NEURAL AND HORMONAL SYSTEMS MODULE 3

Question 1

Neuron

Answer 1

a nerve cell, the basic building block of the nervous system

new neurons are born and unused neurons wither away

Question 2

cell body

Answer 2

the part of the neuron that contains the nucleus; the cell’s life support center

Question 3

axon

Answer 3

the neuron extension that passes messages through its branches to other neurons or to muscles or glands

Question 4

dendrites

Answer 4

a neuron’s bushy, branch-like extensions that receive and integrate messages, conducting impulses toward the cell body

Question 5

Myelin sheath

Answer 5

fatty tissue layer that covers the axons of neurons; speeds up transmission

• if the myelin sheath degenerates MS
• communication to muscles slows and loss of muscle control occurs

Question 6

Glial cells

Answer 6

cells that support, nourish, and protect neurons; may also play a role in learning, thinking, and memory
-if neurons are the queen bee, glial cells are the worker bees

Question 7

Action potential

Answer 7

a brief electrical charge that travels down an axon; a neural impulse
-which is faster- your brain or a computer?

Question 8

excitatory

Answer 8

increases a signal; the gas pedal

Question 9

inhibitory

Answer 9

decreases a signal; the brake pedal

Question 10

Threshold

Answer 10

the level of stimulation required to trigger a neural impulse

Question 11

refractory period

Answer 11

a brief resting pause that occurs after a neuron has fired; no actions can occur until the axon returns to its normal state
neurons needs breaks

Question 12

All-or-none response

Answer 12

a neuron’s reaction of either firing (with a full strength response) or not at all
-increasing stimulation does not increase neural intensity (a gun doesn’t fire harder or faster just because you squeeze the trigger harder)

-intensity of stimulus is determined by number of neurons triggered

Question 13

Synapse

Answer 13

the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron; tiny gap at this junction is called the synaptic gap

Question 14

Neurotransmitters

Answer 14

chemical messengers

• neurotransmitters will cross the synaptic gap and fit into receptor sites like a key in a lock
• they will either excite or inhibit the neuron’s readiness to fire
• excess neurotransmitters are broken down by enzymes or reabsorbed by the sending neuron (reuptake)
• SSRIs

Question 15

Agonist

Answer 15

a molecule that increases a neurotransmitter’s action

opioids (mimics endorphin- pain reduction/ euphoria)

Question 16

Antagonist

Answer 16

a molecule that inhibits or blocks a neurotransmitter’s action
botox (blocks Ach-paralyzes fascial muscles)

Question 17

Nervous system

Answer 17

the body’s speedy electrochemical communication network, consisting of all of the nerve cells of the peripheral nervous system (PNS) and the central nervous system (CNS)

Question 18

Central nervous system (CNS):

Answer 18

the brain and spinal cord; decision maker

Question 19

Peripheral nervous system (PNS):

Answer 19

the sensory and motor neurons that connect the CNS to the rest of the body; gatherer and transmitter

Question 20

Nerves

Answer 20

bundled axons that form neural cables connecting the CNS with muscles, glands, and sense organs

Question 21

Sensory neurons

Answer 21

neurons that carry incoming information from the body’s tissues and sensory receptors to the brain/ spinal cord;
smell

Question 22

Motor neurons

Answer 22

neurons that carry outgoing information from the brain/ spinal cord to the muscles and glands
turning a steering wheel

Question 23

Interneurons

Answer 23

neurons within the brain/ spinal cord; communicate internally and process information between the sensory inputs and motor outputs
-this is where most of the complexity lies
billions and billions of interneurons exist (compared to millions of sensory and motor)

Question 24

Somatic nervous system

Answer 24

controls the body’s skeletal muscles; also called the skeletal nervous system

Question 25

Autonomic nervous system (ANS):

Answer 25

controls the glands and muscles of the internal organs (such as the heart, lungs, digestions); automatic; has 2 divisions: sympathetic and parasympathetic

Question 26

sympathetic nervous system

Answer 26

arouses and expends energy

Question 27

parasympathetic nervous system

Answer 27

calms and conserves energy

Question 28

Spinal cord

Answer 28

a two-way information highway connecting the PNS and the brain

Question 29

reflex

Answer 29

a simple, automatic response to a sensory stimulus; knee-jerk response; touching a hot stove

Question 30

Endocrine system

Answer 30

the body’s “slow” chemical communication system; a set of glands that secrete hormones into the bloodstream

Question 31

Hormones

Answer 31

chemical messengers that are made by the endocrine glands that travel through the blood and affect other tissues

Question 32

Fight or flight

Answer 32

the ANS tells the adrenals glands to secrete epinephrine/ norepinephrine

Question 33

adrenal glands

Answer 33

a pair of endocrine glands that sit just above the kidneys

effects can linger long after threat is gone

Question 34

Pituitary gland

Answer 34

the master gland; pea sized; located in the core of the brain, controlled by the hypothalamus
directs other glands to release their hormones