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Neurons
• Neurons are basic nerves cells
– Dendrites branching extensions of neurons that
receive chemical messages
– Axon an extension from the cell body through which
messages pass to other neurons
– Myelin sheath a layer of fatty tissue that enables
faster transmission speed of neural impulses
– Action potential the electrical charge that travels
down the axon causing the neuron to “fire”
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Neural Structure
Dendritic Spines
Basket cell
(Cerebellum)
Golgi type II
(cortex)
Neural Activity
• Inside the neuron has a negative ionic charge
• (negative inside/positive outside) = resting
potential
• Neurons are selectively permeable (usually
blocking POSITIVELY charged sodium ions until
given the signal to fire
• Depolarization occurs when neurons allow
sodium ions inside causing neurological firing
Neural Activity
• All or nothing response neurons either fire or
they don’t…There is no in between
• The gaps between neurons are called synapse
or the synaptic gap or cleft
• Neurotransmitters are chemical messengers
that travel between the synaptic gap; binding to
receptors determining whether the neuron will
generate an impulse and allowing depolarization
to occur
Neural Structure
AXON HILLOCK
Neurotransmitters

This Info can be excitatory or inhibitory to a
neighboring neuron
Neurotransmitters
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•
•
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•
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Acetylcholine
Dopamine linked
Seratonin
Endorphins
Norepinephrine
Excessive amounts of neurotransmitters
are reabsorbed by the neurons in a
process called reuptake
Neurotransmitters
Neurotransmitters
• Agonists excite; blocking reuptake and
cause neurons to fire rapidly
– Black widow venom causing convulsions,
muscular contractions (++ACl)
• Antagonists inhibit the neurotransmitters
release
– Botox paralyzing muscular function
Nervous System
• The body’s electrochemical network that
consists of all the nerve cells of the:
– Central Nervous system (CNS)
– Peripheral Nervous system
Nervous System
• Central Nervous System
– Brain
– Spinal cord
• Peripheral Nervous System (everything else)
– Sensory neurons
– Motor neurons
– Sensory neurons and motor neurons connect
the CNS to the rest of the body
Peripheral Nervous System
• Consists of 3 types of neurons
– Sensory neurons send info from the body’s
tissues and organs to the CNS
– Motor neurons send info from the CNS back
to the body’s tissues
– Interneurons process and interpret info from
sensory and motor neurons
Sensory Neuron
Bipolar -------(vision)
--- Unipolar
(Pain & Touch)
Peripheral Nervous system
• Somatic nervous system
– Skeletal muscles
• Autonomic Nervous system
– Internal organs
– Glands
Autonomic Nervous system
• Sympathetic nervous system
– Arouses and alerts
• Parasympathetic nervous system
– Calms and conserves energy
Central Nervous System
• Consists of the brain and spinal cord
• Reflexes are automatic responses to stimuli
– Single sensory neuron and a motor neuron
• Knee jerk reflex
– Pain reflexes often work in the same way
• Stepping on a nail but jumping away before realizing what
you stepped on
• Neural networks
– Clusters of neurons that strengthen connections
– Learning builds and stimulates neural networks
Endocrine System
• Endocrine system refers to the body’s other chemical
messengers HORMONES
• Neurotransmitters quickly send messages and
communicate; hormones slowly send messages but
have long lasting effects
• The endocrine system effects
–
–
–
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Growth
Reproduction
Metabolism
Mood
• The pituitary gland is the master gland which is
controlled by the hypothalamus
• Medulla
– Involuntary functioning, heart rate, breathing, blood
pressure
• Reticular formation
– arousal
• Thalamus
– Central processing unit, routes your senses except
smell
• Cerebellum
– Balance, motor functioning, coordination
Brain structure
• Limbic system
– the C shaped structure that is the hub of the brain’s older
structures and the cerebral hemispheres
• Hippocampus
– Processes memory
• Hypothalamus
– Hunger, thirst, sex drive
– Controls the pituitary gland
– Reward centers of the brain
• Amygdala
– Pea shaped structures linked to fear and aggression
• Pons
– Sleep regulation
• Corpus callosum
– The bundle of nerves that separates the
hemispheres of the brain
• Cerebrum
– Consciousness, memory, problem solving
Lobes of the Brain
• The cerebral hemispheres are divided into 4 lobes
• Each lobe has a function but many functions require the
interplay of several lobes
• Frontal lobe
– Personality, attention span, emotional control, coordination of
hands, feet, arms and legs
• Parietal lobe
– Sense of touch, awareness of your body, depth perception
• Occipital lobe
– Interprets signals sent from your eyes creates the mental images
you see
• Temporal lobe
– Sense of hearing and smell
Brain structures
• Motor cortex
– Rear of the frontal lobe controls voluntary movement
• Somatosensory cortex
– Rear of the frontal lobe; in front of the parietal lobe receives info
from senses
– Provides processing for your sense of touch
• Association areas
– Specialized areas of the brain that are involved in higher mental
functioning
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Broca’s area language expression (speak your own words)
Wernickes area controls language reception (speak meaningfully)
Angular gyrus visual cues into auditory
Visual cortex constructs our moving mental picture to the occipital
lobe
• Auditory cortex helps interpret sounds
Headache
• The brain is not sensitive to pain because it
lacks pain-sensitive nerve fibers.
• Types of “headaches”
– Vascular- migraines headaches which are
neurological in nature
– Muscular/myogenic- tensing or tightening of the
facial and neck muscles
– Cervicogenic- disorders of the neck precipitated by
awkward neck positioning or neck movement
– Traction and inflammatory- stems from other
disorders ranging from a stroke to sinus infection
Brain injury
• Temporal lobe
– Sound recognition, voice recognition
• Occipital lobe
– blindness
• Parietal lobe
– Defects in touch, self perception
• Frontal lobe
– Concentration, abstract thinking, gross and fine motor ability
• Thalamus
– Altered states of arousal, memory defects, speech defects
• Hypothalamus
– Uncontrollable eating/drinking, hyposexuality
• Cerebellum
– Motor control issues/coordination
Sensory and Motor defects
• Brain lesions are the most common
causes of sensory and motor defects
• Lesions are tissue that has been altered
by:
– Chemical imbalance in the brain
– Physical injury
– Infection
• Plasticity
– The brains ability to modify itself after damage
Sensory and Motor defects
• Amnesia
– Memory loss
• Anomia
– Inability to find words to things
• Alexia
– Inability to read
• Aphasia
– Impaired speech or writing ability
• Anopia
– Inability to see
Brain Imagery
• EEG (electroencephalogram)
– Records an amplified reading of the brain’ss electrical
activity or waves
• PET (positron emissions tomography) scan
– Visual scan of glucose activity in areas of the brain
when stimulation is present
• MRI (magnetic resonance imaging)
– Uses magnetic fields and radio waves to create a
computer generated image of the brain
– Allows doctors to see brain structures
• fMRI (functional magnetic resonance imaging)
– Allows doctors to see blood flow and brain activity
Figure 2.12 An electroencephalograph providing amplified tracings of waves of electrical activity in the brain
Myers: Psychology, Eighth Edition
Copyright © 2007 by Worth Publishers
Figure 2.13 The PET scan
Myers: Psychology, Eighth Edition
Copyright © 2007 by Worth Publishers
Figure 2.14 MRI scan of a healthy individual (left) and a person with schizophrenia (right)
Myers: Psychology, Eighth Edition
Copyright © 2007 by Worth Publishers
Figure 2.15 Brain reading
Myers: Psychology, Eighth Edition
Copyright © 2007 by Worth Publishers