Chapter 10

Question 1

Describe the anatomical and functional divisions of the nervous system

Answer 1

CNS consists of brain and spinal cord

PNS consists of peripheral nerves connecting CNS to other parts of body

ANS controls involuntary effectors

Somatic nervous system controls consciously controlled movements

Question 2

What forms the anatomical divisions of nervous system

Answer 2

CNS

PNS

Question 3

What forms the functional divisions of the nervous system

Answer 3

Somatic nervous system

ANS

Question 4

List the basic functions of the nervous system

Answer 4

Sensory receptors at end of peripheral Neurons provide nervous systems sensory functions

Sensory receptors relay info in response to environmental changes

Information converted to nerve impulses

Impulses processed so motor functions can act appropriately

Effectors (o/s nervous system) are response structures

Effectors include: contractile muscle/glands that secrete and perform other reactive functions

SNS controls conscious motor functions & skeletal muscles

ANS controls involuntary effectors: heart, smooth muscle in BVs and certain glands

Maintains homeostasis

Question 5

List the important structural components of a neuron

Answer 5

Neurons have rounded cell body (soma) with extensions. Dendrites and axons

Neurons have 1 axon which arises from atonal hillock on cell body

Some Neurons have short or no axons

In others, axon makes up entire neuron length

Neurons are larger than other cells in nervous system because they are highly specialised In conduction Of impulses

Similar in structure but vary in size

Dendrites have multiple branches and Are tapered/short and have diffusely branched extensions

Question 6

Define the neuron

Answer 6

Structural and functional units of nervous system

Question 7

What do the multiple branches of dendrites make up

Answer 7

Main receptive surfaces

Question 8

Describe synapses and synaptic transmission

Answer 8

Happens in 1 direction and carried by biochemicals (neurotransmitters)

When impulse reaches synaptic knob synaptic vesicle releases neurotransmitter

Diffuses across cleft to react with certain receptors on post synaptic neuron membrane either exciting or inhibiting a post synaptic cell

This depends on the combined effect of excitatory and inhibitory inputs from presynaptic Neurons

Question 9

What do chemical synapses allow

Answer 9

Release and reception of chemical neurotransmitters

Question 10

What is a chemical synapse more common than.

What is it made up of

Answer 10

Electrical synapses

Axon terminal

Neurotransmitter receptor region

Question 11

What does axon terminal contain and what is this made up of

Answer 11

Synaptic vesicles

Small membrane bounded sacs holding thousands of neurotransmitter molecules

Question 12

Where is the neurotransmitter receptor region located

Answer 12

Post synaptic Neurons membrane

On cell body or dendrite

Question 13

What is the synaptic cleft

Answer 13

Fluid filled space separating presynaptic/postsynaptic membranes

Question 14

What size is the cleft

Answer 14

1 millionth of 1 inch wide

Question 15

What dissipates in each synaptic cleft

Answer 15

Electrical current from presynaptic membrane

Question 16

Due to dissipation of electrical current what happens

And what happens instead

Answer 16

Chemical synapses prevent nerve impulses being directly transmitted between Neurons

Instead they’re transmitted through chemical events based on release, diffusion and receptor building of neurotransmitter molecules

Question 17

Neurons have what type of communication between them

Answer 17

Unidirectional

Question 18

List the major types of neurotransmitters

Answer 18

Acetylcholine

AAs (GABA and glutamic)

Monoamines (dopamine, histamine, norepinephrine, serotonin)

Neuropeptides (endorphins, enkephalins, substance P, gases nitric oxide)

Question 19

Define action potential

Answer 19

Basis for nerve impulse

Based on cell membrane reaching threshold potential

Is a brief reversal of membrane potential with a change in voltage of 100Mv

Question 20

Explain classifications of nerve fibres

Answer 20

Classified by
Diameter
Degree of myelination
Speed of conduction

Group A: serve joints, skeletal muscle, skin. Are somatic sensory and motor fibres.
Largest diameter of all fibre types and thick myelin sheaths.
Conduct impulses <300mph

Group B: intermediate diameter
Light myelination
Impulses conducted <20mph

Group C: non myelinated
Smallest diameter
Can’t create saltatory conduction
Conduct impulses <2mph

Question 21

What Neurons can be replaced and what are the ones that can’t be replaced known as

Answer 21

Olfactory epithelium Of nose and regions of hippocampus in brain (memory)

Amitotic losing ability to divide

Question 22

What do Neurons require and why

Answer 22

O2 and glucose due to high metabolic rate

Question 23

What happens without o2

Answer 23

Neurons don’t last more than a few mins

Question 24

Where does biosynthesis occur in the neuron

Answer 24

Cell body (soma)

Question 25

What part of the neuron contains process and what part contains cell bodies and processes

Answer 25

Processes: PNS

Cell bodies and processes: CNS

Question 26

What is the dendrite portion of the neuron

Answer 26

Primary receptive surface (input region) with large surface area for neural signals