Nervous System (Biomedical Science)

Cells To Systems - Nervous System
Overview Of The Nervous System

The Nervous System:
2 Types:

1. Central Nervous System (CNS)
2. Peripheral Nervous System (PNS)

Central Nervous System (CNS):

 Functions to send rapid messages from 1 part of the body to another
 Includes the brain and spinal cord

Peripheral Nervous System (PNS):

 Consists of nerves and ganglia outside of the brain and spinal cord

3 Systems:

1. Somatic - Communicates information about sensory (skin) and motor
2. Autonomic - Things that you do automatically (consists of sympathetic and parasympathetic nervous system)
3. Enteric - System of neuronal networks. To do with the guts

Cells Of The Nervous System:
Systems - Made up of lot of cells that go together to make organs which then make the systems
Glial Cells - Accessory cells that help the neurons do what they need to do e.g. astrocytes, ependymal cells,
oligodendrocytes, microglia, neurons

 Neurons and glia can be found in the nervous system
 Glial cells are helper cells




5 Types Of Glial Cells:

1. Astrocytes
2. Ependymal cells
3. Oligodendrocytes
4. Microglia
5. Neurons

Astrocytes:

 Majority, neurotransmitter regulation, synaptic function, etc
 Helps neurons with communication jobs
 Helps clear up neurotransmitters
 Helps regulating synapses
 Helps with synaptic transmission
 Helps with transmission
 Not sending signals themselves
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, Cells To Systems - Nervous System
Ependymal Cells:

 Found on the edges of the brain
 Produces and moves cerebrospinal fluid (CSF) (brain and spinal cord sit in this fluid)
 Protects the brain and cushions it
 Helps to move around wastes Produces CSF

Oligodendrocytes:

 Main function is myelination
 Found in the CNS
 Myelination of axons
 Helps provide myelination coating around the neurones to help speed up synaptic transmission
along an axon

Microglia:

 Brain macrophages (type of immune cell) Microglia = green
 Functions to clear dead cells and microbes to protect the brain from any invading pathogens

Neurons:

 Messenger cells that are part of the NS
 Allows communication with the rest of the body

Roberta de Ceglia et al. recently published a paper in nature that shows that certain astrocytes are
capable of releasing glutamate at a speed and manner comparable with synaptic transmission. Could
have implications for pathologies such as epilepsy, Alzheimer’s and Parkinson’s Disease.

The Neuron:

 Most neuronal cells send the signal from cell body end to the axon terminal end (always this direction)
 Nucleus is situated in the cell body
 The signal will come in through dendrites, get sent along the axon and will come out the axon terminals




Ion Concentration At Rest:
Permeability - How freely it can pass from the inside to the outside (whether or not something can pass)

Sodium:

 High concentration on the outside than inside
 Not very permeable

Potassium:

 Low concentration on the outside than inside
 Very permeable


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