PS101 Midterm Review
Plato believed the mind was inside the brain. Aristotle believed that the mind was within the
Psychologists say that the mind and brain are one
Blueprint of the Nervous System
Central Nervous system (CNS): (brain and spinal cord) receives, processes, interprets, & stores
incoming sensory information; sends out messages to muscles, glands, and organs. (tastes,
sounds, smells, colour, pressure on the skin, etc)
- The spinal cord is a bridge between the brain and parts of the body below the neck. A
collection of neurons and supportive tissue running from the base of the brain down the
centre of the back, protected by a column of bones (the spinal column)
Peripheral Nervous System (PNS): handles input and output from the CNS; All portions of the
nervous system outside the brain & spinal cord
- Sensory nerves carry messages from special receptors in the skin, muscles, and other
internal and external sense organs to the spinal cord, which sends them along to the brain.
(Activities of our own bodies)
- Motor nerves carry orders from the central nervous system to muscles, glands, and internal
organs. (Enable us to move, includes hormones)
- Somatic nervous system: the subdivision of the PNS that connects to sensory receptors and
to skeletal muscles; sometimes called the skeletal nervous system. (when you feel a bug on
your arm, your somatic nervous system is active)
- The autonomic nervous system: A subdivision of the PNS that regulates the internal organs
and glands. Composed of the nerves that connect to the heart, blood vessels, smooth muscles
o Sympathetic and Parasympathetic nervous system: these two parts work together in
apposing ways, to adjust the body to changing circumstances
o Sympathetic works as the accelerator of a car, mobilizing the body for action and an
output of energy. (fight or flight)
o Parasympathetic acts like the brakes. It does not stop the body, but it does slow things
down to keep them running smoothly.
Communication in the Nervous System:
- Neurons (nerve cells) conduct electrochemical signals; basic unit of the nervous system.
Estimates of the number of neurons range from 100-500 billion. They range in size and
- Glia cells that support nurture, and insulate neurons, remove debris when neurons die,
enhance the formation & maintenance of neural connections, and modify neural functioning.
They work like glue. About 90% of brain cells are Glial cells. Neuron Structure
Dendrites Branch like fibres that receive info from
other neurons & transmit towards cell bodies.
Cell body Keeps neurons alive & plays a key role in
determining whether neuron will fire
Axon Extending fibre that conducts impulse away
from cell body and transmit to other cells
*Branches at the end are called axon terminals
*Maybe collected together in bundles called nerves.
Myelin Sheath A fatty insulation that may surround
the axon of a neuron.
Neurogenesis the production of new cells
StemCells Immature cells that renew themselves and
have the potential to develop into mature cells; given
encouraging environments, stemcells from early
embryos can develop into anycells.
Neurons communicate through
the synapse. Includes the axon
terminal, synaptic cleft, and receptor sites in the membrane of the receiving cell. This is where a
transmission of a nerve impulse from one nerve cell to another occurs.
Action potential is a brief change in electrical voltage that occurs between the inside and outside
of an axon when a neuron is stimulated; it serves to produce an electrical impulse.
Neurotransmitter is a chemical substance that is released by transmitting neuron at the synapse
and that alters the activity of a receiving neuron. (Serotonin, dopamine, acetylcholine,
norepinephrine, GABA, Glutamine)
Each neurotransmitter has different effects
o Serotonin: sleep, appetite, sensory perception, temperature regulation, pain suppression,
o Dopamine: voluntary movement, learning, memory, emotion, pleasure or reward,
response to novelty
o Acetylcholine: muscle action, cognitive functioning, memory, and emotion
o Norepinephrine: increased heart rate, slowed intestinal activity during stress, learning,
memory, dreaming, waking, emotion
o GABA: major inhibitory neurotransmitter o Glutamate: Major excitatory neurotransmitter in brain
How Neurons Communicate:
- Excitatory changes- voltage shift in a positive direction
o Increases probability of receiving neuron firing
- Inhibitory changes a voltage shift in a negative direction
o Decreases probability of receiving neuron firing
Reuptake: Neurotransmitters in the synapse are reabsorbed into the sending neurons through the
process of reuptake. This process applies brakes on neurotransmitter action.
Key & Lock Mechanism
Brain plasticity: The ability to change and adapt in response to experience
- Behavioural deficits that occur as a result of brain damage may be lessened by enriching
environment people live in.
Endorphins are the brains natural opiates. Hormones are long distance messengers
- endocrine glands: internal organs that produce hormones and release them into the
- Melatonin regulate daily biological rhythms, sleep.
- Oxytocin Chilbirth contractions, milk ejection
- Adrenal hormones emotion, stress, epinephrine
- Sex hormones angrogens & estrogens
Mapping the Brain.
- Lesion method: involves damaging or removing section of brain in animals and then
observing the effects
- Electrical and magnetic detection the brain can be probed with devices called electrodes
that are connected to a machine that translates the electrical energy from the brain into wavy
lines. (medical diagnoses)
- Electrical Detection Electroencephalography (EEG) regarding neural activity dected by
electrodes, limited precision as recording multiple cells. (focuses on sleep studies,
investigation of seizures, unusual behavior analysis) It is compared to MRI, PET, CAT.
- PET scan (positron-emission tomography) is the method for analyzing biochemical activity in
the brain using injections of a glucose-like substance containing a radioactive element. This
visually displays info about areas that are active or quiet during an activity or response and
about changes associated with disorders
- MRI (magnetic resonance imaging) is a method for studying body and brain tissue using
magnetic fields and special radio receivers. MRIs usually look for tumors, shrinkage of
cerebellar hemispheres, and enlarged ventricles.
Touring the Brain:
-Medulla: Responsible for automatic
-Pons: Involved in sleeping, waking and
-Reticular activating systm (RAS): extends
from brain stem; arouses cortex & screens
-Cerebellum: regulates movement and
balance, Involved in learning of certain kinds
of simple skills & acquired reflexes. It plays a
role in complex cognitive tasks(problem
-Thalamus: Brain structure that relays
sensory messages to the cerebral cortex.
Including all sensory messages except those
from olfactory bulb