Chapter 2 Key Terms

Question 1

Neurons

Answer 1

Sends messages to the body. Convey sensory information in the brain. 86 billion neurons in the brain. Responsible for everything we do (move, emotion, memory, thoughts, etc)

Question 2

Cell Body (Soma)

Answer 2

Most prominent part of the neuron. Filled with cytoplasm. Contains the nucleus of the cell and chromosomes.

Question 3

Motor Neuron

Answer 3

Carries commands to the muscles and organs. Demonstrates functions and structures that all neurons have in common.

Question 4

Dendrites

Answer 4

extensions that BRANCH out from the cell to receive information from the neurons

Question 5

Axon

Answer 5

extends like a tail from the cell body and carries information to other locations

Question 6

Axon Terminals

Answer 6

Branches at the END of the axon culminating in swelling

Question 7

Neurotransmitters

Answer 7

released by neurons to a muscle or organ, or the next neuron in a chain

Question 8

Sensory Neurons

Answer 8

carry information from the body or outside world and send it to the brain and spinal cord

Question 9

Interneurons

Answer 9

Neither motor or sensory. They connect one neuron to the other in the same part of the brain or spinal cord.

Question 10

Polarization

Answer 10

means there is a difference in electrical charges between the inside and outside of the neuron

Question 11

Voltage

Answer 11

A difference in charge between two points, such as the poles of a battery or between the inside and outside of a neuron

Question 12

Resting Potential

Answer 12

The difference between the inside and outside of the membrane of a neuron at rest. The voltage is a NEGATIVE number and is between -40-80 milivolts

Question 13

Ions

Answer 13

Atoms that have lost or gained one or more electrons

Question 14

Force of Diffusion

Answer 14

Ions tend to move through the membrane to the side where they are less concentrated

Question 15

Electrostatic Pressure

Answer 15

Ions are repelled from the side they are similarly charged and attracted to the side that they are oppositely charged

Question 16

Sodium Potassium Pump

Answer 16

Significant contributor to polarity. Large protein molecules that move the sodium Ions through the cell membrane to the outside, and the potassium ions back inside

Question 17

Action Potential

Answer 17

Abrupt depolarization of the membrane that allows neurons to communicate over long distances

Question 18

Neurotoxins

Answer 18

Neuron Poisons (snake venom)

Question 19

Optogenetics

Answer 19

research strategy that allows us to create light responsive channels so that they can be controlled by light

Question 20

Graded Potential

Answer 20

varies in magnitude with the strength of the stimulus that produced it.

Question 21

Nondecremental

Answer 21

Travels down the axon with no decrease in size, propogate anew at full strenght at each point along the way

Question 22

Absolute Refractory Period

Answer 22

During the action potential and initial recovery, the sodium and ion channels are open and unresponsive to further stimulation, no matter how intense

Question 23

Relative Refractory Period

Answer 23

action potential can be generated, but only by stronger than threshold stimulus

Question 24

Rate Law

Answer 24

The axon encodes stimulus intensity not in the size of it’s action potential, but in it’s firing rate

Question 25

Glial Cells

Answer 25

nonneural cells that provide a number of supporting functions to neurons

Question 26

Myelin

Answer 26

Fatty tissue that wraps around the axon (like a jellyroll) to insulate it from surrounding fluid and other neurons

Question 27

Oligodendrocytes (glial cells

Answer 27

Myelin produced in the BRAIN and SPINAL CORD

Question 28

Schwann Cells

Answer 28

Myelin produced in the in the NERVOUS SYSTEM

Question 29

Nodes of Ranvier

Answer 29

Gaps in the Myelin Sheath

Question 30

Saltatory Conduction

Answer 30

Action potentials that jump from node to node in a form or transmission

Question 31

Synapse

Answer 31

Connection between to neurons

Question 32

Synaptic Cleft

Answer 32

Neurons are not in direct contact, but separated by a small gap

Question 33

Presynaptic / Postsynaptic

Answer 33

Pre = neuron that is transmitting to another neuron Post = the receiving neuron

Question 34

Vesicles

Answer 34

"little bladders" - at chemical synapses, neurotransmitters are stored in terminals membrane-enclosed BUBBLES

Question 35

Ionotropic Receptors

Answer 35

Form the ion channel and open quickly to produce the immediate action of muscles and sensory processing

Question 36

Metatropic Receptors

Answer 36

Open channels INDIRECTLY through a second messenger. They act slowly and allow for a longer lasting affect

Question 37

Partial Depolarization

Answer 37

Facilitates the occurrence of an action potential

Question 38

Hyperpolarization

Answer 38

inhibits and makes action potential LESS likely to occur

Question 39

Excitatory Postsynaptic Potential (EPSP)

Answer 39

receptors open sodium channels , produces a partial depolarization of the dendrites and cell body

Question 40

Inhibitory Postsynaptic Potential (IPSP)

Answer 40

As potassium moves out of the cell or chloride moves in, it produces Hyperpolarization of the dendrites

Question 41

Spatial Summation

Answer 41

Combines potentials occurring simultaneously at different locations on dendrites and cell body

Question 42

Temporal Summation

Answer 42

Combines potentials arriving a SHORT TIME APART from either the same or separate inputs

Question 43

Reuptake

Answer 43

Transmitters are taken back into the terminals by membrane proteins called transporters

Question 44

Autoreceptors

Answer 44

On the presynaptic terminals sense the amount of transmitter in the cleft

Question 45

Dales Principle

Answer 45

Incorrect belief that a neuron was only able to release a single transmitter

Question 46

Agonists

Answer 46

Drugs that mimic and increase the effects of neurotransmitters

Question 47

Neural Networks

Answer 47

Groups of neurons that function together to carry out a process - the computing part of the brain

Question 48

Human Connectome Project

Answer 48

Large scale, multi university effort to map the circuits of the brain