Chapter12

Question 1

Central Nervous System

Answer 1

Brain and spinal cord of dorsal body cavity

Question 2

Peripheral Nervous system

Answer 2

Nerves that extend from brain and spinal corrd and also cranial nerves

Question 3

Somatic Sensory

Answer 3

Touch, pain, pressure, vibration, temperature, and proprioception in skin (hearing, equilibrium, vision)

Question 4

Visceral Sensory

Answer 4

Stretch pain, tem, chemical changes, and irritation in viscera, nausea and hunger (taste, smell)

Question 5

Somatic Nervous System

Answer 5

Motor innervation of all skeletal muscles (Motor (efferent) division)

Question 6

Autonomic nervious system

Answer 6

Motor innervation of smooth muscle, cardiac muscle, and glands (Motor (efferent) division)

Question 7

Neuroglia

Answer 7

Small cells that surround and wrap delicate neurons

Question 8

Neurons

Answer 8

Excitable cells that transmit electrical signals

Question 9

Astrocytes

Answer 9

Support neurons, capillary, and nueron exchange, guide migration, control chemical environment

Question 10

Microglial

Answer 10

Monitor neurons, migrate toward injured neurons, phagocytize microorganisms and neuronal debris

Question 11

Ependymal Cells

Answer 11

Line cavities to form permeable barrier between cerebrospinal fluid (CSF) in cavities and tissue fluid bathing CNS Cells

Question 12

Olidgodendrocytes

Answer 12

Processes wrap CNS Nerve fibers, forming insulating myelin sheaths

Question 13

Satellite cells

Answer 13

surround neuron cell bodies in PNS, function similar to astrocytes of CNS

Question 14

Schwann Cells

Answer 14

Surround PNS fibers and form myelin sheaths in thicker nerve fibers, regeneration of PNS fibers

Question 15

Tracts

Answer 15

Bundles of neuron processes in CNS

Question 16

Nerves

Answer 16

Bundles of neuron processes in PNS

Question 17

Dendrites

Answer 17

Short, tapering, diffusely branched processes, conveys incoming messages toward cell body as graded potential

Question 18

Anterograde

Answer 18

away from cell body (mitochondria, neurotransmitters)

Question 19

Retrograde

Answer 19

Toward cell body (organelles to be degraded, signal molecuels, viruses, and bacterial toxins)

Question 20

Myelin Sheath

Answer 20

Composed of myelin, a whitish, protein-lipid substance, protects and electrically insulates axon, increases speed of nerve impulses

Question 21

Nodes of Ranvier

Answer 21

Myelin sheath gaps between schwann cells

Question 22

White Matter

Answer 22

Regions of brain and spinal cord with myelinated fibers

Question 23

Gray Mater

Answer 23

Neuron cell bodies and nonmyelinated fibers

Question 24

multipolar

Answer 24

3 or more processes, 1 axon, other dendrites

Question 25

bipolar

Answer 25

2 processes, 1 axon and 1 dendrite (rare, retina and olfactory)

Question 26

Unipolar

Answer 26

1 short process, divides T-like, both branches considered axons

Question 27

Leakage Channels

Answer 27

Always open

Question 28

Gated

Answer 28

Part of protein changes shape to open/close channel

Question 29

Chemically gated (ligand-gated)

Answer 29

Channels: open with binding of a neurotransmitter

Question 30

Voltage-gated

Answer 30

Channels: open and close in response to changes in membrane potential

Question 31

Mechanically gated

Answer 31

Channels: open and close in response to physical deformation of receptors; sensory

Question 32

Gated Channels

Answer 32

When open, ions diffuse quickly across membrane along electrochemical gradients

Question 33

ECF

Answer 33

Higher concentration of NA+, balanced chiefly by chloride ions (Cl-)

Question 34

ICF

Answer 34

Higher concentration of K+, balanced by negative charged protein

Question 35

Na+ Channels Have 2 voltage-Sensitive gates

Answer 35

Activation Gates: closed at rest, open with depolarization; Inactivation Gates: open at rest; block channel once it is operational

Question 36

Threshold

Answer 36

For axon to fire, depolarization must reach threshold

Question 37

Axon Diameter

Answer 37

Larger diameter fibers = less resistance to current flow so faster

Question 38

Saltatory Conduction

Answer 38

30x faster, Voltage-gated Na+ channels are located at myelin sheath gaps. Electrical signal appears to jump rapidly from gap to gap

Question 39

Synapses

Answer 39

Junctions that mediate information transfer in neurons

Question 40

Presynaptic Neuron

Answer 40

Neuron conducting impulses toward synapse

Question 41

Postsynaptic Neuron

Answer 41

Neuron transmitting electrical signal away from synapse

Question 42

Electrical Synapses

Answer 42

Neurons electrically coupled by gap junctions. Communication very rapid, synchronized. Less common but more abundant in embryonic nervous tissue

Question 43

Synaptic Cleft

Answer 43

30-50 nm wide, prevents nerve impulses from directly passing from one neuron to next, unidirectional

Question 44

Summate

Answer 44

When Excitatory postsynaptic potential and Inhibitory postsynaptic potential together can influence a postsynaptic neuron

Question 45

Biogenic Amines

Answer 45

Broadly distributed in brain. Play roles in emotional behaviors and biological clock

Question 46

Acetylcholine (Ach)

Answer 46

Released at neuromuscular junctions and by some CNS and ANS neurons. Degraded by enzyme acetylcholinesterase

Question 47

Peptides: Substance P

Answer 47

Mediator of pain signals

Question 48

Peptides: Endorphins

Answer 48

Beta endorphin, dynorphin and enkephalins. Act as natural opiates; reduce pain perception

Question 49

Peptides: Gut-Brain peptides

Answer 49

Somatostatin and cholecystokinin

Question 50

Direct Action

Answer 50

neurotransmitter binds to and opens ion channels. Promotes rapid responses by altering membrane potential