book notes - exam 2

book notes - exam 2 - Physiology Chapters 14,15,12, 16,9...

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Physiology – Chapters 14,15,12, 16,9 Chapter 14 The afferent division of the nervous system includes the receptors, sensory, neurons and sensory pathways The efferent division includes the nuclei, motor tracts, and motor neurons that control peripheral effectors Sensory receptors - Specialized Cells that m onitor sp ecific conditions in the body or the - Passes info to the CNS in the form of Action Potentials Sensory Pathways - Nerves, nuclei, a nd tracts that deliver so m atic and visceral s ensory info Sensory Receptors and their Classification General senses = temp, pain, touch, pressure, vibration and proprioception. - Interpreted on the b asis of frequency of action potentials Sens ation = arriving information Perception = awaren ess of sensation SENSORY RECEPTORS - Detects the arrival stimulus a nd translates it into action potential that can be conducted to the CNS. (Transduction) - If transduction doesn’t occur the stimulus doesn’t exist (as far as your o Ex Dogs can he ar sounds we cant Free Nerve endings - The branching tips of Dendrites - Extend through tissue like grass roots THE DETECTION - Receptor specificity
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o Each receptor has characteristic specificity. ( may have receptors  for pressure but not chemical stimuli) - Free nerve endings o The simplest receptors are dendrites o The branching of these dendrites are called FREE NERVE ENDINGS - Receptive field: o The area monitored by a single  receptor cell. o The larger the field the poorer your ability to localize (or pin point)  the a stimulus. - Generator potential : o A receptor potential larger enough to create an action potential - Sensory codng: o Translation of complex sensory information into meaning ful  patterns of Action potentials o Tonic Receptors: Always active Rate of action potential generation change accordingly with the  increase or decrease of stimulus  o Phasic Receptors: Provides info about intensity  and the rate of change of a  o Sometimes they are combined, =  and convey extremely  complicated sensory info ADAPTATION - The reduction in sensitivity in the presence of a constant stimulus o Happens quickly with those that are painless and constant - Peripheral adaptation:
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o Occurs when the level of receptor activity changes o Receptor responds quickly at first , but declines there after o Reduces the amount of info that reaches the CNS - Fast Adapting o Characteristic Phasic Ex: temperature - Slow Adapting o Tonic receptors  Ex: pain (nociceptors)  - Central Adaptation o The inhibition of nuclei along a sensory pathway Ex: smell becomes virtually non existent minutes after being  At a sub conscious level, it restricts the amount of detail that  arrives at the cerebral  cortex GENERAL SENSES - Each has a different structural and functional purpose
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book notes - exam 2 - Physiology Chapters 14,15,12, 16,9...

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