CHAPTER 8 CNS spinal cord and brainstem cerebrum cerebellum Brainstem increases heart rate blood pressure breathing bottom of brain Cerebellum very bottom part of brain Cerebrum located above the cerebellum and brainstem Cerebral cortex bark of the brain where cerebral neurons are located the more connections between parts of cortex greater surface area but more wrinkly Gryus the bulging part of a wrinkle on the cortex Sulcus the valley of the fold in between the wrinkles Ventricles spaces in brain and spinal cord filled with cerebral spinal fluid CSF Afferents and efferents Spinal nerves the whole spinal cord 31 in total Cranial nerves sensory motor nerves that come straight to and from brain 12 in total 4 lobes of the cerebrum 1 frontal lobe front by eyes 2 parietal lobe top to back of brain 3 occipital lobe back of the brain through to eye 4 temporal lobe underneath part of brain Somatosensory cortex right behind central sulcus termination of sensory information coming from skin Motor cortex right in front of central sulcus cerebral neurons that initiate movement sending axons directly and indirectly to spinal motor neurons Homunculus little person map of sensory input to the somatosensory cortex and motor output of motor cortex parts of body with highest density of sensory receptors bigger share of somatosensory cortex parts of body with finest motor control more muscles bigger share of motor cortex somatosensory relays and motor relays cross over so left side of body right side of cortex and vice versa CHAPTER 9 Sympathetic and parasympathetic nervous systems Sympathetic nervous system fight of flight Nerves from spinal cord send axons to ganglia right outside of CNS and then to glands and smooth muscle mobilize energy divert blood to muscle prepare to flight flee Parasympathetic nervous system nerves from brainstem spinal cord run to glands and smooth muscle prepare for digestion energy storage convert glucose to fat divert blood flow to gut heart rate goes down opposite of sympathetic Autonomic nervous system 2 neurons between CNS and target organ controlled by hypothalamus and brainstem pupil dilation 1 in dim light from superior cervical ganglion through postganglionic sympathetic axon NE 2 in normal light radially arranged smooth muscle fibers of iris circularly arranged smooth muscle fibers of iris and pupil 3 in bright light from cranial nerve through postganglionic parasympathetic axon Ach Drugs cocaine increases NE levels so pupils dilate atropine block muscarinic Ach receptors and parasympathetic constriction pupil dilates sweating glands only receive sympathetic innervation sympathetic synapse uses Ach as NT Preganglionic cell bodies going into ganglion Cell body in spinal cord send axon where it will synapse with postganglionic neuron Sympathetic chain ganglia nerves run from the spinal cord to chain ganglia and then to glands and smooth muscle in sympathetic nervous system Adrenal medulla circuitry modified sympathetic ganglion preganglionic fibers stimulate cells to secrete epinephrine and NE into blood Neurotransmitters Parasympathetic NS Sympathetic NS Preganglionic release Ach to nicotinic receptors Postganglionic release Ach to target owners via muscarinic receptors Preganglionic release Ach to nicotinic receptors Postganglionic release NE onto target organs via adrenergic receptors Thermoregulation and Fever Set Point regulation areas of hypothalamus integrate temp info and attempt to maintain temp at particular setpoint Thermoregulatory responses engage if body temp moves away from setpoint responds to restore body temp rise in set point fever temp setpoint too hot drop in set point fever breaking temp setpoint too cold central setpoint changes responds to bring body temp to new set point lowering setpoint body responds as if too hot raising setpoint body responds as if too cold Hypothalamus controls body temp areas Chemical signals induce fever 1 preoptic area heat dissipation panting sweating hyperthermia 2 posterior area heat conservation shivering hypothermia lipopolysaccharide active fragment of endotoxin from gram negative bacteria induces synthesis and release of pro inflammatory cytokines from activated immune system cells monocytes and macrophages cytokines IL 1a IL 1b and TNFa COX2 enzyme infection induces COX2 enzymes to produce prostaglandins prostaglandins signal to brain to respond to infection promotes blood clotting shows prostaglandin as an antagonist also implicated in a wide variety of regulatory functions 20 C long fatty acid with a 5 membered carbon ring CHAPTER 10 General properties of sensory systems Sensory systems All have same sensory neurons but differ in the types of receptors 4 types of receptors 1 Mechanoreceptor 2 Pain receptor 3 Chemoreceptors 4 Photoreceptors Stimulus mechanical force touch pressure Mechanism deforms cell membrane of sensory dendrites and hair cells that activate the sensory nerve endings Stimulus tissue damage Mechanism damaged tissues release chemicals that excited sensory ends Stimulus dissolved chemicals Mechanism chemical interaction affects ionic permeability of sensory cells Smell and taste Stimulus light Mechanism reaction affects ionic permeability of receptor cell Rods and cones in retina of eye Receptor fields the area of skin where each somatosensory neuron innervates mechanoreceptors Feature extraction putting together all the pieces perceived from sensory neurons mixed with more detailed extractions from the cortex by detecting orientation of pressures across multiple receptive fields and the direction of movement of touch across multiple receptive fields results in cognition higher cortical levels extract more complex features 3D shapes Somatosensation Types of receptors 1 Meissner respond to light touch rapidly adapting phasic receptor fires lots of action potentials and then slows located in upper dermis 2 Merkel respond to light touch slow adapting tonic receptor fires constant slower action potentials constant pressure being applied located at base of epidermis 2 Pacinian deep receptor respond to stronger force rapidly adapting and phasic response located deep in dermis 3 Ruffini deep receptor respond to stronger force slowly adapting and tonic response located deep in dermis and hypodermis Dorsal root ganglia where cell bodies of the sensory neurons are gathered One DRG for each vertbra Receptive fields map to specific area on the body of where sensory neurons are responding to
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