Introduction to Brain and Behavior
Chapter 3
Golgi He said that the nervous system is composed of a network of interconnected fibers: a
"nerve net." He said this during an early 1900s debate on what a neuron is
Cajal Nervous system is made of discrete cells. He came up with the neuron hypothesis:
neurons are the units of brain function.
Basic subdivisions of the neuron Dendrites, Cell Body/Soma, Axon
Dendrites Part of the neuron that gathers information from other neurons
Cell Body/Soma Core region of the neuron; contains the nucleus. Part of the neuron that
integrates the information
Axon Part of the neuron that carries information to be passed on to other cells
Dendritic Spines Protrusion from a dendrite that greatly increases its surface area and is the
usual point of contact with axons of other cells.
Axon Hillock Juncture of soma and axon where the action potential begins
Axon Collaterals Branch of an axon
Teleodendria End branches of an axon
Terminal Button Knob at the tip of an axon that conveys information to other neurons; also
called an end foot
Synapse Gap between one neuron and another neuron. It's usually located between an end
foot of the axon of one neuron and a dendritic spine of another neuron
, Information flow in a neuron Dendrite to Cell Body to Axon to End Foot
Different types of neurons Sensory Neurons, Interneurons, Motor Neurons
Sensory Neurons Bring information to the central nervous system
Interneurons Associate sensory and motor activity within the central nervous system
Motor Neurons Send signals from the brain and spinal cord to muscles
Neural Connections The appearance of each neuron tells us something about the connections
that it must make. In general, neurons with large cell bodies have extensions that are very long;
neurons with small cell bodies have short extensions
The Language of Neurons: Excitation and InhibitionEach neuron receives thousands of
excitatory and inhibitory signals every second. Neurons "sum" these signals and respond
accordingly: they become active or not. From the simple "yes-no" language of the neurons
emerges enormous possibilities for behavior
Five types of Glial Cells Ependymal Cells, Astrocyte, Microglial Cell, Oligodendroglial
Cell, Schwann Cell
Ependymal Cells Small, ovoid; found in the walls of the ventricles. They make and secrete
cerebrospinal fluid (CSF).
Hydrocephalus Build-up of pressure in the brain and swelling of the head caused if the
flow of CSF is blocked. Can result in retardation
Astrocyte Star shaped, symmetrical cell. Structural support for neurons. Transports
substances between neurons and capillaries (blood-brain barrier). Conveys signals from neuron
to vessels to dilate and provide more oxygen, glucose. Scar tissue formation.
Tumor Mass of new tissue that grows uncontrolled and independent of surrounding structures.
Grow from glia, not neurons
Microglia Originate in the blood as offshoot of immune function. Uses phagocytosis to
scavenge debris (e.g., dead cells)
Oligodendroglia Cell Glial cell in the CENTRAL nervous system that myelinates axons.
Myelin Glial coating that surrounds axons
Schwann Cell Glial Cell in the PERIPHERAL nervous system that myelinates axons
Multiple Sclerosis (MS) Nervous system disorder that results from the loss of myelin
around axons
Chapter 3
Golgi He said that the nervous system is composed of a network of interconnected fibers: a
"nerve net." He said this during an early 1900s debate on what a neuron is
Cajal Nervous system is made of discrete cells. He came up with the neuron hypothesis:
neurons are the units of brain function.
Basic subdivisions of the neuron Dendrites, Cell Body/Soma, Axon
Dendrites Part of the neuron that gathers information from other neurons
Cell Body/Soma Core region of the neuron; contains the nucleus. Part of the neuron that
integrates the information
Axon Part of the neuron that carries information to be passed on to other cells
Dendritic Spines Protrusion from a dendrite that greatly increases its surface area and is the
usual point of contact with axons of other cells.
Axon Hillock Juncture of soma and axon where the action potential begins
Axon Collaterals Branch of an axon
Teleodendria End branches of an axon
Terminal Button Knob at the tip of an axon that conveys information to other neurons; also
called an end foot
Synapse Gap between one neuron and another neuron. It's usually located between an end
foot of the axon of one neuron and a dendritic spine of another neuron
, Information flow in a neuron Dendrite to Cell Body to Axon to End Foot
Different types of neurons Sensory Neurons, Interneurons, Motor Neurons
Sensory Neurons Bring information to the central nervous system
Interneurons Associate sensory and motor activity within the central nervous system
Motor Neurons Send signals from the brain and spinal cord to muscles
Neural Connections The appearance of each neuron tells us something about the connections
that it must make. In general, neurons with large cell bodies have extensions that are very long;
neurons with small cell bodies have short extensions
The Language of Neurons: Excitation and InhibitionEach neuron receives thousands of
excitatory and inhibitory signals every second. Neurons "sum" these signals and respond
accordingly: they become active or not. From the simple "yes-no" language of the neurons
emerges enormous possibilities for behavior
Five types of Glial Cells Ependymal Cells, Astrocyte, Microglial Cell, Oligodendroglial
Cell, Schwann Cell
Ependymal Cells Small, ovoid; found in the walls of the ventricles. They make and secrete
cerebrospinal fluid (CSF).
Hydrocephalus Build-up of pressure in the brain and swelling of the head caused if the
flow of CSF is blocked. Can result in retardation
Astrocyte Star shaped, symmetrical cell. Structural support for neurons. Transports
substances between neurons and capillaries (blood-brain barrier). Conveys signals from neuron
to vessels to dilate and provide more oxygen, glucose. Scar tissue formation.
Tumor Mass of new tissue that grows uncontrolled and independent of surrounding structures.
Grow from glia, not neurons
Microglia Originate in the blood as offshoot of immune function. Uses phagocytosis to
scavenge debris (e.g., dead cells)
Oligodendroglia Cell Glial cell in the CENTRAL nervous system that myelinates axons.
Myelin Glial coating that surrounds axons
Schwann Cell Glial Cell in the PERIPHERAL nervous system that myelinates axons
Multiple Sclerosis (MS) Nervous system disorder that results from the loss of myelin
around axons
