AP Psychology Chapter 3 The Biology of Psychology

Chapter 3: The Biology of Psychology Neuroanatomy ● Parts of the Neuron: o Dendrites: root-like parts of the cell that stretch out from the cell body, they grow to make synaptic connections with other neurons, receives messages from other cells to soma o Cell body (soma): contains the nucleus and other parts of the cell necessary for its life o Axon: wire like structure ending in the terminal buttons that extend from the cell body, sends electrical impulses out of the cell body o Myelin sheath: a fatty covering around the axon of some neurons that speeds neural impulses o Terminal buttons: end buttons, terminal branches of axon, synaptic knobs; branched end of the axon; contains neurotransmitters o Neurotransmitters: chemicals contained in terminal buttons that enable neurons to communicate o Synapse: the space between the terminal buttons of one neuron and the dendrites of the next neuron o Synaptic Cleft- the space between neurons at a nerve synapse across which a nerve impulse is transmitted by a neurotransmitter Neurons Firing ● Resting State: neuron has negative charge with positive ions surrounding the cell ● Steps: o Neuron is stimulated, releases neurotransmitters o Neurotransmitters bind to receptor sites on the dendrites of the receiving neuron o If the threshold is reached, the cell membrane of the receiving neuron becomes permeable o positive ions rush in o Action Potential: the membrane potential of a specific cell location rapidly rises and falls o Axons release neurotransmitters to another neuron ● All-or-None Principle: the neuron will fire completely or not at all ● Neurotransmitters: o Acetylcholine: motor movement and memory ▪ too little → leads to Alzheimer’s ▪ too much → decreased heart rate o Dopamine: motor movement and alertness ▪ too little → Parkinson’s disease ▪ too much → schizophrenia o Endorphins: pain control, released during exercise, can be addictive ▪ too little → OCD ▪ too much → on edge o Serotonin: happiness/mood, sleep ▪ too little → clinical depression ▪ too much→ decreased motor skills, seizures o GABA: inhibitory, calms you down ▪ too little → seizures, anxiety ▪ too much → depression, insomnia, seizures Nervous System ● Afferent Neurons (Sensory Neurons): take information from the senses to the brain ● Interneurons: send information to elsewhere in the brain or to efferent neurons ● Efferent (Motor) Neurons: take information from the brain to the rest of the body ● Central Nervous System (CNS): consists of the brain and the spinal cord (which is just a bundle of nerves), the body’s command center ● Peripheral Nervous System (PNS): all nerves not encased in bone, collects info to send to SNA o Somatic: controls voluntary muscle movements o Autonomic: controls involuntary muscle movements ▪ controls responses to stress ▪ sympathetic arouses ▪ parasympathetic calms ● Ways to Study the Brain o Lesions: the removal or destruction of part of the brain and studying the effects o Electroencephalogram (EEG): detects brain waves and examines them in different stages of consciousness, especially sleep o Computerized Axial Tomography (CAT) Scan: a sophisticated x-ray that shows brain structure in 3D o Magnetic Resonance Imaging (MRI): uses magnetic fields to measure the density and location of brain material and structure ▪ no radiation ▪ more detailed than a CAT scan o Positron Emission Tomography (PET) Scan: radioactive glucose is injected into the system; it shows how much of a certain chemical parts of the brain are using, essentially measures which parts of the brain are most active during certain tasks (think PET=giving glucose/sugar to your pet) o Functional MRI (FMRI): ties brain structure to brain activity during cognitive tasks (combines elements of MRI and PET) o Case study: studying specific people in unique situation ▪ Phineas Gage: a rod went through his head but he lived; his personality changed and eventually caused seizures ● Brain Structure and Function (summary on p21) o Hindbrain/brain stem: controls basic biological functions that keep us alive ▪ Medulla: controls blood pressure, heart rate, and breathing ▪ Pons: controls facial expressions, connects the hindbrain with the rest of the brain ▪ Reticular formation: runs through middle of medulla and pons; selective attention, ignoring repeating stimuli, alertness ▪ Cerebellum (aka “little brain”): coordinates muscle movement from the bottom of the brain ▪ Thalamus: receives sensory signals coming up the spinal cord and sends them to other forebrain areas (sits atop brain stem, might be MB) o Midbrain: coordinates simple movements with sensory information & integrates sensory information and muscle movements ▪ Hypothalamus: controls hunger, sexual arousal, thirst, and the endocrine system ▪ Amygdala: controls emotion ▪ Hippocampus: vital for memory and retaining new information o Cerebral Cortex: gray wrinkled surface of the brain (the wrinkles are called fissures) ▪ Cerebral hemispheres: 2 sections of the cortex for contralateral control ● left hemisphere- right half of body ● right hemisphere- left half of body ● Brain lateralization (hemispheric specialization): the specialization of function in each hemisphere ● Split brain patients: the corpus callosum has been cut to treat severe epilepsy, but patients can’t orally report information presented to only the right hemisphere of the brain o Association area: any area of the cerebral cortex not associated with receiving sensory information or controlling muscle movements o Lobes: ▪ Frontal lobes ● Prefrontal cortex: at front of frontal lobe, acts as the brain’s central executive: foreseeing consequences, pursuing goals, and emotional control ● Broca’s area: at the left hemisphere of frontal lobe, controls the muscles involved in producing speech (think boca!) ● Motor cortex: at the back of the frontal lobe, controls our voluntary movements ▪ Parietal lobes ● Sensory (somatosensory) cortex: located right behind the motor cortex, receives incoming touch sensations ● Cognition, information processing, spatial orientation, speech, senses, math, reading, writing ● Above temporal, behind frontal ▪ Temporal lobes ● process sound (sound waves are processed by the ears and turned into neural impulses that temporal lobes interpret) ● Wernicke’s area: comprehending speech and sound (left temporal) ▪ Occipital lobes: vision o Brain plasticity: parts of the brain can adapt to perform other functions if needed because dendrites grow throughout our lives ▪ Younger brains are more plastic Endocrine System ● Adrenal Glands: produce adrenaline → “fight or flight” prep (handles stress) ● Ovaries and Testes (gonads): produce sex hormones, controlled by the hypothalamus ● Pituitary gland: (aka master gland) secretes HGH, influences all other hormonesecreting glands, the master gland ● Pineal gland: located near the base of cerebrum, secretes melatonin ● Thyroid gland: located in the neck, regulates growth and metabolism with thyroxine ● Pancreas gland: controls blood sugar levels by secreting insulin and glucagons Chromosomes ● Twins o Identical (monozygotic) twins: came from 1 zygote; physical similarity in twins causes them to be treated the same way ● Chromosomal Abnormalities o Turner’s Syndrome: only single X chromosome; causes shortness, webbed necks, and different sexual development o Klinefelter’s Syndrome: XXY chromosome pattern; causes minimal sexual development and extreme introversion o Down’s Syndrome: extra chromosome on 21st pair; intellectual disability