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nervous tissue - Coggle Diagram
nervous tissue
neuron
structure
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Nodes of Ranvier:
- bare gaps in the myelin sheath where Saltatory Conduction occurs
synapse
Presynaptic element:
- Contains synaptic vesicles filled with neurotransmitters
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classification
multipolar
- multiple dendrites
- multiple axons
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pyramidal neuron
- multilayer before reach the ...
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golgi division
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golgi type II
- short axon
- local interneuron
- terminate close to the cell body
- area of grey matter
- star-like
anatomical basis
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central nervous system
- grey and white matter
- protect by bone and meninges
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brain
- (inserire immagine: structure of the cerebral cortex)
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functional basis
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Neurotransmitter:
Acetylcholine (ACh), excitatory to the muscle
Somatic sensory neurons (touch, pain, temperature, proprioception).
autonomic nervous system
- involuntary
- Smooth muscle, cardiac muscle, and glands
sympathetic nervous system
"Fight or Flight"
- Acetylcholine at the ganglion
- Norepinephrine (NE) at the target organ
- anatomical source origins: Thoracolumbar outflow (spinal segments T1 to L2)
parasymapthetic nervous system
"Rest and Digest"
- Acetylcholine at the ganglion and the target organ
- anatomical source origins: Craniosacral outflow(Cranial nerves III, VII, IX, X + spinal segments S2 to S4)
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gray
- cortex: outermost layer of brain
- innermost in spinal cord --> butterfly shape
- composition: Neuronal cell bodies (soma), dendrites, unmyelinated axons, axon terminals, and neuroglia.
- Function: Information processing and integration.
Neuropil:
- dense, tangled network of unmyelinated axons, dendrites, and glial cell processes that fills the space between neuronal cell bodies
WHITE:
- Inner layer of the brain
- outer layer of the spinal cord
- Components: Mainly myelinated axons and oligodendrocytes.
- white color --> high lipid content of myelin
- Function: Fast signal transmission and communication
tracts/fasciculi
- Bundles of myelinated axons
- inside the CNS running a common route
ex: corticospinal tract
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In CNS:
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Microglia (Phagocytes)
- derived from monocytes (bone marrow origin)
Ependymal cells (CSF)
- ciliated (to move cerebrospinal fluid)
- form the Choroid Plexus (which produces CSF)
choronoid plexus
- Composed of specialized ependymal cells + fenestrated capillaries
Astrocytes:
- Blood-Brain Barrier: highly selective semipermeable border that protects the CNS microenvironment from circulating toxins and pathogens
- Protoplasmic (found in gray matter)
- Fibrous (found in white matter)
3 Histological Layers:
- Fenestrated/Non-fenestrated Endothelial Cells:
continuous capillaries with tight junctions (zonula occludens) that prevent paracelluar leakage.
- Basement Membrane:
continuous basal lamina shared by the endothelial cells and pericytes.
- Astrocyte Foot Processes (Perivascular Feet):
Completely surround the outer surface of the capillary basal lamina
induce and maintain the barrier properties