Lecture 2: Nervous System 1 cont, 2, and 3

Question 1

Two major efferent systems:

Answer 1

Somatic Nervous System

Autonomic Nervous System

Question 2

The SNS innervates _____ _____, which is under ______ control.

Answer 2

skeletal muscle

voluntary

Question 3

Cell bodies of the SNS lie in

Answer 3

the CNS

Question 4

SNS axons extend

Answer 4

into the periphery to innervate one or more neuromuscular junctions

Question 5

The ANS is under ______ control and innervates

Answer 5

involuntary

all peripheral effectors that is not skeletal muscle

Question 6

Axons of ANS motor neurons inside the CNS synapse where?

Answer 6

On neurons in the peripheral autonomic (motor) ganglia

Question 7

Ganglionic neurons of the ANS control

Answer 7

peripheral effectors

Question 8

Preganglionic fibers

Answer 8

Part of the ANS

Axons that extend from the CNS to a ganglion

Question 9

Postganglionic fibers

Answer 9

Part of ANS

Axons connecting ganglionic cells with the peripheral effectors

Question 10

The basic structural unit of the nervous system is the

Answer 10

Neuron

Question 11

Three parts of a neuron

Answer 11

• Cell body
• Dendrites
• Axon

Question 12

Cell bodies

Answer 12

• Contains the nucleus and other organelles

- Serves as the nutritional center of the neuron

Question 13

Dendrites

Answer 13

Cytoplasmic extensions that receive stimuli and conduct impulses to the cell body

Question 14

Axon (nerve fiber)

Answer 14

Conducts impulses away from the cell body

Question 15

Axon arises from

Answer 15

a thickened region of the cell body called the axon hillock

Question 16

Action potentials first appear

Answer 16

at the initial segment of the axon

Question 17

Collaterals

Answer 17

Branches along the length of the axon

Question 18

Collaterals enable a single neuron to

Answer 18

communicate with several other cells

Question 19

The main axon trunk and collaterals end in

Answer 19

fine extensions called telodendria

Question 20

Synaptic knobs (terminal button)

Answer 20

Located at the tips of the telodendria, they form synaptic connections with other cells

Question 21

Communication between cells at synapse most often involves the release of ______ by the ______ _____

Answer 21

neurotransmitters

Synaptic knob

Question 22

Motor end plate

Answer 22

specialized portion of the muscle cell membrane immediately under the synaptic knob

Question 23

Four functional segments of the neuron

Answer 23

1. Receptive segment
2. Initial segment
3. Conduction segment
4. Transmissive (Effector) segment

Question 24

Receptive segment of neuron

Answer 24

• Receives and processes synaptic inputs from numerous other neurons.
• Resolutions of these processes will be passed on to the next segment only if it is sufficiently stimulated

Question 25

Initial segment of neuron

Answer 25

The trigger zone of the neuron, where processed neural information from the receptive segment is converted to a nerve impulse (action potential).

Question 26

The initial segment of a neuron has a _____ threshold because it has many _____ channels

Answer 26

low

sodium

Question 27

Conduction segment of neuron

Answer 27

Conveys the results of neural processing of receptive segment via nerve impulses to the terminal segment

Question 28

Transmissive (Effector) segment of neuron

Answer 28

Contains axon terminals that convert the stimulation of the nerve impulse to release chemical neurotransmitters at its synapses, which exert influences upon receptor sites of an effector cell

Question 29

The two types of transport systems that carry materials from the cell body to the axon terminals and back:

Answer 29

Slow axonal transport (axoplasmic flow)

Fast axonal transport

Question 30

Slow axonal transport is a ____-way transport away from cell body

Answer 30

one

Question 31

How fast is slow axonal transport?

Answer 31

moves 1-5mm/day

Question 32

Bulk of the movement in slow axonal transport is in

Answer 32

the axoplasm

Question 33

Slow axonal transport is accompanied by

Answer 33

peristaltic waves of the axon membrane

Question 34

Purpose of slow axonal transport

Answer 34

to supply materials necessary to maintain axons and dendrites.

Question 35

Does slow axonal transport require ATP?

Answer 35

Yes

Question 36

Fast axonal transport speed

Answer 36

400-2000 mm/day

Question 37

What does fast axonal transport move?

Answer 37

Varies organelles and materials that form the membranes of the axolemma, synaptic bulbs, and synaptic vessels away from the cell bodies.
Also transports acetylcholinesterase

Question 38

Does fast axonal transport require ATP?

Answer 38

Yes

Question 39

Kinesin

Answer 39

transport protein for moving material along microtubules, from the cell body to the axonal terminal (anterograde transport)

Question 40

Retrograde flow

Answer 40

When cells are returned to the cell body to be recycled or degraded

Question 41

When can retrograde flow be detrimental?

Answer 41

It can carry the rabies virus and the tetanus toxin into the CNS, producing potentially fatal results

Question 42

Transport protein for retrograde flow?

Answer 42

dynein

Question 43

What is the membrane potential and what is it measured in?

Answer 43

The separation of charges across a membrane.

Measured in millivolts (mV)

Question 44

Resting membrane potential

Answer 44

potential for electrical activity along the plasma membrane of a resting neuron

Question 45

What two major factors contribute to the resting membrane potential?

Answer 45

• The distribution of ions across a membrane

- The relative permeability of the membrane to Na- and K+

Question 46

In a resting neuron, the membrane permeability to __ is about 50 to 100 times greater than it is to __

Answer 46

K

Na