Nervous System and Special Senses Review

Comprehensive vocabulary flashcards covering the nervous system divisions, neuron physiology, brain anatomy, action potentials, and special senses based on the lecture notes.

Central Nervous System (CNS)

The major division of the nervous system made up of the brain and spinal cord.

Peripheral Nervous System (PNS)

All nerves located outside of the brain and spinal cord.

Afferent pathway

A sensory pathway that carries information toward the CNS.

Efferent pathway

A motor pathway that carries information away from the CNS.

Somatic nervous system

The part of the nervous system responsible for the voluntary motor control of skeletal muscles.

Autonomic nervous system

The part of the nervous system providing involuntary control of smooth muscle, cardiac muscle, and glands.

Sympathetic division

The division of the autonomic nervous system responsible for the "fight or flight" response.

Parasympathetic division

The division of the autonomic nervous system responsible for the "rest and digest" response.

Neuron

The basic functional unit of the nervous system.

Dendrites

Neuron structures that receive incoming signals.

Soma (Cell body)

The part of the neuron that contains the nucleus and performs cell maintenance.

Axon hillock

The specific region of a neuron where action potentials begin.

Axon

A long projection that carries nerve impulses away from the cell body.

Myelin

A lipid-rich insulating covering around axons that speeds up nerve impulse conduction.

Nodes of Ranvier

Gaps in the myelin sheath where ion exchange occurs.

Saltatory conduction

The process by which action potentials "jump" from node to node along a myelinated axon.

Axon terminals

The endings of an axon that release neurotransmitters.

Amitotic

A characteristic of neurons meaning they rarely divide.

Gray matter

Nervous tissue composed of neuron cell bodies, dendrites, and unmyelinated fibers; it appears gray because it contains little myelin.

White matter

Nervous tissue composed of myelinated axons; it appears white due to the presence of lipids in myelin.

Synapse

A junction where neurons communicate with one another.

Synaptic cleft

The small gap between neurons at a synapse.

Neurotransmitters

Chemical messengers that transmit signals across the synaptic cleft between neurons.

Acetylcholine

A specific neurotransmitter commonly involved in triggering muscle contraction.

Meninges

Protective membranes surrounding the brain and spinal cord, consisting of the dura mater, arachnoid mater, and pia mater.

Dura mater

The tough, superficial outer layer of the meninges.

Arachnoid mater

The web-like middle layer of the meninges.

Pia mater

The delicate inner layer of the meninges that is directly attached to the brain.

Gyrus

An elevated ridge on the surface of the brain.

Sulcus

A shallow groove on the brain surface.

Fissure

A deep groove that separates distinct regions of the brain.

Cerebrum

The major brain region responsible for conscious thought, memory, sensation, and voluntary movement.

Primary motor cortex

Located in the precentral gyrus, it controls voluntary skeletal muscle movement.

Broca’s area

The brain's speech production center; damage here results in difficulty speaking.

Primary somatosensory cortex

Located in the postcentral gyrus, it receives information regarding touch, pressure, pain, and temperature.

Thalamus

A structure within the diencephalon that acts as a relay station for sensory information.

Hypothalamus

A diencephalon structure that maintains homeostasis by regulating temperature, hunger, thirst, hormones, and the autonomic nervous system.

Medulla oblongata

A part of the brain stem that regulates vital functions such as breathing, heart rate, and blood pressure.

Cerebellum

The brain region responsible for balance, posture, coordination, and motor learning.

Resting membrane potential

The electrical charge of a neuron at rest, approximately $-70\,mV$, maintained by ion gradients.

Sodium-potassium pump

An ATP-powered transport protein that moves $3\,Na$ ions out of the cell and $2\,K$ ions into the cell.

Depolarization

The stage of an action potential where sodium channels open and $Na$ enters the neuron, making the membrane voltage more positive.

Repolarization

The stage where potassium channels open and $K$ leaves the neuron to restore internal negativity.

Threshold

The minimum stimulus required to trigger an all-or-none action potential.

Refractory period

The time during which a neuron cannot immediately fire another action potential, preventing backwards movement of the impulse.

Cornea

The part of the eye that bends and focuses incoming light.

Retina

The light-sensitive inner layer of the eye containing photoreceptors.

Rods

Photoreceptors specialized for dim light and black-and-white vision.

Cones

Photoreceptors specialized for color and detailed vision.

Fovea centralis

The area on the retina providing the sharpest vision.

Auditory ossicles

The three bones of the middle ear (malleus, incus, and stapes) that amplify sound vibrations.

Cochlea

The hearing organ within the inner ear that contains hair cells.

Semicircular canals

Structures in the inner ear responsible for detecting balance.