L5 Neural Tissues Flashcards
What is the purpose of the nervous system?
Communication through sensory detection, information processing, motor activity leading to behaviour.
What is the central nervous system?
Brain and spinal cord.
Information processing, reflexes and behaviour.
What is the peripheral nervous system?
Cranial and spinal nerves.
Sensory detection and motor activation.
What is an afferent neurone?
Transmits sensory information to the brain and spinal cord.
What is an efferent neurone?
Motor neurone transmit information from the brain to the effector organ.
What is a ganglion?
A group of cells outside the CNS (excluding basal ganglia in the brain).
What is a motor ganglion?
Autonomic.
Parasympathetic ganglion, Smaller neurones, eccentric nuclei.
What is a sensory ganglion?
Dorsal root ganglion.
Big neurones with central nuclei.
What are Brodmann Areas?
Numeric (1-52) regions of the cortex with particular inputs and outputs.
4 primary motor cortex
17 primary visual cortex
What defines a CNS neurone?
Nucleus within cell body and extends one or more processes.
What is myelin?
Wraps around to electrically insulate the axon, made of many layers of cell membrane, and increase conduction velocity.
What is a multipolar neurone?
1 axon, many dendrites.
What is a pyramidal cell?
Found in the neocortex with a small axon, linked to thinking.
What is a Purkinje cell?
In the cerebellum, dendrites are long with many interactions with other layers.
What is a dorsal root ganglion?
Psuedounipolar sensory neurone, found just before the spinal cord. Surrounded by satellite cells.
What is a bipolar neurone?
1 dendrite and 1 axon, rare sensory neurones.
Found in the retina.
What is pseudounipolar neurone?
1 axon and 1 dendrite, dorsal root ganglion.
2 processes move toward each other and fuse.
Unipolar have no dendrites.
What are interneurons?
Inhibitory or excitatory relay neurone, connects dorsal and ventral roots in the spinal cord.
How do glia differ from neurones?
No action potentials Able to divide Form myelin sheaths Do not form synapses Many more glia Supportive and protective role Smaller
What cells are a common source of tumours in the nervous system?
Glial cells.
What is an oligodendrocyte?
Production and maintenance of the myelin sheath in the CNS.
1 myelinates many axons.
What is an astrocyte?
Supports and assists a neurone in development and growth (nourishment)
Protects from harmful substances (blood brain barrier)
Controls vasodilatation of local blood vessels (blood flow)
What are microglia?
Immune cells, formed from mesoderm
Protect neurones from disease, migrate to injury sits and engulf microbes.
Can develop from monocytes
Quick moving and active
What are ependymal cells?
Line brain ventricles and central canal of the spinal cord.
Form cerebrospinal fluid from fluid, electrolyes and salts.
Cilia and microvilli on apical membrane.
Act as epithelium.
What are Schwann cells?
Produce and maintain myelin sheath in the PNS, 1 neurone has many Schwann cells.
1 axon per Schwann cell.
Allow PNS regeneration.
What are satellite cells?
Support neurones, regulate exchange of materials between neurones and interstitial fluid.
PNS astrocytes.
What are the layers of the meninges?
3 meningeal layers:
Dura matter
Arachnoid (thick, contains blood vessels)
Pia matter (like epithelium)
What is a glioma?
Largest group of primary tumours, derived from glial cells Highly malignant Rapid growth Hard to fully remove surgically Inside cranium usually Poor prognosis unless caught early
What is a neuroblastoma?
Common paediatric tumour
Outside the cranium (ie abdomen)
Derived from neural crest cells from sympathetic nervous system (leads to an increase in catecholamines ie noradrenaline)
Good initial prognosis but survival rates and treatment depends on the type
Survivors often develop neurological problems around 30 years later
