number of them)

kill me

110
Q

where do helper T cells vs. cytotoxic T cells get their messages?

A

MHC II: raise the alarm

MHC 1: kill the cell

111
Q

clonal selection

A

select the B and T cells that you need and then start cloning them like crazy

112
Q

B cell antibody receptors are created at random and thats why they can possibly be made to react with your own body. how is this prevented (2 ways)

A
  1. whatever B cell binds to something in the bone marrow will be killed ==> vetting
  2. B cell that escapes that reacts to self, also need a T cell that does the same thing to activate it (unlikely)
113
Q

B cell antibody receptors are created at random and thats why they can possibly be made to react with your own body. how is this prevented (2 ways)

A
  1. whatever B cell binds to something in the bone marrow will be killed ==> vetting
  2. B cell that escapes that reacts to self, also need a T cell that does the same thing to activate it (unlikely)
114
Q

thoracic duct

A

The function of the thoracic duct is to transport lymph back into the circulatory system. Interstitial fluid is collected by lymph capillaries from the interstitial space. Lymph then moves through lymphatic vessels to lymph nodes. Lymphatic vessels merge to create the lymphatic ducts which drain into the venous system

115
Q

mast cells release ______

A

histamine

histamine release causes vasodilation

116
Q

mast cells release ______

A

histamine

histamine release causes vasodilation

117
Q

megakaryocity

A

makes platelets

118
Q

lymphatic system notes

A
  • another plumbing system that collects fluid and bring it back to circulation via lymphatic vessels
  • some fluid that gets forced out in the arteriole end gets pushed back in at the venous end (osmotic pressure caused by increased concentration) (more goes out than comes back in)(need to get these nutrients to cells outside the capillaries)
119
Q

do lymphatic vessels form a closed loop?

A

no

120
Q

lymph re-enters the circulatory system ____

A

subclavian veins

the very end of the veinous system (lower pressure)

121
Q

how does lymph move in the lymphatic system?

A

valves (same as in heart and veins)

smooth muscle can also contract

122
Q

a cut usually does not actually infect the blood but the tissues near it

A

serious infections get into the blood

123
Q

bacteria and macrophages get swept into ____ and carried to ____

A

lymphatic vessels lymph nodes

124
Q

B and T cells in lymph nodes get carried via ______ back to the blood

A

lymph nodes

125
Q

B and T cells in lymph nodes get carried via ______ back to the blood

A

lymph nodes

126
Q

what are the 3 roles of the lymphatic system?

A

return fluid to circulation
help with immunity
transport lipid and protein

127
Q

there is _____ protein in blood than lymph

A

more

128
Q

what is the function of the spleen

A

acts as a storage area for white blood cells and platelets, a recycling center for red blood cells, and a filter of blood and lymph for the immune system

129
Q

name the agranulocytes

A

the lymphocytes (B cells and T cells) and monocytes/macrophages

130
Q

humoral immunity is driven by ____ cells while cell-mediated immunity is driven by ____ cells

A

B cells

T cells

131
Q

where does B cell maturation occur?

A

spleen or lymph nodes

132
Q

what is the role of mucus membranes in the respiratory tract?

A

lined with cilia to trap particulate matter and push it up toward the oropharynx, where it can be sallowed or expelled. Traps smoke, dirt, bacteria, and viruses.

133
Q

what is special about the GI tract in newborns?

A

the infant’s immune system is not well-developed and the GI tract is not colonized with bacteria yet so antibodies in breast milk help the gastrointestinal tract from infections.

134
Q

which cells display MHC class I

A

all nucleated cells in the body

135
Q

the MHC-I pathway is also called the _____ pathway because it binds antigens that come from inside the cell

A

endogenous

136
Q

difference between the exogenous and endogenous pathway for MHC

A

endogenous - MHC I - cell infected, antigen picked up and presented from inside cell
exogenous - MHC II - cell not infected, antigen picked up from outside the cell and brought in and then presented (these are professional antigen-presenting cells).

137
Q

what are the professional antigen presenting cells?

A

macrophages, dendritic cells in skin, some B cells, and certain activated epithelial cells.

138
Q

how does histamine cause inflammation?

A

causes inflammation by inducing vasodilation and the movement of fluid and cells from the bloodstream into tissues a

139
Q

where is lysozyme present?

A

tears and saliva

140
Q

what is another name for antibody?

A

immunoglobulin

141
Q

what are the 2 locations that antibodies can be in?

A

they can be present on the surface of the cell or secreted into body fluids

142
Q

what holds the heavy and light chains of amino acids together?

A

noncovalent interactions and disulfide bonds.

143
Q

the constant region of the antibody _____

A

sticks out and it binds to receptors on other immune cells

144
Q

do both B and T cells undergo clonal selection?

A

yes

145
Q

what is the name of the peptide hormone secreted by thymic cells that facilitates the maturation of T-cells

A

thymosin

146
Q

what is another name for helper T cells

A

CD4+ T cells

147
Q

what are lymphokines and what secretes them?

A

lymphokines are chemicals that are capable of recruiting other immune cells (such as plasma cells, cytotoxic T-cells, and macrophages) and increasing their activity

148
Q

what is human immunodeficiency virus (HIV) causes by?

A

affects CD4+ T cells and allows weak infections to have drastic affects as the body can no longer mount a proper immune response.

149
Q

CD4+ T cells respond to antigens presented on MHC ___ molecules

A

II

150
Q

CD4+ T cells are better at fighting _____ infections, while CD8+ T-cells are better at targeting _____ infections.

A

extracellular

intracellular

151
Q

what do CD8+ T cells do and what MHC class doe they respond to?

A

kill virally infected cells by injecting toxic chemicals that promote apoptosis into the infected cell
respond to antigens presented on MHC-I

152
Q

self-tolerance

A

when suppressor T cells turn off self-reactive lymphocytes to prevent autoimmune diseases

153
Q

what are the 5 types of infectious pathogens?

A

bacteria, viruses, fungi, parasites, and prions

154
Q

is there an immune defense for prions?

A

no

155
Q

what are examples of parasites

A

protozoa, worms, insects

156
Q

do all cells have self-antigens?

A

yes

157
Q

what is one type of therapy to treat autoimmune diseases?

A

glucocorticoids ==> immunosuppressants

158
Q

adaptive vs. active immunity

A

adaptive: part of the immune response that uses B and T cells
active immunity: immunity that occurs through exposure to a pathogen.

159
Q

lymphatic vessels become ____ as they move toward the center of the body

A

larger

160
Q

where is the thoracic duct located and where does it carry fluid?

A

posterior chest

left subclavian vein near the heart

161
Q

lymph nodes

A

small, bean shaped structures along the lymphatic vessels. Contain an artery, vein, and lymphatic channel

162
Q

what are two main functions of the lymphatic system?

A

equalization of fluid distribution: lymphatic vessels drain tissues and subsequently return the fluid to the bloodstream
transportation of biomolecules: transports fats from digestive system into the bloodstream

163
Q

edema

A

swelling due to fluid collecting in tissue

164
Q

lacteals

A

small lymphatic vessels, located near the center of each villus in the small intestine. Fats, packaged into chylomicrons by intestinal mucosal cells, enter the lacteal for transport.

165
Q

chyle

A

lymphatic fluid carrying many chylomicrons, has a milky white appearance

166
Q

germinal centers

A

location in the lymph nodes where B cells proliferate and mature

167
Q

what structure is primarily responsible for returning materials from lymphatic circulation to the cardiovascular system?

A

thoracic duct

168
Q

where are dendritic cells found?

A

the skin

169
Q

an absence of T-cells would leave an individual unable to fight off what type of infections?

A

fight off viral infections

170
Q

where does the lymphatic system accept chylomicrons from and where does it deliver them?

A

accepts them from the small intestine and delivers them to the cardiovascular system via the thoracic duct.

171
Q

discuss how dendritic cells are involved in the link between innate and adaptive immunuty?

A

dendritic cells traveling to lymph nodes to present antigen

172
Q

where does positive and negative selection occurs for T cells?

A

in the thymus, where they mature.

173
Q

are macrophages capable of causing lymphoma?

A

no, they are not from the lymphoid lineage. Only B and T cells are capable of causing lymphoma.

174
Q

are dendritic cells phagocytes?

A

yes, they can sample and present any type of material

compared to neutrophils, they are only present in the skin, while neutrophils are present in the blood stream.

MCAT Bio (12 decks)

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