Intro to Neuro Exam One

Neural Signals

Electrical impulses that transmit information within the nervous system.

Resting Potential

The electrical charge difference across a neuron's membrane when it is not actively firing, typically around -70 mV.

Action Potential

A rapid change in membrane potential that occurs when a neuron fires, resulting in a brief positive charge inside the cell.

Graded Potentials

Changes in membrane potential that vary in size and can lead to action potentials if the threshold is reached.

Sodium-Potassium Pump

A protein that actively transports Na+ out of and K+ into the neuron to maintain resting potential.

Refractory Periods

Phases after an action potential during which a neuron cannot fire (absolute refractory) or requires a stronger stimulus to fire (relative refractory).

Synapse

The junction between two neurons where neurotransmitters are released to transmit signals.

Neurotransmitters

Chemical messengers that transmit signals across the synapse, such as dopamine, serotonin, and GABA.

Ligands

Molecules that bind to receptors to activate or block them, including endogenous (natural) and exogenous (drugs) ligands.

EPSP (Excitatory Postsynaptic Potential)

A small local depolarization that makes a neuron more likely to fire.

IPSP (Inhibitory Postsynaptic Potential)

A small local hyperpolarization that makes a neuron less likely to fire.

Myelin Sheath

A fatty layer that insulates axons, speeding up the transmission of electrical signals.

Glial Cells

Supportive cells in the nervous system that provide structure, nourishment, and protection for neurons.

Neurogenesis

The process of generating new neurons from neural stem cells.

Synaptogenesis

The formation of new synapses between neurons.

Apoptosis

Programmed cell death that occurs in the nervous system to eliminate excess neurons.

Neurotrophic Factors

Proteins that support neuron survival and growth, such as nerve growth factor (NGF).

Plasticity

The ability of the brain to change and adapt in response to experience, including the strengthening or weakening of synapses.

Addiction

A chronic disorder characterized by compulsive drug use despite harmful consequences, often involving changes in brain circuitry.

unipolar

Neuron type with a single extension, receptive and output, and travels through axon like a cable.

bipolar

Neuron type with one axon and one dendrite, usually sensory.

multipolar

Neuron type with many inputs and only one road out, slower with 10 thousand entrances for one cell.

astrocytes

Most numerous glial cells in the brain, provide support between neurons, and regulate extracellular space.

oligodendrocytes

Wrap axons with myelin sheaths, each one wrapping several axons, with gaps called nodes of Ranvier.

ependymal cells

Line ventricles, secrete and absorb spinal fluid.

microglia

Clean up dead neurons and glia, scan for abnormalities like cancer, and support immune function.

sensory neurons

Neurons that respond to environmental stimuli like light, odor, and touch.

motor neurons

Neurons that contract muscles or glands.

interneurons

Neurons that receive input from and send input to other neurons for integration.

Pyramidal cell

Type of neuron focused on, with dendritic spines exhibiting neural plasticity for learning.

synapses

Points where neurons connect, transmitting chemical and electrical information.

Central nervous system

Comprising the brain and spinal cord, providing precise control and simultaneous activity.

Sympathetic activation

Prepares the body for action, activating during stress responses.

Parasympathetic activation

Deactivates the body after stress, promoting rest and digestion.

Medial

Directional term meaning 'middle'.

Ipsilateral

Directional term meaning 'same side'.

anterior

Directional term meaning 'head end'.

proximal

Directional term meaning 'near center'.

dorsal

Directional term meaning 'towards back'.

lateral

Directional term meaning 'toward the side'.

contralateral

Directional term meaning 'opposite side'.

posterior

Directional term meaning 'tail end'.

distal

Directional term meaning 'toward periphery'.

ventral

Directional term meaning 'toward the belly'.

Coronal

Brain separation from front to back, resembling a butterfly.

Sagittal (midsagittal)

Brain separation slicing not at the midline, showing each half.

Horizontal

Brain separation from top to bottom.

Afferent

Impulses carrying sensory information into a region of interest.

Efferent

Impulses carrying motor information away from a region of interest.

White matter

Axons bundled together with myelin sheaths, appearing white.

Grey matter

Clusters of neuron cell bodies with a dark grey appearance.

Thalamus

Central brain structure responsible for relaying sensory and motor signals.

Basal ganglia

Brain region involved in motor control functions.

Limbic system

Brain system regulating emotions, emotional memory, and reactions based on emotions.

Cerebellum

Brain region responsible for motor coordination, learning, and balance.

Midbrain

Brain region housing the reticular formation responsible for sleep and arousal.

Meninges

Brain protective wrappings including dura mater, arachnoid membrane, and pia mater.

Subdural hematoma

Bleeding in the subdural space that can compress the brain, reducing survival chances.

Cerebral ventricles

Brain structures producing cerebrospinal fluid, surrounding and cushioning the brain.

Integration zone

Region within a neuron where different zones interact.

Santiago Ramon

Credited with the neuron doctrine, distinguishing between Golgi's and his neuron theories.

anterograde transport

Movement of materials from soma to terminals along microtubules using the protein kinesin.

Refractory periods

Phases of neuron activity including absolute and relative refractory phases, affecting action potential generation.

Na+ channel

Sodium channel involved in action potential generation and propagation.

Myelin

Increases speed of signal transmission and saves energy.

Periodic Paralysis

Condition where muscles can become temporarily paralyzed.

Activation Gate

A gate that fails to function properly in transmitting signals.

Genetic Defect in Na Channel

An issue in the sodium channel gene in muscle cells.

Synapses

Junctions where signals are transmitted between neurons.

Electrical Signal - Chemical Signal - Electrical Signal

The process of signal transmission at chemical synapses.

EPSP and IPSP

Excitatory and inhibitory postsynaptic potentials that affect neuron membrane potential.

Reuptake

Process where neurotransmitters are reabsorbed by the neuron that released them.

Neurotransmitter Degradation

Breakdown and inactivation of neurotransmitters by enzymes.

Electrical Synapses

Connections where ions flow directly between neurons without delay.

Acetylcholine Receptor

Receptor that binds acetylcholine to trigger a cellular response.

Up-Regulation

Increase in the number of receptors in response to certain stimuli.

Down-Regulation

Decrease in the number of receptors due to various factors.

Na Channel

Stays open too long, linked to epilepsy

Tonic Clinic Seizure

Involves stiffening for 20 seconds followed by jerking

Absence Seizure

Also known as petit mal seizure, characterized by stopping and staring with no muscle activity

Focal Seizure, Impaired Awareness

Occurs in one part of the brain

Myoclonic Seizure

Involves rhythmic shrugging and rapid muscle contractions on both sides of the body

Tetanus

Caused by tetanospasmin binding at synapses, leading to generalized rigidity and opisthotonus

Ionotropic Receptor

Direct receptor subtype, likened to a key in a lock

Metabotropic Receptor

Indirect receptor subtype, compared to a link between where the key is placed

Agonist

Initiates normal receptor effects, akin to using a key to open a door

Antagonist

Prevents receptor activation by other ligands, with competitive and noncompetitive types

Amino Acids

Include Glutamate, Aspartate, Glycine, and GABA, each with specific roles in neurotransmission

Dopamine

Main neurotransmitter for movement, with pathways linked to addiction, learning, and motor control

Norepinephrine

Impacts mood, arousal, and sexual functions

Serotonin

Influences sleep, sexual behavior, and anxiety

Nitric Oxide

Acts as a gas neurotransmitter, diffusing instantly and synchronizing neighboring neurons

Acetylcholine

Neurotransmitter with nicotinic and muscarinic receptors, affecting muscle and CNS functions

Endogenous Opiates

Include enkephalins, endorphins, and dynorphins, producing analgesia and well-being

Adenosine

Neuromodulator inhibiting catecholamine release, blocked by caffeine to induce arousal

Antipsychotic Drugs

Used to treat schizophrenia, typically acting as dopamine antagonists

Antidepressants

Include monoamine oxidase inhibitors and tricyclics, affecting monoamine levels in synapses

Anxiolytics

Reduce nervous system activity, with benzodiazepines acting on GABA receptors

Barbiturates

Depress neural activity by blocking sodium channels and increasing chloride ion flow

Alcohol

Has complex effects on behavior, acting as a stimulant at low doses and a sedative at higher doses