Download Exercise 17 - Harford Community College

Exercise 17
Marieb & Mitchell
page 257
Neurons
specialized cells that conduct messages in the form of
electrical impulses throughout the body
“typical” neuron components
• SOMA
– also called the perikaryon
– major biosynthetic center containing the usual organelles
except for centrioles
• Dendrites
– cell processes that are the receptive regions of the cell
• Axon
– generates and conducts nerve impulses away from the cell body
to the axon terminals
– myelin sheath
– whitish, fatty, segmented covering
– protects, insulates, and increases conduction velocity
Axons do not have Nissl bodies
or Golgi apparati
Axons
REGIONS
• Axon Hillock
• Initial Segment
• Collaterals
• Telodendria
• Synaptic
Terminals
Glia of the CNS
astrocytes
– maintain blood-brain barrier
– provide structural framework for brain due to
extensive cytoskeleton
– repair damaged neural tissue
– guide neuronal development
– regulating interstitial environment
Glia of the CNS
ependymal cells
– line the central cavities
of the brain and spinal
cord
– help circulate
cerebrospinal fluid
oligodendrocytes
– wrap around axons to
form myelin sheaths
Glia of the CNS
microglia
– least numerous and smallest CNS cells
– patrol CNS as “immune” cells
Glia of the PNS
satellite cells
• found surrounding neuron cell bodies within
ganglia
Schwann cells
• surround nerve fibers, sometimes form myelin
sheath
Structure of a nerve
Activities
• Do activities 1-3 and then we will go over
the questions and look at some
representative pictures.
Activity 1
Activity 1
Activity 2
•
•
•
Cerebellar Cortex
molecular layer: fibers
granual cell layer: cells
Activity 2
•
Cerebral Cortex: Pyramidal Cells
Activity 2
• dorsal root ganglion
Activity 3