Intro to Neuroscience Lecture Notes

Vocabulary flashcards covering cellular neurobiology, neuroanatomy, anatomical orientation, autonomic divisions, and functional brain structures from Intro to Neuroscience.

Golgi stain

A light microscopy staining method discovered by Golgi (also known as the black reaction) that turns neurons black, making the brain appear as a giant net of connected cells.

Reticular theory

The theory proposed by Golgi holding that all nervous system cells are merged into one continuous giant net.

Neuron doctrine

The theory improved by Cajal in $1887$ using modified staining timing and younger tissue, proving that nervous system cells are actually discrete and separated by a tiny gap.

Neuron (Nerve cell)

A highly specialized, postmitotic information-processing cell with distinct morphology (dendrites and axons) that communicates with other neurons over long distances.

Dendrites

The input functional part of a neuron that receives incoming information from other cells; acts as the receiver.

Axon hillock

The integration functional part of a neuron that computes information to determine whether to fire a binary electrical signal or not.

Axon

A single cellular process that conducts output information away from the cell body as an electrical impulse; acts as the wire.

Axon terminals

The output functional structures at the end of the axon that communicate activity to other cells; act as the sender.

Synapse

The junction where neurons communicate, converting an electrical action potential into a chemical release.

Presynaptic membrane

The membrane located on the axon terminal of the presynaptic neuron that sends information across the synapse.

Postsynaptic membrane

The membrane located on the dendrite or cell body of the receiving neuron across the synapse.

Synaptic cleft

The microscopic gap separating the presynaptic membrane from the postsynaptic membrane.

Efferent

Refers to signals or nerves exiting the central nervous system to carry messages from the brain to the rest of the body.

Afferent

Refers to signals or nerves approaching the brain to convey information from the body and outside world.

Motor neurons

Efferent neurons that transmit commands from the central nervous system to muscles and glands to trigger movement.

Sensory neurons

Afferent neurons that convey sensory information from sensory organs (such as eyes and nose) back to the brain.

Interneurons

Neurons with short axons (just a few micrometers) that receive information from other neurons, process it, and pass it to other neurons.

Unipolar neuron

A neuron morphology where a single process or branch exits the cell body at one pole.

Bipolar neuron

The least common neuron morphology characterized by $2$ extensions from the cell body (one dendrite entering and one axon exiting), found in special sensory systems for vision and smell.

Multipolar neuron

The most common neuron morphology characterized by many dendrites and a single axonal projection, typical of motor neurons.

Pseudo-unipolar neuron

A neuron type conveying pain and touch information, characterized by a single extension that splits into $2$ branches extending to the periphery and central nervous system.

Oligodendrocytes

Glial cells in the central nervous system that insulate multiple axon segments across multiple neurons at a time with myelin.

Schwann cells

Glial cells in the peripheral nervous system that insulate a single axon segment at a time with myelin and facilitate peripheral nerve regeneration.

Myelin sheath

A high-fat lipid coating around axons that acts as an electrical insulator, significantly increasing signal conduction speed.

White matter

Brain tissue consisting primarily of myelinated axons, named for the white appearance of lipid coatings.

Grey matter

Brain tissue consisting of neuronal cell bodies (somas) and dendrites, serving as the sites for electrical integration.

Ganglion

A group or cluster of neuronal cell bodies located within the Peripheral Nervous System (PNS).

Nucleus (Neuroanatomy)

A cluster of neuronal cell bodies located within the Central Nervous System (CNS).

Nerve

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

Tract

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

Multiple sclerosis

A neurodegenerative disease caused by the degradation of myelin, resulting in cognitive slowing and muscle control issues.

Astrocytes

CNS glial cells that weave around neurons, wrap around axon terminals, help form outer membranes, remove waste, and dilate blood vessels.

Microglial cells

CNS glial cells that function as the janitors of the cell, containing and cleaning up sites of injury.

Central Nervous System (CNS)

The main neural division consisting of the brain and spinal cord, encased in bone.

Peripheral Nervous System (PNS)

The nervous system division consisting of nerves that connect peripheral organs and tissues with the brain and spinal cord.

Somatic Nervous System

The voluntary sensory and motor nervous system utilizing a simple, direct single-neuron pathway from the spinal cord to muscle.

Autonomic Nervous System

The involuntary nervous system controlled by the hypothalamus that utilizes a $2\text{-neuron}$ pathway to regulate visceral organs and glands.

Parasympathetic nervous system

The rest and digest division of the autonomic system, originating in the brainstem and sacral spinal cord, using acetylcholine for slow, long-lasting, independently targeted activation.

Sympathetic nervous system

The fight or flight division of the autonomic system, originating in thoracolumbar regions ($T1\text{-}L2$ and $L3$), using norepinephrine for rapid, short-term, simultaneous activation.

Enteric system

An independent nervous system in the gut capable of operating without input from the central nervous system.

Horizontal plane

An anatomical plane parallel to the ground (also called axial or transverse) that divides the top/anterior from the bottom/posterior.

Sagittal plane

A vertical anatomical plane running top to bottom that divides the brain or body into right and left halves.

Coronal plane

A vertical anatomical plane (also called frontal) that divides the front (anterior) from the back (posterior).

Ipsilateral vs. Contralateral

Ipsilateral refers to structures located on the same side of the body, whereas contralateral refers to structures on opposite sides.

Gyri

The raised ridges of tissue created by the folding (gyrification) of the cerebral cortex.

Sulci

The crevices or grooves that separate gyri from each other in the cerebral cortex.

Fissure

An especially deep sulcus on the cerebral cortex.

Brainstem

A continuation of the spinal cord comprising the midbrain, pons, and medulla (excluding the cerebellum) that controls vital life functions and serves as the entry/exit point for cranial nerves.

Medulla (oblongata)

A brainstem region controlling vital reflexes and life functions, where damage is often fatal.

Pons

A brainstem structure that acts as a bridge connecting the forebrain to the cerebellum, involved in sleep, norepinephrine production, and cranial nerve pathways.

Midbrain

A brainstem region involved in reflexive orienting to visual and auditory stimuli, intrinsic descending pain control, and dopamine production.

Substantia nigra

A major dopamine-producing region in the midbrain involved in movement regulation.

Ventral tegmental area (VTA)

A major dopamine-producing region in the midbrain that projects to the cortex for cognition and limbic regions for reinforcement.

Cerebellum

A structure ('little brain') with its own cortex involved in movement coordination, well-learned motor routines, posture, balance, and cognitive functions like language.

Corpus callosum

The primary band of axonal fibers that connects the left and right cerebral hemispheres.

Precentral gyrus (M1)

The primary motor cortex located in the frontal lobe anterior to the central sulcus, responsible for voluntary motor control of the opposite side of the body.

Postcentral gyrus (S1)

The primary somatosensory cortex located in the parietal lobe posterior to the central sulcus, receiving somatosensory inputs from the entire body.

Thalamus

An egg-shaped central structure containing many nuclei that serves as the primary relay station for all sensory information (except smell) destined for the cortex.

Hypothalamus

A subcortical structure located below the thalamus that regulates autonomic and endocrine systems, homeostasis, circadian rhythms, and drive behaviors ($4\text{ F's}$: feeding, fighting, fleeing, fornication).

Pituitary gland

The master endocrine gland hanging off the hypothalamus that produces and secretes numerous hormones under hypothalamic direction.

Pineal gland

An endocrine gland that produces and secretes melatonin to regulate sleep-wake cycles along with daily and seasonal rhythms.

Wernicke's area

A region located exclusively in the left temporal lobe responsible for language comprehension and processing.

Broca's area

A region located exclusively in the left frontal lobe responsible for language production.

Prefrontal cortex (PFC)

The region of the frontal lobe responsible for executive functions, decision-making, planning, working memory, cognitive flexibility, foresight, insight, and impulse control.

Basal Ganglia

A cluster of deep subcortical gray matter nuclei (caudate nucleus, putamen, globus pallidus) that acts as a gatekeeper/filter to modulate, refine, and suppress unwanted movement.

Striatum

A subcortical structure within the basal ganglia formed by the combined caudate nucleus and putamen.

Limbic System

An interconnected network of structures (hippocampus, amygdala, fornix, cingulate gyrus) spanning multiple regions to regulate emotion, learning, memory, and motivation.

Hippocampus

A limbic structure located inside the temporal lobe that plays a central role in memory.

Amygdala

A limbic system structure primarily responsible for emotional processing and emotional attachments to memories.