The Body and the The Body and the BrainBrain

THE BRAINTHE BRAIN The brain is divided into three sections: the The brain is divided into three sections: the

HindbrainHindbrain, the , the MidbrainMidbrain, and the , and the ForebrainForebrain.. THE HINDBRAINTHE HINDBRAIN:: The The medulla medulla is involved in vital functions is involved in vital functions

such as heart rate, blood pressure, and such as heart rate, blood pressure, and breathing.breathing.

The The PPons ons is located in the front of the is located in the front of the medulla and is involved in regulating body medulla and is involved in regulating body movement, attention, sleep, and alertness.movement, attention, sleep, and alertness.

The The cerebellum cerebellum is responsible for balance is responsible for balance and coordination. A person with an injured and coordination. A person with an injured cerebellum might walk funny or fall over.cerebellum might walk funny or fall over.

THE MIDBRAIN:THE MIDBRAIN: The midbrain contains the parts of the The midbrain contains the parts of the

brain that are involved in brain that are involved in visionvision and and hearinghearing..

The The reticular activating system reticular activating system is is important for attention, sleep, and arousal.important for attention, sleep, and arousal.

Stimulation of this portion of the brain Stimulation of this portion of the brain makes us alert and increases brain makes us alert and increases brain activity.activity.

Some drugs, such as alcohol, reduce the Some drugs, such as alcohol, reduce the activity of the RAS, which mean the activity of the RAS, which mean the alertness and reaction time will decrease.alertness and reaction time will decrease.

THE FOREBRAIN:THE FOREBRAIN: The forebrain contains four key areas.The forebrain contains four key areas. The The thalamus thalamus is a relay station for sensory is a relay station for sensory

stimulation.stimulation. The thalamus transmits sensory input such The thalamus transmits sensory input such

as pain or images captured by the eyes.as pain or images captured by the eyes. The The hypothalamus hypothalamus (hypo – Greek prefix (hypo – Greek prefix

meaning “under”) is located under the meaning “under”) is located under the thalamus.thalamus.

The hypothalamus regulates body The hypothalamus regulates body temperature, hunger, thirst, sexual temperature, hunger, thirst, sexual behavior, caring for offspring, etc.behavior, caring for offspring, etc.

The hypothalamus is all about instinct, but The hypothalamus is all about instinct, but humans, unlike animals, use cognitive humans, unlike animals, use cognitive thoughts – not just instinct.thoughts – not just instinct.

The The limbic systemlimbic system is involved in learning is involved in learning and memory, emotion, hunger, sex, and and memory, emotion, hunger, sex, and aggression. aggression.

If a part of the limbic system is damaged, If a part of the limbic system is damaged, people can remember old memories, but people can remember old memories, but cannot form new memories.cannot form new memories.

Damage can also lead people to act Damage can also lead people to act passively or aggressively without cause.passively or aggressively without cause.

The The cerebrum cerebrum (Latin for brain) makes up (Latin for brain) makes up 70% of the weight of the brain.70% of the weight of the brain.

The The cerebral cortex cerebral cortex is the outer layer of the is the outer layer of the brain. brain.

It is composed of two sides – the right and It is composed of two sides – the right and the left. Each side is called a hemisphere.the left. Each side is called a hemisphere.

The information transmitted from one side The information transmitted from one side is transmitted to the is transmitted to the otherother side of the body. side of the body.

The structure that connects the two The structure that connects the two hemispheres is the hemispheres is the corpus callosumcorpus callosum..

The LobesThe Lobes Each hemisphere has four Each hemisphere has four

parts, or lobes.parts, or lobes. The The frontal lobefrontal lobe is is

sometimes called the sometimes called the “executive center” “executive center”

This is where we solve This is where we solve problems, make decisions, problems, make decisions, and store working and store working memory.memory.

Within the Within the frontal lobefrontal lobe, , Broca’s areaBroca’s area controls controls facial muscles – so when facial muscles – so when people injure this area, people injure this area, they may speak slowly and they may speak slowly and simply.simply.

The The occipital lobe occipital lobe contains contains the primary visual area of the primary visual area of the cortex.the cortex.

When light strikes the eye, When light strikes the eye, neurons in the occipital neurons in the occipital lobe fire, allowing us to lobe fire, allowing us to see.see.

Damage to this lobe can Damage to this lobe can cause people to recognize cause people to recognize an object, but they could an object, but they could be unable to differentiate be unable to differentiate that object from a similar that object from a similar object.object.

Skin sensations are Skin sensations are felt through the felt through the parietal lobeparietal lobe..

Different neurons Different neurons fire depending on fire depending on the sensation – such the sensation – such as stubbing your as stubbing your toe, or getting toe, or getting stung by a bee.stung by a bee.

The The temporal lobetemporal lobe collects sounds collects sounds picked up by the picked up by the thalamus – and we thalamus – and we hear sounds!hear sounds!

Association areas Association areas shape information shape information into something into something meaningful, and meaningful, and each lobe has its each lobe has its own association own association area.area.

The Two SidesThe Two Sides The The cerebral cortex cerebral cortex is is

composed of two sides – or composed of two sides – or hemispheres.hemispheres.

HemiHemi – Greek for “half” – Greek for “half” The left hemisphere controls The left hemisphere controls

the the rightright side of your body. side of your body. The right hemisphere controls The right hemisphere controls

the the leftleft side of your body. side of your body. The The corpus callosum corpus callosum aids in aids in

getting info from one side to getting info from one side to the other.the other.

For right-handed people, For right-handed people, language originates on the language originates on the left.left.

The language functions are The language functions are usually associated with math usually associated with math and logic.and logic.

People who are supposedly People who are supposedly logical are logical are “left-brained”.“left-brained”.

The right brain (non-language The right brain (non-language side) is more emotional, side) is more emotional, creative.creative.

““Right-Brain”Right-Brain” types are types are artistic and imaginative. artistic and imaginative.

However, this “right/Left-However, this “right/Left-brain” is mostly invalid and brain” is mostly invalid and based on myth.based on myth.

Testing the BrainTesting the Brain Accidents give researchers a window into the brain.Accidents give researchers a window into the brain. Examples, such as Phineas Gage, show psychologists and Examples, such as Phineas Gage, show psychologists and

scientists how different parts of the brain respond to damage.scientists how different parts of the brain respond to damage. In 1969, In 1969, Jose DelgadoJose Delgado experimented with electrical stimulation on experimented with electrical stimulation on

the brain.the brain. He determined that when an implanted electrode in a bull’s 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 he could use electrical charges to stop a bull in the middle of a charge.charge.

Basically, his thesis stated that electrical stimulation to various Basically, his thesis stated that electrical stimulation to various parts of the brain could change behaviorparts of the brain could change behavior. .

An EEG – or An EEG – or electroencephalogramelectroencephalogram – is a device that records the – is a device that records the electrical activity of the brain.electrical activity of the brain.

Electrodes attached to the skull pick up on the electrical charges – Electrodes attached to the skull pick up on the electrical charges – called brain waves – and patterns of these waves can be called brain waves – and patterns of these waves can be associated with sleep, thought, and relaxation.associated with sleep, thought, and relaxation.

A CAT – or A CAT – or computerized axial tomographycomputerized axial tomography – scan determines how – scan determines how dense brain tissue is by recording how much radiation is absorbed dense brain tissue is by recording how much radiation is absorbed by an X-ray.by an X-ray.

A PET – orA PET – or Positron Emission Tomography Positron Emission Tomography – shows brain activity as – shows brain activity as it occurs so researchers can see which parts of the brain are it occurs so researchers can see which parts of the brain are stimulated when listening to music, performing math, or having a stimulated when listening to music, performing math, or having a discussion with friends.discussion with friends.

PET scanPET scan

CAT scanCAT scan

MRI of brain on MethMRI of brain on Meth

The Nervous SystemThe Nervous System The nervous system regulates our internal functions.The nervous system regulates our internal functions. The The central nervous systemcentral nervous system consists of the brain and the spinal consists of the brain and the spinal

cord.cord. The The peripheral nervous systemperipheral nervous system is made up of nerve cells that send is made up of nerve cells that send

messages between the central nervous system and all the parts of messages between the central nervous system and all the parts of the body.the body.

Neurons Neurons - or nerve cells – run through our bodies and - or nerve cells – run through our bodies and communicate with each other.communicate with each other.

Neurons send and receive messages from other structures of the Neurons send and receive messages from other structures of the body, such as muscles and glands.body, such as muscles and glands.

Each of us has over 100 billion neurons – mostly found in our Each of us has over 100 billion neurons – mostly found in our brains.brains.

Neurons look like trees.Neurons look like trees. Each neuron is made up of a Each neuron is made up of a cell bodycell body, a , a dendritedendrite, and an , and an axonaxon.. The The cell body cell body looks like the top of the trunk. looks like the top of the trunk. The cell body The cell body

produces energy that fuels the activity of the cellproduces energy that fuels the activity of the cell.. The The axonsaxons look like the root of a tree. look like the root of a tree. They carry messages away They carry messages away

from the center cell body.from the center cell body. The The dendrites dendrites look like the branches of the tree. look like the branches of the tree. They receive They receive

information from other neurons and pass the message through the information from other neurons and pass the message through the cell bodycell body..

Some neurons are as small as an inch in length.Some neurons are as small as an inch in length. Others, like the neurons that run through our Others, like the neurons that run through our

legs, can be several feet long.legs, can be several feet long. Myelin is a white fatty substance that insulates Myelin is a white fatty substance that insulates

and protects the axon.and protects the axon. The myelin casing also helps to speed up the The myelin casing also helps to speed up the

transmission of the message.transmission of the message. The fibers at the end of the axon are called The fibers at the end of the axon are called axon axon

terminalsterminals.. Messages are sent from the Messages are sent from the axon terminalsaxon terminals of one of one

neuron to the neuron to the dendritesdendrites of other neurons. of other neurons. In order for the messages to be sent to each In order for the messages to be sent to each

other, they must travel across the other, they must travel across the synapse – or synapse – or the junction between the the junction between the axon terminalsaxon terminals of one of one neuron and the neuron and the dendritesdendrites of another. of another.

The coolest part about the synapse is the fact The coolest part about the synapse is the fact that new ones develop between neurons when we that new ones develop between neurons when we learn something new.learn something new.

Neurons travel in varying directions depending on Neurons travel in varying directions depending on the message.the message.

For example, when you stub your toe, the For example, when you stub your toe, the sensory sensory neuronsneurons carry information received by the senses carry information received by the senses to the central nervous system.to the central nervous system.

Motor neuronsMotor neurons are the nerve cells that carry are the nerve cells that carry information from the CNS to the muscles and information from the CNS to the muscles and glands and influence their functions.glands and influence their functions.

When you touch the hot stove, the When you touch the hot stove, the sensory sensory neurons neurons tell the CNS that the stove is hot.tell the CNS that the stove is hot.

The The motor neurons motor neurons then travel from the CNS to then travel from the CNS to tell the muscle to move the hand away from the tell the muscle to move the hand away from the stove.stove.

Other Other motor neurons motor neurons may stimulate the heart and may stimulate the heart and make it beat faster because of the situation.make it beat faster because of the situation.

A A neurotransmitter neurotransmitter is a chemical that is is a chemical that is stored in sacs in the axon terminals.stored in sacs in the axon terminals.

There are several types of There are several types of neurotransmitters.neurotransmitters.

When a person thinks about a friend, When a person thinks about a friend, waves their hand, or yawn, waves their hand, or yawn, neurotransmitters are involved.neurotransmitters are involved.

Dopamine is a neurotransmitter that is Dopamine is a neurotransmitter that is involved primarily in motor behavior.involved primarily in motor behavior.

A deficiency in dopamine levels A deficiency in dopamine levels contributes to Parkinson’s Disease – which contributes to Parkinson’s Disease – which involves a loss of muscle control filled in involves a loss of muscle control filled in with tremors and rigid movement.with tremors and rigid movement.

An excess of dopamine contribute to An excess of dopamine contribute to schizophrenia. schizophrenia.

The Central Nervous SystemThe Central Nervous System The The spinal cordspinal cord extends from the brain extends from the brain

down the back, ending below the hips. down the back, ending below the hips. The spinal cord is a column of nerves and The spinal cord is a column of nerves and

it is protected by the bones of the spineit is protected by the bones of the spine.. The spinal cord is also responsible for The spinal cord is also responsible for

spinal reflexes.spinal reflexes. A A spinal reflex spinal reflex is an automatic response to is an automatic response to

something – like the hot stove/pull away something – like the hot stove/pull away situation.situation.

Why do we blink when dust gets in our Why do we blink when dust gets in our eyes? Why do some of us sneeze when we eyes? Why do some of us sneeze when we sniff pepper? sniff pepper?

The The peripheral nervous system peripheral nervous system lies lies outside the central nervous system.outside the central nervous system.

The The somatic nervous systemsomatic nervous system transmits sensory messages to the transmits sensory messages to the CNS. CNS.

The SNS allows us to experience the The SNS allows us to experience the difference between hot and cold, pain difference between hot and cold, pain and pleasure.and pleasure.

The The autonomic nervous systemautonomic nervous system regulates the body’s vital functions, regulates the body’s vital functions, such as heartbeat, breathing, such as heartbeat, breathing, digestion, and blood pressure.digestion, and blood pressure.

The autonomic nervous system is The autonomic nervous system is interesting because is can be effected interesting because is can be effected by emotion.by emotion.

The The fight-or-flight fight-or-flight response occurs because the response occurs because the sympathetic system is activated when a person is sympathetic system is activated when a person is “going into action”.“going into action”.

This This sympathetic systemsympathetic system can disturb the ANS. Stress can disturb the ANS. Stress can cause digestion to falter, can increase and can cause digestion to falter, can increase and decrease the heartbeat in specific situations, and decrease the heartbeat in specific situations, and can elevate the blood pressure.can elevate the blood pressure.

The The parasympathetic system parasympathetic system restores peace in the restores peace in the body.body.

ANSANS

GLANDSGLANDS The The endocrine system endocrine system consists of glands that consists of glands that

secrete substances called secrete substances called hormoneshormones into the into the bloodstream.bloodstream.

Hormones Hormones stimulate growth and reactions, such stimulate growth and reactions, such as changes in mood and activity levels.as changes in mood and activity levels.

Hormones are produced by several different Hormones are produced by several different glands.glands.

The The pituitary glandpituitary gland (just the size of a pea and (just the size of a pea and situated under the hypothalamus), controls situated under the hypothalamus), controls growth hormonesgrowth hormones, hormones (, hormones (OxytocinOxytocin) that ) that stimulate labor for pregnant women, and stimulate labor for pregnant women, and “mothering instincts”.“mothering instincts”.

The The thyroid glandthyroid gland produces thyroxin which produces thyroxin which affects the body’s affects the body’s metabolism.metabolism.

Too little thyroxin leads to hypothyroid disorder Too little thyroxin leads to hypothyroid disorder – and these people can be overweight.– and these people can be overweight.

Too much thyroxin leads to hyperthyroid Too much thyroxin leads to hyperthyroid disorder, which can make people lose weight, disorder, which can make people lose weight, become hyperactive, or sleepless.become hyperactive, or sleepless.

The The adrenal glands adrenal glands are located above the kidneys are located above the kidneys and secrete cortical steroids.and secrete cortical steroids.

Cortical steroids increase resistance to stress and Cortical steroids increase resistance to stress and promote muscle development.promote muscle development.

The The adrenaladrenal glands also release glands also release adrenalineadrenaline… meant … meant to help people in a stressful situation.to help people in a stressful situation.

Nonadrenaline also steps in to help calm people Nonadrenaline also steps in to help calm people during the stressful situation, whereas adrenaline during the stressful situation, whereas adrenaline prepares people for a fight. (Fight-or-Flight prepares people for a fight. (Fight-or-Flight response)response)

The The Testes Testes produce testosterone and small amounts produce testosterone and small amounts or estrogen and progesterone in males.or estrogen and progesterone in males.

It is responsible for pushing boys through puberty so It is responsible for pushing boys through puberty so that they are ready to reproduce.that they are ready to reproduce.

The The ovaries ovaries produce estrogen and progesterone and produce estrogen and progesterone and small amounts of testosterone in women.small amounts of testosterone in women.

Again, the ovaries prepare women for puberty – Again, the ovaries prepare women for puberty – which lead to reproduction and childbirth.which lead to reproduction and childbirth.

Really, sexual attraction is very chemical (or Really, sexual attraction is very chemical (or hormonal) because women have higher libido’s when hormonal) because women have higher libido’s when they are ovulating because there is more estrogen in they are ovulating because there is more estrogen in their body.their body.

HeredityHeredity Heredity Heredity is the transmission of characteristics is the transmission of characteristics

from parents to offspring.from parents to offspring. Heredity – while determining hair color, eye color Heredity – while determining hair color, eye color

and height – can also determine some and height – can also determine some psychological traits.psychological traits.

Shyness, leadership, aggressiveness, etc., can be Shyness, leadership, aggressiveness, etc., can be linked to heredity.linked to heredity.

However, for years, the debate has raged on However, for years, the debate has raged on about about Nature vs. NurtureNature vs. Nurture..

Does heredity really determine behavior?Does heredity really determine behavior? Or is it purely based on upbringing?Or is it purely based on upbringing? As humans, we loath the nature idea because it As humans, we loath the nature idea because it

states that everything is predetermined – states that everything is predetermined – meaning that we cannot become smarter or more meaning that we cannot become smarter or more athletic than our biology allows.athletic than our biology allows.

Some psychologists argue that heredity cannot Some psychologists argue that heredity cannot determine destiny because the environment determine destiny because the environment DOES determine how a person develops.DOES determine how a person develops.

The best way to test this debate is by studying….?The best way to test this debate is by studying….? Twins.Twins. Identical twins share 100% of their genes. Identical twins share 100% of their genes. Their DNA is identical, yet their fingerprints are Their DNA is identical, yet their fingerprints are

different…different… Fraternal twins, however, only share about 50% of Fraternal twins, however, only share about 50% of

their genes.their genes. Therefore, identical twins are more likely to share Therefore, identical twins are more likely to share

traits – both positive and negative.traits – both positive and negative. Identical twins, for example, are more likely to both Identical twins, for example, are more likely to both

develop autism than fraternal twins.develop autism than fraternal twins. Beginning in 1979, Thomas Bouchard began studying Beginning in 1979, Thomas Bouchard began studying

twins that were being reared aparttwins that were being reared apart.. He found that twins who had never met one another He found that twins who had never met one another

– and had been “nurtured” differently – still shared – and had been “nurtured” differently – still shared unique mannerismsunique mannerisms..

Researchers also study adopted children because Researchers also study adopted children because they are removed from their biological families and they are removed from their biological families and can still share commonalities with their actual can still share commonalities with their actual parentsparents..

These studies can be controversial because it relies These studies can be controversial because it relies on twins, siblings, or children to remain apart – on twins, siblings, or children to remain apart – which is difficult to maintain ethically at times.which is difficult to maintain ethically at times.