Lecture 2.2: Neural Components and Networks

Question 1

What are the 2 Types of Cells in the Nervous System?

Answer 1

1) Neuroglia
2) Neurones

Question 2

What are the Roles of Neuroglia? (3)

Answer 2

• Ensure structure, support, nourishment and
  protection
• More numerous than neurons (3:1)
• Maintain ionic state, scaffolding, aid recovery/
  restructure

Question 3

What are the Roles of Neurones? (3)

Answer 3

• Functional units of the nervous system (89 billion in
  the brain)
• React to chemical and sensory stimuli
• Conduction of impulses
• Emit specific chemical regulators

Question 4

What Neuroglia are found in the CNS? (4)

Answer 4

• Astrocytes
• Oligodendrocytes
• Microglia
• Ependymal Cells

Question 5

What does the CNS consist of? (2)

Answer 5

• Brain
• Spinal Cord

Question 6

What is the Role of Astrocytes?

Answer 6

Maintain electrochemical environment for neurones
and help form the BBB

Question 7

What is the Role of Oligodendrocytes?

Answer 7

Myelinate neurons in the CNS

Question 8

What is the Role of Microglia?

Answer 8

• Macrophage-like cells
• Scavengers, modulate inflammation, cell turnover and
  death

Question 9

What is the Role of Ependymal Cells?

Answer 9

Control the production and flow of cerebrospinal fluid (CSF), brain metabolism, and waste clearance

Question 10

What Neuroglia are found in the PNS? (2)

Answer 10

• Schwann Cells
• Satellite Cells

Question 11

What is the Role of Schwann Cells?

Answer 11

Myelination of Axons

Question 12

What is the Role of Satellite Cells?

Answer 12

Maintain electrochemical environment for neurones in the PNS, sympathetic and parasympathetic systems

Question 13

What are Synapses?

Answer 13

Junctions that allow information to be transferred from 1 neurone to another neurone or from a motor neurone to a skeletal muscle fibre

Question 14

What are the 2 Types of Synapses?

Answer 14

• Chemical (most common)
• Electrical

Question 15

How do Electrical Synapses work?

Answer 15

• Pre and post-synaptic membranes are linked via gap
  junctions
• Chemical signals simply diffuse through
• Quicker
• Allows mass coordination of neurones

Question 16

What are the 2 Broad Categories of Neurotransmitters?

Answer 16

1) Small Molecule Neurotransmitters
2) Neuropeptides

Question 17

Examples of Small Molecule Neurotransmitters (7)

Answer 17

• Acetylcholine
• GABA
• Dopamine
• Adrenaline
• Noradrenaline
• Serotonin
• Histamine

Question 18

What are Neuromodulators?

Answer 18

• Subset of neurotransmitters
• Do not act directly on ion channels
• Act diffusely, at a distance
• Slower action: often modulate synaptic transmission,
  often via presynaptic GPCRs

Question 19

Why are Neuromodulators important?

Answer 19

Important molecular targets for CNS-active drugs

Question 20

Botulinum Toxin MoA

Answer 20

Toxin inhibits the release of acetylcholine at the neuromuscular junction, leads to paralysis

Question 21

What is Motor Neurone Disease?

Answer 21

• Group of disorders that leads to loss of motor
  neurones
• Progressive
• Upper / lower or combined motor neuron signs
• Poor prognosis

Question 22

How is diagnosis of Motor Neurone Disease done?

Answer 22

• Normal nerve conduction studies
• MRI brain may show cortical atrophy

Question 23

What is the Treatment of Motor Neurone Disease?

Answer 23

Only supportive

Question 24

What is Multiple Sclerosis?

Answer 24

• 2 or more, separate, episodes of CNS demyelination
• Plaques seen in white matter of brain or spinal cord
• More commonly - per-ventricular/corpus callosum/
  optic tracts
• Oligoclonal bands in CSF

Question 25

Symptoms of Multiple Sclerosis (8)

Answer 25

* Fatigue * Difficulty Walking * Vision Problems * Problems controlling the Bladder * Numbness/Tingling * Muscle Stiffness & Spasms * Problems with balance and co-ordination * Problems with thinking, learning and planning

Question 26

What are Oligoclonal Bands in CSF? What do they indicate?

Answer 26

* They are proteins called immunoglobulins * Indicates inflammation of the central nervous system * Indicate Multiple Sclerosis

Question 27

Guillain-Barre Syndrome

Answer 27

* Rapid onset muscle weakness due to auto-immune damage to myelin in the PNS * Peripheral neuropathy * Predominantly motor

Question 28

Management of Guillain-Barre Syndrome

Answer 28

* Plasma exchange * IV immunoglobulin * 20% of patients may need respiratory support

Question 29

Symptoms of Guillain-Barre Syndrome (9)

Answer 29

* Difficulty Walking * Paralysis * Difficulty Breathing * Blurred or Double Vision * Difficulty Speaking * Problems Swallowing/Chewing * Difficulty Peeing * Constipation * Persistent and/or Severe Pain

Question 30

What is Myasthenia Gravis?

Answer 30

* Auto-antibodies against acetylcholine receptors: Autoimmune synaptopathy * Autoimmune destruction of myelin all over * This prevents nerve impulses from triggering muscle

Question 31

Symptoms of Myasthenia Gravis (7)

Answer 31

* The more the muscle is used the weaker it becomes * Drooping Eye Lids * Avoidance of Activities * Intermittent Double Vision * Issues Chewing Foods * Speech Dysarthria

Question 32

Treatment of Myasthenia Gravis (3)

Answer 32

* Cholinesterase Inhibitors * Immunosuppression * Thymectomy

Question 33

Neurotransmitters & Disease Linkages: Dopamine

Answer 33

* Parkinson’s Disease * Schizophrenia

Question 34

Neurotransmitters & Disease Linkages: Acetylcholine

Answer 34

* Alzheimer’s Disease

Question 35

Neurotransmitters & Disease Linkages: Dopamine & Noradrenaline

Answer 35

* ADHD

Question 36

Neurotransmitters & Disease Linkages: GABA

Answer 36

* Alcohol Addiction * Anxiety