Neuoroscience

Question 1

What are the two major divisions of the nervous system? (2)

Answer 1

Central nervous system (CNS)

• Btrain
• Spinal Chord

Peripheral nerveus system (PNS)
-Somatic nervous system
Skin, joints, muscles
-Autonomic nervous system
-Internal organs, blood vessels, glands

Question 2

Describe the Neuroanatomical terms?

insert image into lecture slide 12/13

Question 3

What are the key areas of the brain

Answer 3

Forebrain (blue)

• Cerebral hemispheres
• Thalamus & Hypothalamus

Midbrain (pink)

Hindbrain (green)

• Pons
• Cerebellum
• Medulla

Brainstem = a functional unit

Question 4

Describe the ventricular system?

Answer 4

Series of cavities in the brain, form ventricles
Cerebral aqueduct lead the fourth ventricle. Flows down to the central canal that goes to the spinal chord
Filled with cerebral fluid
Provides physical protection

Question 5

What makes up grey matter?

Answer 5

Cell bodies of neurons and gila

Question 6

What makes up white matter?

Answer 6

Neuoronal axons wrapped on myelin

Question 7

Describe the Spinal cord functional divisions?

Answer 7

Dorsal is where sensory info is processed

Ventral is where motor info is sent out
Two types of fibres run in the same nerve
Afferent – sensory
Efferent – motor
Ganglion, similar to a nuclei 0 clusyter of beuronal cell bodies in peripeeheral nervous

D -orsal
A -afferent
V -entral
E -effernet

Question 8

What are neurones?

Answer 8

excitable cells that conduct impulses

Question 9

What is the role of neurones?

Answer 9

Integrate and relay information within a neural circuit

Question 10

What are gilia?

Answer 10

supporting cells - the ‘glue’

Question 11

What is the main purpose of gilia?

Answer 11

Maintain homeostasis, protection, assist neural function

Question 12

What method is used to visualise neurones?

Answer 12

-Nissl (Franz) staining
Allows us to distinguish between neurons and glia
Nucleolus of all cells stained
Neurons also have Nissl bodies

Question 13

What are the 4 major components of neurones? (4)

Answer 13

1. Cell body, (soma, perikaryon)

Neurites:

2. Dendrites
3. Axons
4. Presynaptic terminal

Question 14

What is contained in the soma?

Answer 14

Nucleus

Organelles for protein synthesis and processing:
Ribosomes
Rough ER
Golgi apparatus

Mitochondria

Question 15

What is the cytoskeleton of a neurone made up of?

Answer 15

Microtubules
Microfilaments
Neuorofilament

Question 16

What are the parts of the axon? (4)

Answer 16

Axon hillock
Axon initial segment
Axon collaterals
Axon terminal or terminal bouton

Question 17

How is the cytoplasm of the presynaptic terminal specialised?

Answer 17

No microtubules
Synaptic vesicles
Specialised proteins
Mitochondria

Question 18

Describe dendrites?

Answer 18

• Dendritic branches together form dendritic trees (dendritic arbors)
• Structure to function relationship - convergence
• Can have thousand of synapses

Question 19

How are dendritic spines specialised

Answer 19

Increase SA

Isolate chemical reactions

Question 20

What are the methods of visualising neurones? (6)

Answer 20

Nissl stain - cresyl violet, neurons vs glia, cytoarchitecture

Golgi stain - silver chromate, highlights some neurons, neuron doctrine

Immunohistochemistry - fixed tissue, antibodies, fluorescent microscope

Live imaging of fluorescent dye - genetic or injected

Electron microscope - synapses and organelles

Retrograde tracers - HRP - find cell body location

Question 21

How do we classify neurones? (2)

Answer 21

-By structure:
Number of neurites
Dendritic geometry
Connections - where do they project?
Axon length 

-By gene expression:
Underlies structural differences
Defines neurotransmitter expression

Question 22

Describe the different number of neurites? (3)

Answer 22

Unipolar - Small area for receiving synaptic input, highly specialised function so less integration so info is faithfully relayed

Bipolar - Main job of bipolar cells is to faithfully relay information for the most part, reliably relay info

Mulitpolar - Very good at integrating info, bigger the dendritic tree more integration

Question 23

Describe the types of dendritic geometry? (2)

Answer 23

Pyramidal:
Distinct apical and basal dendritic trees
Pyramidal shaped soma

Stellate:
Star shaped dendritic arbour

Question 24

Describe the types of connection projections?

Answer 24

Sensory

Motor

Interneuron - largest class:
-Relay or projection neurons
Connect brain regions
-Local interneurons 
Short axons
Process info in local circuits

Question 25

What fills the space around neurones?

Answer 25

Gilia, can regenerate and replenish

Question 26

What are the different types of gilia? (3)

Answer 26

Homeostatic - useful in helping neurons stay healthy, maintain correct ionic environment around neurons

Myelinating cells – produce myelin that wraps around the neurons

Phagocytic - immune cells of nervous system

Question 27

Describe astrocytes?

Answer 27

• Control environment surrounding neurones
• Spatial domains
• Unique marker - Glial fibrillary acidic protein (GFAP)
• Many subtypes:

Fibrous
Protoplasmic
Radial glial cells - developmental
Muller cells of the retina
Bergmann glia of the cerebellum
Ependymal cells line the ventricles and central canal

Question 28

How do astrocytes act as fuel suppliers?

Answer 28

Glycogen stores of the brain
5-10 minutes supply
Metabolise glycogen and supply lactate
Endfeet take up glucos

Question 29

What does the tripartite synapse do?

Answer 29

Terminates neurotransmitter activity
Recycles neurotransmitters to presynaptic terminals
Astrocytes have receptors too

Question 30

What do astrocytes do?

Answer 30

Buffer extracellular potassium

Form part of the blood brain barrier

Couple neuronal activity to blood supply

Question 31

What is the role of the microglia?

Answer 31

Immune cells of CNS

They are phagocytic, so clear away cellular debris, takes in and breaks down
Can help neurons grow by releasing growth factors
Can help aid myelination
Also involved synaptic pruning, if area of neuron not used can be removed to specifically project to different area

Question 32

What is the role of the Oligodendrocytes?

Answer 32

Myelinating oligodendrocytes form myelin sheaths of CNS axons

Question 33

What is the role of Schwann cells?

Answer 33

Form myelin sheaths of PNS

One schwann cell provides one myelin segment to a single axon

Question 34

How is the myelin sheath formed?

Answer 34

Process of oligo cytoplasm wraps many times around the axon

Cytoplasm squeezed out of layers by compaction

Question 35

What is the function of myelin?

Answer 35

Myelination is insulating and creates nodes of ranvier enabling saltatory conduction

Question 36

What does the nervous system do?

Answer 36

System of communication that allows an organism to react rapidly and modifiably to changes in its environment

Question 37

How does the nervous system perform its role?

Answer 37

• Electrical activity provides a rapid, reliable, and (flexible) means for neurones to receive, integrate and transmit signals.
• Chemical messengers (and receptors) between and within cells provide much more flexibility e.g. for inhibition.

Question 38

What are the Electrical Properties Of Neurons?

Answer 38

-Electrical signals may be divided into
Action potentials: fixed size, all-or-nothing signals that travel along (propagate) the axon
Graded potentials: variable size, local signals not propagated over long distances
Action potentials can pass either way along an axon, but tend to go one way (with important exceptions)
Graded potentials pass both ways along the neuronal membrane

Question 39

Why do neurons have a resting potential?

Answer 39

-Inevitable consequence of:
Selectively permeable membrane
Unequal distribution of charged molecules / ions
Physical forces

Question 40

What two forces control movement of ions in aqueous solutions? (2)

Answer 40

• Diffusion

- Electrical field

Question 41

How is the ionic concentration set up in the neurones?

Answer 41

Through ion pumps

Important ion pumps:
Na+ / K+ ATPase
Ca2+ pumps (not just in the plasmamembrane)