Mod3-Obj3+4: Neuron, nucleus, ganglion, tract and nerve

Question 1

Neural tissue mostly consists of two cell types

Answer 1

• Neuroglia

- Neurons (nerve cells)

Question 2

Neuroglia

Answer 2

1. ) Support neuron development and function

2. ) Six different types of cells which collectively nourish, protect, insulate and structurally support neurons

Question 3

PNS

Answer 3

• Satellite cells

- Schwann cells

Question 4

CNS

Answer 4

• Ependymal cells
• Astrocytes
• Microglia
• Oligodenrocytes

Question 5

Neurons

Answer 5

Are specialised for communication

-They are excitable (they can change their resting membrane potential)

Question 6

When neurons are stimulates they…

Answer 6

• Convert the stimulus information into an electrical signal
• Rapidly conduct this signal from one part of the body to another

Question 7

Neurons have…

Answer 7

• Longevity
• Both oxygen and glucose requiring
• Are unable to divide and replace themselves if destroyed

Question 8

Structural components of a neuron

Answer 8

Vary in size, shape, length, however most have 4 common parts

1. ) Dendrites
2. ) Cell body
3. ) Axon
4. ) Axon terminals

Question 9

Dendrites

Answer 9

Short processes that extend from the cell body

• Are the main receptive or input regions of a neuron
• Convey signals to the neuron cell body

Question 10

Dendrites act as sensory receptors…

Answer 10

• Detect stimuli and convert the stimulus information into an generate electrical signals (Graded potentials)
• Receive information (signals) from other neurons

Question 11

Cell body

Answer 11

Control centre of the cell

• Contains a nucleus and organelles e.g.) ribosomes to synthesise chemical reactions
• Integrates incoming signals and conveys outgoing decisions/signals towards the axon

Question 12

Cell body-receptive region

Answer 12

Can receive signals from other neurons

Question 13

A cluster of cell bodies within the PNS forms a ganglion (ganglia) and in the CNS is a nucleus (nuclei)

Answer 13

Functional integration centres that process and interpret sensory input, make decisions and generate motor output

Question 14

Axon (fiber)

Answer 14

Originates from the axon hillock of the cell body

• Is the conducting region of a neuron
• Generates signals at the initial segment (action potential) and conducts these signals to the axon terminal

Question 15

Bundles of axons form:

Answer 15

• Spinal and cranial nerves (in PNS): which relay information to and/or from the CNS
• Tracts (in CNS): relay information through the CNS

Question 16

The axon may be covered with a segmented…

Answer 16

Myelin sheath

Question 17

Myelin

Answer 17

Produced by Schwann cells (PNS) and oligodendrocytes (CNS)

• Protects and electrically insulates the axon
• Increases the speed of signal conduction

Question 18

Segments of the myelin are separated by gaps called…

Answer 18

Nodes of Ranvier (internodes)

Question 19

Destruction of myelin (oligodendrocytes) in the CNS can lead to

Answer 19

Multiple sclerosis

Question 20

Axon terminals

Answer 20

Form a synapse (junction) with another cell = neuron, muscle or gland

Question 21

Axon terminals are the secretory region of a neuron and…

Answer 21

Store and release neurotransmitters: Chemicals that pass the signal onto another cell

Question 22

Dendrites down a neuron

Answer 22

Receives and conveys information, in the form of an electrical signal (graded potential), towards the cell body

Question 23

Cell body down a neuron

Answer 23

Combines or integrates incoming signals and conveys them to the axon

Question 24

Axon down a neuron

Answer 24

Conducts signal (action potentials) away from the cell body, towards the axon terminals

Question 25

Myelin sheath down a neuron

Answer 25

Increases speed of signal conduction

Question 26

Axon terminals

Answer 26

Transmits the signal to another neuron, a muscle or gland