Neural Tissues Flashcards
Central nervous system
Brain and spinal cord
Information processing including reflexes and behaviour
Peripheral nervous system
Sensory detection
Motor activation
Afferent neurone
Transmit sensory information to brain/ spinal cord
Efferent neurone
Motor neurones transmitting information from brain to effector organ
Ganglion
Group of cell bodies outside CNS
Broadmann areas of the neocortex
Regions of cortex are numbered 1-52
Boundaries determined by cellular architecture
Each has particular set of inputs and outputs
Broadmann area 4
Primary motor cortex
Broadmann area 17
Primary visual cortex
CNS neurone
Nucleus within cell body and extends one or more processes
Myelin
Wrapped around axon
Electrically insulates
Nodes of ranvier are gaps
Classifications of neurones
Multipolar
Bipolar
Unipolar
Important neurones
Pyramidal cell: neocortex
Purkinje cell: cerebellum
Dorsal root ganglion: sensory neurone
Divergent
A single neurone sends its output signal to many neurones
e.g. skin
Convergent
Multiple inputs influence a single neurone
e.g. retina
Interneurones
Only occur in CNS
Neither motor not sensory
Glia
Have no action potentials
Able to divide
Do not form synapses
Form the myelin sheathes
Many more glia than neurones
Oligodendrocyte
Production/ maintenance of myelin sheath in CNS
One oligodendrocyte myelinates multiple axons
Astrocyte
Supports neurones
- assists neuronal development/ growth
- protects neurones from harmful substances
Control vasodilation of local blood vessels
Microglia
Immune cells
Protect neurones from disease
Migrate to injury sites
Engulf microbes/ debris
Mesodermal origin
Develop from monocytes
Ependymal cells
Line brains ventricles and central canal of spinal cord
Form CSF
Schwann cells
Production/ maintenance of myelin sheath
PNS regeneration
1 axon wrapped per Schwann cell
Satellite cells
Support neurones
Regulate exchange of materials between neurones and interstitial fluid
CNS glia
Astrocyte
Oligodendrocyte
Ependymal cell
Microglial cell
PNS glia
Schwann cell
Satellite cell
Glioma
Largest group of primary tumours derived from glial cells
Usually highly malignant
Grow rapidly
Difficult to remove completely with surgery
Usually inside cranium
Neuroblastoma
Tumour (cancer)
Most common in children and infants
Outside cranium
Derived from neural crest cells from SNS
Often increased catecholamine levels
Survival rates vary
Initial prognosis typically good
