Chapter 4 - Nervous System

Question 1

Neurons

Answer 1

Specialized cells capable of transmitting electrical impulses and then chemical signals

Question 2

Action Potentials

Answer 2

Transmission of electrical impulses down the axon

Question 3

Myelin sheath

Answer 3

Maintains electrical signal within one neuron
- Increases speed of conduction in axon

Question 4

Nodes of Ranvier

Answer 4

Small breaks in myelin sheath

Question 5

Nerve terminal/ Synaptic button

Answer 5

Maximize transmission of the signal to the next neuron and ensure proper release of neurotransmitters

Question 6

Synaptic Cleft

Answer 6

Small space into which the terminal portion of the axon releases neurotransmitters

Question 7

Synapse

Answer 7

Nerve terminal, synaptic cleft, and postsynaptic membrane

Question 8

Nerve

Answer 8

Multiple neurons bundled together in PNS

Question 9

Tracts

Answer 9

Axons bundled together in CNS

Question 10

Glial cells/Neuroglia

Answer 10

Structural and supportive cells

Question 11

Astrocytes

Answer 11

Nourish neurons and form blood-brain barrier

Question 12

Ependymal cells

Answer 12

Line ventricles of brain and produce cerebrospinal fluid

Question 13

Microglia

Answer 13

Phagocytic cells that ingest and break down waste products

Question 14

Oligodendrocytes/ Schwann cells

Answer 14

Produce myelin around axons

Question 15

Action Potential

Answer 15

All or nothing messages used to relay electrical impulses

Question 16

Resting membrane potential

Answer 16

Net electric potential difference that exists across the cell membrane, created by movement of charged molecules across that membrane

Question 17

Potassium leak channels

Answer 17

Allow slow leak of potassium out of cell

Question 18

Sodium leak channels

Answer 18

Sodium pushed into cell

Question 19

Na+/ K+ ATPase

Answer 19

Continually pumps sodium and potassium back to where they started: K+ into cell and Na+ out of cell

Question 20

Depolarization

Answer 20

Raising membrane potential, Vm, from resting potential
- Excitatory input
- More likely to fire action potential

Question 21

Hyperpolarization

Answer 21

Lowering membrane potential from resting potential
- Less likely to fire action potential

Question 22

Summation

Answer 22

Additive effect of multiple signals

Question 23

Temporal

Answer 23

Multiple signals integrated during short time period

Question 24

Spatial

Answer 24

Based on number and location of signals

Question 25

Closed sodium channel

Answer 25

Before threshold, after inactivation has been reversed

Question 26

Open sodium channel

Answer 26

threshold to ~ +35 mV

Question 27

Inactive sodium channel

Answer 27

~ + 35 mV to resting potential

Question 28

Repolarization

Answer 28

Restoration of resting membrane potential in neurons from being depolarized by both active and passive processes

Question 29

Absolute refractory period

Answer 29

No stimulation can cause another action potential

Question 30

Relative refractory period

Answer 30

Greater than normal stimulation to cause action potential

Question 31

Presynaptic neuron

Answer 31

Neuron preceding cleft

Question 32

Postsynaptic neuron

Answer 32

Neuron after cleft

Question 33

Effector

Answer 33

Neuron signals to gland or muscle

Question 34

Sensory (afferent) neurons

Answer 34

sensory info from receptors to brain and spinal cord

Question 35

Motor (efferent) neruon

Answer 35

Motor info from brain and spinal cord to muscles and glands

Question 36

Interneurons

Answer 36

Linked to reflexive behavior

Question 37

Central nervous system (CNS)

Answer 37

Brain and spinal cord

Question 38

White matter

Answer 38

Axons encased in myelin sheath

Question 39

Grey matter

Answer 39

Unmyelinated cell bodies and dendrites

Question 40

Peripheral nervous system (PNS)

Answer 40

Cranial and spinal nerves - 2 divisions

Question 41

Somatic nervous system

Answer 41

Sensory and motor neurons throughout skin, joints, and muscles

Question 42

Autonomic nervous system

Answer 42

Manages involuntary functions - 2 divisions

Question 43

Sympathetic nervous system

Answer 43

activated by stress; "fight or flight"

Question 44

Parasympathetic nervous system

Answer 44

conserve energy; "rest and digest"

Question 45

Monosynaptic reflex arc

Answer 45

Single synapse between the sensory neuron that receives stimulus and motor neuron that responds - knee jerk

Question 46

Polysynaptic reflex arc

Answer 46

at least 1 interneuron between the sensory and motor neurons - withdrawal r