Nervous System

Question 1

What is the nervous system composed of

Answer 1

Nerve cells called neurons

Question 2

What do a bunch of neurons form

Answer 2

A nerve

Question 3

What is the central nervous system

Answer 3

System that includes the spinal cord and brain

Question 4

What is the peripheral nervous system

Answer 4

The system that contains the rest of the body besides the brain and spine

Question 5

What is the somatic nervous system

Answer 5

The nerves under conscious control (voluntary)

Question 6

What is the Autonomic nervous system

Answer 6

Nervous system thats not under conscious control

(Involuntary)

Question 7

What is sensory input

Answer 7

The conduction of electrical signals from sensory receptors

Question 8

What is integration

Answer 8

When information is interpreted and a response is generated by the central nervous system

Question 9

What is motor output

Answer 9

When signals from the CNS are conducted to effector cells like muscle, gland, organ which carry out the response

Question 10

What are the two main types of nerves in the nervous system

Answer 10

Neurons and neuroglia

Question 11

What does a neuron do

Answer 11

Transmits messages in the form of nerve impulses

Question 12

Where are neurons found

Answer 12

All throughout the bodies nervous system (PNS and CNS)

Question 13

What do neuroglia do

Answer 13

They are supporting cells, provides structure, protection, insulation, and nourishment to neurons

Question 14

What is a dendrite/function

Answer 14

A part of a neuron that receives signals and conducts an impulse towards the cell body

Is usually the branches

Question 15

What is the cell body/function

Answer 15

A part of a neuron that contains a nucleus and organelles

It maintains the cell

Question 16

What is the axon/function

Answer 16

A part of the neuron that conducts impulses away from the cell body

Question 17

What are dendrites and axons also called

Answer 17

Fibers

Question 18

What are longer fibers covered by

Answer 18

A myelin sheath

Question 19

What are the spaces within myelin sheaths called

Answer 19

Nodes of ranvier

Question 20

What is the myelin sheath in the PNS composed of

Answer 20

Schwann cells (a neuroglia cell)

Question 21

What is the myelin sheath produced by in the CNS

Answer 21

Cells called oligodendrocytes

Question 22

What are the myelin sheaths functions

Answer 22

To insulate the neurons from each other as they pass through the nerve

Helps to speed up the impulse

Also plays an important role in nerve regeneration

And if a nerve is severed it may remain as a passageway for new nerve growth

Question 23

Where does nerve regeneration not occur

Answer 23

The CNS

Question 24

What are nodes of ranvier

Answer 24

The points between schwann cells/ gaps where there is no myelin sheath

Question 25

What does the node of ranvier do

Answer 25

Speeds the impulse as it jumps from node to node

Question 26

What are the three types of neurons

Answer 26

Sensory neuron Motor neuron Interneuron

Question 27

What does the sensory neuron do

Answer 27

Takes a message from a sense organ to the brain

Question 28

What is the sensory neuron made of and where is it found

Answer 28

A long dendrite and a short axon (CNS)

Question 29

What does a motor neuron do

Answer 29

Takes a message away from CNS to a muscle fiber or gland

Question 30

What us a motor neuron made of

Answer 30

Short dendrites and a long axon

Question 31

What does an interneuron do

Answer 31

Conveys messages between the parts of the system Conducts impulses from sensory to motor neuron and will sum up all messages before communicating with motor neurons

Question 32

What is the interneuron made of and where is it

Answer 32

Its completely in the CNS and is made of dendrites and axons that are both long and short

Question 33

What are nerve bundles

Answer 33

A bundle if long fibers from neurons in the PNS

Question 34

When does an action potential occur

Answer 34

When a nerve is stimulated by an electric shock, pH change, or mechanical stimulation

Question 35

What does an action potential do

Answer 35

Generates a nerve impulse

Question 36

What are nerve impulses

Answer 36

They are electrical chemical changes Changes in voltage and changes in an ion that make a membrane potential difference

Question 37

What are nerve impulses measured in

Answer 37

Millivolts (mV)

Question 38

What are the three phases in the generation of a nerve impulse

Answer 38

Resting phase Action phase: depolarization and repolarization Recovery phase

Question 39

What is the concentration of ions in resting potential

Answer 39

Na+ ions are more concentrated on the outside and K+ more concentrated on the inside

Question 40

How is the uneven distribution of ions maintained

Answer 40

Through active transport across Na+/K+ pumps

Question 41

What are the charges of the inside/outside of neurons at rest

Answer 41

The outside is slightly more positive compared to the inside of the neuron

Question 42

What voltage is resting potential

Answer 42

-70mV (voltage inside is -70mV compared to outside)

Question 43

What is the negative polarity at resting potential caused by

Answer 43

The presence of large organic negative ions inside the axoplasm

Question 44

What is axoplasm

Answer 44

The cytoplasm inside an axon

Question 45

Where are there more Na+/K+ ions at rest

Answer 45

More Na+ outside of the axon More K+ inside of the axon

Question 46

What is action potential

Answer 46

It is when a nerve is stimulated, a nerve impulse is generated and the rapid change in voltage can be detected This nerve impulse is action potential

Question 47

Why is action potential all or nothing

Answer 47

Because an action potential only occurs if a stimulus causes the axonal membrane to depolarize to a certain level (Has to hit a threshold to happen and wont stop once it does)

Question 48

What happens to action potential if an intense stimulus is given

Answer 48

The axon will fire more often instead of stronger firing since the strength of action potential does not change

Question 49

What are the two parts to action potential

Answer 49

Depolarization and repolarization

Question 50

What happens when the membrane depolarizes

Answer 50

Na+ ions move from the outside to the inside of an axon The sodium gates open first when an action potential occurs hence Na+ flows into the axon

Question 51

What happens when the membrane repolarizes

Answer 51

K+ moves from outside to inside of axon Potassium gates open second so K+ flows outside the axon

Question 52

What is the recovery phase

Answer 52

When K+ ions are returned to the inside of axon and Na+ to the outside actively by the Na+/K+ pump With the use of ATP Done slowly

Question 53

What color are nerves

Answer 53

They have a white appearance

Question 54

Along a myelin sheath why can action potential only occur at nodes of ranvier

Answer 54

Because the myelin sheath insulates against ion loss

Question 55

What is a synapse

Answer 55

The region between end of an axon and the cell body or dendrite to which it is attached

Question 56

What are synaptic endings

Answer 56

The knobs on the ends of an axon

Question 57

What is a presynaptic membrane

Answer 57

The membrane if the axon synaptic ending (before the synapse)

Question 58

What is a postsynaptic membrane

Answer 58

The membrane of the next neuron after the synapse

Question 59

What is the synaptic cleft

Answer 59

The space between the presynaptic and the postsynaptic membranes

Question 60

What are neurotransmitters

Answer 60

The chemicals that transmit the nerve impulses across a synaptic cleft

Question 61

What are synaptic vesicles

Answer 61

Objects that contain the neurotransmitters

Question 62

What are the 4 important neurotransmitters

Answer 62

Acetylcholine, noradrenalin, serotonin, and adrenalin