Neuoroscience Flashcards by Martin Kalaydjiev

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

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

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Describe the Neuroanatomical terms?

insert image into lecture slide 12/13

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What are the key areas of the brain

Forebrain (blue)

Cerebral hemispheres
Thalamus & Hypothalamus

Midbrain (pink)

Hindbrain (green)

Pons
Cerebellum
Medulla

Brainstem = a functional unit

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Describe the ventricular system?

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

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What makes up grey matter?

Cell bodies of neurons and gila

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What makes up white matter?

Neuoronal axons wrapped on myelin

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Describe the Spinal cord functional divisions?

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

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What are neurones?

excitable cells that conduct impulses

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What is the role of neurones?

Integrate and relay information within a neural circuit

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What are gilia?

supporting cells - the ‘glue’

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What is the main purpose of gilia?

Maintain homeostasis, protection, assist neural function

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What method is used to visualise neurones?

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

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

Cell body, (soma, perikaryon)

Neurites:

Dendrites
Axons
Presynaptic terminal

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What is contained in the soma?

Nucleus

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

Mitochondria

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What is the cytoskeleton of a neurone made up of?

Microtubules
Microfilaments
Neuorofilament

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What are the parts of the axon? (4)

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

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How is the cytoplasm of the presynaptic terminal specialised?

No microtubules
Synaptic vesicles
Specialised proteins
Mitochondria

Describe dendrites?

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

How are dendritic spines specialised

Increase SA

Isolate chemical reactions

What are the methods of visualising neurones? (6)

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

How do we classify neurones? (2)

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

-By gene expression:
Underlies structural differences
Defines neurotransmitter expression

Describe the different number of neurites? (3)

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

Describe the types of dendritic geometry? (2)

Pyramidal:
Distinct apical and basal dendritic trees
Pyramidal shaped soma

Stellate:
Star shaped dendritic arbour

Describe the types of connection projections?

Sensory

Motor

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

What fills the space around neurones?

Gilia, can regenerate and replenish

What are the different types of gilia? (3)

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

Describe astrocytes?

- 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 ```

How do astrocytes act as fuel suppliers?

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

What does the tripartite synapse do?

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

What do astrocytes do?

Buffer extracellular potassium Form part of the blood brain barrier Couple neuronal activity to blood supply

What is the role of the microglia?

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

What is the role of the Oligodendrocytes?

Myelinating oligodendrocytes form myelin sheaths of CNS axons

What is the role of Schwann cells?

Form myelin sheaths of PNS One schwann cell provides one myelin segment to a single axon

How is the myelin sheath formed?

Process of oligo cytoplasm wraps many times around the axon | Cytoplasm squeezed out of layers by compaction

What is the function of myelin?

Myelination is insulating and creates nodes of ranvier enabling saltatory conduction

What does the nervous system do?

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

How does the nervous system perform its role?

- 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.

What are the Electrical Properties Of Neurons?

-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

Why do neurons have a resting potential?

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

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

- Diffusion | - Electrical field

How is the ionic concentration set up in the neurones?

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