Biological Basis of BehaviorChapter 2
What are the different ways for doctors to see inside your body?
• CAT (CT Scan)– noninvasive medical test that
helps physicians diagnose and treat medical conditions
– scans of internal organs, bones, soft tissue and blood vessels
– one of the best and fastest tools for studying the chest, abdomen and pelvis
PET- Positron Emission Tomography Scan
• nuclear medicine imaging• uses small amounts of radioactive material to
diagnose or treat a variety of diseases, including many types of cancers, heart disease and certain other abnormalities within the body
• scan measures important body functions
MRI- Magnetic Resonance Imaging
• uses a powerful magnetic field, radio frequency pulses and a computer to produce detailed pictures of organs, soft tissues, bone and virtually all other internal body structures.
Functional MR Imaging (F-MRI)
• imaging uses a powerful magnetic field, radio frequency pulses and a computer to produce detailed pictures of organs, soft tissues, bone and virtually all other internal body structures
• examine the anatomy of the brain
EEG- Electroencephalogram
• test used to detect abnormalities related to electrical activity of the brain
• most common reason an EEG is performed is to diagnose and monitor seizure disorders
Transcranial Doppler
• test that measures the velocity of blood flow through the brain's blood vessels
Ultrasound• Involves exposing part of the
body to high-frequency sound waves to produce pictures of the inside of the body
• Ultrasound is used to help physicians evaluate symptoms such as:
• pain • swelling • infection
How does our body work?
You’ve Got a Lot of Nerve!!
• The brain can not work without your Nervous System.
• The nervous system acts as a choreographer; it constantly sends and receives messages that coordinate the stage show of human behavior.
Neuron StructureSynapse
Synapse
It all begins with the Neuron
An individual nerve cellThese neurons send information throughout our whole body
Pg. 59
Three types of neurons–Sensory (sometimes called Afferent)
–Motor (sometimes called Efferent)
–Inter (interneuron)
Sensory Neurons(Afferent Neurons)
• Take information from the senses to the brain.
Activity
Motor Neurons(Efferent Neurons)
• Take information from brain to the rest of the body.
Activity
Inter Neurons• Takes messages from
Sensory Neurons to other parts of the brain
or to Motor Neurons.
Think of it this way…• You are sitting in math class and that
really annoying guy sneezes on the back of your head.
• Sensory nerves send the feeling of sticky wetness up your spinal cord to your brain.
• Sensory nerves pass the information off to interneurons.
• Interneurons then tell the motor nerves the plan.
• Motor nerves then travel down your body and help your hand reach around and smack the guy upside the head.
How Does A Neuron Work?How does it send a message in our body??
When a neuron is hanging out doing nothing, it is called Resting Potential
When it decides to go to work and send a message it is called Action Potential(the process by which a neuron fires)
Pg. 60
Steps of Action PotentialDendrites receive a chemical message
from another neuron across the synapse.Pieces of this chemical message stick to
the dendrite and these pieces keep adding up.
When the dendrite has taken as much of the chemical that it can hold the soma reaches its threshold and must fire
This is called the all-or-none response.
The All-or None Response• The idea that either
the soma (cell body) fires or it doesn’t –no part way firing–And it is same
strength each time…no stronger or weaker signals–And it is the same
direction each time
• The message then travels down the axon in the next neuron where it is stored waiting to reach its next threshold
• Terminal buttons turn these messages into chemicals (neurotransmitter) and shoots the message to next neuron across the synapse.
• The process is repeated again and again until the message reaches where it needs to go
Steps of Action Potential – cont.
• Sometimes there is too much chemical that is sent across the synapse and it is involved in a process called Reuptake– Chemical that is extra goes back to the neuron
that sent it out • Natures version of recycling
– If Reuptake doesn’t happen, there could be some type of bodily problem
Pg 61
Refractory Period
• The amount of time it takes for an excitable membrane to be ready for a second stimulus once it returns to its resting state following excitation
Field Trip
Reflexes• Normally, sensory
(afferent) neurons take info up through spine to the brain.
• Some reactions occur when sensory neurons reach just the spinal cord.
• Survival adaptation.
Neurotransmitters• Natural chemical
messengers released by terminal buttons
• Different ones do different things to your body.
• Each neurotransmitter has a specific shape that fits into a specific shape of a dendrite
Acetylcholine (ACH)• Its function is memory, mood and motor
movementTo much and you will…
Not enough and you will experience…
Lack of ACH has been linked to Alzheimer’s disease.
shake
paralysis
Dopamine• Its function is motor movement and feelings
of excitementLack of dopamine is associated with Parkinson’s disease.•People can’t make smooth movements
Overabundance is associated with schizophrenia.
Serotonin• Deals with mood
control.Lack of serotonin has been linked to depression.
Too much..headaches
Norepinephrine• Plays a role in attention and focus• Plays a part in flight or fight
To much… fear andanxiety
Not enough…depression
Endorphins• Its function is with pain
control.– The body’s natural pain killer– “runners high”
We become addicted to endorphin causing feelings.
GABA• A major inhibitory
neurotransmitter: controls neural excitement throughout the nervous system
• Regulates muscles tone
• Used to treat ADHD
• Undersupply linked to seizures, tremors and insomnia
Glutamate
• Major excitatory neurotransmitter; involved in memory and learning
• Oversupply = overstimulated brain causing migraines or seizures
• This is why people avoid MSG in foods!
Now, although we have all of these neurotransmitters naturally in
our bodies, modern medicine has figured out a way to manipulate
them using what we call
Agonists and Antagonists
Agonists Chemicals that mimic the action
of a particular neurotransmitter Nicotine, morphine, and caffeine
are examples A copy of the “key”
Antagonists Chemicals that block the action of
a particular neurotransmitter. Because they occupy the receptor
site, they prevent otherneurotransmitters from acting.
Some drugs can block the neurotransmitter responsible for movement thus paralyzing an individual