Cells Week 4

Question 1

What is Golgi’s theory on the nervous system and how did he find this?

Answer 1

• Nervous system is composed of a network of interconnected fibres, a ‘nerve net’
• found this by immersing a brain slice in a solution containing silver nitrate

Question 2

What did Cajal use the Golgi stain to show and what hypothesis did this support?

Answer 2

• To show that the nervous system was made up of discrete cells
• Supporting neuron hypothesis

Question 3

What is Neurone theory?

Answer 3

• Neurons are the systems functional units
• Includes ideas that the interactions between neurone enables behaviour
• The more neurone there are the more complex and animal’s behaviour will be

Question 4

What are neurons specialised for?

Answer 4

Reception
Conduction
Transmission

Question 5

What are Glial cells for?

Answer 5

Support
Repair

Question 6

Role of Cell body

Answer 6

Contains nucleus

Question 7

Role of Dendrites

Answer 7

Collect info

Question 8

Role of Axon

Answer 8

Carries messages to other neurons

Question 9

Role of Dendritic spines + what is it

Answer 9

Greatly increases surface area
Point of contact with axons of other cells
Protrusion from a dendrite

Question 10

What is the Axon hilock and what occurs here?

Answer 10

Junction of the Soma + Axon
This is where the action potential begins

Question 11

What are axon collaterals?

Answer 11

Branches of an axon

Question 12

What is the Terminal button + its role + what can it also be called?

Answer 12

• Knob at the tip of an axon
• Conveys info to other neurons
• also called the end foot

Question 13

What are the two types of cells in the nervous system?

Answer 13

• Neurons
• Glial cells

Question 14

What is the synapse + where is it?

Answer 14

Gap between neurons
Between neurons, usually between endfoot + dendritic spine

Question 15

General summary of the flow of information through a neurone?

Answer 15

Synapse
Dendrite
Cell body
Axon
End foot
Synapse
Dendrite

Question 16

What are Nuclei?

Answer 16

Clusters of cell bodies in the CNS

Question 17

What are Ganglia?

Answer 17

Clusters of cell bodies in the PNS

Question 18

What are Tracts?

Answer 18

Bundles of axons in the CNS

Question 19

What are Nerves?

Answer 19

Bundles of axons in the PNS

Question 20

What do Sensory neurons do?

Answer 20

Bring info to the CNS

Question 21

What do interneurons do and what are they also known as?

Answer 21

Also known as association neurons
Associate sensory + motor activity within the central nervous system

Question 22

What do motor neurons do?

Answer 22

Send signals from the brain + spinal cord to muscles

Question 23

What is general rule about the correlation between cell bodies and extensions?

Answer 23

Large cell bodies = very long extensions
Small cell bodies = short extentions

Question 24

Efferent V. Afferent axons?

Answer 24

Efferent = Where signal leaves, outgoing info
Afferent = Where signal will enter, incoming info

Question 25

Outline the neuronal network?

Answer 25

Sensory neurons (collect afferent info)
Interneurons (process this info)
Motor neurons (efferent connections move muscles, therefore producing behaviour)

Question 26

What decides whether neurons become active or not and what is this known as?

Answer 26

Sum of inhibitory and excitatory signals and whether a positive or negative level is reached
Summation

Question 27

What are the five types of Glial cell?

Answer 27

Ependymal cell
Astrocyte
Microglial cell
Oligodendroglial cell
Schwann cell

Question 28

Features and function of an ependymal cell

Answer 28

Small ovoid
Secretes cerebrospinal fluid (CSF)

Question 29

Features and function of an Astrocyte

Answer 29

Star shaped
Contributes to neuronal nutrition, support and repair
Contributes to forming blood-brain barrier and to healing scarring after injury

Question 30

Features and function of Microglial cells

Answer 30

Small, derived from blood
Defensive function to remove dead tissue
Phagocytosis

Question 31

Features and functions of Oligodendroglial cells

Answer 31

Forms myelin around CNS axons in brain + spinal cord

Question 32

Features and functions of Oligodendroglial cells

Answer 32

Forms myelin around CNS axons in brain + spinal cord

Question 33

Features and functions of Schwann cells

Answer 33

Wraps around nerves to form myelin

Question 34

What is hydrocephalus?

Answer 34

Buildup of pressure in the brain and swelling of the head caused if the flow if CSF is blocked, can result in severe intellectual impairment

Question 35

What is multiple sclerosis and what is it associated with?

Answer 35

Nervous system disorder
The loss of myelin sheath

Question 36

Outline how a neurone is repaired?

Answer 36

When a peripheral axon is cut, axon dies
Schwann cells shrink and then divide, forming glial cells along from axon path
Neurone sends out axon sprouts, one of which find the Schwann cell path and becomes a new axon
Schwann cells envelop the new axon, forming new myelin