1.1 Cells of the NS Flashcards
What are the two cells found in the brain?
Neurons and Neuroglia
What different structures do neurons have to other types of body cells?
- Axon
- Dendrite
- Synapse
What is the axon in a neuron?
Output side of the cell.
That can travel distances ranging from distances ranging from microns to metres.
The axonal membrane ‘excitable.’
What is the dendrite in a neuron?
Input side of the cell.
It is highly branched with a number of processes extended from it.
They receive most of the excitatory input.
They contain filaments and are dynamic.
What is the synapse on a neuron?
Point of specialised contact between two neurons.
What similarities do neurons have to regular cells?
- Nucleus
- Rough ER
- Smooth ER
- Golgi complex
- Mitochondria
- Lysosomes
- Cytoskeleton
What is a nucleus?
Site at which a cells DNA is stored.
What is a rough ER?
Synthesises proteins
What is smooth ER?
Synthesises fat
What is mitochondria?
Powerhouse of the cell
What are lysosomes?
Waste disposal system
What is cytoskeleton?
Maintains cells shape and provides ‘rails’ for transport
What are the 3 ways that neurons can be classified?
- According to the number of processes
- According to the length of the axon
- According to the shape of a cell
How are neurons classified in terms of the numbers of processes they have?
Bipolar: 1 dendrite
Multipolar: 1+ dendrite
How are neurons classified in terms of their length?
Golgi type 1: long axon and is large
Golgi type 2: short axon
How are neurons classified in terms of their shape?
Ovoid (egg shape)
Fusiform (spindle like shape)
Triangular
How can neuroglia be described?
Nerve glue
What are the types of neuroglia found in the CNS?
- Oligodendrocytes
- Astrocytes
- Microglia
What is the type of neuroglia found in the PNS?
Schwann cells
What do oligodendrocytes make?
-Form myelin
What is myelin? What is are myelinated segments and unmyelinated segments known as?
- single sheet of membrane, wrapped tightly around axonal segment
- myelinated segments are known as internodes
- unmyelinated segments are known as nodes of ranvier
What shape are astrocytes?
Star
How much of the brain volume do astrocytes make up?
20-50%
What connect astrocytes? What do they cover?
They are connected by gap junctions
They cover capillaries
How do astrocytes ‘fence’ in neurons
- make a cuff around the nodes of ranvier
- ensheathing synapses and dendrites
- projecting processes to cell somas
What are astrocytes function?
- induce/maintain tight junctions in endothelial cells that form BBB
- uptake of neurotransmitters
- neurovascular coupling
What are microglia?
Small rod shaped stomas which have numerous processes extended out symmetrically
What are microglia’s function?
They are representatives of the immune system in the brain, as the brain is ‘immunologically privileged site.’
This is because the BBB restricts access id immune cells from the blood.
