Exam 2-FND OF BRAIN & BEHAV.

This set of flashcards covers key concepts and terminology related to neuroscience, including the contributions of prominent scientists, the structure and function of neurons, and mechanisms of synaptic transmission.

Camillo Golgi

Developed the Golgi stain (silver nitrate) that allowed individual neurons to be visualized; believed in the reticular theory.

Santiago Ramón y Cajal

Used Golgi stain but concluded that neurons are separate cells and proposed the neuron doctrine.

Luigi Galvani

Discovered that electrical stimulation causes muscle contraction, showing that nerves use electricity.

Hodgkin & Huxley

Studied the squid giant axon and explained action potentials via sodium and potassium movement.

Action potential

a rapid, temporary reversal of electrical charge (membrane potential) that travels along the membrane of a neuron or muscle cell.

Resting membrane potential

About -70 mV; the inside of the neuron is negative relative to the outside.

Dendrites

Receive incoming signals.

Soma (cell body)

Contains the nucleus and integrates signals.

Axon

Sends electrical signals away from the soma.

Axon hillock

The decision point for firing an action potential.

Myelin sheath

Insulates the axon and increases conduction speed.

Nodes of Ranvier

Gaps in myelin where action potentials regenerate.

Astrocytes

Support neurons, regulate the blood-brain barrier, and maintain ion balance.

Oligodendrocytes

Form myelin in the central nervous system (CNS).

Schwann cells

Form myelin in the peripheral nervous system (PNS).

Microglia

Immune defense cells of the brain.

Korsakoff’s syndrome

Caused by thiamine (Vitamin B1) deficiency, usually due to chronic alcoholism.

Symptoms of Korsakoff’s syndrome

Severe memory impairment, confabulation, and learning deficits.

Biological target of Korsakoff’s

Damage to mammillary bodies and thalamus.

Sodium-Potassium Pump

Uses ATP to move 3 Na⁺ out and 2 K⁺ in against their gradients.

Leak channels

Always open; allow K⁺ to pass freely.

Voltage-gated channels

Open in response to changes in membrane voltage.

Ligand-gated channels

Open when a neurotransmitter binds.

Concentration gradient

Movement of ions from high to low concentration.

Depolarization

Membrane becomes less negative due to Na⁺ influx.

Hyperpolarization

Membrane becomes more negative due to K⁺ efflux.

Refractory period

Time after an action potential when the neuron cannot fire.

Reflex arc order

Sensory (afferent) → Interneuron → Motor (efferent).

Conduction speed factors

Increased by myelin and larger diameter.

EPSP

Excitatory postsynaptic potential; Na⁺ enters resulting in depolarization.

IPSP

Inhibitory postsynaptic potential; Cl⁻ enters or K⁺ leaves resulting in hyperpolarization.

Firing decision mechanism

Summation at the axon hillock; threshold must be reached.

Neurotransmitter storage location

Stored in synaptic vesicles in the presynaptic terminal.

Neurotransmitter release process

Ca²⁺ enters terminal, vesicles fuse, and neurotransmitters are released through exocytosis.

Effects of drugs on neurotransmitters

Agonists mimic action and antagonists block; may increase release or block reuptake.

Synaptic transmission steps

AP arrives → Ca²⁺ channels open → Ca²⁺ enters → vesicles fuse → NT released → binds to receptors.

Ionotropic receptors

Fast receptors that directly open ion channels.

Metabotropic receptors

Slow receptors that activate G-proteins and second messengers.

First messenger

The neurotransmitter that initiates a response.

Second messenger

small, fast-diffusing intracellular molecules or ions—such as

cAMP, Ca2+cap C a raised to the 2 plus power 𝐶𝑎2+

, IP3, and DAGthat relay signals from surface receptors to target proteins, amplifying and mediating responses like metabolism, growth, and gene expression.

Neurotransmitter removal methods

Reuptake, enzymatic breakdown, or diffusion.

Neurotransmitter vs Hormone

Neurotransmitters act locally and quickly; hormones travel in the bloodstream and act more slowly.

Neuropeptides

Large neurotransmitters that often act as neuromodulators.

Neuromodulators

Substances that modify neuron activity rather than directly excite or inhibit.

Afferent neurons

Sensory neurons that carry information TO the CNS.

Efferent neurons

Motor neurons that carry information AWAY from the CNS.

Neuromodulators

brain chemicals—such as dopamine, serotonin, and norepinephrine…

.These substances can enhance or dampen the effects of neurotransmitters and influence mood, pain, and cognition.

Neurotransmitters

chemical messengers released by neurons into synapses to transmit signals across the brain and body, impacting mood, movement, memory, and cognition.