Midterm 1

Question 1

Nervous system

Answer 1

part of an animal that coordinates its actions by transmitting signals to and from different parts of its body

Question 2

immunity

Answer 2

combination of all mechanisms used by the body as protection to environmental agents that are foreign (“non-self”) to the body (“self”)

Question 3

Immune system

Answer 3

a series of obstacles to limit and inhibit pathogen entry and then attack and destroy those organisms once they enter the body

Question 4

foreign invaders

Answer 4

viruses, bacteria, fungi, parasites (amoebae, worms, plasmodium, etc)

Question 5

internal corruption

Answer 5

dead tissue, tumors

Question 6

neuroimmunology

Answer 6

field combining neuroscience, the study of the nervous system, and immunology, the study of the immune system

Question 7

intracellular chemical messenger

Answer 7

a hormone; a chemical substance, a molecule, that is secreted by one cell of the body and modifies the function of another cell of the body.

primary vehicle for intercellular communication

Question 8

neurocrine signaling

Answer 8

synaptic transmission

Question 9

neurotransmitters

Answer 9

chemical messengers secreted by neurons that diffuse across the small gap to the target cell

Question 10

endocrine signaling

Answer 10

happens when 1 cell (specialized cell or many nonspecialized endocrine cells that can secrete substances which are hormones (messengers which operate in the endocrine system)), and these hormones are released first into interstitial. From this, they diffuse into the bloodstream and carried to distant organs where they exit the circulation. If there is a target cell which expresses specific receptor at plasma membrane, it will initiate intracellular events leading to a specific response of the target cell.

Question 11

hormones

Answer 11

chemical messengers secreted by endocrine cells into the blood. carried with blood to distant targets.

Question 12

Receptors

Answer 12

• binding of receptor with agonist produces a conformation change in the receptor itself.
• cells lacking specific receptors do not recognize the hormones cytokine. binding of a hormone/cytokine to the specific receptor initiates downstream signaling leading to a specific response.
• location of receptors are tissue/organ specific
• receptor distribution across the immune and neuronal systems forms the basis for communication

Question 13

Autocrine signaling

Answer 13

when the cell releases a hormone but also experiences in response to the presence of this hormone by itself. major regulator of immune cells.

cell is targeting itself.

Question 14

paracrine signaling

Answer 14

major feature: hormone doesn’t enter into circulation. the producer releases hormone and the hormone travels short distance to activate receptors on neighboring cell.

Question 15

neuroendocrine signaling

Answer 15

happens when neurons spill neurotransmitters (operating in narrow space in synaptic cleft) that are specialized and release them into circulation. These neurotransmitters then act in endocrine fashion (travel in blood and activate receptors on distant target cells)

Question 16

neurohormones

Answer 16

chemical messengers secreted by neurons into the blood for action at the distant targets.

Question 17

extravasation

Answer 17

moving of the lymphocytes from bloodstream into the tissue. instead of hormones, leukocytes bring themselves into specific area of the body, where they can either release specialized intracellular messengers called cytokines.

Question 18

cytokines

Answer 18

hormones operating in the immune system; usually small peptides. can be released by any type of cell, not just immune cells in response to insult.

• hydrophilic, membrane impermeable
• typical feature of cytokines: modification of gene expression

Question 19

antigen presenting cell/juxtacrine or direct signaling

Answer 19

major type of communication and recognition of antigen.

Question 20

Janus kinase (JAK)

Answer 20

protein kinase (many cytokines work through activation of JAK); signal transducer and activator of Transcription (STAT) pathway is a common signaling pathway used by many cytokines

Question 21

cytokine receptors

Answer 21

multiple cytokines can cross-link the same receptor

a single type of receptor can activate multiple downstream signaling cascades

Question 22

pleiotropy

Answer 22

cytokine pleiotropy is the ability of a cytokine to exert many different types of responses (often on different cell types)

Question 23

redundancy

Answer 23

cytokine redundancy refers to the fact that different cytokines can induce similar signals

Question 24

microbiota

Answer 24

a cohort of microorganism which inhibit animal or human bodies

• vast majority are beneficial (commensal). Hosts evolved to require colonization by beneficial commensals.
• can become pathogenic if they translocate into the body.

Question 25

innate immune system

Answer 25

barriers to pathogens. first responders after barrier is breached and mount the first response to localize and eradicate these harmful invaders before it spreads to the whole body and kills the host. Nonspecific! - physical: skin, mucosal membranes - mechanical: flow of fluids, sweat, mucus, saliva - chemical: fatty acids, acidity, antimicrobial peptides - biological: normal/commensal microbiota

Question 26

epidermis

Answer 26

where living cells reside. very dense layer that creates a physical barrier

Question 27

dermis

Answer 27

where most cells reside. these cells are macrophages, natural killer cells, dendritic cells, etc

Question 28

innate immune cells

Answer 28

epithelial barriers, phagocytes, dendritic cells, complement, NK cells

Question 29

adaptive immunity

Answer 29

2nd response; activated when innate fails to eradicate and contain foreign pathogen. activation takes a long time. Specific to the pathogen! - as a result of activation, two types of effector signals are formed: antibodies and mounts a response against pathogens through effector T cells.

Question 30

T lymphocytes

Answer 30

through multiple steps of activation maturation information, they confront pathogens or infected cells through producing lytic granules to physically kill them.

Question 31

lymphatic system

Answer 31

co-exists with blood, necessary to pick up the fluid which accumulates in different tissues as a result of fluid exchange during blood movement through the tissues, and lymphatic picks up the residual fluid, which leak from the blood capillaries (into the tissues), and returns it into circulation (blood) - passive; it is pushed through the blood due to contraction of smooth muscle cells surrounding the capillary and the contraction of skeletal muscles

Question 32

capillary bed

Answer 32

penetrated by lymphatic capillaries which collect left over fluids moved into tissue and not reabsorbed by capillaries. move fluid back into circulatory system.

Question 33

Specific organ of lymphatic system

Answer 33

lymph-nodes - an enlargement.

Question 34

Blood-lymph circulatory system

Answer 34

lymphatic capillaries are near blood capillaries. they collect lymph fluid (plasma that leaks out of the cardiovascular capillaries) and proteins from the tissues. - pathogens and their antigens are also transported from tissues via lymphatic vessels to the lymph nodes where they encounter immune cells. - lymph moves in one direction toward the heart, which prevents pathogens from flowing through the entire body.

Question 35

lymphoid tissues

Answer 35

immune cells tend to accumulate in the lymphoid organs; they develop (arise) in the primary lymphoid organs, and they interact with the foreign antigens in the secondary lymphoid organs

Question 36

primary lymphoid organs

Answer 36

bone marrow and thymus

Question 37

bone marrow

Answer 37

adult hematopoietic cells arise from pluripotential bone marrow stem cells - site of B cell development

Question 38

thymus

Answer 38

site of T cell development (t cells are "educated" to distinguish between "self" and "non-self")

Question 39

secondary lymphoid organs

Answer 39

spleen and lymph nodes

Question 40

spleen

Answer 40

filters and collects antigens from blood | - harbors cells of innate and adaptive immunity

Question 41

lymph nodes

Answer 41

- placed throughout the body; are most densely distributed towards the center of the body, particularly around the neck, intestines and armpits - filter lymph and collects antigens from tissues - place where T cells can interact with antigen-presenting cells - place of T cell clonal expansion

Question 42

hematopoiesis

Answer 42

development of immune and other blood cells from a small population fo stem cells known as hematopoietic stem cells

Question 43

erythropoiesis

Answer 43

production of erythrocytes, RBC

Question 44

leukopoiesis

Answer 44

production of leukocytes, WBC

Question 45

leukocytes

Answer 45

any WBC, which plays role either in innate or adaptive immunity

Question 46

phagocytes

Answer 46

process by which a cell engulfs a solid particle or another cell

Question 47

phagocytic

Answer 47

a type of cell capable of engulfing and absorbing bacteria and other small cells and particles by phagocytosis

Question 48

Cells of Myeloid Lineage

Answer 48

major cells of innate immunity; highly phagocytic (neutrophils, monocytes, macrophages, dendritic cells) major are involved in immediate protection against most pathogens - other: granulocytes (eosinophils, basophils, mast cells) other are involved in defense against parasites and allergic reactions

Question 49

Cells of Lymphoid lineage

Answer 49

B lymphocytes, T lymphocytes (T cells), Natural killer cells (NKs), Natural Killer T cells (NKT)

Question 50

B lymphocytes (B cells)

Answer 50

major effector function: secretion of antibodies (Ab), proteins which bind pathogens or their toxic products in the extracellular spaces of the body

Question 51

T lymphocytes (T cells)

Answer 51

major effector function: secretion of lymphokines to direct immune response (helper T cells, CD4+) or destroy infected cell (cytotoxic T cells, CD8+)

Question 52

Natural Killer Cells (NK)

Answer 52

lymphoid in origin, but part of the innate immunity that recognizes and kills pathogens or infected cells by releasing lytic enzymes

Question 53

Natural Killer T Cells (NKT)

Answer 53

both innate (kill pathogens) and adaptive mechanisms (secrete cytokines)

Question 54

Cluster of Differentiation (CD)

Answer 54

cell surface protein typically expressed on the cells of the specific lineage and type. each molecule is assigned a different number (think: CD1, CD2, CD3, etc). -functionally different leukocytes has specific CD expression pattern (example: CD4+ = T helper cells; CD8+ = cytotoxic T cells)

Question 55

vasodilation

Answer 55

capillaries become wider and more blood flow that surrounds damaged area

Question 56

inflammation

Answer 56

defensive process that a living body initiates against local tissue damage; protective response and serves to bring defense and healing mechanisms to the site of injury

Question 57

inflammation triggers

Answer 57

physical agents: burns, trauma, radiation chemicals: drugs, toxins, caustic substances microbial infections: bacterial, viral, fungal immunologic reactions: autoimmunity

Question 58

PAMPs

Answer 58

pathogen-associated molecular patterns - evolutionally conserved structures expressed on the surface of many pathogens (proteins, lipids, nucleic acids, carbohydrates)

Question 59

DAMPs

Answer 59

danger associated molecular patterns. - tissue damage/necrotic cell products (heat-shock proteins (HSP), uric acid crystals, aggregated peptides, ATP) - misfolded proteins (e.g. amyloid beta)

Question 60

PRRs

Answer 60

PRRs recognize PAMPs or DAMPs. Each PRR recognizes a DAMP or PAMP that is shared by many different damaged cells or pathogens -> broad recognition since there is a limited collection of molecular patterns that can be recognized. - PRRs expressed by innate leukocytes, macrophages, and mast cells in peripheral tissues.

Question 61

Toll-Receptor

Answer 61

common type of pathogen recognition receptor.

Question 62

innate phagocytes

Answer 62

resident: macrophages, dendritic cells recruited: neutrophils, monocytes - engulf and destroy pathogens - capable of engulfing particles larger than themselves - pseudopods

Question 63

pseudopods

Answer 63

fine sheets of membrane that macrophages extend to engulf cells

Question 64

chemotaxis

Answer 64

movement of a motile cell or organism, or part of one, in a direction corresponding to a gradient of increasing or decreasing concentration of a particular substance.

Question 65

chemoattractants

Answer 65

small soluble molecules which attracts motile cells of a particular type

Question 66

monocytes

Answer 66

differentiate into macrophages in inflamed tissues | - not actively phagocytic; provide help to other macrophages by expansion to macrophages

Question 67

granulocytes

Answer 67

neutrophils, basophils, and eosinophils; short lived phagocytes

Question 68

ELAM1

Answer 68

epithelial cell adhesion molecule-1

Question 69

selectins

Answer 69

carbohydrate-binding proteins

Question 70

chemokines

Answer 70

any cytokines with function of chemoattractants, including attracting WBC (leukocytes) to sites of infection/tissue damage

Question 71

acute phase of inflammation

Answer 71

characterized by the rapid influx of blood granulocyte, typically neutrophils, rapidly followed by monocytes - monocytes proliferate and mature into inflammatory (M1) macrophages - phagocytosis is carried on by recruited and resident phagocytes - Phase 1 and 2

Question 72

Resolution phase of inflammation

Answer 72

the usual outcome of the acute inflammatory program is successful resolution and repair of tissue damage - phase 3 and 4

Question 73

principal phagocytes

Answer 73

neutrophils and macrophages share powerful phagocytic capacity and elaborate intracellular killing machineries

Question 74

neutrophils

Answer 74

- rapid increase in numbers during acute phase response - found only in inflamed tissues - single mature form - short-lived (6-24 hrs), die after phagocytosis - form pus (dead neutrophils and debris)

Question 75

macrophages

Answer 75

- slightly increased levels during inflammation - found in healthy tissues - several mature forms - long-lived, survive after phagocytosis

Question 76

insults

Answer 76

metabolic deprivation, toxicity, pathgens, trauma

Question 77

meninges

Answer 77

three thin layers of tissue that cover and protect the brain and spinal cord. the meninges comprise of the: - DURA MATER - ARACHNOID MATER - PIA MATER

Question 78

CSF

Answer 78

produced in the choroidplexus in the ventricles of the brain and flows between the arachnoid and the pia maters of meningeal layers. - provides mechanical support, regulates ion composition, and maintains chemical stability

Question 79

Blood-brain barrier (BBB)

Answer 79

highly selective semipermeable border of endothelial cells that prevents solutes in the circulating blood from non-selectively crossing into the extracellular fluid of the CNS. Protects CNS (brain and spinal cord) from the toxins and pathogens that may be traveling through the blood capillary network. - formed by tight junctions between endothelial cells liming cerebral micro-vessels, in addition to glial cells

Question 80

Glia limitations

Answer 80

astrocyte end "feet" that cover the vessels that go to the brain and provide barrier between meninges and PIA MATER - separates the brain parenchyma from the CSF/perivascular spaces and plays a major role in compartmentalizing CNS immune reactions

Question 81

Pericytes (PC)

Answer 81

contractile cells that control blood flow

Question 82

BCSFB

Answer 82

formed by tight junctions between epithelial cells at the choroid-plexus, endothelial cells of the veins, and venules within the subarachnoid space, and the epithelial cells of the arachnoid mater

Question 83

olfactory system

Answer 83

bypasses the cellular barriers of the CNS and provides a direct portal from the nasal cavity to the olfactory bulb within the brain. this is where the pathogen breaches CNS to produce infection

Question 84

CNS innate system cells

Answer 84

microglia, astrocytes, macrophages

Question 85

what are not found in the CNS innate immune system

Answer 85

NO neutrophils, no NK cells, no antigen-presenting DCs, machrophages are restricted to perivascular space

Question 86

microglia

Answer 86

keeps surveillance for damage or infection. phagocytic scavenger that is highly motile; responsive to injury, infection, and neuronal electric activity; synaptic pruning; removal of dead cells by phagocytosis. - only hematopoietic cells found in parenchyma of the CNS - unique myeloid population - derived from yolk sac during embryogenesis - in parenchyma, sustained by proliferation of resident progenitors independent of blood cells - related to resident tissue macrophages - activation is accompanied by morphological and functional changes (phagocytic macrophages)

Question 87

astrocytes

Answer 87

derived from neuroepithelial stem cells like neurons. - ensheathe vasculature and synapses - regulate neuronal excitability and synaptic transmission - protects from "excitotoxicity" by removing excess of neurotransmitters (glutamate) and buffering K+ - exclusively convert glutamate to glutamine - secrete extracellular matrix proteins - implicated in neurogenesis and cell migration - activation is triggered by any alteration in brain homeostasis

Question 88

Pro-inflammatory type 1 cytokines

Answer 88

``` interleukin 1beta interleukin 18 interleukin 6 interleukin 17 tumor necrosis factor alpha interferon gamma histamine ```

Question 89

anti-inflammatory type 2 cytokines

Answer 89

transforming growth factor beta interleukin 4 interleukin 10

Question 90

brain parenchyma

Answer 90

brain tissue composed on neurons and glial cells

Question 91

Perivascular space

Answer 91

separates the capillary endothelial cell layer from the astrocytes end feet - believed to play a role in antigen drainage from the CNS parenchyma - largely the CSF, which contains peripheral immune cells

Question 92

postcapillary venule

Answer 92

surrounded by a perivascular space

Question 93

immune surveillance

Answer 93

theory that the immune system patrols the body to recognize and destroy invading pathogens and host cells that become cancerous

Question 94

antigens

Answer 94

molecules from pathogens; move from the CSF compartment to mandibular and deep cervical lymph nodes by exiting through perineural pathways (olfactory and optic nerves) and lymphatic vessels traversing the dura mater into lymphatic vessels that reside outside the CNS.