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Published byHelena Cecilia Wells Modified over 9 years ago
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1 Nervous system organization fig 6-37
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2 Brain structure fig 6-38
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3 Brain structure (notes) Cerebrum structure Structure lobes: frontal, parietal, occipital, temporal (named for bones) cerebral hemispheres, subcortical nuclei (basal ganglia) Functions motor functions, sensory functions learning, reasoning, memory Thalamus (paired) Hypothalamus (paired) Cerebellum Brain stem = midbrain + pons + medulla oblongata
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4 Cerebral hemispheres: motor function fig 10-10 Primary & supplementary motor cortex (frontal lobe) skilled movements, particularly of distal muscles
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5 Cerebral hemispheres: motor function fig 10-11 Primary motor cortex motor “homunculus”; area related to fine motor control
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6 Cerebral hemispheres: basal nuclei fig 6-39 Basal nuclei coordination of motor activity, control movement & posture defective in Parkinson’s disease Corpus callosum: connection between right & left hemispheres
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7 Cerebral hemispheres: sensory function Visual cortex (occipital lobe) Auditory cortex (temporal lobe) Taste cortex (parietal lobe) fig 7-14
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8 Cerebral hemispheres: sensory function Somatosensory cortex (parietal lobe) touch, pressure, kinesthesia, temperature, pain sensory “homunculus” fig 7-20
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9 Cerebral hemispheres: sensory function Olfactory cortex (frontal lobe) only sense not via thalamus, ~1000 odorant receptors afferent fibers to olfactory cortex & limbic system fig 7-45
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10 Cerebral hemispheres: learning & memory Declarative memory (language, names, faces, events, facts) Short term: involves hippocampus & other temporal lobe structures ongoing graded or action potentials susceptible to shock, trauma, coma, electroconvulsive therapy Long term: many areas of association cortex involves protein synthesis, synapses, post-synaptic receptors Procedural memory (actions, emotional responses, fears) Short term various parts of brain Long term basal nuclei, cerebellum, sensorimotor cortex
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11 Thalamus Sensory relay (synapses) for all sensory input except olfactory fig 6-39 (cropped)
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12 Hypothalamus Functions: regulates anterior pituitary gland (produces releasing factors) nuclei for posterior gland hormones (antidiuretic hormone & oxytocin) regulates thirst & hunger involved in regulation of autonomic system regulates reproductive system (hormones & autonomics) circadian rhythms (clock in suprachiasmatic nucleus) regulates body temperature (integrative center) important component of limbic system
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13 Limbic system Components: thalamus, hypothalamus, hippocampus, septal nuclei, olfactory bulbs, cingulate gyrus Functions: emotional responses (subjective feeling & behavior), memory fig 6-40
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14 Cerebellum Location: on brain stem, over pons Input from sensorimotor cortex and vestibular (balance), visual, & musculature Output to cerebral cortex & brainstem nuclei Functions: comparing intended movements with actual outcomes, and making appropriate adjustments; coordinates movements, some procedural memories Cerebellar disease: intention tremor
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15 Brain stem Components: mid brain, pons, medulla oblongata General functions: ascending & descending pathways cranial nerve nuclei for III through XII brainstem nuclei associated with posture, balance & walking reticular activating system centers for control of cardiovascular, respiratory, swallowing, vomiting
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16 Reticular activating system Location: loose network in brain stem, widely distributed input/output Function: arousal (positive feedback), wakefulness, awareness, focus function essential for life
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17 Spinal cord fig 6-41 Gray matter: cell bodies & synapses White matter: ascending & descending tracts Ventral root: efferent pathways Dorsal root: afferent pathways Dorsal root ganglion: cell bodies of afferent neurons
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18 Nervous system organization fig 6-37
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19 Peripheral nervous system: efferent division fig 6-43 Somatic: single neuron, innervates skeletal muscle, voluntary control Autonomic: 2 neuron chain, innervates smooth, cardiac muscle, glands, largely involuntary control
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20 Autonomic nervous system: anatomy fig 6-46 cropped Parasympathetic: long preganglionic, short post ganglionic, ganglia often in end organ, little divergence, specific action Sympathetic: short perganglionic, long post ganglionic, much divergence adrenal medulla: endocrine supplement, acts as a unit
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21 Autonomic nervous system: neurotransmitters fig 6-46 cropped preganglionicpostganglionic parasympatheticacetyl choline sympatheticacetyl choline*norepinephrine adrenal medulla:preganglionic - acetyl choline postganglionic (chromaffin cell) - 80% epi, 20% norepi *some exceptions
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22 Autonomic system distribution fig 6-44 parasympathetic: craniosacral outflow long preganglionic especially vagus (X) sympathetic: thoracolumbar outflow short preganglionic
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23 Autonomic nervous system: actions General: parasympathetic (PS): specific actions (rest, digest, rebuild) sympathetic (SY): general action (fight, fright, flight) Models: SY: “Og” caveman chased by saber toothed tiger PS: “Slats Grobnik” lazy, overeating, overdrinking
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24 Autonomic nervous system: actions Heart: PS: rate SY: rate, contractility, cardiac output, blood pressure Vasculature: PS: minimal effects SY: arterioles constrict (especially skin, GI tract, kidneys), veins constrict Lungs: PS: bronchioles constrict, secretion SY: bronchioles dilate, secretion Gastrointestinal system: PS: secretions, motility, sphincters relax, blood to salivary glands SY: secretions, motility, sphincters constrict, blood to salivary glands
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25 Autonomic nervous system: actions Metabolism: PS: anabolic ( insulin), synthesis of fat, glycogen, protein SY: catabolic ( epinephrine, glucagon, cortisol), lipolysis, glycogenolysis, gluconeogenesis Urinary bladder: PS: sphincter relaxes, bladder wall contracts (micturition), SY: sphincter constricts, bladder wall relaxes Sweat: PS: insignificant innervation (Vander is wrong!) SY: hands, feet (adrenergic), general (AcCh) – “cold sweat” Reproductive system: PS: erection (penis, clitoris) – NO is neurotransmitter, not AcCh SY: ejaculation (male), orgasm (female)
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26 Adrenergic receptors Norepinephrine (NE) and epinephrine (E) bind to “adrenergic” receptors Examples: 1, 2, 1, 2, 3 NE & E bind to all types, although NE prefers ’s & E prefers ’s 1 receptors:cause smooth muscle contraction (e.g. arterioles, veins) have IP 3, DAG, Ca ++ as second messengers 1 receptors: are in (1) heart and mediate cardiac responses to SNS have cAMP as second messenger 2 receptors:cause relaxation of smooth muscle (e.g. (2) lung bronchioles) have cAMP as second messenger Smooth muscle response depends on receptor profile
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