1. The Body and the Brain

2. THE BRAIN
The brain is divided into three sections: the Hindbrain, the Midbrain, and the Forebrain.
THE HINDBRAIN:
The medulla is involved in vital functions such as heart rate, blood pressure, and breathing.
The Pons is located in the front of the medulla and is involved in regulating body movement, attention, sleep, and alertness.
The cerebellum is responsible for balance and coordination. A person with an injured cerebellum might walk funny or fall over.

7. THE MIDBRAIN:
The midbrain contains the parts of the brain that are involved in vision and hearing.
The reticular activating system is important for attention, sleep, and arousal.
Stimulation of this portion of the brain makes us alert and increases brain activity.
Some drugs, such as alcohol, reduce the activity of the RAS, which mean the alertness and reaction time will decrease.

9. THE FOREBRAIN:
The forebrain contains four key areas.
The thalamus is a relay station for sensory stimulation.
The thalamus transmits sensory input such as pain or images captured by the eyes.
The hypothalamus (hypo – Greek prefix meaning “under”) is located under the thalamus.
The hypothalamus regulates body temperature, hunger, thirst, sexual behavior, caring for offspring, etc.
The hypothalamus is all about instinct, but humans, unlike animals, use cognitive thoughts – not just instinct.

12. The limbic system is involved in learning and memory, emotion, hunger, sex, and aggression.
If a part of the limbic system is damaged, people can remember old memories, but cannot form new memories.
Damage can also lead people to act passively or aggressively without cause.
The cerebrum (Latin for brain) makes up 70% of the weight of the brain.
The cerebral cortex is the outer layer of the brain.
It is composed of two sides – the right and the left. Each side is called a hemisphere.
The information transmitted from one side is transmitted to the other side of the body.
The structure that connects the two hemispheres is the corpus callosum.

14. The Lobes Each hemisphere has four parts, or lobes.
The frontal lobe is sometimes called the “executive center”
This is where we solve problems, make decisions, and store working memory.
Within the frontal lobe, Broca’s area controls facial muscles – so when people injure this area, they may speak slowly and simply.
The occipital lobe contains the primary visual area of the cortex.
When light strikes the eye, neurons in the occipital lobe fire, allowing us to see.
Damage to this lobe can cause people to recognize an object, but they could be unable to differentiate that object from a similar object.

15. Skin sensations are felt through the parietal lobe.
Different neurons fire depending on the sensation – such as stubbing your toe, or getting stung by a bee.
The temporal lobe collects sounds picked up by the thalamus – and we hear sounds!
Association areas shape information into something meaningful, and each lobe has its own association area.

18. The Two Sides
The cerebral cortex is composed of two sides – or hemispheres.
Hemi – Greek for “half”
The left hemisphere controls the right side of your body.
The right hemisphere controls the left side of your body.
The corpus callosum aids in getting info from one side to the other.
For right-handed people, language originates on the left.
The language functions are usually associated with math and logic.
People who are supposedly logical are “left-brained”.
The right brain (non-language side) is more emotional, creative.
“Right-Brain” types are artistic and imaginative.
However, this “right/Left-brain” is mostly invalid and based on myth.

19. Testing the Brain Accidents give researchers a window into the brain.
Examples, such as Phineas Gage, show psychologists and scientists how different parts of the brain respond to damage.
In 1969, Jose Delgado experimented with electrical stimulation on the brain.
He determined that when an implanted electrode in a bull’s brain, he could use electrical charges to stop a bull in the middle of a charge.
Basically, his thesis stated that electrical stimulation to various parts of the brain could change behavior.
An EEG – or electroencephalogram – is a device that records the electrical activity of the brain.
Electrodes attached to the skull pick up on the electrical charges – called brain waves – and patterns of these waves can be associated with sleep, thought, and relaxation.
A CAT – or computerized axial tomography – scan determines how dense brain tissue is by recording how much radiation is absorbed by an X-ray.
A PET – or Positron Emission Tomography – shows brain activity as it occurs so researchers can see which parts of the brain are stimulated when listening to music, performing math, or having a discussion with friends.

21. PET scan

22. CAT scan

23. MRI of brain on Meth

24. The Nervous System
The nervous system regulates our internal functions.
The central nervous system consists of the brain and the spinal cord.
The peripheral nervous system is made up of nerve cells that send messages between the central nervous system and all the parts of the body.
Neurons - or nerve cells – run through our bodies and communicate with each other.
Neurons send and receive messages from other structures of the body, such as muscles and glands.
Each of us has over 100 billion neurons – mostly found in our brains.
Neurons look like trees.
Each neuron is made up of a cell body, a dendrite, and an axon.
The cell body looks like the top of the trunk. The cell body produces energy that fuels the activity of the cell.
The axons look like the root of a tree. They carry messages away from the center cell body.
The dendrites look like the branches of the tree. They receive information from other neurons and pass the message through the cell body.

26. Some neurons are as small as an inch in length.
Others, like the neurons that run through our legs, can be several feet long.
Myelin is a white fatty substance that insulates and protects the axon.
The myelin casing also helps to speed up the transmission of the message.
The fibers at the end of the axon are called axon terminals.
Messages are sent from the axon terminals of one neuron to the dendrites of other neurons.
In order for the messages to be sent to each other, they must travel across the synapse – or the junction between the axon terminals of one neuron and the dendrites of another.
The coolest part about the synapse is the fact that new ones develop between neurons when we learn something new.

27. Neurons travel in varying directions depending on the message.
For example, when you stub your toe, the sensory neurons carry information received by the senses to the central nervous system.
Motor neurons are the nerve cells that carry information from the CNS to the muscles and glands and influence their functions.
When you touch the hot stove, the sensory neurons tell the CNS that the stove is hot.
The motor neurons then travel from the CNS to tell the muscle to move the hand away from the stove.
Other motor neurons may stimulate the heart and make it beat faster because of the situation.

29. A neurotransmitter is a chemical that is stored in sacs in the axon terminals.
There are several types of neurotransmitters.
When a person thinks about a friend, waves their hand, or yawn, neurotransmitters are involved.
Dopamine is a neurotransmitter that is involved primarily in motor behavior.
A deficiency in dopamine levels contributes to Parkinson’s Disease – which involves a loss of muscle control filled in with tremors and rigid movement.
An excess of dopamine contribute to schizophrenia.

30. The Central Nervous System
The spinal cord extends from the brain down the back, ending below the hips.
The spinal cord is a column of nerves and it is protected by the bones of the spine.
The spinal cord is also responsible for spinal reflexes.
A spinal reflex is an automatic response to something – like the hot stove/pull away situation.
Why do we blink when dust gets in our eyes? Why do some of us sneeze when we sniff pepper?

32. The peripheral nervous system lies outside the central nervous system.
The somatic nervous system transmits sensory messages to the CNS.
The SNS allows us to experience the difference between hot and cold, pain and pleasure.
The autonomic nervous system regulates the body’s vital functions, such as heartbeat, breathing, digestion, and blood pressure.
The autonomic nervous system is interesting because is can be effected by emotion.

33. The fight-or-flight response occurs because the sympathetic system is activated when a person is “going into action”.
This sympathetic system can disturb the ANS. Stress can cause digestion to falter, can increase and decrease the heartbeat in specific situations, and can elevate the blood pressure.
The parasympathetic system restores peace in the body.

34. ANS

36. GLANDS
The endocrine system consists of glands that secrete substances called hormones into the bloodstream.
Hormones stimulate growth and reactions, such as changes in mood and activity levels.
Hormones are produced by several different glands.
The pituitary gland (just the size of a pea and situated under the hypothalamus), controls growth hormones, hormones (Oxytocin) that stimulate labor for pregnant women, and “mothering instincts”.
The thyroid gland produces thyroxin which affects the body’s metabolism.
Too little thyroxin leads to hypothyroid disorder – and these people can be overweight.
Too much thyroxin leads to hyperthyroid disorder, which can make people lose weight, become hyperactive, or sleepless.

38. The adrenal glands are located above the kidneys and secrete cortical steroids.
Cortical steroids increase resistance to stress and promote muscle development.
The adrenal glands also release adrenaline… meant to help people in a stressful situation.
Nonadrenaline also steps in to help calm people during the stressful situation, whereas adrenaline prepares people for a fight. (Fight-or-Flight response)
The Testes produce testosterone and small amounts or estrogen and progesterone in males.
It is responsible for pushing boys through puberty so that they are ready to reproduce.
The ovaries produce estrogen and progesterone and small amounts of testosterone in women.
Again, the ovaries prepare women for puberty – which lead to reproduction and childbirth.
Really, sexual attraction is very chemical (or hormonal) because women have higher libido’s when they are ovulating because there is more estrogen in their body.

40. Heredity
Heredity is the transmission of characteristics from parents to offspring.
Heredity – while determining hair color, eye color and height – can also determine some psychological traits.
Shyness, leadership, aggressiveness, etc., can be linked to heredity.
However, for years, the debate has raged on about Nature vs. Nurture.
Does heredity really determine behavior?
Or is it purely based on upbringing?
As humans, we loath the nature idea because it states that everything is predetermined – meaning that we cannot become smarter or more athletic than our biology allows.
Some psychologists argue that heredity cannot determine destiny because the environment DOES determine how a person develops.

41. The best way to test this debate is by studying….?
Twins.
Identical twins share 100% of their genes.
Their DNA is identical, yet their fingerprints are different…
Fraternal twins, however, only share about 50% of their genes.
Therefore, identical twins are more likely to share traits – both positive and negative.
Identical twins, for example, are more likely to both develop autism than fraternal twins.
Beginning in 1979, Thomas Bouchard began studying twins that were being reared apart.
He found that twins who had never met one another – and had been “nurtured” differently – still shared unique mannerisms.
Researchers also study adopted children because they are removed from their biological families and can still share commonalities with their actual parents.
These studies can be controversial because it relies on twins, siblings, or children to remain apart – which is difficult to maintain ethically at times.