Biological Psychology Review (PDF)

BIOLOGICAL PSYCHOLOGY Neurons and Synapses Afferent nerves - sensory signals from the senses to the CNS Efferent Nerves - Motor signals...

BIOLOGICAL PSYCHOLOGY Neurons and Synapses Afferent nerves - sensory signals from the senses to the CNS Efferent Nerves - Motor signals from the CNS to the skeletal muscles. Autonomic Nervous System (PNS) SYMPATHETIC - Fight or Flight response - also known as “Adrenergic nervous system” - Secretion of Epinephrine through the stimulation of sweat glands - aroused body to expend energy PARASYMPATHETIC - Rest and Digest - also known as “Cholinergic nervous Division of the Nervous System system” - no effect on sweat glands. CENTRAL NERVOUS SYSTEM - calms body to conserve and maintain - Brain and Spinal Cord energy - Receives sensory signals, stores Q1 memories, and carries thoughts. 1. The brain and the cranium complete PERIPHERAL NERVOUS SYSTEM the CNS - Nerves, neurons, and sensory organs 2. The brain and the spinal cord outside of the CNS. comprise the PNS - Send signals to CNS. stimulates effectors. - NONE o The brain and the spinal cord comprise Peripheral Nervous System (PNS) the Central Nervous System (CNS). SOMATIC o The Peripheral Nervous System (PNS) consists of all the nerves that branch out - interacts with external environments from the brain and spinal cord and extend to other parts of the body, Afferent nerves - sensory signals from including the cranial nerves and spinal the senses to the CNS nerves. Efferent Nerves - Motor signals from the CNS to the skeletal muscles. Q2 AUTONOMIC You are being chased by a dog and were able to escape. you were able to reach your - Regulates the body’s internal home immediately...as you reach your environment. house, what is the response of your body? - SYMPATHETIC Prepared by: Daisy Balueta 2PSYCH1  BIOLOGICAL PSYCHOLOGY Cells of the Nervous System Neurons and Glia (Neuroglia) Neuron - “Nerve Cell” - Basic Building block of the nervous system - Cells that are specialized for the reception, conduction and transmission of electrochemical signals What are the different Types of Neurons Prepared by: Daisy Balueta 2PSYCH1  BIOLOGICAL PSYCHOLOGY MULTIPLE SCLEROSIS - A chronic, typically progressive disease involving damage to the sheaths of nerve cells in the brain and spinal cord. Classes of Neurons Prepared by: Daisy Balueta 2PSYCH1  BIOLOGICAL PSYCHOLOGY NEURON CELL MEMBRANE - lipid bilayer - some membrane protein serves as a channel protein, and some are signal protein Neurotransmitters - A chemical released from a neuron following an action potential. - travels across the synapse to excite or inhibit the target neuron. - Different types of neurons use different neurotransmitters and therefore have different effects on their targets. Classification of Neurotransmitters EXCITATORY - They increase the likelihood that the neuron will fire an action potential. INHIBATORY - They decrease the likelihood that the neuron will fire an action potential. Prepared by: Daisy Balueta 2PSYCH1  BIOLOGICAL PSYCHOLOGY Types of Neurotransmitters Prepared by: Daisy Balueta 2PSYCH1  BIOLOGICAL PSYCHOLOGY Prepared by: Daisy Balueta 2PSYCH1  BIOLOGICAL PSYCHOLOGY GLIAL CELLS - Bare axon - Node of Ranvier - Forgotten Cells NEURONS VS GLIAL Neurons - Generate and propagate electrical and chemical signals. - Has dendrites and axons. - bigger than Glial cells. SCHWANN CELLS Glial - perform as similar function as oligodendrocytes in the PNS - Modulate neuron function and signaling. - 1 =1 ratio as oppose to 1 = many of - Has no dendrites and axons. oligodendrocytes - Smaller than neurons - Only one who can guide axonal ARE THERE MORE GLIAL CELLS THAN regeneration (regrowth) NEURONS? TYPES OF GLIAL CELLS ASTROCYTE - Largest Glial cell - means “star cell” - provide physical support to neurons and clean up debris within the brain by producing and releasing chemicals. MICROGLIA - involve in providing nourishment to - smallest of the glial cells neurons - respond to injury or disease by by - regulate synaptic release of multiplying, engulfing cellular debris, or neurotransmitter and reuptake and even an entire cell (scavenger cell) inactivation of neurotransmitter (e.g., - responsible for the inflammatory GABA and Glutamate) reaction OLIGODENDROCYTES - provide support to axons and produce myelin sheath (80% lipids and 20% protein) in CNS. Prepared by: Daisy Balueta 2PSYCH1  BIOLOGICAL PSYCHOLOGY NERVE IMPULSE GENERATION AND Conduction of Postsynaptic Potentials membrane potential and resting potential Excitatory postsynaptic potential MEMBRANE POTENTIAL (EPSPs) - Difference in electrical charge between - Sodium channels open the inside and the outside of a cell - Depolarization Action potential - When a neuron sends a signal down it's Inhibitory postsynaptic potential (IPSPs) axon to communicate with another - Chloride/ Potassium channels open neuron (-65 mV Threshold) –“All or - Hyperpolarization nothing law/response” Resting potential STAGES OF ACTION POTENTIAL - amount of power that is available to a cell to maintain its homeostatic state (- ACTION POTENTIAL 70 millivolts (mV) as the resting - Threshold of excitation is usually about - potential) hence, polarized. 65 mV - Action potential (AP) as a massive but momentary reversal of the membrane potential from about-70 to about +50 MV - All or none response/law - Two types of summation: spatial and temporal IONIC BASIS OF THE RESTING Potential - positively and negatively charged ions and ions can pass through ion channels - electro static pressure and CONDUCTION OF ACTION POTENTIALS concentration gradient. - Voltage-activated ion channels open or close in response to changes in the level of the membrane potential. STAGES OF ACTION POTENTIALS Depolarization - “upswing” - Positively charged sodium ions rush into a nerve cell - Sodium channels open Prepared by: Daisy Balueta 2PSYCH1  BIOLOGICAL PSYCHOLOGY - the membrane of the stimulated cell Antidromic conduction vs Orthodromic reverses its polarity so that the outside conduction of the membrane is negative relative to the inside. Repolarization - “Downswing” - once reached threshold - Sodium ion channels close and CONDUCTION IN MYELINATED AXON potassium ion channels open - restore the localized negative - Ions can pass through the axonal membrane potential of the cell, bringing membrane only at the nodes of it back to its normal voltage. Ranvier - Rapid and decremental Refractory Phase - Saltatory conduction - “to leap” - The neuron cannot reach action potential during this “rest period.” - The sodium-potassium pump returns sodium ions to the outside and potassium ions to the inside. - Absolute vs relative refractory period. - Depends on two things: The sodium SYNAPTIC TRANSMISSION channels are closed, and potassium is flowing out of the cell at a faster than- - Chemical Transmissions of Signals usual rate. Among Neurons STRUCTURE OF SYNAPSES Axodendritic synapse - Axon to dendrite Axosomatic synapse - Axon to Soma Axoaxonic synapse - Axon to axon AXONAL CONDUCTION OF ACTION POTENTIALS Nondecremental Slower conduction than postsynaptic potentials Directed vs non directed synapse Prepared by: Daisy Balueta 2PSYCH1  BIOLOGICAL PSYCHOLOGY HOW DO NEUROTRANSMITTERS TRAVEL? SYNTHESIS, PACKAGING, AND TRANSPORT OF NEUROTRANSMITTER MOLECULES several types of neurotransmitters large neurotransmitters are all neuropeptides (small chains of amino acids that are synthesized and released by neurons.) Co-existence in many neurons Storage of Transmitters - The presynaptic terminal stores high concentrations of neurotransmitter molecules in vesicles. RELEASE OF NEUROTRANSMITTER MOLECULE Directed Synapse: site of release and Exocytosis contact are in close proximity. - bursts of release of neurotransmitter from the presynaptic neuron. Nondirected synapse: site of release and contact are separated by some distance (e.g., hormones and neuromodulators) Prepared by: Daisy Balueta 2PSYCH1  BIOLOGICAL PSYCHOLOGY ACTIVATION OF RECEPTORS BY NEUROTRANSMITTER MOLECULE neurotransmitters bind to receptors in the postsynaptic membrane (Ligand) ionotropic receptors - ligand-gated ion channels (Glutamate and GABA) metabotropic receptors - require G proteins and second messengers to indirectly modulate ionic activity in neurons Ionotropic synapse VS Metabotropic synapse REUPTAKE, ENZYMATIC DEGRADATION, AND RECYCLING message terminating system enzymatic degradation in the process of reuptake, excess neurotransmitters are returned to the presynaptic neuron. Prepared by: Daisy Balueta 2PSYCH1