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The Brain

Part II

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The Brain

The Nervous SystemMade up of neurons communicating with other

neurons

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Drawing of the brain

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Central Nervous System

Made up of the brain and spinal cord.

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Peripheral Nervous System

somatic nervous system controls the

movements of our skeletal muscles

Controls glands

ANS Flight or fight

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Types of Nerves

Nerves: Sensory Neurons InterneuronsMotor Neurons

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Somatic Nervous System

Controls the movements of our skeletal muscles.

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Peripheral Nervous System

Consists of the somatic & ANS

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ANS

Controls the glands and the muscles of our internal organs.

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Sympathetic & Parasympathetic Nervous System Sympathetic:

arouses us for defense action

Parasympathetic: It conserves energy as it calms you by decreasing your heartbeat, lowering your blood sugar, etc.

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Endocrine System

Endocrine system influences many aspects of our lives, e.g. growth, reproduction, metabolism, mood, working to keep everything in balance while we respond to stress, exertion, and even our own thoughts.

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Hormones

Secreted by the endocrine system – another form of chemical messenger.

Influence our interest in sex, food, and aggression.

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Adrenal Glands

Located on top of the kidneys. Release epinephrine and norepinephrine

(also called adrenaline and noradrenaline).

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The brain stem & medulla

The brain stem begins where the spinal cord enters the skull swelling slightly, forming the medulla.

Here lies the controls for your heartbeat & breathing.

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Pituitary Glands

Pea-sized structure located in the base of the brain – controlled by the hypothalamus.

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Reticular Formation

Experiment: Moruzzi & Magoun – electrically stimulated the reticular formation of a sleeping cat

The role of the reticular formation

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Thalamus

Thalamus = switching station Receives information from all the senses

except smell and routes it to the higher brain regions that deal with seeing, hearing, tasting, and touching.

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Hippocampus

Within the Limbic System, the hypothalamus influences hunger, regulates thirst, body temperature, and sexual behavior.

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Amygdala

If we electrically stimulate the amygdala (within the Limbic System).

1939 kluver & Bucy

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Hypothalamus

Olds & Milner (1954) – discovered that the hypothalamus was the “reward center”.

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The role of Dopamine & pleasure

Dopamine has been found in animal studies to be released when certain pleasures are taking place, e.g. sex, drinking, etc.

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Addictive Behaviors?

Some researchers believe that addictive disorders, such as alcoholism, drug abuse, and binge eating, may stem from a reward deficiency syndrome.

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The Phineas Gage Story

Frontal lobe damage was first connected to personality changes after the classic case of Phineas Gage.

In 1848, a rod was shot up through his left cheek out of the top of his skull leaving his frontal lobe massively damaged.

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Frontal Lobes

The association areas within the frontal lobes helps us to judge, plan, and process new memories.

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Parts of the brain involved with language Aphasia: is the impaired

use of language. Broca’s area – damage to

the specific area to the left frontal lobe leads to problems forming words while still being able to sing familiar songs and comprehend speech.

Disrupts speaking

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Wernicke’s Area

Wernicke’s area – damage to a specific area of the left temporal lobe – people could speak only meaningless words.

Disrupts understanding

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Angular Gyrus

Receives the visual information from the visual area and recodes it into the auditory form, which Wernicke’s area uses to derive its meaning.

Damage to the angular gyrus – leaves the person able to speak and understand but unable to read.

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Visual cortex

Receives written words as visual stimulation

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Motor cortex

The area which controls the motor cortex as it creates the pronounced word.

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Right vs. Left Brain

Left Brain Verbal Speaking writing

Right Brain Recognize faces Nonverbal Spatial tasks Music & Art