Body and behaviorChapter 6

StandardsStandard II: BiopsychologicalBiological basis of behavior IIA-1.1 Structure and function on neuronIIA- 2.1 Organization of the nervous system

The nervous SystemControls your movement, emotions, thinking, and

behavior (almost all you do)Never at restDivided into 2 parts:Central Nervous System (CNS) – the brain and

spinal cordPeripheral Nervous System (PNS) – nerves

branching beyond the spinal cord

Nervous SystemAll parts are protected:Brain – skull and layers of sheathing (coating)Spinal cord – the vertebrae Peripheral – layers of sheathing - nerves about as thick as a pencilExtremities – nerves get smaller and smaller

NeuronsStrips of long cells that carry messages to and

from the brainCarry messages by chemical-electrical signalsNeuron can “fire” over and over againMessages are sent from neuron to neuronBody contains millions

Parts of a neuron4 Basic Parts:DendritesThe cell body (contains the nucleus)An axonAxon terminals

DendritesShort, thin fibers that protrude from the cell body

Receive impulses (messages) from other neurons and sends them to the cell body

AxonSingle extensionCarries impulses from cell body to the axon

terminalsUsually short, but can be several feet longMyelin sheath (white fatty substance)

insulates and protects the axon; can speed the transmition

Axon TerminalBranch out at the end of the axonRelease neurotransmitters to stimulate

dendrites of the next neuronPositioned opposite of the dendrite of another

neuron

Synapse & NeurotransmittersSynapse – space between the neurons;

transmits messages to the next neuronNeurotransmitters – chemicals released by

neurons - locks or excites receptors Ex: endorphin – inhibits pain norepinephrine – involved with memory and learning

Afferent, Efferent, and InterneuronsAfferent neuron (sensory neurons) – relay

messages from the sense organs (eyes, nose, skin) to the brain

Efferent neuron (motor neurons) – send signals from the brain to the glands and muscles

Interneurons – processes signals only to other neurons

Voluntary vs involuntary activitesSomatic Nervous System (SNS) – the part

of peripheral nervous system that controls voluntary activities (skeletal muscles)

Autonomic Nervous System (ANS) – part of the nervous system that controls involuntary activities

Ex: heartbeat, breathing, digestion, etc.

The brainComposed of 3 parts:HindbrainMidbrainForebrain

HindbrainRear base of the skull; controls basic processes of life

Includes: Cerebellum (behind spinal cord) – controls posture, balance and voluntary movements

Medulla – controls heart rate, breathing, and reflexes

Pons – bridge between spinal cord and brain and produces chemicals needed for sleep

MidbrainSmall, above the ponsIntegrates sensory information and sends it upwards

Medulla and pons extends upward into the midbrain

Reticular Activating System (RAS)- spans across medulla, pons, and midbrain

- Alerts brain of incoming signals and involved in sleep/wake cycle

ForebrainBrains central coreIncludes:Thalamus – integrates sensory information

Hypothalamus – controls hunger, thirst, and changes in temperature

Cerebral Cortex & CerebrumCortex - Outer layer of forebrainCerebrum – inner layerHigher thinking processesGives you ability to learn and store complex and abstract information

Site of conscious thinking processes

Limbic SystemCore of forebrainRegulates our emotions and motivationsIncludes: Hypothalamus, thalamus, hippocampus, and amygdala

Amygdala - controls violent emotions such as rage and fear

Hippocampus: - formation of memories

Lobes of the BrainCerebrum – 2 hemispheresConnected by: Corpus callosumEach hemisphere has deep grooves = regions

or lobesOccipital lobe – visionParietal lobe – body sensationsTemporal lobe – hearing, memory, emotion,

speakingFrontal lobe – organization, planning,

creative thinking

Hemispheres (Left & Right)Corpus callosum – carries messages back

and forth between the 2 hemispheres

Right: Controls left side of body - Nonverbal, spatial, and holisticLeft: Controls right side of body - Verbal, Mathematical, Analytic

Corpus CallosumCan be severed = Split-Brain OperationNow have “2” brains; operate

independently, no communication between the two sides

How Psychologists Study the BrainRecord electrical activity in brain – EEG - wires and electrodes attached to a machine

Stimulation – “make” neurons fire on certain parts of brain and record; determine function

Lesions – cutting or destroying part of brain to see if animal behaves differently

Accidents – learn from brain trauma and tragedies

ImagesCT scans – pinpoint injuries and deterioration

PET scans – capture picture of brain as different parts are being used

MRI – able to see/study activity and structures

- combines benefits of CT and PET scans