PBSI 235 Exam Study Guide Vocabulary Flashcards

A comprehensive set of vocabulary flashcards covering the cellular and gross anatomy of the nervous system, electrical and chemical signaling, sensory and motor systems, homeostasis, biorhythms, emotions, memory, consciousness, and language processing.

Neurons

The fundamental information processing unit of the nervous system, also known as nerve cells.

Nucleus

The organelle that houses DNA used as the blueprint for protein synthesis.

Central Dogma of Biology

The process where DNA is transcribed to RNA which is then translated to proteins.

Dendrites

Input regions attached to somas that receive information from other neurons.

Dendritic Spines

Structures that increase surface area on dendrites to receive more chemical signals from the axon terminals of other neurons.

Soma

The cell body that integrates electrical signals from dendrites, houses the nucleus, and regulates cell function.

Axon

A long wire-like extension that funnels information down from the soma to the axon terminals.

Axon Hillock (Initial Segment)

The specific region of the axon that generates action potentials.

Axon Terminals

Structures that contact the dendrites and soma of other neurons to communicate information via chemical signals.

Synapse

The connection between an axon terminal and the next neuron.

Presynaptic Membrane

The part of the axon terminal that releases the neurotransmitter.

Postsynaptic Membrane

The part of the target cell (usually the dendrites) that detects and receives messages from neurotransmitters.

Synaptic Cleft

The space between the presynaptic and postsynaptic membranes.

Cell Theory

The theory stating that all living things are composed of cells, cells are the basic units of life, and all cells arise from preexisting cells.

Neuron Doctrine

Proposed by Santiago Ramon y Cajal, it states that the brain is composed of individual cells called neurons.

Golgi Stain

A technique that completely fills a small percentage of neurons to reveal their structure; used to support Cajal's work.

Reticulum Theory

Proposed by Camile Golgi, it incorrectly states the brain is organized like a giant net with no individual cells or synaptic spaces.

Glia

Cells that provide support to the nervous system via nutrients, raw materials, protection, and general upkeep.

Myelin

A fatty sheath wrapping around axons to provide insulation for efficient action potential conduction.

Oligodendrocytes

Glial cells that create myelin sheaths in the CNS.

Schwann Cells

Glial cells that create myelin outside of the CNS.

Astrocytes

Star-shaped glial cells that connect to neurons and blood vessels to help establish the blood brain barrier.

Blood Brain Barrier

A system that separates the brain from the circulatory system to regulate pathogen and nutrient contact with neurons.

Microglia

Cells that defend the brain by scavenging for pathogens, damaged cells, and debris; exists in resting and reactive states.

Triune Brain Theory

Paul McLean's theory proposing humans inherited three brains (reptilian, lower mammal, human) from ancestors.

Homology

The study of similar traits arising from evolutionary relatedness.

Theory of Localization

Franz Joseph Gall's theory that different parts of the brain carry out different functions.

Phrenology

A pseudoscience suggesting the shape of the skull reflects the brain's structure and a person's psyche.

Neural System

A population of neurons that communicate across brain region boundaries.

Neural Circuit

A population of neurons that communicate within a brain region or between neighboring regions.

Motor Nerves

Nerves that conduct information in an efferent direction away from the CNS to control muscles.

Sensory Nerves

Nerves that convey information in an afferent direction from the body towards the CNS.

Spinal Nerves

$31$ pairs of nerves that enter and exit the spinal cord to carry sensory and motor information.

Cranial Nerves

$12$ pairs of nerves emerging from the base of the brain that control head and neck muscles and convey specialized sensory data.

Somatic Nervous System

The division of the PNS where nerves connect the CNS to sensory and skeletal systems.

Autonomic Nervous System

The division of the PNS where nerves connect the CNS to internal organs; includes sympathetic and parasympathetic parts.

Dorsal Root Ganglia

Clusters containing the cell bodies of specialized neurons that conduct sensory information from the PNS to the CNS.

Sympathetic Nervous System

The "fight-or-flight" division of the autonomic NS that tells tissues to burn energy.

Parasympathetic Nervous System

The "rest-and-digest" division of the autonomic NS that tells tissues to conserve metabolic energy.

Nerves

A bundle of axons in the Peripheral Nervous System (PNS).

Ganglia

A collection of cell bodies in the Peripheral Nervous System (PNS).

Meninges

Fluid-filled sacs that cushion the brain and spinal cord.

Cerebrospinal Fluid (CSF)

Fluid produced in the lateral ventricles that allows the brain to float and provides filtration.

Tract

A bundle of axons in the Central Nervous System (CNS).

Nucleus (Gross Anatomy)

A collection of cell bodies in the Central Nervous System (CNS).

Basal Ganglia

Nuclei deep in the forebrain that initiate voluntary motion.

Limbic System

A group of interconnected structures, including the hippocampus and amygdala, functioning in emotion and memory.

Thalamus

A cluster of nuclei at the forebrain center that directs sensory information to the cortex.

Hypothalamus

A cluster of nuclei ranging in function from energy control to endocrine regulation.

Pituitary Gland

The "master gland" that directs endocrine function in communication with the hypothalamus.

Gyri

The hills or ridges in the wrinkles of the brain's cortex.

Sulci

The valleys or grooves in the wrinkles of the brain's cortex.

White Matter

Brain tissue consisting primarily of myelinated axons.

Gray Matter

Brain tissue consisting primarily of cell bodies, dendrites, and unmyelinated axons.

Frontal Lobe

The cortical lobe responsible for attention, planning, decision making, and motor control.

Parietal Lobe

The cortical lobe responsible for touch and proprioception.

Occipital Lobe

The cortical lobe primarily responsible for vision.

Temporal Lobe

The cortical lobe primarily responsible for hearing.

Neocortex

The primary part of the human cortical surface, composed of $6$ differentiated cell layers.

Lissencephalic

A term describing brains with a smooth cortex.

Gyrencephalic

A term describing brains with a wrinkly cortex.

Tegmentum

The ventral midbrain containing cell bodies that release dopamine to the basal ganglia and cortex.

Tectum

The dorsal midbrain that processes audio and visual information and controls orientation responses.

Medulla

An outgrowth of the spinal cord containing nuclei that create cranial nerves.

Pons

The structure connecting the brain to the cerebellum; it contains nuclei for cranial nerves.

Postsynaptic Potentials

Local changes in electrical charge at a neuron's input region in response to chemical input.

Action Potential

An "all-or-none" electrical signal characterized by a rapid depolarization wave sweeping down an axon.

Resting Potential

The negative charge inside a neuron when not active, typically ranging from $-50\,mV$ to $-80\,mV$.

Sodium-Potassium Pump

An active mechanism that consumes $1$ ATP to pull $2\,K^+$ ions in and push $3\,Na^+$ molecules out.

Hyperpolarization

A change in cell potential making the interior of the neuron more negative.

Depolarization

A change in cell potential making the interior of the neuron more positive.

Ionotropic Receptors

Ion channels that open directly when neurotransmitters bind to them, converting chemical signals to electrical signals.

EPSP (Excitatory Postsynaptic Potential)

A brief depolarization around a synapse caused by cations entering the neuron.

IPSP (Inhibitory Postsynaptic Potential)

A brief hyperpolarization around a synapse caused by anions entering the neuron.

Spatial Summation

The combined influence of postsynaptic potentials across different locations on the neuron.

Temporal Summation

The combined influence of postsynaptic potentials that occur closely together in time.

Threshold Voltage

The specific voltage (usually around $-40\,mV$) required to trigger an action potential.

Refractory Period

The time during which voltage-gated sodium channels recover after closing, preventing multi-directional action potentials.

Saltatory Conduction

The process in myelinated axons where action potentials jump between the Nodes of Ranvier.

Neurotransmitters

Molecules released from axon terminals that cause changes in postsynaptic neurons for communication.

Metabotropic Receptors

Receptors that activate G-proteins to trigger a cascade of intracellular events or open ion channels.

Enzymatic Degradation

A mechanism to inactivate neurotransmitters where enzymes in the synaptic cleft break them down.

Reuptake

A mechanism where transporter molecules on the presynaptic cell pull neurotransmitters out of the synaptic cleft.

Pharmacokinetics

The study of the absorption, distribution, metabolism, and excretion of drugs.

Pharmacodynamics

The study of how drugs affect their specific site of action.

Ligand

Any molecule that binds to a receptor site.

Agonist

An exogenous ligand that binds to a receptor and mimics the effects of an endogenous ligand.

Antagonist

A ligand that binds to a receptor to block the action of endogenous ligands or agonists.

ED50

The dose of a drug that is effective in $50\%$ of subjects.

LD50

The dose of a drug that is lethal in $50\%$ of subjects.

Therapeutic Index

The margin of safety defined by the difference between the effective dose ($ED50$) and lethal dose ($LD50$).

Sensitization

An effect where drug results grow with repeated exposure, shifting the dose-response curve left.

Tolerance

An effect where drug results diminish with repeated exposure, shifting the dose-response curve right.

Dependence

A state where the body becomes accustomed to a drug and reacts with withdrawal symptoms upon its removal.

Classical Neurotransmitters

Synthesized by enzymes in the axon terminal and packaged in synaptic vesicles; includes monoamines and amino acids.

Neuropeptides

Non-classical neurotransmitters made of amino acid chains synthesized in the cell body, such as enkephalins.

Glutamate

The primary excitatory neurotransmitter in the nervous system.

AMPA Receptor

An ionotropic glutamate receptor that acts as a $Na^+$ channel to generate EPSPs.

NMDA Receptor

An ionotropic glutamate receptor that acts as a $Ca^{2+}$ channel to induce synaptic plasticity.

GABA

The primary inhibitory neurotransmitter in the nervous system.