Neural Tissues Flashcards
What is the purpose of the nervous system?
Communication
Describe the central nervous system
Brain and spinal cord
Used for information processing including reflexes and behaviour
Describe the use of the peripheral nervous system
Cranial nerves and spinal nerves
Sensory detection
Motor activation
Define afferent neuron
Transmit sensory information to the brain/spinal cord
Define efferent neuron
Motor neurons transmitting information from the brain to effector organ
What are ganglia?
Group of cell bodies outside the CNS
What is a motor ganglion?
Parasympathetic ganglion
Describe the cells of motor gangion
Smaller neurons with eccentric nuclei
Give an example of sensory ganglion
Dorsal root ganglion
Describe the cells of sensory ganglion
Big neurons with central nuclei
Define rostum
Up/beak
Define caudal
Tail
Define Dorsal
Back
What is brodmann area 4?
Primary motor cortex
What is brodmann area 17?
Primary visual cortex
What are Brodmann areas?
Useful for describing cortical areas
Each has inputs and outputs
Often has a function
Describe the structure of a CNS neuron
Nucleus within cell body and extends one or more processes (dendrites and axon)
What is myelin?
Many layers of cell membrane
Electrical insulation
What is the purpose of myelin?
Increase conduction velocity
How are neurons classified?
Unipolar- 1 process
Bipolar- 2 processes
Multipolar- multiple dendrites
All have just 1 axon
Where is a pyramidal cell found?
Neocortex
Where is a purkinje cell found?
Cerebellum
Where is the dorsal root ganglion found?
Just outside the spinal cord
Describe the structure of a bipolar neuron
one dendrite
one axon
least numerous
sensory neurons
Give an example of a bipolar neuron
In the retina of the eye
Describe the structure of a pseudounipolar neuron
One axon
One dendrite
Give an example of a pseudounipolar neuron
Dorsal root ganglia
Give examples of post synaptic cells
Neuron
Myocyte
Gland
Describe what is meant by divergent
A single neuron sends its output signal to many neurons
Given an example of divergent
Skin
Describe what is meant by convergent
Multiple inputs influence a single neuron
Give an example of convergent
Retina
What are interneurons and where are they found?
Only occur in CNS
Neither motor not sensory
Process signals
Can be inhibitory or excitatory
How do glia differ from neurons?
No action potentials
Are able to divide
Form the myelin sheath
Do not form synapses
What is the function of neurons?
Basic nerve cells
Impulse conducting
What is the function of glial cells?
Supportive
Protective
List the glial cells
Oligodendrocytes Astrocytes Microglia Ependymal cells Schwann cells Satellite cells
What are oligodendrocytes?
Found in CNS
Production/maintenance of myelin sheath in CNS
One oligodendrocyte myelinates multiple axons (from different neurons)
What are astrocytes?
Found in CNS
Supports neurons: assists neuronal development / growth (neurotrophic), protects neurons from harmful substances,
Star shaped
Its “feet” on processes abut blood vessel endothelium – influence BLOOD FLOW and BLOOD-BRAIN BARRIER
What are microglia?
Found in CNS immune cells, protect neurons from disease, migrate to injury sites, engulf microbes / debris, mesodermal origin Of mesodermal origin and develop from monocytes
What are the ependymal cells?
Found in CNS
line brain’s ventricles and central canal of spinal cord,
form CSF
What are schwann cells?
Found in PNS
Production/maintenance of the myelin sheath
1 axon wrapped per schwann cell
What are satellite cells?
Found in PNS
support neurons, regulate exchange of materials between neurons and interstitial fluid
Perform analogous role in PNS to what astrocytes do in CNS
Which glial cells are found in the PNS?
Schwann cell
Satellite cells
Which glial cells are found in the CNS?
Astrocyte
Oligodendrocyte
Ependymal cell
Microglial cell
Describe a glioma
largest group of primary tumours
derived from glial cells
usually highly malignant
grow rapidly
difficult to remove completely with
surgery
Usually inside cranium
Describe a neuroblastoma
tumour (cancer) most common in children & infants outside cranium derived from neural crest cells from sympathetic NS Increased Catecholamine levels (often)
Survival rates vary: depends on type
Initial prognosis is typically good
Survivors often develop neurological problems ~30 years later
treatment depends on type
