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Nervous Tissue
IUSM – 2016
I. Introduction II. Learning Objectives III. Keywords IV. Slides A. Central Nervous System
- General Structures
- Divisions a. Cerebrum b. Cerebellum c. Spinal Cord B. Peripheral Nervous System
- Ganglia a. Sensory (Dorsal Root) b. Autonomic
- Peripheral Nerves V. Summary SEM of myelinated axons in a peripheral nerve.
Nervous Tissue
1. Nervous tissue integrates and coordinates the
activities of the body’s cells and organs through
conduction of electrical impulses and secretion
of chemical neurotransmitters.
2. Nervous tissue consists of two main types of
cells: neurons which are the functional cells of
the nervous system and specialized to receive
stimuli and transmit electrical impulses, and
support cells ( neuroglia ), which do not conduct
impulses but serve to support neuron function.
3. The nervous system is anatomically divided into
the central nervous system (brain and spinal
cord) and the peripheral nervous system
(ganglia, nerves, and sensory receptors).
4. The nervous system is functionally divided into
the somatic nervous system (under conscious
control, except reflex arcs) and autonomic
nervous system (involuntary control), which is
further divided into the sympathetic and
parasympathetic (and enteric ) divisions.
IUSM – 2016
I. Introduction II. Learning Objectives III. Keywords IV. Slides A. Central Nervous System
- General Structures
- Divisions a. Cerebrum b. Cerebellum c. Spinal Cord B. Peripheral Nervous System
- Ganglia a. Sensory (Dorsal Root) b. Autonomic
- Peripheral Nerves V. Summary
Learning Objectives (cont.)
- Understand the histological structure of peripheral ganglia.
- Understand the roles of endothelial cells and astrocytes in the blood- brain barrier.
- Understand the interrelationship among ependymal cells, choroid plexus, and cerebrospinal fluid (CSF) production.
- Understand the structure and functions of the meninges and their relationship to nervous tissue of the CNS.
IUSM – 2016
I. Introduction II. Learning Objectives III. Keywords IV. Slides A. Central Nervous System
- General Structures
- Divisions a. Cerebrum b. Cerebellum c. Spinal Cord B. Peripheral Nervous System
- Ganglia a. Sensory (Dorsal Root) b. Autonomic
- Peripheral Nerves V. Summary
Keywords
Arachnoid mater
Astrocyte
Autonomic ganglia
Central canal
Central nervous system
Cerebellum
Cerebral cortex
Choroid plexus
Dorsal root ganglion
Dura mater
Endoneurium
Ependymal cells
Epineurium
Granular layer
Grey matter
Molecular layer
Motor end plate
Myelinated fiber
Neuron
Neuropil
Nissl substance
Nodes of Ranvier
Oligodendrocyte
Perineurium
Peripheral nerve
Pia mater
Purkinje cell
Satellite cells
Schwann cell
Synaptic vesicles
Terminal bouton
White matter
IUSM – 2016
I. Introduction II. Learning Objectives III. Keywords IV. Slides A. Central Nervous System
- General Structures
- Divisions a. Cerebrum b. Cerebellum c. Spinal Cord B. Peripheral Nervous System
- Ganglia a. Sensory (Dorsal Root) b. Autonomic
- Peripheral Nerves V. Summary
Slide 112: Cerebrum, H&E
connective tissue is absent from the interior of the CNS, but three layers of CT cover the CNS surface (both the
brain and spinal cord); these layers of CT are called the meninges (Gr. “membrane”), and from outermost to
innermost are: dura mater (Lt. “tough mother”), arachnoid (Lt. “spider web-like”), and pia mater (Lt.
“tender mother”)
dura mater is rarely seen on slides of the brain, as it generally remains attached to the skull when removing
the brain; occasionally on slides the arachnoid can be seen as a layer of dense CT above the subarachnoid
space (normally contains CSF) and spanning the sulci (“grooves” of the cerebral cortex); the pia mater is
located directly on the CNS surface so can be seen lining the sulci
look here for
arachnoid
look here for
pia mater
the arachnoid and pia are
normally highly interconnected
by trabeculae and often are
referred to collectively as the pia-
arachnoid or leptomeninges
IUSM – 2016
I. Introduction II. Learning Objectives III. Keywords IV. Slides A. Central Nervous System
- General Structures
- Divisions a. Cerebrum b. Cerebellum c. Spinal Cord B. Peripheral Nervous System
- Ganglia a. Sensory (Dorsal Root) b. Autonomic
- Peripheral Nerves V. Summary
Slide 112: Cerebrum, H&E
pia mater is a delicate layer consisting of flattened, impermeable cells and CT fibers; it rests upon a limiting
layer of astrocyte foot processes known as the glial limitans (not seen in routine slide preparations) which
acts as a barrier between the CNS neural tissue and surrounding non-neural tissue; as blood vessels penetrate
into the CNS, they are initially surrounded by pia mater and the glial limitans , but as the vessels branch into
smaller capillaries, the pia mater is no longer present, leaving only the glial limitans which surrounds the
endothelial cells of the capillaries and facilitates formation of the blood-brain barrier
pia mater
(sulcus)
IUSM – 2016
I. Introduction II. Learning Objectives III. Keywords IV. Slides A. Central Nervous System
- General Structures
- Divisions a. Cerebrum b. Cerebellum c. Spinal Cord B. Peripheral Nervous System
- Ganglia a. Sensory (Dorsal Root) b. Autonomic
- Peripheral Nerves V. Summary
Slide 71: Cerebellum, Cresyl Violet
look in the ventricle
(fourth) near the
cerebellum to see the
choroid plexus
IUSM – 2016
I. Introduction II. Learning Objectives III. Keywords IV. Slides A. Central Nervous System
- General Structures
- Divisions a. Cerebrum b. Cerebellum c. Spinal Cord B. Peripheral Nervous System
- Ganglia a. Sensory (Dorsal Root) b. Autonomic
- Peripheral Nerves V. Summary
Slide 71: Cerebellum, Cresyl Violet
a choroid plexus is found in each of the four ventricles of the brain and is composed of cuboidal ependymal
cells (type of neuroglial cell) and well-vascularized pia mater ; the choroid plexus transports ions and water
from the blood into the ventricles, creating cerebrospinal fluid (CSF)
ependymal cells
blood
vessel
blood
vessel
(lumen)
IUSM – 2016
I. Introduction II. Learning Objectives III. Keywords IV. Slides A. Central Nervous System
- General Structures
- Divisions a. Cerebrum b. Cerebellum c. Spinal Cord B. Peripheral Nervous System
- Ganglia a. Sensory (Dorsal Root) b. Autonomic
- Peripheral Nerves V. Summary
Slide 112: Cerebrum, H&E
in grey matter, neuropil is the region (the “stuff”) between cell bodies containing a dense meshwork of
cellular processes (unmyelinated axons, dendrites, and neuroglial cell process); it is not connective tissue
and its fine organization is not generally discernable in routine slide preparations
blood
vessels
blood
vessels
neuroglial
cells
neuropil
neuropil
IUSM – 2016
I. Introduction II. Learning Objectives III. Keywords IV. Slides A. Central Nervous System
- General Structures
- Divisions a. Cerebrum b. Cerebellum c. Spinal Cord B. Peripheral Nervous System
- Ganglia a. Sensory (Dorsal Root) b. Autonomic
- Peripheral Nerves V. Summary
Slide 112: Cerebrum, H&E
neurons are generally considered the “functional” cells of nervous tissue as they – unlike neuroglial cells – are
capable of impulse conduction and synthesis of neurotransmitters; they can vary greatly in size and shape based
upon location and function (e.g., sensory, motor, or interneuron); however, they usually appear much larger than
surrounding neuroglial cells and have a well-defined nucleus with Nissl substance (rER) in the cytoplasm
neuron
cell body
neuroglial
cells
neuropil
blood
vessel
IUSM – 2016
I. Introduction II. Learning Objectives III. Keywords IV. Slides A. Central Nervous System
- General Structures
- Divisions a. Cerebrum b. Cerebellum c. Spinal Cord B. Peripheral Nervous System
- Ganglia a. Sensory (Dorsal Root) b. Autonomic
- Peripheral Nerves V. Summary
Slide 112: Cerebrum, H&E
microglia are mobile phagocytic cells of neural tissue; they are the resident immune cells of the CNS, which
otherwise is limited in mounting immune responses due to the restrictiveness of the blood-brain barrier;
microglia are the smallest and least numerous of the neuroglial cells, but upon stimulation the cells can
proliferate and change morphology
microglial (?) cells are
difficult to identify with a
high degree of certainty in
routine slide preparations;
they are small cells with
little cytoplasm and a dense,
elongated nucleus, often
resembling a fibroblast
IUSM – 2016
I. Introduction II. Learning Objectives III. Keywords IV. Slides A. Central Nervous System
- General Structures
- Divisions a. Cerebrum b. Cerebellum c. Spinal Cord B. Peripheral Nervous System
- Ganglia a. Sensory (Dorsal Root) b. Autonomic
- Peripheral Nerves V. Summary
Slide 112: Cerebrum, H&E
white matter is located deep to the grey matter of the cerebral cortex; it lacks neuron cell bodies and
primarily contains myelinated axons and supportive neuroglial cells, mainly the oligodendrocytes that
myelinate the axons
IUSM – 2016
I. Introduction II. Learning Objectives III. Keywords IV. Slides A. Central Nervous System
- General Structures
- Divisions a. Cerebrum b. Cerebellum c. Spinal Cord B. Peripheral Nervous System
- Ganglia a. Sensory (Dorsal Root) b. Autonomic
- Peripheral Nerves V. Summary
Slide 71: Cerebellum, Cresyl Violet
white matter
granular
layer
molecular
layer
the grey matter of the cerebellum is further divided into three specific layers: the outermost molecular
layer , the innermost granular layer , and a third Purkinje cell layer located between the two layers and
consisting of a single cell layer of large Purkinje cell neurons
IUSM – 2016
I. Introduction II. Learning Objectives III. Keywords IV. Slides A. Central Nervous System
- General Structures
- Divisions a. Cerebrum b. Cerebellum c. Spinal Cord B. Peripheral Nervous System
- Ganglia a. Sensory (Dorsal Root) b. Autonomic
- Peripheral Nerves V. Summary
Slide 148: Cerebellum, H&E
grey matter
molecular layer (light)
granular layer (dark)
IUSM – 2016
I. Introduction II. Learning Objectives III. Keywords IV. Slides A. Central Nervous System
- General Structures
- Divisions a. Cerebrum b. Cerebellum c. Spinal Cord B. Peripheral Nervous System
- Ganglia a. Sensory (Dorsal Root) b. Autonomic
- Peripheral Nerves V. Summary
