“The Purpose of psychology is to give us a completely different idea of the things we

know best.” -Paul Valery, Tel Quel, 1943

MythBusters: Secrets and Lies

Nervous System – controls and coordinates our perceptions, our thinking, our actions.

Neurons- brain cells and nervous system cells.

Neurons exist to perform three tasks:◦ 1. to receive information (in the form of electrochemical

impulses) from neurons that feed into it.◦ 2. to carry this information down its length◦ 3. to pass the information on to the next neuron in line.

Every behavior, thought, and emotion we experience depends on the

neurons ability to process and move information.Intro to Nervous System

All brain activity hinges on the workings of brain cells called neurons.

3 Types of Neurons◦ Sensory – Respond to input from the senses.◦ Motor – send signals to muscles to control movement◦ Interneurons – stand b/w the neurons that register what is

out there and those that control movement. Average human brain- 100 billion neurons. Neurons either send impulses or they don’t Neurons value is how they affect other neurons

(How useful would the internet be if only one computer was connected to it?)

Brain Circuits – sets of neurons that affect one another. Chain reaction.Neruons

Cell Body – produces energy that fuels the neuron. Contains nucleus and cytoplasm.

Dendrites – thin fibers that carry impulses from other neurons toward the cell body.

Axon- fibers that carry impulses away from the cell body to other neurons.

Myelin Sheath – a fatty substance that insulates and protects axon.

Axon Terminals – small fibers branch out◦ Airport is axon, terminals release planes to other

airports Neurons are the largest cell in the body.

Synapse – area in which two nerve cells come into contact.◦ Transmission of the nerve impulse across the synapse is

accomplished w/ the help of neurotransmitters-chemicals that send signals. Stored in sacs in the axon terminal

Messages only travel in one direction –dominos New synapses can develop b/w neurons that

were not previously connected, as when we learn something new.

Neurotransmitters are released into synapse and converted into an electrical impulse

Fig. 3-4, p. 54

A neuron always fires with the same intensity. Toilet Analogy

◦ Like a neuron, a toilet has an action potential. When you flush, an “impulse” is sent down the sewer pipe.

◦ Like a neuron, a toilet has a refractory period. There is a short period after flushing when the toilet cannot be flushed again while the tank is being refilled.

◦ Like a neuron, a toilet has a resting potential. The toilet is “charged” when there is water in the tank and it is capable of being flushed again.

◦ Like a neuron, a toilet operates on the All –or –None Principle- it always flushes w/ the same intensity regardless of how much force is applied to the handle.

Brain and Spinal Cord◦ Spinal Cord

Main pathway for info b/w brain and Peripheral Nervous System. (Talk about later)

Vertebrae- protective spine of bones Brain - Command Center 3 Major parts of Brain

◦ 1. Cerebrum – 7/8 of the Brain, Center of Intelligence Cerebral Cortex – Gray Matter receives sensory impulses from

the body and coordinates responses. Thalamus – relay center for impulses Hypothalamus – controls bodily functions such as thirst, hunger,

body temp. and blood pressure.

◦ 2. Cerebellum – coordination of muscles◦ 3. Brain Stem – all nerves from spinal cord to cerebrum.◦ Cerebrum and Hypothalamus

Brain Stem Con’t◦ Parts◦ Medulla Oblongata – controls involuntary actions –

circulation, digestion, etc. ◦ Pons – Connects 2 Hemispheres of cerebellum and links

cerebellum w/ cerebrum.◦ Midbrain – controls responses to sight.

2 Hemispheres◦ Corpus Callosum – connects…What happens if it is cut?◦ Most functions occur on both sides◦ Left v. Right

Fig. 4-1, p. 82

Left Brain Right Brain

Uses logic Uses feeling

Detail oriented “big picture” oriented

Facts rule Imagination rules

Words and language Symbols and images

Present and past Present and future

Math and science Philosophy and religion

Can comprehend Can “get it” (i.e. meaning)

Knowing Believes

Acknowledges Appreciates

Order/pattern perception Spatial perception

Knows object names Knows object function

Reality based Fantasy based

Forms strategies Presents possibilities

Practical Impetuous

Fig. 4-6, p. 86

PNS – made up of nerve cells that send messages b/w the central nervous system and all the parts of the body.

Somatic NS◦ Movements◦ Sensory Neurons- fur of a cat, hot or cold – to CNS◦ Motor Neurons – balance, posture – Away from CNS◦ Reflex – doctors check reflexes to tell if there’s nerve

damage. Autonomic NS – occurring involuntarily or

“automatically”◦ Regulates blood pressure, digestive system, heart beat◦ Important to psych b/c involved w/ emotion and stress.

Autonomic NS Con’t◦ Sympathetic – “Fight or Flight”

Prepares body for action Raises blood pressure Pupils dialate Digestive tract slowed Increased respiration

◦ Parasympathetic Calms body Pupils constrict, etc. What parts of the nervous system was affected when I

blew the airhorn? What did your neurons do when I fired the horn? What

was the path that followed down the neuron? Think about when we were in the hall.