Chapter 3 Section 1

Question 1

nervous system

Answer 1

a collection of hundreds of billions of specialized and interconnected cells through which messages are sent between the brain and the rest of the body.

Question 2

central nervous system

Answer 2

made up of the brain and the spinal cord

Question 3

peripheral nervous system

Answer 3

the neurons that link the CNS to our skin, muscles, and glands

Question 4

endrocrine system

Answer 4

the chemical regulator of the body that consists of glands that secrete hormones

Question 5

neuron

Answer 5

a cell in the central nervous system whose function it is to receive and transmit information

Question 6

soma

Answer 6

contains the nucleus of the cell and keeps the cell alive

Question 7

dendrite

Answer 7

collects information from other cells and sends the information to the soma;

Question 8

axon

Answer 8

transmits information away from the cell body toward other neurons or to the muscles and glands. end of an axon has a “terminal button”

Question 9

myelin sheath

Answer 9

a layer of fatty tissue surrounding the axon of a neuron that both acts as an insulator and allows faster transmission of the electrical signal

Question 10

neuron signaling

Answer 10

electrochemical signaling. electric charge moves through the neuron. chemicals between neurons. signal retrieved by dendrites, passed as electrical to soma, then onto axon and terminal buttons. release neurotransmitters (chemicals that cross synapses)

Question 11

synapses

Answer 11

space between terminal button of one neuron and dendrites of others. ingenious system because it lets one axon comm with hundreds of dendrites

Question 12

resting potential

Answer 12

a state in which the interior of the neuron contains a greater number of negatively charged ions than does the area outside the cell

Question 13

neurotransmitter

Answer 13

a chemical that relays signals across the synapses between neurons. lock and key of sender and receiver.

Question 14

excitatory or inhibitory

Answer 14

traits of neurotransmitter; making cell more or less likely to fire.

Question 15

action potential

Answer 15

change in electrical charge that occurs in a neuron when a nerve impulse is transmitted. operates in “all-or-nothing” manner:

Question 16

nodes of ranvier

Answer 16

breaks sausage-like sections of myelin sheath on axon. divides segments as electrical signals travel down the line.

Question 17

refractory period

Answer 17

brief time after firing of the axon in which the axon cannot fire again because neuron has not yet returned to its resting potential

Question 18

reuptake

Answer 18

when neurotransmitters that are in the synapse are reabsorbed by the terminal buttons, ready to be released again when neuron fires

Question 19

anagonist

Answer 19

a drug that has chemical properties similar to a particular neurotransmitter and thus mimics the effect of the neurotransmitter

Question 20

antagonist

Answer 20

a drug that reduces or stops the normal effect of a neurotransmitter. binds to dendrite receptor sites, blocking neurotransmitter

Question 21

Acetylcholine

Answer 21

A common neurotransmitter used in the spinal cord and motor neurons to stimulate muscle contractions. It’s also used in the brain to regulate memory, sleeping, and dreaming.

Alzheimer’s disease is associated with an undersupply of acetylcholine. Nicotine is an agonist that acts like acetylcholine.

Question 22

Dopamine

Answer 22

Involved in movement, motivation, and emotion, Dopamine produces feelings of pleasure when released by the brain’s reward system, and it‘s also involved in learning.

Schizophrenia is linked to increases in dopamine, whereas Parkinson’s disease is linked to reductions in dopamine (and dopamine agonists may be used to treat it).

Question 23

Endorphins

Answer 23

Released in response to behaviors such as vigorous exercise, orgasm, and eating spicy foods.

Endorphins are natural pain relievers. They are related to the compounds found in drugs such as opium, morphine, and heroin. The release of endorphins creates the runner’s high that is experienced after intense physical exertion.

Question 24

GABA (gamma- aminobutyric acid)

Answer 24

The major inhibitory neurotransmitter in the brain.

A lack of GABA can lead to involuntary motor actions, including tremors and seizures. Alcohol stimulates the release of GABA, which inhibits the nervous system and makes us feel drunk. Low levels of GABA can produce anxiety, and GABA agonists (tranquilizers) are used to reduce anxiety.

Question 25

Glutamate

Answer 25

The most common neurotransmitter, it’s released in more than 90% of the brain’s synapses. Glutamate is found in the food additive MSG (monosodium glutamate).

Excess glutamate can cause overstimulation, migraines and seizures.

Question 26

Serotonin

Answer 26

Involved in many functions, including mood, appetite, sleep, and aggression.

Low levels of serotonin are associated with depression, and some drugs designed to treat depression (known as selective serotonin reuptake inhibitors, or SSRIs) serve to prevent their reuptake.