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