CHAPTER 6: BODY AND BEHAVIOR

HOW THE NERVOUS SYSTEM WORKS Divided into 2 parts: 1) Central Nervous System: brain and spinal cord 2) Peripheral NS: nerves branching out from the spinal cord

NEURONS Def: the long, thin cells of nerve tissue along which messages travel to and from the brain Use chemical-electrical signals All-or-none principle: neuron either fires or does not

BASIC PARTS OF A NEURON 3 basic parts: 1) Cell Body: contains nucleus and produces energy for activity 2) Dendrites: short, thin fibers branching out from cell body; receive impulses from other neurons 3) Axon: long fiber that carries impulses from cell body Myelin sheath: white, fatty substance that insulates axons Axon terminals: branch out from end of axon; send msgs to next neuron

NEURON CONNECTION Synapse: the gap that exists between individual nerve cells Neurotransmitters: chemicals released by neurons, which determine the rate at which other neurons fire Lock and key principle: specific NTs will excite or inhibit the next neuron

NEUROTRANSMITTERS Norepinephrine: involved in memory and learning Endorphin: inhibits pain (analgesia) Acetylcholine: movement and memory Dopamine: learning, emotional arousal, movement Serotonin: appetite, sleep, memory/learning, mood Gamma amino butyric acid (GABA): muscle tone; tied to anxiety Glutamate: excitatory relative of GABA; tied to ALS

NEURON ACTIVITY Afferent neurons: sensory neurons; bring msgs from sense organs to the brain Efferent neurons: motor neurons; send msgs from brain to glands and muscles Interneurons: carry impulses between neurons

VOLUNTARY AND INVOLUNTARY Somatic Nervous System (SNS): part of Peripheral NS that controls voluntary movement of skeletal muscles Autonomic Nervous System (ANS): Part of PNS that controls internal biological functions

AUTONOMIC NERVOUS SYSTEM Split into 2 parts: 1) Sympathetic Nervous System: part of ANS that prepares the body for strenuous activities 2) Parasympathetic Nervous System: part of ANS that conserves energy to recover from strenuous activity

SECTION 2: STUDYING THE BRAIN You all have fat heads!

HINDBRAIN Def: part of the brain located at the rear base of the skull that is involved in the basic processes of life Cerebellum: posture, balance, voluntary movements Medulla: breathing, heart rate, various reflexes Pons: connects spinal cord and brain

MIDBRAIN Def: small part of the brain above the Pons that integrates sensory info and relays it upwards Medulla, pons, and midbrain make up brain stem Reticular Activating System: alerts brain to incoming signals

FOREBRAIN Def: part of the brain that covers the brain’s central core Thalamus: integrates sensory info Hypothalamus: 4-Fs—fight, flight, feeding, sexual behavior Cerebral cortex: outer layer; learning, abstract thought, conscious thought, personality Cerebrum: inner layer, covered by cortex

LIMBIC SYSTEM Part of Forebrain Hypothalamus Amygdala: violent emotions Thalamus Hippocampus: formation of memories

LOBES OF THE BRAIN Lobe: different regions into which the cerebral cortex is divided Occipital Lobe: back of brain; vision Parietal Lobe: back top; body senses Temporal Lobe: sides; hearing, memory, emotion, speaking Frontal Lobe: front top; organization, planning, creative thought

LEFT AND RIGHT HEMISPHERES Connected by corpus callosum Not separate---they complement each other

HEMISPHERE ACTIVITY LEFT BRAIN RIGHT BRAIN Right side of the body Speech Math Logic Calculation Left side of the body Visual and spatial relationships Perceptual tasks Creativity Intuition

SPLIT-BRAIN OPERATIONS Used to treat severe epilepsy Helps stop grand mal seizures Operation: sever corpus callosum Shows unique functions of each hemisphere

HOW PSYCHOLOGISTS STUDY THE BRAIN

RECORDING Electrodes measure electrical activity in the brain Electroencephalograph (EEG): machine used to record electrical activity of large portions of the brain

STIMULATION Applying electrical current to specific locations in the brain Can trigger smells, sounds, sights, emotions, memories, or control pain

LESIONS Cutting or destroying a part of the brain to study effects Mostly on animals

ACCIDENTS Random Phineas Gage---located personality Dr. Pierre Paul Broca---speech production

IMAGES Computerized Axial Tomography (CAT): used to pinpoint injuries and deterioration Positron Emission Tomography (PET): used to see which areas are being activated while performing tasks Magnetic Resonance Imaging (MRI): used to study brain structure and activity Functional MRI (fMRI): observe both function and structure

SECTION 3: THE ENDOCRINE SYSTEM

ENDOCRINE SYSTEM Def: a chemical communication system using hormones, by which msgs are sent through the bloodstream Hormones: chemical substances that carry msgs through the body in blood

PITUITARY GLAND Def: the center of control of the endocrine system; secretes large amts of hormones “Master Gland” Monitors hormone levels in blood and corrects imbalances

THYROID GLAND Produces thyroxine to stimulate tissues Hypothyroidism: too little thyroxine; lethargy Hyperthyroidism: too much thyroxine; overactive

ADRENAL GLANDS Activate when angry or scared Release epinephrine (adrenaline) and norepinephrine Releases cortical steroids to develop muscles

SEX GLANDS Testes: male; produce testosterone Ovaries: female; produce estrogen and progesterone

HORMONES VS. NEUROTRANSMITTERS Hormones used for slower, more widespread communication NTs used for rapid, specific msgs

SECTION 4: HEREDITY AND ENVIRONMENT Genes establish what you could be and the environment defines the final product…

HEREDITY Def: the genetic transmission of characteristics from parents to their offspring Sir Francis Galton: Hereditary Genius (1869)---started nature vs. nurture debate John Watson emphasized environment

TWINS Identical twins: twins who come from one fertilized egg; have the same heredity (monozygotic) Genes: basic building blocks of heredity Fraternal twins: twins who come from 2 different eggs fertilized by 2 different sperm (dizygotic)

TWIN STUDIES Identical twins are preferable Studying Iden. twins separated at birth gives good indications of what is genetic and what is environment