Cells of the CNS Flashcards
What is a neurone
Nerve cell that receives and integrates information then transmits electrical impulses to another neurone
A neuron is the main communicating cell of the CNS. True or false?
True
Neuron - what is the function of dendrites ?
Extensions of the cell body. Increase the surface area for receiving information.
Dendrites can carry both excitatory and inhibitory inputs. True or false?
True
Neuron - what is contained in the cell body (soma)
Nucleus and other organelles
Neuron - cell body is where the net excitatory or net inhibitory change in membrane potential occurs. True or false?
True
What is the axon hillock?
Site of initiate of the AP
Where in the neurone has the highest density of voltage activated Na+ channels?
Axon hillock
- this is why it is the site of initiation of AP
Neuron - function of the axon
Conducts output signals as APs
Axonal transport - anterograde direction
Between the soma and pre-synaptic terminal
Axonal transport - retrograde direction
Back to the soma
What is the axon covered by ?
Myelin sheath
IN the CNS, the myelin sheath is composed of ?
Oligodendrocytes
In the PNS, the myelin sheath is composed of ?
Schwann cells
What is the function of the myelin sheath?
Prevents current loss and increases the resistance across the membrane so that local current crosses further
What are nodes of ranvier?
This is where leakage of current occurs
What is a synapse?
The point of chemical communication between neurones
Which part of the brain are the majority of neurones located in ?
Cerebellum
A multipolar neurone has 2 or more dendrites. True or false?
True
Multipolar neurones are sensory/motor?
Motor neurones
Motor neurones have cell body in CNS/PNS and axon in CNS/PNS ?
CNS
PNS
Pre-synaptic neurone - cell body in CNS/PNS, axon in CNS/PNS ?
CNS
PNS
Post-synaptic neurone - cell body in CNS/PNS, axon in CNS/PNS ?
PNS
PNS
Unipolar neurons are sensory/motor?
Sensory neurones
Unipolar neurones have cell body in CNS/PNS and axon in CNS/PNS ?
PNS
PNS
What is a pseudo unipolar neurone?
Cell body ends to a single process but that process only travels a short distance before it bifurcates
What is the most common cell in the CNS ?
Glial cell
Glial cells can give rise to brain tumours. True or false?
True
Name the 4 main types of glial cell
Astrocytes
Oligodendrocytes
Microglia
Ependymal cells
Astrocytes - appearance
Star shaped
- have many processes
Astrocytes - function
Structural support of the brain
Maintains BBB
Which cells are responsible for recycling glutamate?
Astrocytes
What is the main cell involved in repair and scar formation?
Astrocyte
Oligodendrocytes - function
Wraps around axons in the CNS forming the myelin sheath.
Oligodendrocytes have a major reaction to injury. True or false?
False
- limited reaction to injury
Damage to the myelin sheath can result in
Reduced conduction
Axons exposed to injury
Oligodendrocyte damage is a feature of which type of disorders?
Demyelinating disorders
Microglia - where do they originate from?
Bone marrow
Microglia - function
Immune monitoring and antigen presentation.
They wait for something to happen and then become activated and invade the CNS
Microglia - important in response to injury. True or false?
True
Ependymal cells - location
Line the ventricles of the brain
Ependymal cells - infectious agents produce changes in these cells. true or false?
True
Ependymal cells have a limited response to injury. True or false?
True
