Biology 12: Nervous System Vocabulary

Flashcards covering the parts and functions of the nervous system, neurons, impulse transmission, synapses, the central nervous system, and memory.

Neurons

Nerve cells that carry impulses.

Brain

Responsible for making decisions.

Spinal Cord

Pathway for signals traveling between the body & brain.

Central Nervous System (CNS)

Brain and spinal cord.

Peripheral Nervous System (PNS)

Allows the CNS to communicate with the body.

Somatic Nerves

Attach to muscle, skin, and joints, taking messages to or from the CNS.

Autonomic Nerves

Nerves that regulate involuntary body functions (e.g., heart, digestion).

Sympathetic Nerves

Prepare the body for "fight or flight" response by speeding up heart rate and breathing, contracting the spleen, slowing digestion, and increasing blood glucose level.

Parasympathetic Nerves

Slow down body activities when not stressed, working with acetylcholine.

Dendrites

Pick up impulses from other neurons or receptors with a large surface area.

Cell Body

Metabolic center of cell, containing organelles.

Axon

Sends nerve impulses away from the cell body toward other neurons or effectors.

Myelin

Tightly packed spirals of lipid membranes formed by Schwann cells that insulate neurons.

Schwann Cells

Produce myelin.

Nodes of Ranvier

Gaps in between Schwann cells that allow more rapid conduction of nerve impulses.

Synaptic Endings

Located at the ends of axons, containing neurotransmitter substances.

Sensory Neuron

Takes signals from a sense organ (eye, skin, etc.) to the CNS.

Motor Neuron

Carries messages from the CNS to an effector (muscle, organ, or gland).

Interneuron (Association Neuron)

Conducts impulses between parts of CNS.

Ganglia

Collections of cell bodies within the PNS.

Receptor

Sense organs that receive environmental stimuli.

Effector

Muscle, gland, or organ that carries out orders from the brain.

Synapse

Point where two neurons meet.

Resting Potential

Neuron is not conducting an impulse.

Action Potential

Rapid change in polarity across the neuron membrane as a nerve impulse begins.

Depolarization

Membrane becomes more permeable to Na+ which rushes inside.

Repolarization

Section becomes permeable to K+ which diffuses out.

Recovery Period

Na+/K+ pump uses active transport to pump Na+ to the outside & K+ to the inside; no nerve impulse conduction.

Reflex Arc

Involves only the spinal cord and allows us to respond rapidly to external stimuli.

Synapse

Where impulses are transmitted from one neuron to another.

Pre-synaptic membrane

Membrane of the first neuron.

Postsynaptic membrane

Membrane of the second neuron.

Excitatory Neurotransmitters

Make postsynaptic membrane more permeable to Na+ ions, results in depolarization.

Inhibitory Neurotransmitters

Make the postsynaptic membrane less permeable to Na+, results in hyperpolarization.

Central Nervous System (CNS)

Consists of the brain & spinal cord.

Gray Matter

Neuron cell bodies and dendrites.

White Matter

Myelinated nerve tracts (bundles of axons).

Medulla Oblongata

Control center for heart rate, respiration, & blood pressure, as well as reflex centers.

Pons

Works with the medulla oblongata to control breathing rate and has reflex centers.

Midbrain

Relay station between forebrain & spinal cord.

Hypothalamus

Center for homeostasis, hunger, thirst, water balance, body temp., & sleep. Controls pituitary gland.

Thalamus

Relay station for sensory neurons carrying info to cerebrum; the gatekeeper to the cerebrum.

Cerebrum

Largest part of the brain responsible for all consious activities.

Frontal Lobe

Movement of voluntary muscles & higher mental processes.

Parietal Lobe

Receives info from skin receptors.

Temporal Lobe

Hearing & smelling receptors.

Occipital Lobe

Vision.

Cerebellum

2nd largest brain structure, responsible for coordination, muscle tone, and balance.

Limbic System

Connects with portions of the frontal lobes, temporal lobes, thalamus, & hypothalamus and involved with emotion.

Short-term Memory

Recalling information for a few seconds.

Long-term Memory

Depends upon reinforcement, neurotransmitters in the limbic system and protein.