1) Neurons have a cell body that contains a nucleus.
- The nucleus has the hereditary material that will determine how the cell will
function.
- Neurons are held together by glial cells (fatty insulated things)
- Glial cells nourish the neurons, insulate them, help repair damage and help
support neural functioning.
- The neuron has a cell body with a cluster of fibres (dendrites) at one end.
o Dendrites receive messages
- Opposite end is a long, slim, tube-like extension (axon)
o Axon carries messages
- Axons end in small bulges (terminal buttons)
o Terminal buttons send messages
- Most axons are protected by Myelin Sheath
o Myelin Sheath prevents messages from short-circuiting one another
o It also insulates the axon
2) Neurons either fire or they don’t fire.
- “All-or-none” law – neurons are either on or off.
- Before a neuron fires, it’s in a resting state – has a negative charge.
- When a message arrives at a neuron, its cell membrane opens briefly to allow
positively charges ions to rush in.
- These positive ions turn the neuron from negative to positive.
- When the positive charge reaches a critical level, and electrical impulse
(action potential) travels along the axon of the neuron.
- The action potential moves from one end of the axon to the other.
- As the impulse travels along the neuron, the movement of ions causes a
change in charge from negative to positive in successive (following one
behind the other) sections of the axon.
- After the impulse has passed through a particular section of the axon,
positive ions are pumped out of that section, and its charge returns to
negative.
- When the nerve impulse comes to the end of the axon and reaches a terminal
button, the terminal button releases a chemical courier (neurotransmitter).
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Each neurotransmitter has a distinctive configuration (like a jigsaw puzzle
piece) that allows it to fit into a specific type of receptor site on the receiving
neuron.
o Only when it fits perfectly, is the communication complete.
After the neurotransmitter fits, its either an excitatory or inhibitory message.
o Excitatory Message: a chemical message that makes a neuron more
likely to fire and an action potential will travel down its axon/
o Inhibitory Message: a chemical message that prevents or decreases the
likelihood that a neuron will fire.
The extra neurotransmitters that remained at the site of the synapse go to
reuptake.
o Reuptake is the reabsorption of neurotransmitters by a terminal
button.
3) Neurotransmitters
- Acetylcholine (ACh)
o Muscle movement, cognitive functioning
- Glutamate
o Forming and storing memories
- Gamma-amino Butyric Acid (GABBA)
o Eating, aggression, sleeping
- Dopamine
o Muscle disorders, mental disorders, Parkinson’s Disease
- Serotonin
o Sleeping, eating, mood, pain, depression
- Endorphins
o Pain suppression, pleasurable feelings, appetites, placebos.
4) Central Nervous System
- Brain and spinal cord
- Brain controls behaviour
- Spinal cord transmits messages between the brain and the body
Peripheral Nervous System
- Contains all parts of the nervous system other than the brain and the spinal
cord
- Somatic Division/Autonomic Division
o Somatic Division
 Controls voluntary muscle movements
 Communicates info to and from sense organs.
 IE: motion of eyes to read this
o Autonomic Division
 Involuntary, automatic and unconscious movements.
 You don’t think about doing them.
 IE: breathing, heartbeat
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Subdivides of Autonomic Division – Sympathetic and Parasympathetic
Division
o Sympathetic Division
 Prepares the body for action in stressful situations
 “Fight or flight” response.
 Adrenaline rush feeling
 Heart accelerates, digestion slows, pupils widen, sweating
o Parasympathetic Division
 Calms the body after the emergency has ended
 “Rest and Digest”
 Brings everything back down
 Heart slows, digestion increases, pupils constrict, no sweating
5) Central Core
- Medulla
o Critical body functions/unconscious functions
o Heart rate, breathing
- Pons
o Transmitter of motor information
o Muscle coordination, integrates movement between right and left
halves of the body, sleep
- Cerebellum
o Balance
- Reticular Formation
o Attention and concentration
o Makes decisions
o Soccer Goalie – concentrates ONLY on the ball
- Thalamus
o Relay station for information about senses
- Hypothalamus
o Maintains homeostasis and produces vital basic behaviour
 Homeostasis = keeping everything in balance
o Eating, drinking, sexual behaviour
Limbic System
- Controls eating, aggression, and reproduction
- Self preservation, learning, memory
6) Cerebral Cortex
- Frontal Lobe
o Planning and organizing ability
o Coordinating and initiating complex body movements
o Broca’s Area – controls speech production
- Parietal Lobe
o Somatosensory Strip – responsible for receiving bodily sensations for
specific parts of the body
- Temporal Lobe
o Auditory information is registered
o Language
7) – The left hemisphere controls the right side of your body; the right hemisphere
controls the left side of your body
- Researchers found that people with speech difficulties tended to have
physical damage to the left side of the brain.
- Physical abnormalities in the right side caused fewer speech problems
o Language is lateralized (left side of the brain)
 Lateralized means its located more in one hemisphere than the
other
- Left hemisphere
o Language, speech, writing, calculation, time sense, rhythm
- Right hemisphere
o Nonverbal, perceptual skills, visualization, recognition of patterns,
faces, melodies
- Split Brain – corpus callosum cut surgically
- Right and left hemispheres specialize in handling different sorts of
information
o However, both are capable of understanding, knowing and being
aware of the world, just in different ways.
8) Endocrine System
- Made up of glands that secrete chemicals directly into the blood stream of the
lymph system.
o Chemicals = hormones