Lecture 12: Components of the Control and Communication Network

Question 1

What are the components of the control and communication netwrok

Answer 1

• endocrine system
• Central Nervous system: brain, spinal cord
• Peripheral Nervous System: somatic and autonomic
• support and defence system

Question 2

What is a reflex?

Answer 2

• sensory neurons of pheripheral NS synapase at spinal cord but not all information goes immediately to brain
• reflex arc: allows for rapid reflex without delay, brain receives information a bit after. First response is reflex and second is brain recognizing pain.

Question 3

What are the 5 major cell types of adult human CNS

Answer 3

-neurons, oligodendrocytes (CNS) and Schwann cells (PNS), astrocytes, microglia, ependymal cells

Question 4

What is multiple sclerosis

Answer 4

destruction of myelin sheath due to autoimmune disorder

Question 5

What is the difference between myelinated and unmyelinated neurons

Answer 5

• unmyelinated: 0.5-2m/sec response, very few

- myelinated: 6-120m/s very fast. note pain fibres are not myelinated

Question 6

what is the dogma for neurotransmitters?

Answer 6

one type of neurotransmitter for a given pre-synaptic neuron
- might not be true though

Question 7

What are examples of neurotransmitters

Answer 7

dopamine, serotonin, norepinephrine, acetylcholine

Question 8

What happens if you have insufficient levels of dopamine, serotonin or norepinephrine

Answer 8

associated with depression

Question 9

What is associated with lack of acetylcholine

Answer 9

alzheimers

Question 10

How do different neurons and neurotransmitters affect a post synaptic cell body?

Answer 10

• net response is based on overall summation effect of all inputs
• determines whether an action potential is generated

Question 11

How do neurons diverge, converge and form networks?

Answer 11

• remodelling of brains neural network at age 0

- developing of new synapses and pruning away unused ones

Question 12

how are teenage brains developing

Answer 12

• growth is 90% complete, undergoes massive reorganization and development of synapses (networking)
• increased sensitivity to dopamine and myelination

Question 13

What are Oligodendrocytes and schwann cells?

Answer 13

• both produce myelin
  Oligodendrocytes: CNS, span multiple axons w/ each supporting up to 30 myelin rolls
  Schwann: PNS, does not span multiple axons

Question 14

What are microglia?

Answer 14

mobile macrophage-like immune cells

Question 15

What are ependymal cells

Answer 15

line ventricles to form a barrier: produce cerebrospinal fluid

Question 16

What are astrocytes

Answer 16

• more abundant than neurons
• stellate (star like) morphology critical for communication
• regulate function of blood brain barrier, ventricle ependymal cells (lining) and nodes of ranvier
• serve as ‘hubs’ for neural networks via calcium signalling (astocyte clouds), signal propagated from astocyte to astrocyte by gap junctions
• for tripartite synapses with neurons

more recently:
- control breathing, respond to chemical changes and desire to physically move (seem to be mediated by insulin)

Question 17

What is the blood brain barrier?

Answer 17

• very tight control over what gets through to the bain and protects against most bacteria and toxins
• small lipid soluble compounds, caffine, alcohol, glucose gets through
• to make drug non drowsy modify to it cant crss barrier

Question 18

What is a pericyte

Answer 18

a contractile cell

Question 19

What are tight junctions

Answer 19

within endothelial cell, prevents things from getting in