Nervous System

Question 1

neurons

Answer 1

specialized cells capable of transmitting electrical impulses

Question 2

soma

Answer 2

cell body of a neuron, where nucleus is located

Question 3

dendrites

Answer 3

receive incoming messages from other cells

Question 4

axon hillock

Answer 4

integrates the incoming signals from the dendrites, plays an important role in action potentials (transmission of electrical impulses down the axon)

Question 5

axon

Answer 5

long appendage that terminates in close proximity to a target structure (muscle, gland, another neuron)

Axons carry it Away from the soma

Question 6

What produces myelin in the CNS?

Answer 6

Oligodendrocytes

Question 7

What produces myelin in the PNS?

Answer 7

Schwann cells

Question 8

Breaks in myelin sheath are called?

Answer 8

nodes of Ranvier

Question 9

At the end of the axon it is called the?

Answer 9

Nerve terminal/synaptic bouton (knob)

Question 10

Neurotransmitters

Answer 10

chemicals that transmit information between neurons

Question 11

Space between terminal portion of the axon and dendrites of the adjacent neuron

Answer 11

synaptic cleft

Question 12

Nerve terminal, synaptic cleft, and postsynaptic membrane are known as the…?

Answer 12

Synapse

Question 13

Types of nerves in the PNS

Answer 13

Sensory, motor, or mixed–> refers to the type of information they carry

Question 14

Axons can be bundled together to form?

Answer 14

tracts

only carry one type of information

Question 15

Cell bodies of neurons in the same tract are grouped together to form?

Answer 15

Nuclei

Question 16

Glial cells/neuroglia

Answer 16

cells in the nervous system that play structural and supportive roles

ex. astrocytes, ependymal cells, microglia, oligodendrocytes (CNS) and Schwann cells (PNS)

Question 17

Astrocytes

Answer 17

nourish neurons and form the blood brain barrier, which controls the transmission of solutes from the bloodstream into nervous tissue

Question 18

Ependymal cells

Answer 18

line the ventricles of the brain and produce cerebrospinal fluid, which physically supports the brain and serves as a shock absorber

Question 19

Microglia

Answer 19

phagocytic cells that ingest and break down waste products and pathogens in the central nervous system

Question 20

What is all or nothing?

Answer 20

An action potential!

Question 21

What is a cell’s resting membrane potential?

Answer 21

-70 mV

Potassium (K+) and sodium (Na+) help maintain the resting potential

Question 22

Potassium leak channels

Answer 22

allows the slow leak of potassium out of the cell

Question 23

Sodium leak channels

Answer 23

Slow leak of sodium into the cell

Question 24

Na+/K+ ATPase

Answer 24

continually pumps sodium and potassium back to where they started: potassium into the cell and sodium out of the cell

Question 25

Depolarization

Answer 25

raises the membrane potential, caused by excitatory input if it hits its threshold value, will trigger an action potential

Question 26

Hyperpolarization

Answer 26

lowering the membrane potential from its resting potential

Question 27

summation

Answer 27

additive effect of multiple signals

Question 28

Temporal summation

Answer 28

multiple signals are integrated during a relatively short period of time

Question 29

Spatial summation

Answer 29

the additive effects are based on the number and location of the incoming signals

Question 30

How does action potential occur

Answer 30

it's at -70 mV, there's a Na+ influx that raises the membrane potential to about 35 mV, then there is a K+ efflux that lowers the membrane potential to back to -70 mV, with the Na+/K+ pump helping to re-stabilize from the hyperpolarization

Question 31

Electrochemical gradient

Answer 31

promotes the migration of sodium into the cell

Question 32

3 states of sodium channels?

Answer 32

1. Closed-> before the cell reaches threshold and after inactivation has been reversed 2. Open --> from threshold to about 35 mV 3. Inactive --> from approximately +35 mV to the resting potential

Question 33

absolute refractory period

Answer 33

no amount of stimulation can cause another action potential to occur

Question 34

relative refractory period

Answer 34

there must be a greater than normal stimulation to cause an action potential to occur, bc the membrane is starting from a potential that is more negative than its resting value

Question 35

Impulse propagation

Answer 35

Action potential travels down the axon and initiates neurotransmitter release

Question 36

Saltatory conduction

Answer 36

the signal hoping from node to node

Question 37

effector

Answer 37

if a neuron signals to a gland or muscle, rather than another neuron

Question 38

acetylcholine

Answer 38

a neurotransmitter that is broken down by acetylcholinesterase; responsible for parasympathetic response in the body (we don't want constant signaling to a postsynaptic cleft)

Question 39

reuptake carriers

Answer 39

a way in which neurotransmitters can be brought back into the presynaptic neuron ex. serotonin, dopamine, and norepinephrine can all go back this way

Question 40

Nitric oxide

Answer 40

a signaling molecule that diffuses out of the synaptic cleft

Question 41

supraspinal circuit

Answer 41

when input from the brain or brainstem is needed to process a stimuli

Question 42

grey matter

Answer 42

consists of unmyelinated cell bodies and dendrites

Question 43

Sections of the spinal cord?

Answer 43

Cervical, thoracic, lumbar, sacral It is protected by the vertebral column, transmits nerves at the space between the adjacent vertebrae

Question 44

Dorsal root ganglia

Answer 44

cell bodies of sensory neurons are found in the dorsal root ganglia

Question 45

somatic nervous system

Answer 45

consists of sensory and motor neurons distributed throughout the skin, joints, and muscles. Sensory neurons transmit information through afferent fibers

Question 46

autonomic nervous system

Answer 46

regulates heartbeat, respiration, digestion, and glandular secretions

Question 47

first neuron in the autonomic nervous system is called the...?

Answer 47

preganglionic neuron

Question 48

second neuron in the autonomic nervous system is called the...?

Answer 48

postganglionic neuron

Question 49

parasympathetic nervous system

Answer 49

conserves energy, rest and digest constricts pupils, stimulates flow of saliva, constricts bronchi, slows heartbeat, stimulates peristalsis and secretion, stimulates bile release, contracts bladder

Question 50

functions of the sympathetic nervous system

Answer 50

fight or flight dilates pupils, inhibits salivation, relaxes bronchi, accelerates heartbeat, stimulates sweating or piloerection, inhibits peristalsis and secretion, stimulates glucose production and release, secretion of adrenaline and noradrenaline, inhibits bladder contraction, stimulates orgasm

Question 51

monosynaptic reflex arc

Answer 51

there is a single synapse between the sensory neuron that receives the stimulus and the motor neuron that responds to it ex. knee-jerk reflex

Question 52

polysynaptic reflex arc

Answer 52

there is at least one interneuron between the sensory and motor neurons ex. withdrawal reflex (step on a nail), interneurons in the spinal cord provide the connections from incoming sensory information to the motor neurons in the supporting limb