Nerve and development Flashcards
nervous tissue
- ectoderm
- detect and analyze sensory input, coordinate body activities, store and recal experiences
- parts=PNS and CNS
somatotopic organiztion
- different brain areas dedicated to different body parts or different modes of info
- gyri=bumps on outer portion
- sulci=groves on outer cortical portion of brain
- primary motor cortex=precentral gyrus, anterior to central sulcus
- primary sensory cortex=postcentral gyrus posterior to central sulcus
spinal chord
- ascending tracts carry sensory info to brain, located dorsally
- descending tracts send motor information, located ventrally
peripheral nervous system
=all nerves except brain and spinal chord, mixed motor and sensory
afferent sensory nerves enter spinal chord via dorsal roots
efferent motor nerves exit via ventral nerve roots
somatic portion of PNS
- carry consciously percieved info like voluntary mm contraction
- consists of single neuron connections
autonomic/visceral portion of PNS
-unconscious info like proprioception and contraction of involuntary or cardiac muscle, gland secretion
-multiple nerve connections and lots of integration
divided into parasympathetic (nerves origionating in midbrain, cervical, and sacral regions) and sympathetic (thoracic and lumbar region nerves)
nervous tissue cell types
- neurons-excitable
- neuroglial cells-non-excitable but enhance transmission
- support cells (from mesoderm) includes blood vessel cells like endothelium and fibroblasts and microglia (CNS immune cells)
neurons
soma has nucleus, cytoplasm with cytoskeleton, nissal bodies (ribosome rich RER)
dendrites has mitochondria, SER, microtubules and neurofilaments but no golgi
axon has mitochondria and SER but few/no ribosomes and many microtubules
axon terminal
axonal transport
anterograde=from soma to axon terminal
retrograde from terminal to soma
ganglion
PNS-cluster of nerve cell bodies where many synapses occur
nucleus
CNS-cluster of cell bodies where many synapses occur
six steps of synaptic transmission
- vesicle transport 2. vesicle loading 3. depolarization 4. exocytosis 5. binding of neurotransmitter and 6. further depolarization
glia
different cell types that contribute to neurotransmission
-help speed up impulses my forming myelin sheath around axons in CNS
schwann cells
myelinate axons in PNS
1 schwann cell/1-2mm of axon
can swallow axons (10) but not myelinate them-they can communicate w/extracellular space still
oligodendrocytes (CNS)
myelinate CNS neurons