C. Lack, Ph.D.
PSY 2003
Chapter 4 Outline
Page 1 of 8
Neurons, Hormones, and the Brain
Section One:
Nervous System
What’s ahead…
•Why do you automatically pull your hand away from something hot?
•Is it possible to consciously control things like heartbeat or blood pressure?
•Which part of your nervous system activates in an emergency?
Nervous System
•Two major divisions
– Central nervous system (CNS)
– Peripheral nervous system (PNS)
– Somatic system
– Autonomic system
Central nervous system
•Consists of the brain and _________________
•Two major functions
–Carries sensory information from body to brain through afferent nerve fibers
–Carries information from brain to muscles and glands through efferent nerve
fibers
–Involved in spinal reflexes
Peripheral nervous system
•Consists primarily of nerves
•Two subdivisions
– Somatic system: connects CNS to ________________ muscles
C. Lack, Ph.D.
PSY 2003
Chapter 4 Outline
Page 2 of 8
– Autonomic system: connects CNS to involuntary muscles, glands, and organs;
divided into two major parts
Autonomic nervous system
•Sympathetic nervous system
– Readies the body to expend energy
•Parasympathetic nervous system
– Readies the body for the restoration or conservation of ____________
Section Two:
Communication in the Nervous System
What’s ahead…
•Which cells are the nervous system’s communicators and how to they “talk”?
•How do learning and experience alter the brain?
•Why do neural impulses travel more slowly in children than adults?
•What happens when neurotransmitters are too low or too high?
Neuronal structure
•Three basic parts comprise a neuron
– Cell body – center of the neuron
– Axons – conducts action potential ___________ from cell body
– _____________ – brings action potential towards cell body
•There may be as many as 100 BILLION neurons in the human brain
•Other neuronal parts
– Myelin sheath
– Glial cells
– Axon terminal buttons
– Synapses
C. Lack, Ph.D.
PSY 2003
Chapter 4 Outline
Page 3 of 8
Neuronal function
•The purpose of the neuron is to transmit information within the brain
•Communication within the neuron occurs through means of action potentials and
graded potentials
Graded potentials
•Basic type of signal within neurons
•Strength varies depending on strength of the _______________ stimulus
•Usually carries info towards the cell body from the dendrite
•If there is a large enough amount of graded potentials being generated, an action
potential is released
Action potentials
•Basic signal of the nervous system
•A change in the electric potential moving across the neuron
•An ________________________ response
– Occurs at full strength or not at all
Synaptic transmission
•Communication between different neurons occurs because of the release of
____________________________ (NTs)
•NTs are released from synaptic vesicles and across the synaptic gap, where they are
picked up by receptors
Neurotransmitters
•Can be either excitatory or inhibitory
•Many different types
C. Lack, Ph.D.
PSY 2003
Chapter 4 Outline
Page 4 of 8
–Acetylcholine
–Dopamine
–Serotonin
•Certain drugs can mimic the effects of NTs (agonists) or can inhibit the effects of NTs
(antagonists)
Endorphins
•Chemical messengers that function similar to opiates
– Reduce pain
– Promote pleasure
•Act primarily as neuromodulators, limiting or prolonging neurotransmitter effects
•Shoot up when under ________________
•Also function to help with social bonding
•Why would these be useful?
Endocrine System
•System designed for communication within the body
•Consists of various glands that secrete _____________ into bloodstream
–Includes the pituitary and adrenal glands
Hormones
•Regulate a variety of bodily processes
•Responsible for actions such as increasing heart rate or blood pressure, governing the
function of sex organs, and metabolic regulation
Section Three:
Mapping the Brain
C. Lack, Ph.D.
PSY 2003
Chapter 4 Outline
Page 5 of 8
What’s ahead…
•Why are patterns of electrical activity called “brain waves”?
•What are different scanning technologies that allow people to see the living, working
brain?
Studying the brain
•Multiple methods to use
•_____________ in animals
•People with brain damage
•Types of measurement
Electroencephalograms
•EEGs place electrodes on skull
•Record neural activity
Positron Emission Tomography
•Records changes in brain by measuring blood flow, O2, or radiation
•Shows which areas are active during which activities
Magnetic Resonance Imaging
•MRI uses magnetic fields and radio frequencies to vibrate atoms
•Converts vibrations to high contrast pictures
Section Four:
A Tour of the Brain
What’s ahead…
•Which part is the “traffic officer” to incoming sensations?
C. Lack, Ph.D.
PSY 2003
Chapter 4 Outline
Page 6 of 8
•Which part is the “gateway to memory” and what happens if it is damaged?
•What is good about the brain being so wrinkled?
Brain Stem
•Oldest part of the brain (500 million years old)
•Begins just above spinal cord and goes into middle of brain
•Regulates _______________ processes
Parts of brain stem
•Medulla – breathing and heartbeat
•Pons – sleep and arousal
•Cerebellum – basic motor activities
•Midbrain – primitive centers for vision and hearing
•RAS – dense network of neurons, screens incoming info, arouses attention
Cerebellum

On top of brain stem
•Controls sense of balance, coordination
•Remembers simple motor skills and reflexes
C. Lack, Ph.D.
PSY 2003
Chapter 4 Outline
Page 7 of 8
Thalamus
•The “traffic officer”
•Receives information from all the _____________ organs (except smell)
•Sorts and transmits to different parts of the brain
Hypothalamus
•Three main roles
•Regulation of autonomic nervous system
•Homeostasis of body
•Regulation of ____________________ behavior
–i.e. eating, aggression, mating
Pituitary Gland
•Sends hormonal messages out to other glands
Limbic system
•A set of structures that play a role in emotional reactions
•Amygdala – involved in aspects of emotional control and formation of highly
emotional memories
Hippocampus
•Involved in the formation of new memories
•Much information due to brain-damaged patients like H.M.
Cerebrum
•Largest part of brain
•Two separate halves, connected by corpus callosum
C. Lack, Ph.D.
PSY 2003
Chapter 4 Outline
Page 8 of 8
Cerebral cortex
•Refers to the outer covering of the cerebral hemispheres or “gray matter”
•Much larger in humans compared to other _____________
•Fits in our skulls because it’s folded
•The “association cortex” plays an important role in complex cognitive activities
The Four Lobes
•Frontal – motor control, speech production, planning
•Parietal – somatosensory cortex
•Occipital – vision
•Temporal – hearing, language comprehension
The Four Lobes
•_________________ enables us to function even if one area of the brain is damaged
•The injured section’s function will be “rerouted” to an undamaged section
The Divided Brain
•The hemispheres each show lateralization
–They specialize in certain tasks
•Right hemisphere – motor movements
•Left hemisphere – verbal and speech tasks
•The corpus callosum connects the hemispheres and allows them to communicate