How does myelin increase the conduction velocity of action potentials along axons?

It insulates the internodal axon to reduce membrane capacitance and prevent charge leakage, forcing action potentials to jump from node to node via saltatory conduction.

What proteins constitute the core SNARE complex responsible for vesicle docking and fusion at the presynaptic active zone?

v-SNARE synaptobrevin (VAMP) on the vesicle, and t-SNAREs syntaxin-1 and SNAP-25 on the presynaptic plasma membrane.

Which cranial nerve provides the primary parasympathetic innervation to thoracic and abdominal visceral organs?

The vagus nerve (Cranial Nerve X).

What is the primary excitatory neurotransmitter in the mammalian central nervous system, and what are its two major ionotropic receptors?

L-Glutamate; its primary ionotropic receptors are AMPA receptors and NMDA receptors.

What is the immunological role of IgE, and which cells express high-affinity Fc-epsilon receptors that bind it?

IgE mediates defense against parasitic helminths and triggers type I hypersensitivity allergic reactions by binding Fc-epsilon-RI on mast cells and basophils.

What biochemical event produces microbicidal reactive oxygen species (ROS) in activated phagocytes during phagocytosis?

The respiratory (oxidative) burst, mediated by NADPH oxidase converting molecular oxygen to superoxide radicals.

What ionic trigger couples action potential arrival at the presynaptic terminal to neurotransmitter exocytosis?

Opening of voltage-gated calcium channels (VGCCs) and influx of Ca2+, which binds synaptotagmin to trigger SNARE-mediated synaptic vesicle fusion.

What is the primary inhibitory neurotransmitter in the adult brain, and what ion passes through its ionotropic receptor channel?

Gamma-aminobutyric acid (GABA); binding to GABA-A receptors opens ligand-gated chloride (Cl-) channels, causing hyperpolarizing IPSPs.

What key cytokines are produced by T helper 1 (Th1) versus T helper 2 (Th2) subsets, and what immune responses do they drive?

Th1 produces interferon-gamma (IFN-gamma) and IL-2 to drive cell-mediated immunity against intracellular pathogens; Th2 produces IL-4, IL-5, and IL-13 to drive humoral immunity, eosinophils, and parasite defense.

Why is the NMDA receptor unique among ligand-gated ion channels in requiring both ligand binding and membrane depolarization?

It requires glutamate and glycine binding, plus sufficient membrane depolarization to eject a physiological magnesium ion (Mg2+) blocking the pore.

What receptors on innate immune cells recognize Pathogen-Associated Molecular Patterns (PAMPs) such as lipopolysaccharide (LPS)?

Pattern Recognition Receptors (PRRs), prominently including Toll-Like Receptors (TLRs, e.g., TLR4 for LPS).

How do selective serotonin reuptake inhibitors (SSRIs) increase serotonergic transmission at central synapses?

They selectively block the serotonin transporter (SERT), preventing serotonin reuptake into the presynaptic terminal and prolonging its presence in the synaptic cleft.

How does temporal summation differ from spatial summation at the neuronal axon hillock?

Temporal summation combines multiple postsynaptic potentials generated in rapid succession at a single synapse; spatial summation combines potentials generated simultaneously at multiple distinct synapses.

Describe the quaternary subunit architecture of a monomeric immunoglobulin G (IgG) antibody molecule.

Two identical heavy (H) chains and two identical light (L) chains joined by covalent disulfide bonds, forming a Y-shape with two antigen-binding Fab arms and one crystallizable Fc stem.

Which immunoglobulin isotype is secreted as a pentamer during the primary humoral immune response?

Immunoglobulin M (IgM), joined by a joining (J) chain.

What genetic mechanism generates the vast repertoire of B cell receptors (antibodies) and T cell receptors?

V(D)J somatic recombination catalyzed by RAG1 and RAG2 recombinases, joined with junctional diversity by terminal deoxynucleotidyl transferase (TdT).

What anatomical structure forms the physical blood-brain barrier (BBB) to protect the central nervous system parenchyma?

Non-fenestrated brain capillary endothelial cells joined by continuous tight junctions (claudins/occludins), supported by pericytes and astrocyte end-feet.

How do MHC Class I and MHC Class II molecules differ in their tissue distribution and antigen presentation pathways?

MHC I is expressed on all nucleated cells, presents endogenous cytosolic antigens to CD8+ cytotoxic T cells; MHC II is expressed on professional APCs (dendritic cells, macrophages, B cells), presenting exogenous antigens to CD4+ helper T cells.

What is the membrane attack complex (MAC) in the complement cascade, and what is its cytolytic mechanism?

A multi-protein pore assembly (C5b-C6-C7-C8-poly-C9) that inserts into microbial lipid membranes, causing osmotic lysis and cell death.

What synaptic plasticity phenomenon is widely recognized as the primary cellular model for learning and long-term memory formation?

Long-Term Potentiation (LTP), characterized by persistent strengthening of synapses following high-frequency stimulation.

Where does T lymphocyte positive and negative selection occur, and what is the outcome of negative selection?

In the thymus; negative selection eliminates developing thymocytes that bind self-antigen/MHC complexes with high affinity to prevent autoimmunity (central tolerance).

What electrical event initiates the depolarizing upstroke of a neuronal action potential once threshold is reached?

Rapid opening of voltage-gated Na+ channels, causing massive regenerative Na+ influx down its electrochemical gradient.

What is the resting membrane potential of a typical mammalian motor neuron, and what ion gradients establish it?

Approximately -70 mV, established by high intracellular K+ and high extracellular Na+ maintained by the Na+/K+ pump and passive inward K+ leak channels.

What is the physiological cause of the absolute refractory period in excitable neuronal membranes?

Voltage-gated Na+ channels are locked in their inactivated state and cannot be reopened until the membrane repolarizes to resting potentials.

What two gating events terminate the action potential spike and initiate repolarization?

1. Inactivation of voltage-gated Na+ channels (via their intracellular inactivation gate/ball-and-chain). 2. Delayed opening of voltage-gated K+ channels allowing K+ efflux.

What cytotoxic molecules do CD8+ cytotoxic T lymphocytes and NK cells exocytose to induce apoptosis in virally infected target cells?

Perforin (which forms pores in the target plasma membrane) and granzymes (serine proteases that enter pores to trigger apoptotic caspase cascades).

What are the primary differences between innate and adaptive immunity regarding response speed, specificity, and immunological memory?

Innate immunity acts immediately (minutes/hours), uses broad non-specific pattern receptors, and lacks memory; adaptive immunity takes days to develop, is highly antigen-specific, and generates long-lived immunological memory.

Which glial cells synthesize myelin in the central nervous system (CNS) versus peripheral nervous system (PNS)?

Oligodendrocytes in the CNS (myelinating multiple axons); Schwann cells in the PNS (myelinating a single axon segment).

Immunologie — Avancé (C1/C2) 2: Immunology & Neurobiology

[Français] Immunologie: Innate and adaptive immunity, antibody structure, action potentials, synaptic transmission, and sensory processing mechanisms

Level: advanced
Languages: fr → fr
Cards: 32
Markdown: Immunologie — Avancé (C1/C2) 2: Immunology & Neurobiology (.md)

Flashcards (32)

#	Front (Term / Question)	Back (Definition / Answer)
1	How does myelin increase the conduction velocity of action potentials along axons?	It insulates the internodal axon to reduce membrane capacitance and prevent charge leakage, forcing action potentials to jump from node to node via saltatory conduction.
2	What proteins constitute the core SNARE complex responsible for vesicle docking and fusion at the presynaptic active zone?	v-SNARE synaptobrevin (VAMP) on the vesicle, and t-SNAREs syntaxin-1 and SNAP-25 on the presynaptic plasma membrane.
3	Which cranial nerve provides the primary parasympathetic innervation to thoracic and abdominal visceral organs?	The vagus nerve (Cranial Nerve X).
4	What is the primary excitatory neurotransmitter in the mammalian central nervous system, and what are its two major ionotropic receptors?	L-Glutamate; its primary ionotropic receptors are AMPA receptors and NMDA receptors.
5	What is the immunological role of IgE, and which cells express high-affinity Fc-epsilon receptors that bind it?	IgE mediates defense against parasitic helminths and triggers type I hypersensitivity allergic reactions by binding Fc-epsilon-RI on mast cells and basophils.
6	What biochemical event produces microbicidal reactive oxygen species (ROS) in activated phagocytes during phagocytosis?	The respiratory (oxidative) burst, mediated by NADPH oxidase converting molecular oxygen to superoxide radicals.
7	What ionic trigger couples action potential arrival at the presynaptic terminal to neurotransmitter exocytosis?	Opening of voltage-gated calcium channels (VGCCs) and influx of Ca2+, which binds synaptotagmin to trigger SNARE-mediated synaptic vesicle fusion.
8	What is the primary inhibitory neurotransmitter in the adult brain, and what ion passes through its ionotropic receptor channel?	Gamma-aminobutyric acid (GABA); binding to GABA-A receptors opens ligand-gated chloride (Cl-) channels, causing hyperpolarizing IPSPs.
9	What key cytokines are produced by T helper 1 (Th1) versus T helper 2 (Th2) subsets, and what immune responses do they drive?	Th1 produces interferon-gamma (IFN-gamma) and IL-2 to drive cell-mediated immunity against intracellular pathogens; Th2 produces IL-4, IL-5, and IL-13 to drive humoral immunity, eosinophils, and parasite defense.
10	Why is the NMDA receptor unique among ligand-gated ion channels in requiring both ligand binding and membrane depolarization?	It requires glutamate and glycine binding, plus sufficient membrane depolarization to eject a physiological magnesium ion (Mg2+) blocking the pore.
11	What receptors on innate immune cells recognize Pathogen-Associated Molecular Patterns (PAMPs) such as lipopolysaccharide (LPS)?	Pattern Recognition Receptors (PRRs), prominently including Toll-Like Receptors (TLRs, e.g., TLR4 for LPS).
12	How do selective serotonin reuptake inhibitors (SSRIs) increase serotonergic transmission at central synapses?	They selectively block the serotonin transporter (SERT), preventing serotonin reuptake into the presynaptic terminal and prolonging its presence in the synaptic cleft.
13	How does temporal summation differ from spatial summation at the neuronal axon hillock?	Temporal summation combines multiple postsynaptic potentials generated in rapid succession at a single synapse; spatial summation combines potentials generated simultaneously at multiple distinct synapses.
14	Describe the quaternary subunit architecture of a monomeric immunoglobulin G (IgG) antibody molecule.	Two identical heavy (H) chains and two identical light (L) chains joined by covalent disulfide bonds, forming a Y-shape with two antigen-binding Fab arms and one crystallizable Fc stem.
15	Which immunoglobulin isotype is secreted as a pentamer during the primary humoral immune response?	Immunoglobulin M (IgM), joined by a joining (J) chain.
16	What genetic mechanism generates the vast repertoire of B cell receptors (antibodies) and T cell receptors?	V(D)J somatic recombination catalyzed by RAG1 and RAG2 recombinases, joined with junctional diversity by terminal deoxynucleotidyl transferase (TdT).
17	What anatomical structure forms the physical blood-brain barrier (BBB) to protect the central nervous system parenchyma?	Non-fenestrated brain capillary endothelial cells joined by continuous tight junctions (claudins/occludins), supported by pericytes and astrocyte end-feet.
18	How do MHC Class I and MHC Class II molecules differ in their tissue distribution and antigen presentation pathways?	MHC I is expressed on all nucleated cells, presents endogenous cytosolic antigens to CD8+ cytotoxic T cells; MHC II is expressed on professional APCs (dendritic cells, macrophages, B cells), presenting exogenous antigens to CD4+ helper T cells.
19	What is the membrane attack complex (MAC) in the complement cascade, and what is its cytolytic mechanism?	A multi-protein pore assembly (C5b-C6-C7-C8-poly-C9) that inserts into microbial lipid membranes, causing osmotic lysis and cell death.
20	What enzyme rapidly degrades acetylcholine in the synaptic cleft of the neuromuscular junction to terminate muscle excitation?	Acetylcholinesterase (AChE).
21	What synaptic plasticity phenomenon is widely recognized as the primary cellular model for learning and long-term memory formation?	Long-Term Potentiation (LTP), characterized by persistent strengthening of synapses following high-frequency stimulation.
22	Where does T lymphocyte positive and negative selection occur, and what is the outcome of negative selection?	In the thymus; negative selection eliminates developing thymocytes that bind self-antigen/MHC complexes with high affinity to prevent autoimmunity (central tolerance).
23	What electrical event initiates the depolarizing upstroke of a neuronal action potential once threshold is reached?	Rapid opening of voltage-gated Na+ channels, causing massive regenerative Na+ influx down its electrochemical gradient.
24	What is the resting membrane potential of a typical mammalian motor neuron, and what ion gradients establish it?	Approximately -70 mV, established by high intracellular K+ and high extracellular Na+ maintained by the Na+/K+ pump and passive inward K+ leak channels.
25	Which immunoglobulin class is predominantly found in mucosal secretions (saliva, tears, colostrum) as a secretory dimer?	Immunoglobulin A (IgA).
26	What is the physiological cause of the absolute refractory period in excitable neuronal membranes?	Voltage-gated Na+ channels are locked in their inactivated state and cannot be reopened until the membrane repolarizes to resting potentials.
27	What two gating events terminate the action potential spike and initiate repolarization?	1. Inactivation of voltage-gated Na+ channels (via their intracellular inactivation gate/ball-and-chain). 2. Delayed opening of voltage-gated K+ channels allowing K+ efflux.
28	Which neurotransmitter is depleted in the substantia nigra pars compacta in patients with Parkinson's disease?	Dopamine.
29	What cytotoxic molecules do CD8+ cytotoxic T lymphocytes and NK cells exocytose to induce apoptosis in virally infected target cells?	Perforin (which forms pores in the target plasma membrane) and granzymes (serine proteases that enter pores to trigger apoptotic caspase cascades).
30	What are the primary differences between innate and adaptive immunity regarding response speed, specificity, and immunological memory?	Innate immunity acts immediately (minutes/hours), uses broad non-specific pattern receptors, and lacks memory; adaptive immunity takes days to develop, is highly antigen-specific, and generates long-lived immunological memory.
31	Which immunoglobulin isotype is most abundant in serum, crosses the placenta to confer passive neonatal immunity, and opsonizes pathogens?	Immunoglobulin G (IgG).
32	Which glial cells synthesize myelin in the central nervous system (CNS) versus peripheral nervous system (PNS)?	Oligodendrocytes in the CNS (myelinating multiple axons); Schwann cells in the PNS (myelinating a single axon segment).