Histology Of Neural Tissue Flashcards
What are the functions of neural tissue?
Gather information
Transmit information (to processing area of brain and spinal cord)
Integration/process information
Send information to effector tissue
How many neurons are there in the brain?
More than 100 billion neurons
How many glial cells are in the brain?
10x the number of neurons
What is a multipolar neuron?
Many processes (dendrites) extending from soma/cell body
Give an example of a multipolar neuron
Spinal motor neuron
Pyramidal neuron
(Purkinje cell)
What is a bipolar neuron?
Two processes extending from cell body/soma
Axon and dendrite
Give an example of a bipolar neuron
Retinal cells
Olfactory epithelium cells
What is a pseudounipolar neuron?
Neuron with only one process
Axon that splits, one branch to spinal cord and other to skin/muscle
Give an example of a pseudounipolar neuron
Dorsal root ganglion cells
What part of an astrocyte forms the blood-brain barrier?
Astrocyte perivascular end-feet
What is the function of a dendrite?
Increase surface area for connections/synapsing with other neurons
What are the smaller processes on dendrites?
Dendritic spines
What part of the cell body faces the axon?
Axon hillock
What are Nissl bodies?
RER
What parts of the cytoskeleton are present in the axon?
Neurofilaments
Microtubules
What transports vesicles and enzyme systems towards the synapse?
Microtubules with kinesin
What part of the cytoskeleton drives dendritic spine protrusion and retraction?
Actin
What increases the rate of action potential propagation?
Myelination
Higher temperature
Larger axon diameter
How many axons can an oligodendrocyte myelinate?
Up to 16
What is myelin?
Electrical insulator
Layers of modified membranes containing a higher proportion of lipid (than other cells)
What are the gaps between myelinated sections called?
Nodes of Ranvier
What are the sections between nodes of Ranvier called?
Internode
How do action potentials travel along a myelinated axon?
Saltatory conduction
What are regions of uncompacted myelin called?
Schmidt-Lanterman clefts
What is the function of Schmidt-Lanterman clefts?
Allow maintenance of myelin
What is the forebrain called?
Cerebrum
What is the hindbrain called?
Cerebellum
What is the function of the central nervous system?
Integrate inputs and coordinate outputs
What causes Herpes Zoster “Shingles”?
Varicella zoster virus (resides in ganglia after initial “chicken-pox” infection)
What stimuli does the somatic nervous system receive signals for?
Heat
Pain
Touch
What does the somatic nervous system control?
Voluntary muscles
What does the autonomic nervous system control?
Involuntary muscles
Secretory glands
Where does the sympathetic nervous system arise from (spinal cord)?
T1-L2
What are the layers of connective tissue in nerves?
Endoneurium
Perineurium
Epineurium
Where is endoneurium in a nerve?
Surrounding individual nerve fibres (axon and Schwann cells)
Where is perineurium in a nerve?
Surrounding fascicles
What does the perineurium consist of?
Layer of fibroblasts with cell to cell contact
Where is epineurium in a nerve?
Surrounding the whole nerve
On an electron micrograph of a nerve, what cells do the nuclei belong to?
Schwann cells
What is a motor unit?
Set of muscle fibres innervated by the axonal branches of a single motor neuron
What is the term used to describe the dynamic synaptic connections?
Plasticity
