Nervous and Endocrine Systems.pdf

Evolution, Biology, and Behavior ▪ How did human behavior evolve? ▪ What is the structure of the brain? ▪ How does the nervous system work? 1  Heredity and Behavior ▪ Causal Explanations in Psychology – Nature vs. Nurture – Heredity vs. Environme...

Evolution, Biology, and Behavior ▪ How did human behavior evolve? ▪ What is the structure of the brain? ▪ How does the nervous system work? 1  Heredity and Behavior ▪ Causal Explanations in Psychology – Nature vs. Nurture – Heredity vs. Environment ▪ Natural Selection – Favorable adaptations to features of the environment allow some members of a species to reproduce more successfully than others (C. Darwin, Origin of Species, 1859) 2 Natural Selection: Darwin’s Finches ▪ According to Darwin, finches on Galápagos descended from common flock ▪ Spread out to different islands with different habitats with different food sources – Those finches who, by chance, possessed features suited to competing for food on their particular island tended to survive and reproduce – Over millennia, this natural selection of finches that were fit to each environment led to different species ▪ Grant & Grant (1989) – Natural selection can also work in the short term 3  Natural Selection ▪ Genotype – Genetic structure ▪ Phenotype – Observable characteristics 4 How Natural Selection Works Environmental pressure (changes in the environment) Competition (for resources) Selection of fittest phenotype (among a variety of phenotypes) Reproductive success (genotype corresponding to fittest phenotype passed to next generation) Frequency of that genotype (and phenotype) increases (in next generation) 5  Natural Selection in Humans ▪ Two Major Adaptations: – Bipedalism – Encephalization ▪ Related Advantages: – Language – Cultural Evolution 6 Variation in the Human Genotype ▪ Genetics: – Study of biological transmission of traits from parents to offspring – Pioneered by Mendel (1822-1884) Proposed that each parent contributes pair of “factors” that determine offspring’s features “Factors” = Genes 7  Basic Genetics ▪ DNA: – Physical basis for the transmission of genetic information – Resides in nucleus of every cell ▪ Genes: – Biological units of heredity – Made up of distinct sequences of proteins (nucleotides) within DNA – Recipes for protein synthesis 8  Genes and Behavior ▪ Genome defined: – Full sequence of genes found on the chromosomes with the associated DNA 9  Genes and Behavior ▪ Human Behavior Genetics – Evaluates the genetic components of individual differences regarding behaviors and traits – Heritability 0 = Mostly due to Environment 1 = Mostly due to Heredity – Adoption Studies – Twin Studies Monozygotic vs. Dizygotic 10  Genes and Behavior ▪ Sociobiology – Provides evolutionary explanations for social behavior and social systems of humans and other species 11  Sociobiological Research ▪ Focus on Reproductive Strategies – Monogamy – Polygyny – Polyandry – Polygynandry ▪ Why is polygyny favored? – Role of sex differences in parental investment 12  Sociobiological Research ▪ Focus on Altruism – Why have organisms evolved the tendency to help others at a cost to themselves? – Role of kin selection – Role of reciprocal altruism 13  Biology and Behavior ▪ Neuroscience defined – Scientific study of the brain and of the links between brain activity and behavior 14 The Case of Phineas T. Gage 15  Eavesdropping on the Brain ▪ Broca’s Area of the Brain – Named after brain researcher Paul Broca – Case study of “Tan” suggested that specific area of the brain translates thoughts into speech or sign 16  Interventions in the Brain ▪ Lesions – Localized brain injuries created to increase control over specific timing and location of damage – Only possible in non-human animals – Comparisons made between results of animal lesion studies and neuropsychological observations of humans 17  Interventions in the Brain ▪ Repetitive Transcranial Magnetic Stimulation (rTMS) – Pulses of magnetic stimulation create temporary reversible lesions to briefly inactivate the brain for study ▪ Direct electrical brain stimulation 18 Recording and Imaging Brain Activity ▪ Electroencephalogram (EEG) – Electrical activity of the brain monitored – Good temporal resolution; bad spatial resolution 19 Recording and Imaging Brain Activity ▪ Magnetic Resonance Imaging (MRI) – Scans the brain using magnetic fields and radio waves 20 Recording and Imaging Brain Activity Functional MRI (fMRI) – Detects magnetic changes in blood flow to cells in the brain 21  Nervous System ▪ Central Nervous System (CNS) – Brain and spinal cord ▪ Peripheral Nervous System (PNS) – Connects the body’s sensory receptors to the CNS and the CNS to muscles and glands 22  Nervous System ▪ Somatic Nervous System (SNS) – A sub-division of the peripheral nervous system that connects the CNS to the skeletal muscles and skin 23  Nervous System ▪ Autonomic Nervous System (ANS) – A sub-division of the peripheral nervous system that controls involuntary life-sustaining functions 24  Nervous System Peripheral Nervous System Central Nervous System (neural tissue outside brain (brain and spinal cord) and spinal cord) Somatic nervous system Autonomic nervous system (sensory and motor (internal systems, nerves, voluntary) involuntary) Sympathetic division Parasympathetic division (emergency response) (routine tasks) 25 Cross Section of the Brain 26 F 4.35 27 F 4.36 28  The Cerebrum ▪ Cerebral Cortex ▪ Cerebral Hemispheres ▪ Corpus Callosum 29 30 Brain and Somatosensory Association 31 32 Hemispheric Lateralization 33 Hemisphere Lateralization 34 Sperry’s Methodology 35  Lateralization of Language ▪ Language typically controlled by LH – Revealed in split brains and patients with LH damage, ▪ Sign language controlled by LH as well ▪ LH not “better” in all respects! 36  Endocrine System ▪ Endocrine System – Network of glands that manufacture and secrete hormones ▪ Hormones – Chemical messengers that regulate metabolism and influence body growth, sexual characteristics, etc. 37 The Neuroendocrine System 38  Endocrine System ▪ Hypothalamus – Controls pituitary gland ▪ Pituitary Gland (“Master Gland”) – Growth and sex hormones – Controls other glands 39  The Neuron ▪ The Neuron – A cell in the nervous system specialized to receive, process, and/or transmit information to other cells 40  The Neuron ▪ Dendrites ▪ Soma ▪ Axon ▪ Terminal Buttons 41  Major Classes of Neurons ▪ Sensory Neurons: – From sense receptors toward the CNS ▪ Motor Neurons: – From CNS toward muscles and glands ▪ Interneurons: – From sensory neurons to other interneurons or to motor neurons 42 Pain Withdrawal Reflex 43  Glial Cells: Multiple Functions 1. “Glue” neurons in place 2. Guide newly formed neurons to proper location 3. Absorb wastes and excess material between neurons 4. Create myelin sheaths around axons, speeding neuronal communication 5. Astrocytes form blood-brain barrier 44  How do neurons communicate? ▪ Action Potential: – The nerve impulse ▪ Resting Potential: – Polarization of cellular fluid within a neuron, which provides the capacity to produce an action potential 45 The Action Potential Ion channels and ion transporters regulate the number of ions inside and outside the axon F 4.7 46 The Action Potential F 4.8 47 The Action Potential Ion channels and ion transporters regulate the number of ions inside and outside the axon F 4.7 48  Properties of Action Potentials ▪ All-or-None Law ▪ Vary in speed – Nodes of Ranvier allow skipping 49 Myelinated Neuron 50  Properties of Action Potentials ▪ All-or-None Law ▪ Vary in speed ▪ After “firing” neuron enters refractory periods – Absolute followed by relative 51 Action Potentials 52  Synaptic Transmission ▪ Synapse – The gap between one neuron and another 53  Synaptic Transmission ▪ Neurotransmitters released into synaptic cleft ▪ Bind to receptor molecules in dendrites of postsynaptic membrane 54  Neurotransmitters ▪ Acetylcholine – Memory and muscle contraction ▪ GABA (gamma-aminobutyric acid) – Most common inhibitory neurotransmitter ▪ Catecholamines (Dopamine & Seratonin) – Role in psychopathology ▪ Endorphins – Pleasure and reduction of pain – Neuromodulators 55