Nerves 12 Flashcards
PNS three divisions
Somatic - somatic receptors in head, body wall, limbs, special. Motor to skeletal muscles only.
Autonomic - sensory from visceral organs. Motor to smooth, cardiac muscles, glands.
Sympathetic - action, fight or flight.
Parasympathetic - rest and digest.
Enteric - GI tract. 100 million.
Number of cranial and spinal nerves, spinal by area
Cranial 12 pairs Spinal 31 pairs Cervical 8 Thoracic 12 Lumbar 5 Sacral 5 Coccygeal 1
Neuron parts - 9
Nissl bodies - rough ER Neurofibrils - intermediate Microtubules Nerve fiber dendrite Nerve fiber axon Axoplasm Axolemma Axon terminal Synapse, synaptic end bulbs
Neuron structural classification - 3
Multipolar - several dendrites - most neurons in brain and spinal chord
Bipolar - one dendrite one axon - eye, ear, olfactory
Unipolar - dendrites and axon fused into one process off the cell body - sensory receptors, cell body in ganglia of spinal/cranial nerves
Neuron functional class - 3
Sensory - afferent
Motor - efferent
Interneurons
Named neurons 2
Purkinje - cerebellum
Pyramidal - cerebrum
Neurons in brain - count
85 billion
Sensory receptors - 3
Corpuscle of touch
Lamellated corpuscle
Tactile epithelial
CNS neuroglia 5
Oligodendrocyte - form myelin sheath
Microglial - phagocytes
Fibrous astrocytes - white matter, BBB
Protoplasmic astrocytes - grey matter, strength and support
Ependymal - produce and assist circulation of CSF
PNS neroglia 2
Schwann cell - form myelin sheath
Satellite cell - support, exchange btw neuron and interstitial fluid
Cluster of neuronal cell bodies PNS CNS
PNS ganglion
CNS nucleus
Ion channels 4
Leak channels - random - all cells dendrite, axon, body
Ligand-gated - sensory, interneuron, motor. Dendrite
Mechanically-gated - pressure, touch - dendrite of some sensory
Voltage-gated - voltage stim - axon of all neurons
Nerve regeneration - where and how fast
PNS only, 1.5 mm per day
Saltatory vs continuous conduction
Saltatory in myelinated, leaps from one node of Ranvier to the next
