Anatomy and Physiology of the Central Nervous System

These vocabulary flashcards cover the gross anatomy of the brain, spinal cord, anatomical terminology, neuronal structure, glial cells, membrane potentials, synaptic transmission, and sensory systems based on the lecture notes.

Coronal Plane

A vertical plane that separates the brain or the body into anterior (front) and posterior (back) sections.

Midsagittal Plane

A vertical plane that divides the brain into equal left and right hemispheres.

Transverse Plane

A horizontal plane that divides the brain or the body into superior (top) and inferior (bottom) sections.

Anterior

Towards the front of the brain or body; also referred to as ventral in humans.

Posterior

Towards the back of the brain or body; also referred to as dorsal.

Rostral

A directional term meaning towards the nose or the front of the brain.

Caudal

A directional term meaning towards the tail or the back of the brain.

Afferent

Sensory pathways that carry information towards the central nervous system (CNS).

Efferent

Motor pathways that carry information away from the CNS to muscles or glands.

Brainstem

The lower extension of the brain that connects the cerebrum to the spinal cord and controls vital life functions such as breathing and heart rate.

Midbrain

Part of the brainstem involved in visual and auditory reflexes, motor controls, and alertness.

Pons

Part of the brainstem that acts as a bridge between the cerebellum and cerebrum; involved in sleep, respiration, and facial movement.

Medulla

Part of the brainstem that regulates vital autonomic functions such as breathing, heart rate, and blood pressure.

Cerebrospinal Fluid (CSF)

A clear, colorless fluid produced by the choroid plexus that cushions the brain, provides buoyancy, and removes waste products.

Cerebellum

A structure located posterior to the cerebrum responsible for coordination of voluntary movement, balance, and motor learning.

Thalamus

A major sensory relay station in the diencephalon where most sensory information (except smell) passes before reaching the cortex.

Hypothalamus

A part of the diencephalon that maintains homeostasis by regulating temperature, hunger, thirst, and circadian rhythms.

Frontal Lobe

The cerebral lobe responsible for voluntary motor control, executive functions (planning, decision-making), personality, and speech production.

Parietal Lobe

The cerebral lobe responsible for somatosensory processing (touch, pain, temperature) and spatial awareness.

Temporal Lobe

The cerebral lobe responsible for hearing, language comprehension (Wernicke's area), and memory.

Occipital Lobe

The cerebral lobe primarily responsible for visual processing.

Gyri

The raised ridges of the cerebral cortex that increase its surface area.

Sulci

The shallow grooves located between the gyri of the cerebral cortex.

Dura Mater

The tough, outermost layer of the three protective meninges surrounding the brain and spinal cord.

Pia Mater

The thin, delicate innermost layer of the meninges that adheres directly to the brain tissue.

Neuron

A specialized excitable cell that transmits information via electrical impulses (action potentials) and chemical signals (neurotransmitters).

Dendrites

Branch-like extensions from the neuronal cell body that receive signals and carry them towards the soma.

Axon

A long signal projection of a neuron that carries electrical impulses away from the cell body.

Astrocytes

The most numerous glial cells in the brain that provide structural support, regulate the chemical environment, and help form the blood-brain barrier.

Oligodendrocytes

Glial cells in the central nervous system that produce the myelin sheath around axons to speed up electrical conduction.

Schwann Cells

Glial cells in the peripheral nervous system (PNS) that form myelin around a single segment of one axon.

Microglia

The immune cells of the CNS that act as macrophages to remove debris, damaged cells, and pathogens.

Anterograde Transport

The movement of material from the cell body to the axon terminal, fueled by the protein kinesin.

Retrograde Transport

The movement of material from the nerve terminal to the cell body, fueled by the protein dynein.

Wallerian Degeneration

The process where an axon degenerates due to the interruption of protein transport from the cell body.

Membrane Potential ($V_m$)

The difference in electrical charge between the inside and outside of a cell membrane.

Resting Membrane Potential

The stable electrical charge of a neuron when it is not sending a signal, typically measured at approximately $-65\,mV$ to $-70\,mV$.

Sodium-Potassium Pump

An enzyme (ATPase) that maintains ionic gradients by actively transporting three $Na^+$ ions out of the cell and two $K^+$ ions into the cell using ATP.

Action Potential

A rapid reversal of electrical charge across the neuronal membrane where the inside becomes positive relative to the outside.

Threshold

The critical level of depolarization (typically $-55\,mV$) required to open voltage-gated sodium channels and trigger an action potential.

Absolute Refractory Period

The period during which a neuron cannot generate another action potential because voltage-gated sodium channels are inactivated.

Saltatory Conduction

The rapid propagation of action potentials jumping from one node of Ranvier to the next in myelinated axons.

Electrical Synapse

A simple synapse that allows the direct transfer of ionic current from one cell to the next through gap junctions.

Chemical Synapse

The predominant form of synapse in the nervous system where neurotransmitters are released into a synaptic cleft to communicate with the postsynaptic neuron.

Glutamate

The major amino acid neurotransmitter in the CNS responsible for producing neuronal excitation.

GABA

The major amino acid neurotransmitter in the mature brain responsible for producing neuronal inhibition.

Agonist

A substance or drug that binds to a receptor and mimics the actions of a naturally occurring neurotransmitter.

Antagonist

A substance or drug that inhibits or blocks the effects of a neurotransmitter receptor.

Tastant

A chemical stimulus that must reach a minimum concentration threshold to be detected by taste receptor cells.

Olfactory Epithelium

A thin sheet of cells high up in the nasal cavity containing olfactory receptor cells, supporting cells, and basal cells.

Phototransduction

The process by which photoreceptors in the retina convert light energy into neuronal signals.

Rods

Photoreceptors that are highly sensitive to light and responsible for vision in nighttime or low-light conditions.

Cones

Photoreceptors responsible for high-resolution vision in bright light and color detection.

Organ of Corti

The structure on the basilar membrane that contains auditory hair cells responsible for converting mechanical sound energy into neural signals.

Mechanoreceptors

Sensory receptors in the skin that respond to mechanical forces such as pressure, vibration, and stretching.

Nociceptors

Free nerve endings that act as pain receptors, activated by stimuli that threaten tissue damage.

Proprioception

The sensation of body position and joint movement, primarily processed in Area 3a of the somatosensory cortex.

Agnosia

A clinical condition resulting from damage to the posterior parietal cortex where a person can sense objects but cannot recognize them.