Biology 30 - Unit 1 Booklet 1: The Nervous System (Terms)

CNS (Central Nervous System)

Coordinates incoming and outgoing information and makes decisions based on this information. Includes the brain and spinal cord

PNS (Peripheral Nervous System)

Carries information between organs and the CNS by acting on and processing commands. Includes the nerves

Glial Cell

Provides strucural support and resources required for metabolism of nerve cells

Neuron

The functional unit of the nervous system that is responsible for most of the work in the system

Dendrite

Part of a neuron that receives information from the environment or other neurons. Conducts nerve impulses towards the cell body

Axon

Part of a neuron that conducts nerve impulses away from cell body and towards other neurons or effectors

Effector

The tissue (cell, organ, gland, muscle, etc.) that will respond to stimulus

Myelin Sheath

A supportive structure that acts as insulation for neurons. Speed up nerve impulses together with nodes of Ranvier

Node of Ranvier

Areas between sections of the myelin sheath. Speed up nerve impulses together with myelinated cells

Schwann Cell

Specialized glial cell found in the PNS. Forms the myelin sheath and the neurilemma

Neurilemma

A thin outer membrane surrounding the axon that promotes regeneration of damaged axons

White Matter

Nerves containing a myelin sheath

Gray Matter

Nerves lacking a myelin sheath

Sensor

What the body uses to obtain information from its environment. Includes both the 5 senses and unconscious bodily sensors

Ganglion

A group or cluster of nerve cells that are closely related

Sensory Neuron

Neuron that receives information from sensory receptors and relays it to the CNS

Interneuron

Link neurons to other neurons (particularly sensory neurons to motor neurons). They integrate and interpret sensory information

Motor Neuron

Neuron that relays information from the CNS to effectors

Reflex Arc

The simplest nerve pathway that protects the body quickly when presented with a stimulus perceived as dangerous. Is involuntary and unconscious

Resting Potential

The voltage across the membrane when the neuron is not transmitting an impulse/at rest

Depolarization

A reversal of charge on the inside of a neuron due to the opening of Na+ channels

Repolarization

The return of the inside of the neuron to a negative charge due to the opening of K+ channels and the closing of Na+ channels

Hyperpolarization

A period of time during the refractory period in which the inner membrane is more negative than at resting potential

Refractory Period

The time it takes for repolarization

Saltatory Conduction

Generation of action potentials off of Nodes of Ranvier in myelinated axons

All or None Principle

The principle followed by nerves in which they will either fire completely or not at all

Synapse

The space between neurons or between neurons and effectors

Neurotransmitter

A chemical that allows for communication between neurons and can have excitatory and inhibitory effects on action potential

Acetylcholine

An excitatory neurotransmitter that stimulates action potential by initiating the depolarization of the postsynaptic neuron

Summation

The effects of neurotransmitters from multiple presynaptic knobs that must add together in order to induce an action potential

Meninges

3 layers of protection around the brain and spinal cord

Cerebrospinal Fluid

Fluid circulated between innermost and middle meninges of brain that functions as a shock absorber and transport medium

Dorsal Root

Area of a nerve that brings information into the spinal cord

Ventral Root

Area of a nerve that carries motor information out of spinal cord to effectors

Corpus Callosum

A bundle of nerves through which the left and right hemispheres of the cerebrum communicate with one another

Thalamus

Section of forebrain that relays and sorts incoming information to the cerebrum

Hypothalamus

Section of forebrain that maintains body’s homeostasis

Cerebrum

The largest part of the forebrain responsible for most brain activity

Frontal Lobe

The lobe of the cerebrum that is responsible for movement of voluntary muscles, intellectual activities, and personality

Temporal Lobe

The lobe of the cerebrum that is responsible for hearing and memory

Parietal Lobe

The lobe of the cerebrum that is responsible for touch and temperature awareness and emotions

Occipital Lobe

The lobe of the cerebrum that is responsible for vision

Midbrain

Four spheres of grey matter below the thalamus that serve as a relay center for eye and ear reflexes

Cerebellum

The largest section of the hindbrain that controls limb movements, balance, involuntary movement, and fine motor control

Pons

The bridge that passes information between cerebellum and the medulla oblangata

Medulla Oblangata

The section of the hindbrain that connects the CNS with the PNS, controls involuntary muscle movements, and acts as a coordinating center for the autonomic nervous system

Sensory-Somatic Nervous System

The PNS system responsible for voluntary/somatic control and reflex arcs that brings information from external environment to the CNS and sends back information to skeletal muscles

Autonomic Nervous System

The PNS system responsible for involuntary control that brings information about the body’s internal environment to the CNS and regulates the body by carrying syginals from CNS to muscles and organs

Sympathetic Nervous System

The divison of the autonomic nervous system that correlates with the “fight-or-flight”/stress response

Parasympathetic Nervous System

The divison of the autonomic nervous system that correlates with the “rest and digest”/relax response