BIOL 252 1st Edition Lecture 5 Outline of Last Lecture I. Cessation of the SignalII. Postsynaptic PotentialsIII. Neuronal CircuitsIV. Autonomic Nervous System (Visceral Motor Division)Outline of Current LectureI. Enteric Nervous System II. Poll EverywhereIII. Single InnervationIV. Control of Autonomic FunctionV. Sensory SystemsCurrent LectureI. Enteric Nervous Systema. The nervous system of the digestive tractb. “Intrinsic wiring”c. How can the parasympathetic and sympathetic divisions give different instructions to their target organs?i. It depends on which neurotransmitters are present1. Neurons innervating the same structure release different neurotransmittersii. Dual innervation: the heart1. Sinus rhythma. + NE from sympathetic NSi.b. + ACh from parasympathetic NSi.II. Poll Everywherea. A man has a cervical spinal cord lesion. NE would cause his pupils to dilate These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.b. Eye dilation = sympathetici. Thoracic lumbar regionii. Long postsynaptic and short presynaptic iii. Cervical lesion – dimmer lights are not sufficient, need NE III. Single Innervationa. Blood vesselsb. Sufficient to control vasoconstriction AND vasodilationc. Vasoconstriction: blood pressure pushing outi. Strong sympathetic stimulation => smooth muscle contraction (opposes blood pressure)ii. However, if stimulus is weak, blood pressure wins (smooth muscle relaxation = vasodilation)d. Tone = slight state of contraction = vasomotor tone IV. Control of Autonomic Functiona. Cerebral cortex: not control but influence (emotions)b. Hypothalamus: control center of visceral motor, initiates c. Midbrain, pons, medulla (brainstem): nuclei for cardiac/vasomotor control, salvation, swallowing, sweating, pupillary changesd. Spinal cord: defecation and micturition (urination) reflexese. ANS regulated by several levels of CNSV. Sensory Systemsa. Sensory info transmitted to CNSi. Intensity: strength of stimulus, transmitted by frequency of neurons goingto CNS; low intensity = slow firing rateii. Modality = type: pain, texture, temperature; different types of energy andenvironmental stimuliiii. Location: receptive fieldiv. Duration: how long the stimulus lastsb. The Chemical Sensesi. Gustation: Sense of Taste1. Visible bumps = papillae (not taste buds)a.b. Sense texture2. Taste budsa. Sense chemicalsb.ii. Physiology of Taste1. Salty – produced by metal ions (sodium and potassium)2. Sweet – associated with carbohydrates3. Sour – acids such as in citrus fruits4. Bitter – associated with alkaloids (nicotine, caffeine, quinine)5. Umami – ‘meaty’ or “savory” taste of amino acid
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