Chapter 12: Nervous System

Question 1

3 nervous system functions

Answer 1

sensory receptors monitor changes inside and outside the body; processes and interprets sensory input; dictates a response by activating effector organs

Question 2

Central Nervous System (CNS)

Answer 2

brain and spinal cord; integration and command center

Question 3

Peripheral Nervous System (PNS)

Answer 3

nerves extending from brain and spinal cord; link all regions of body to CNS

Question 4

sensory

Answer 4

afferent signals picked up by sensory receptors; carried by nerve fibers of PNS to CNS

Question 5

motor

Answer 5

efferent signals carried away from the CNS; innervate muscles and glands

Question 6

somatic sensory

Answer 6

dectect touch, pain, pressure, hearing balance and proprioceptive senses (detect stretch in tendons and muscles)

Question 7

visceral sensory

Answer 7

stretch, pain, hunger, taste, and smell

Question 8

somatic motor

Answer 8

contraction of skeletal muscles; voluntary control

Question 9

visceral motor

Answer 9

regulates contraction of smooth and cardiac muscle; involuntary control

Question 10

neurons

Answer 10

excitable cell that transmits electrical signals

Question 11

neuroglia

Answer 11

nonexcitable support cells; surround and wrap neurons

Question 12

ganglia

Answer 12

clusters of cell bodies; lie along nerves in PNS

Question 13

special charcteristics of neuron

Answer 13

longevity(live and function for a lifetime); do not divide; high metabolic rate(require abundant oxygen and glucose

Question 14

dendrites

Answer 14

extensive branching from cell body; receptive sites

Question 15

axons

Answer 15

one per neuron; impulse generators and conductors; transmit impulses away from cell body

Question 16

neurotransmitters

Answer 16

excite or inhibit neurons; released from axon terminals

Question 17

presynaptic neuron

Answer 17

conducts signal toward a synapse

Question 18

postsynaptic neuron

Answer 18

transmits electrical activity away from a synapse

Question 19

multipolar

Answer 19

possess more than 2 processes

Question 20

bipolar

Answer 20

possess two processes

Question 21

unipolar

Answer 21

pseudounipolar; possess one short, single process

Question 22

astrocytes

Answer 22

most abundant glial cell type; extract blood sugar from capillaries; take up and release ions to control environment and neurons

Question 23

microglia

Answer 23

smallest and least abundant glial cell; phagocytes(macrophages of the CNS); derive from blood cells called monocytes

Question 24

ependymal cells

Answer 24

lines the central cavity of the spinal cord and brain

Question 25

oligodendrocytes

Answer 25

have fewer branches; wrap their cell processes around axons in CNS

Question 26

satellite cells

Answer 26

surround neuron cell bodies within ganglia

Question 27

schwann cells

Answer 27

neurolemmocytes; surround axons in the PNS

Question 28

oligodendrocytes

Answer 28

form the myelin sheaths in the brain and spinal cord (CNS)

Question 29

nerves

Answer 29

cablelike organs in the PNS

Question 30

endoneurium

Answer 30

layer of delicate loose connective tissues surrounding the axon

Question 31

perineurium

Answer 31

connective tissue wrapping that surround nerve fascicles

Question 32

nerve fascicles

Answer 32

groups of axons bound into bundles

Question 33

epineurium

Answer 33

whole nerve is surrounded by tough fibrous sheath

Question 34

neuron

Answer 34

nerve cell

Question 35

nerve fiber

Answer 35

long axon

Question 36

nerve

Answer 36

collection of axons in the PNS

Question 37

gray matter

Answer 37

gray-colored zone that surrounds hollow central cavities of the CNS; forms butterfly-shaped region in spinal cord; where synapses occur; contains cluster of neuron cell bodies

Question 38

white matter

Answer 38

external to gray matter; contains no neuron cell bodies; contains axons and neuroglia

Question 39

tracts

Answer 39

bundles of axons traveling to similar destinations

Question 40

reflex arcs

Answer 40

simple chains of neurons; determine structural plan of nervous system; responsible for reflexes

Question 41

5 components of reflex arc

Answer 41

receptor, sensory neuron, integration center, motor neuron, and effector

Question 42

monosynaptic reflex

Answer 42

simplest and fastest reflex; one synapse

Question 43

polysynaptic reflex

Answer 43

more common type of reflex; one or more interneurons involved; ex: withdrawal reflexes

Question 44

neuronal circuits

Answer 44

how interneurons of the CNS are interconnected in multiple ways

Question 45

diverging circuit

Answer 45

one presynaptic neuron synapses with several neurons ex: stretch reflex

Question 46

converging circuit

Answer 46

many neurons synapse on a single postsynaptic neuron

Question 47

reverberating circuit

Answer 47

one neuron in the circuit receives feedback from another neuron in the same circuit