Unit 3

Biological Bases of Behavior

https://www.youtube.com/watch?v=zLp-edwiGUU

The Nervous System• The nervous system

consists of the brain, spinal cord, sensory organs, and all of the nerves that connect these organs with the rest of the body.

• Together, these organs are responsible for the control of the body and communication among its parts.

Divisions of the Nervous System

Spinal Injury

• Risk Taking Story

Neurons • Messages to and from the brain

travel along the nerves or strings of long, thin cells called neurons.

• Chemical electrical signals travel down the neurons

• Neurons can fire over and over, hundreds of times a minute

• Neurons fire on an all-or-none principle

• On average a human has 100 Billion neurons

• Dendrites– short thin fibers that

stick out from the cell body

– Receive impulses, or messages, from other neurons and send them to the cell body

Dendrites

• Nucleus – Contains genetic

material for the cell – Acts as the cells brain

Nucleus

• Cell Body– Protects the nucleus – Produces the energy

needed to fuel neuron activity

Cell Body

• Myelin sheath – Insulates and protects

the axon for some neurons

– Multiple sclerosis – myelin sheath is destroyed resulting in erratic and uncoordinated behavior.

– Myelin sheath speeds up the transmission of impulses.

Multiple Sclerosis Video

Myelin sheath

• Axon – Long fiber – Carries the impulses

away from the cell body toward the dendrites of the next neuron.

Axon

• Axon terminals – Small fibers which

branch out at the end of the axon

– Releases the neurotransmitters - chemical messages

• Synapse – Junctions between the

axon terminal and dendrite

Types of Neurotransmitters

• Norepinephrine - memory and learning • Endorphin – inhibit pain • Acetylcholine – movement and memory (too little

Paralysis and Alzheimer’s disease) • Dopamine – learning, emotional arousal and

movement (too much schizophrenia, too little Parkinson’s disease)

• Serotonin – feelings of well being an happiness (too little depression)

https://www.youtube.com/watch?v=W4N-7AlzK7s

The Brain

Crash Course: Meet Your Master

• The human brain is the largest brain of all vertebrates relative to body size

• It weighs about 3 pounds (1.4 kilograms)

• The brain makes up about 2 percent of a human's body weight

• It contains about 100 billion nerve cells (neurons)

3 Major Parts

HINDBRAIN

• The ________________ is involved in the most basic processes of life and includes structures such as the cerebellum, medulla, and pons.

• The ________________ is located behind the spinal cord and helps control posture, balance and voluntary movements.

• The medulla controls _______________, ________________, and ______________________.

• The pons functions as a ________________ between the brain and spinal cord and also provides chemicals necessary to ________________.

MIDBRAIN

• The _________________ is the smallest part of the brain. It is responsible for ________________ sensory information and _________________ it upward.

FOREBRAIN • The forebrain covers the brain’s

______________________. • All sensory information with the exception of

____________________ enters the _________________ and relayed to the appropriate part of the cortex.

• The hypothalamus controls functions such as ________________, _________________, and ______________________.

• The outer layer of the forebrain is known as the _______________________________________.

• The inner layer of the forebrain is known as the _______________________________________.

• The ___________________ gives you the ability to learn and store complex and abstract information.

• The cortex or __________________ of the cerebrum is the site of your ____________________ thinking process, yet it is less than one-fourth inch thick.

• The limbic system found in the ____________________ of the forebrain, is composed of a number of different structures in the brain that regulate our _____________________, and __________________.

• Included in the limbic system are the ___________________, ______________________, _______________________, _________________________.

• The _______________________ controls violent emotions such as ______________and _____________________.

• The hippocampus is important in the formation of _____________________________________.

THE LOBES• The ___________________ is really two

hemispheres, or ______________________. • The two sides are connected by fibers called the

__________________________. • Each cerebral hemisphere has deep groves, some of

which mark regions or ________________.

LEFT BRAIN/RIGHT BRAIN

• In reality the two hemispheres of the brain _______________ and _______________ each other.

• The ___________________ carries messages between the two hemispheres.

• Each hemisphere is connected to one-half of the body in a ___________________ fashion.

• The left hemisphere is specialized for ____________________, ____________________, and ___________________________.

• The right hemisphere is more adept at___________________ and __________________.

STUDYING THE BRAIN • Psychologist who map out the brain’s fissures and inner recesses

using methods such as recording, stimulating, lesioning, accidents and imaging are known as _____________________________.

• The __________________________ activity of whole areas of the brain can be recorded with an ____________________________.

• Brain surgeon __________________________________ stimulated the brains of his patients during surgery to determine what functions the various parts of the brain perform.

• Scientists sometimes create _________________- by cutting or destroying part of an animal’s brain. If the animal behaves differently after the operation, they assume that the destroyed brain area is involved with that type of behavior.

• In the 1940s Dr. Walter Freeman gained fame for perfecting the lobotomy, then hailed as a miracle cure for the severely mentally ill. But within a few years, lobotomy was labeled one of the most barbaric mistakes of modern medicine.

• https://www.youtube.com/watch?v=_0aNILW6ILk

• Psychologist can learn from the tragedies when some people suffer ____________________. These accidents may involve the brain. Psychologists try to draw a connection between the damaged parts of the brain and a person’s behavior.

• http://www.youtube.com/watch?v=oPAqTP7058Q

• Today psychologists and medical researchers are using sophisticated techniques to study the brain including CAT scans, PET scans, MRIs, EEGs and

• ___________________________________________is used to pinpoint injuries and brain deterioration.

• ___________________________________________is used to see which brain areas are being activated while performing tasks.

• ___________________________________________ is used to study the brain structure and activity.

WHAT ARE THOSE SCANS USED FOR ANYWAY?

Scan What you can see

CATBetter suited for bone injuries, Lung and Chest imaging, cancer detection. Widely used on Emergency Room patients.

MRIBetter suited for Soft tissue evaluation, e.g. ligament and tendon injury, spinal cord injury, brain tumors etc.

PEThow organs and tissues are working

EEGChanges in brain activity resulting from: Epilepsy or other seizure disorder, Brain tumor, Head injury, Inflammation of the brain, Stroke, Sleep disorders, Memory impairment

Endocrine System

• System of glands that secrete hormones – chemical messengers that coordinate and direct target cells and organs.

• Controlled by the hypothalamus - Nerve cells in the hypothalamus control the pituitary gland by producing chemicals that either stimulate or suppress hormone secretions from the pituitary.

Pituitary Gland

• Size of a pea• Located at the base of the

brain • Known as the “Master Gland”. • Produces hormones that

control many functions of other endocrine glands

• Releases many hormones known as releasing hormones or releasing factors.

Thyroid Gland

• Shaped like a butterfly • Located on either side of

larynx, over the trachea• Influences metabolism,

growth and development, and body temperature.

• Thyroxine – controls rate of metabolism

• Calcitonin – helps regulate calcium levels to prevent hypercalcemia

Parathyroid Glands

• Four glands tiny glands about the size of a grain of rice

• Located on thyroid• Controls blood calcium

levels and prevents hypocalcaemia.

• Parathormone

Thymus

• Two irregular shapes • Located in the chest• Helps produce T-cells to

fight of infection and build immunity.

• Begins to disappear during puberty.

Adrenal Glands • Two glands shaped like a

kidney bean. They are about the size of your upper thumb.

• Located at the top of each kidney.

• Have many functions one of which is to control your stress response.

• Release epinephrine and norepinephrine (common name adrenaline and noradrenaline)

Gonads • Ovaries in females and testes in males • Ovaries are about the shape or an

almond. • Testes are two oval shaped glands • located in the pelvic area. • Estrogen – development of female

reproductive organs, secondary sex characteristics.

• Progesterone – plays part in the menstrual cycle

• Testosterone – development of male reproductive organs and secondary sex characteristics

Pancreas

• long, flat gland• Located behind the

stomach• Helps with digestion

and controlling blood sugar levels.

• Insulin – promotes utilization of glucose

• Glucagon – raises glucose levels

Nature Versus Nurture

Are you who you are because of:• The way you were born-

Nature.– Genetics

• The way you were raised- Nurture.– Environmental factors

• Family • Culture • Education • Individual experiences

Identical Twins

• Best way to really study genetics because they come from the same zygote.

• Bouchard Study – 137 sets of twins were separated and raised apart.

• .69 Correlational coefficient for IQ tests of identical twins raised apart.

• .88 raised together.

• http://www.youtube.com/watch?v=Wd5Y3-F79LY

Identical Strangers

• https://www.youtube.com/watch?v=0yTCShemS_0

• Questions: – Why were they

separated? – How were the two

similar? – What does this suggest

about where these traits come from?

Genetics

• Every human cell contains 46 chromosomes (23 pairs).

• Made up of deoxyribonucleic acid- DNA.• Certain segments of DNA control specific

proteins that control some human traits• The segments of DNA are known as genes

– Dominant – Recessive (two recessive means trait will be

expressed)