1. ORGANIZATION OF THE NERVOUS SYSTEM
85 to 180 billion neurons in the human brain?! How does anything get done?

2. CENTRAL NERVOUS SYSTEM
Brain and spinal cord.

3. 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

4. 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…

5. 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

6. AUTONOMIC NERVOUS SYSTEM
Def: nerves that connect to the heart, blood vessels, smooth muscles, and glands
Controls involuntary functions
Subdivided into 2 branches…

7. SYMPATHETIC AND PARASYMPATHETIC DIVISIONS
Sympathetic division: mobilizes body’s resources for emergencies
Parasympathetic division: conserves bodily resources

8. 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

9. 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

10. THE BRAIN In the skull Weighs c. 3 lbs
Contains billions of interacting cells
Numerous ways to study…

11. 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…

12. ELECTRICAL RECORDINGS
Electroencephalograp h (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

13. 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

14. 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

15. BRAIN-IMAGING PROCEDURES
Computerized Tomography (CT) scan: X-ray of brain structure
Creates a horizontal “slice” of the brain
Least expensive and widely used

16. BRAIN-IMAGING PROCEDURES
Positron Emission Tomography (PET) scanning
Used to examine brain function
Maps actual activity
Provides color coded map of brain

17. 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