Neural tissue Flashcards
Cell types found in Neural tissue
neurons (form parenchyma) and glial cells (form stroma)
Neurons
(S, F, L)
Structure: structural and function unit of the nervous system. Diverse in shape and size
Function: sense and respond to stimuli and initiate movements
Location: throughout the body
Perikaryon
(S, F, L)
Structure: biggest portion of the neuron
Function: production of neurotransmitters, maintenance of neuron structural integrity
Location: depends on the type of neuron: one end of multipolar neuron, midportion of bipolar neron, varying areas in unipolar neuron
Neuron nucleus
(S, F, L)
Structure: large, round euchromatic, distinct nucleolus
Function: regulation and transcription and neuron function
Location: central portion of the cell body
Nissl bodies
(S, F, L)
Structure: stacks of rough endoplasmic reticulum (rER), observed as basophilic roots in cytoplasm
Function: translation, neurotransmitter production
Location: throuhgout the cell body
Axon hillock
(S, F, L)
Structure: trianglular, pale-staining area on the cell body
Function: origination of the axon and near where the summation of impulses occurs to generate action potential
Location: one pole of the cell body
Axon
(S, F, L)
Structure: single, often very long cellular projection from the cell body; pale staining
Function: transduction of action potential from the cell body to another neuron or to an effector cell, transport of vesicles and organelles between cell body and axon terminals
Location: long, single projection from the cell body
Initial segment of axon
(S, F, L)
Structure: the first portion out of the axon hillock
Function: action potential generation
Location: between the axon hillock and the first myelin sheath
Myelin sheath
(S, F, L)
Structure: clear staining glial cells (oligodendrocytes in CNS; schwann cells in PNS), wrapping around axon at regular intervals
Function: axon insulation to ensure quicker transmission of axon potential
Location: throuhgout the length of the myelinated axons
Nodes of Ranvier
(S, F, L)
Structure: unmyelinated segments of axon between myelin sheaths
Function: action potential propagation
Location: in between two myelin sheaths
Axon terminals (boutons)
(S, F, L)
Structure: branched, dilated ends of an axon
Function: storage of neurotransmitter-filled vesicles, release and reuptake of neurotransmitters into and from synaptic cleft
Location: ends of the axon, forming synapses with other neuron effector cells/organs
Multipolar neuron
(S, F, L)
Structure: large cell body, many dendrites, a single axon
Function: relay motor information or form a part of an integrating network with other neurons
Location: numerous found throughout neural tissue
Bipolar neuron
(S, F, L)
Structure: only two cellular processes from a fusiform cell body, one dendrite and one axon
Function: relay special sensory information to the CNS
Location: rare, found in special sensory organs such as retina and inner ear
Unipolar (pseudounipolar) neuron
(S, F, L)
Structure: a spherical cell body that has a single cellular process that immediately brances into two long processes, one travelling to the CNS and the other to the periphery
Function: relay sensory information from the periphery to the CNS
Location: numerous found throughout neural tissue. Collections of unipolar neuron cell bodies are found in spinal ganglia and cranial nerve ganglia
Glial cells
(S, F, L)
Structure: group of non-conducting cells that together function as the supporting component of the neural tissue
Function: physical support, insulation of the neurons an synapti clefts; repair of injured neurons, and aid in metabolic exchange
Location: found throughout the PNS and CNS
Astrocytes
(S, F, L)
Structure: highly branches, indistinct cell boundaries, small rounded nuclei with mxiture of heterochromatin and euchromatin “salt and pepper” pattern or pepperoni pizza.
Function: providing physical support, participating in blood brain barrier through end feet, taking part in metabolic exchange between neurons and vasculature
Location: Only in CNS; most numerous glial cells in CNS; Protoplasmic astrocytes in gray matter; fibrous astrocytes in white matter
Oligodendrocytes
(S, F, L)
Structure: indistinct cell boundaries, smallest round heterochromatic, punctate nuclei
Function: myelinating axons of the CNS; single cell can myelinate more than one axon
Location: only in CNS
Microglia
(S, F, L)
Structure: indistinct cell boundaries; elongated heterochromatic nuclei
Function: mediating neuroimmune reactions; phagocytossis of pathogens and cell debris
Location: only in CNS
Ependymal cells
(S, F, L)
Structure: cuboidal, clear cytoplasm, rounded nuclei, form simple cuboidal epithelium
Function: line the ventricles (including the choroid plexus), central canal of CNS, produce CSF
Location: only in the CNS, lining of the ventricles, choroid plexus and lining og the central canal
Schwann cells
(S, F, L)
Structure: each wrap around a single segement of an axon, oval to elongated nuclei in the cell periphery
Function: myelinating axons in the PNS
Location: only in the PNS
Satellite cells
(S, F, L)
Structure: indistinct cell boundaries, round small condensed nuclei
Function: supporting neuronal structures in the PNS
Location: only in the PNS, surrounding neuronal cell bodies in the ganglia
Meninges
(S, F, L)
Structure: three layers of membranes (dura, arachnoid, pia) that cover the CNS
Function: protect, anchor, and cushion brain and spinal cord
Location: surrounding brain and spinal cord
Dura mater
(S, F, L)
Structure: dense connective tissue
Function: protecting and anchoring the brain and spinal cord
Location: outermost covering
Epidural space
(S, F, L)
Structure: potential space above dura
Function: potential space, normally closed off in the skull and filled with fatty tissue in the vertebral column
Location: between dura mater and skull in the head: between dura mater and vertebrae in the vertebral column
Subdural space
(S, F, L)
Structure: potential space below dura
Function: potential space, normally closed off
Location: between dura and arachnoid mater
Arachnoid mater
(S, F, L)
Structure: delicate sheet of loose connective tissue
Function: providiing nutritional support and limited protection
Location: deep to and in contact with the inside of the dura mater
Arachnoid trabeculae
(S, F, L)
Structure: web-like extensions of arachnoid mater
Function: providing limited structural support to the subarachnoid space and vasculature
Location: subarachnoid space
Subarachnoid space
(S, F, L)
Structure: actual space filled with CSF
Function: providing cushioning mechanism and vascular supply for brain and spinal cord
Location: between arachnoid and pia mater
Pia mater
(S, F, L)
Structure: delicate and thin sheet of connective tissue
Function: lining outermost layer of the CNS
Location: outermost layer of the brain and spinal cord
Motor neurons
Multipolar neurons that synapse with muscle cells to trigger contraction
Sensory neurons
Most are unipolar enurons that carry sensory input from the periphery to the CNS. Cell bodies of the unipolar nerons are accumulated in varous ganglia throughout the body. Special sensory neurons of the retina and inner ear are bipolar neurons.
Interneurons
Multipolar neurons that integrate input from other neurons and relay the overal signal onto the next neuron
Cerebellar cortex
(S, F, L)
Structure: grat matter composed of three distinct layers of neuronal cell bodies
Function: site of synapse and integration of chemical signals and regulation of coordinated body movments and balnce
Location: outer, highly convoluted layer of the cerebellum
Molecular layer of cerebellum
(S and L)
Structure: relatively small neuronal cell bodies evenly distributed among glia
Location: Outermost layer, immediately below pia mater
Purkinje cell layer of cerebellum
(S and L)
Structure: single layer of large pyramidal, multipolar neurons
Location: between molecular and granular layer
Granular layer of cerebellum
(S and L)
Structure: densely distributed, smalles neuronal cell bodies
Location: deepest laer of the cerebellar cortex
Cerebellar medulla
(S, F, L)
Structure: mostly myelinated axons that form a thin, banched pattern of white matter (arbor vitae)
Function: conduction of neural impuse throughout axon fibers
Location: deep to cerebllar cortex
Cortex vs. Medulla of Brain
Cortex - gray matter with abundant cell bodies; outer layer of the brain
Medulla - white matter with abudant axons (mostly myelinated); inner layer of the brain
Tracts
(S, F, L)
Structure: regions within the medulla where white matter makes striations distinct lines as a collection of axons travel together
Function: house bundles of axons and associated glia
Location: throughout the medula: corpus callosum, internal capsule, etc
Cortex vs. Medulla of Spinal Cord
Cortex - white matter; axon bundles and glia forming tracts
Medulla - butterfly shaped gray matter, neuronal cell bodies and glia
Ventral Horn
(S, F, L)
Structure: anterior swelling of medulla containing cell bodies and motor neurons and glia
Function: neural integration, inhibition or propagation of action potential that results in muscle contraction
Location: anterior arms of the medulla
Dorsal Horn
(S, F, L)
Structure: cell bodies of interneurons; efferent axons of the sensory neurons and glia
Function: sensory neural integration; inhibition or propagation of action potential
Location: posterior arms of the medulla
Central canal
(S, F, L)
Structure: narrow tubule in the spinal cord lined with ependymal cells and filled with CSF
Function: contain small amount of CNS
Location: center of the medulla in spinal cord
