Histology - Nervous System Flashcards
Nueroglial cells
Aka glia
Non-conducting cells located close to neurons
CNS central neuroglia - oligodendrocytes, microglia, astrocytes, and ependymal cells
PNS peripheral nuerolgia - Schwann cells and satellite cells
Fx - providing physical support and protection for neurons
Insulating nerve cell bodies and processes (myelin)
Reparising neuoranal injury
Regulating the internal fluid environment of the CNS
Clearing neurotransmitters from synaptic clefts
Facilitating metabolic exchange between the vascular system and neurons
Nissl bodies
Rough ER and polyribosomes - appear as clumps of basophilic material
Neuronal type of dorsal root ganglia
Pseudo-unipolar neurons
Neuronal cell type of the retina
Bipolar neurons
Purkinje and pyramidal cells
Found within the CNS
Afferent processes of neurons
Dendrites - they receive information from other neurons or from the environment
Dendrites are generally unmyelinated
Lack golgi but otherwise organelle profile similar to that of the cell body
Dendritic spines
Increase surface area and are the sites of synapses
Efferent processes of neurons
Axons - initial segment located below or distal to the axon hillock (where action potentials are generated)
Recurrent axonal branching
Near the cell body
Collateral axonal branching
Near the target
Organelle profile of axons
Arrays of microtubules and neurofilaments
Mitochondria
Vesicles
Derivatives of smooth ER
Direction of axonal transport
Biderectional
Anterograde - via kinesin motors - moves organelles and secretory vesicles along microtubules
Retrograde - moving endosomes via dynein motors
Types of synapses
Axosomatic
Axodendritic
Axoaxonic
Most common form of synapse in humans
Chemical synapses
Excitatory synapses
Allow Na+ to enter postsynaptic cells, dpolarizing the membrane and causing an action potential
Inhibitory synapses
Allow Cl- to enter postsynaptic cells, hyperpolarizing the membrane and making acxtion potentials less likely
Astrocytes
Provide physical and metabolic support for neurons and form the blood-brain barrier.
Fibrous astrocytes are found in white matter, while protoplasmic astrocytes are found in gray matter