The Neuron

Question 1

Afferent (sensory) neurons

Answer 1

inward: sends messages from organs and sensory receptors to brain and spinal cord

Question 2

Efferent (motor) neurons

Answer 2

Outward: carries instructions from CNS (brain and spinal cord) to muscles, glands of body

Question 3

Interneurons

Answer 3

Neurons between the ones of the brain and spinal cord that communicate and pass information between sensory input and motor output

Question 4

Dendrites

Answer 4

receivers of signals from other neurons (conducts info towards cell body)

Question 5

Cell body

Answer 5

receives incoming signals from dendrites and passes them on

Question 6

Nucleus

Answer 6

carries out metabolic (life-sustaining) function, contains genetic material

Question 7

Axon

Answer 7

passes out messages away from cell body, down the tail, to other neurons/muscles/glands

Question 8

Myelin Sheath

Answer 8

white fatty coating (bubbles covering axon.) Purpose is to speed up neural impulses (signals)

Question 9

Nodes of ranvier

Answer 9

gaps in between myelin sheath that also speeds up neural impulse

Question 10

Synapse

Answer 10

junction between transmitting neurons and receiving neurons, releasing chemical signals

Question 11

Axon terminals

Answer 11

Terminal branches of axon through which axons make synaptic contact with other nerve cells.

Question 12

Synaptic cleft

Answer 12

The fluid-filled gaps between the transmitting neuron (axon) and receiving neuron (dendrite). Area that the synaptic vesicles (neurotransmitters) will cross to penetrate the dendrite through receptor sites.

Question 13

Synaptic vesicles

Answer 13

Little circles stored in axon that house neurotransmitters. These will be released when electricity changes the permeability of the membrane and the vesicles fuse to the membrane so that they can cross the synaptic gap.

Question 14

How do neurons communicate?

Answer 14

Comm. STARTS with electricity (impulse/action potential)

Question 15

What changes the permeability of a cell membrane?

Answer 15

Electricity

Question 16

Neurotransmitters

Answer 16

in synaptic vesicles until they are stimulated by action potential. They are a messenger of chemical substance between neurons.

Question 17

Receptor sites

Answer 17

located on the receiving neuron. Neurotransmitters are lite a key that fits perfectly into these.

Question 18

Glial cells (glial sounds like glue)

Answer 18

hold neurons together, smaller than them, half of brain volume, removes waste (dead neurons)

Question 19

4 steps of communication

Answer 19

1. At rest= negative (resting potential) 2. Stimulated = positive (action potential / electricity) 3. Fires positive ions 4. back at rest (-) once the electricity (+) has exited *neurons fire all or nothing at all.

Question 20

Weak vs strong stimuli

Answer 20

weak= fewer neurons firing more slowly. strong= more neurons firing quickly

Question 21

What happens after neurotransmitters enter the receptor

Answer 21

1. one of two things happen: excitatory reaction (neurons fire) or inhibitory reaction (neurons do not fire). 2. The cell body creates more neurotransmitters. 3. The unused ones can be broken down & taken back in axon terminals, or reuptake.

Question 22

Reuptake

Answer 22

unused neurotransmitters are taken back into axon terminals AS IS to be used IMMEDIATELY.