NERVOUS TISSUE Flashcards
Tissue composed of neurons (nerve cells) and associated gliocytes (supporting cells)
Nervous Tissue
Nervous Tissue is derived from
Neural ectoderm
It makes up the structural and functional components of the nervous system.
It makes up the structural and functional components of the nervous system.
Neural ectoderm
Amorphous ground substance – minimal
Intercellular substance
Intercellular substance fiber?
very fine collagen
FLUID
Cerebrospinal fluid produced by ependymal cells of the
choroid plexus
Is a mass of villi that originate from the tela choroidea and form a fuzzy tuft of epithelium that extends into the brain vesicles.
choroid plexus
Cells
Major component of nervous tissue
Classified as
Neuron and gliocyte
Basic functional unit of the nervous system.
Specifically designed to receive stimuli from the environment, conducts electrical impulses throughout the body, and process information.
Neuron or Nerve Cell
Cell membrane is called ?
neurolemma
Cytoplasm is called ?
neuroplasm
Neurons are highly secretory and they have lots of RER (Nissl substance or chromophilic substance in neurons)
Is visible as a clump of basophilic materials in the perikaryon except in the axon hillock and axon.
The chromophilic substance
Presents neurofibrils and neurofilaments that corresponds to the
myofibrils and myofilaments, respectively of myocytes.
Unlike other cells, neuron it is composed of two major parts:
cell body and processes.
Stimulate by environmental changes or the activities of other cells
dendrites
contain the nucleus and mitochondria, ribosomes and other organelles and inclusion.
cell body
conducts nerve impulse (action potential) toward synaptic terminas.
axon
Affect another neuron or affector organ (muscle or gland)
Synaptic terminals
Nerve cell
i. Expanded part of the neuron
Contains relatively large, centrally located euchromatic, round nucleus with nucleolus, and the main part of the neuroplasm.
Cell Body
Nerve cell
ii. Cytoplasmic extensions that arise from the soma
There are two processes
processes
There are two processes:
Axon and Dendrites
That transmits impulses
Axon
That receives impulses.
Dendrite
All neuron have only one axon, which is usually the longer of the two processes
The junction where a neuron communicates with another neuron or an effector cell (e.g. muscle fiber) is called
synapse.
A single long process that arise from the bulging portion of the cell body
Axon hillock
Has a uniform diameter throughout its length and is generally straight except at its end where it gives of terminal branches collectively called the
telodendron
The terminal part of the axon releases a chemical called
Which acts on the membrane of the other cells.
neurotransmitter
i. An axon enveloped by one fold of plasma membrane of neurolemmal cells (schwann cells)
Has a smaller diameter than the myelinated nerve fiber Conducts impulses more slowly
Unmyelinated nerve fiber
An axon enveloped by plasma membrane of oligodendrocyte (in CNS) or neurolemmocyte (in PNS) that wraps spirally around it several time to form the lipid-rich ?
Myelin sheath
Starts at the point where the axon emerges from the axon hillock.
Myelination
The myelin sheath is discontinuous at intervals called
myelin node (nodes of Ranvier)
Is a bulb-like junction between two adjacent neurolemmal cells (the node is located between one schwann cell and the next)
myelin node
Is constricted because myelin is not formed in it.
Node
The areas of the axon covered by myelin sheath are called
which are sites of impulse propagation and saltatory conduction (impulse “jumps from node to node”)
internodes
is the cytoplasmic region of myelin between the internode and the node of Ranvier
Paranode