Transcript AP Psych Chpt 3 Sct 2

ORGANIZATION OF THE
NERVOUS SYSTEM
85 to 180 billion neurons in the human brain?!
How does anything get done?
CENTRAL NERVOUS SYSTEM

Brain and spinal cord.
PERIPHERAL NERVOUS SYSTEM
(PNS)
Def: all nerves that lie outside the brain and
spinal cord
 Nerves: bundles of neuron fibers
 PNS is subdivided into the Somatic Nervous
System and Autonomic Nervous System

SOMATIC NERVOUS SYSTEM
Def: nerves that connect to voluntary skeletal
muscles and to sensory receptors
 Carry info to and from Central Nervous System
 2 types of nerve fibers…

AFFERENT AND EFFERENT NERVE
FIBERS
Afferent nerve fibers: axons that carry info.
inward to the central nervous system from the
periphery of the body
 Efferent nerve fibers: axons that carry info.
outward from the central nervous system to the
periphery of the body

AUTONOMIC NERVOUS SYSTEM
Def: nerves that connect to the heart, blood
vessels, smooth muscles, and glands
 Controls involuntary functions
 Subdivided into 2 branches…

SYMPATHETIC AND
PARASYMPATHETIC DIVISIONS
Sympathetic division: mobilizes body’s resources
for emergencies
 Parasympathetic division: conserves bodily
resources

CENTRAL NERVOUS SYSTEM
Def: brain and the spinal cord
 Surrounded by Cerebrospinal Fluid: nourishes
the brain and provides a protective cushion
 CSF comes from blood
 Substances must pass the Blood-brain barrier:
semipermeable membrane-like mechanism that
controls which substances pass btwn the blood
and brain

SPINAL CORD
Connects the brain to the rest of the body
through the PNS
 An extension of the brain
 Runs from brain to just below the waist

THE BRAIN
In the skull
 Weighs c. 3 lbs
 Contains billions of interacting cells
 Numerous ways to study…

RESEARCH METHODS FOR
THE BRAIN
Brain function is difficult to examine…Unless
someone wants to volunteer to have their brain
dissected while they are still living. Technology
has helped…
ELECTRICAL RECORDINGS
Electroencephalograph (EEG): a device that
monitors electrical activity of the brain over time
by means of electrodes attached to the scalp
 Invented by Hans Berger in 1929
 Translates info. into brain waves

LESIONING
Def: destroying a piece of the brain
 Used to study cause-and-effect relations btwn
brain damage and behavior
 Attach an electrode to a specific area and burn
the tissue

ELECTRICAL STIMULATION OF THE
BRAIN (ESB)
Def: ESB involves sending a weak electrical
current into a brain structure to activate it
 Used mostly on animals
 Used in brain surgery for humans

BRAIN-IMAGING PROCEDURES
Computerized Tomography (CT) scan: X-ray of
brain structure
 Creates a horizontal “slice” of the brain
 Least expensive and widely used

BRAIN-IMAGING PROCEDURES
Positron Emission Tomography (PET) scanning
 Used to examine brain function
 Maps actual activity
 Provides color coded map of brain

BRAIN-IMAGING PROCEDURES
Magnetic Resonance Imaging (MRI) scan
 Uses magnetic fields, radio waves, and
computerized enhancement to map brain
structure
 Produces 3-D image of brain
 Functional Magnetic Resonance Imaging (fMRI)
monitors blood and oxygen flow in the brain
