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Unformatted text preview: y depolarize or hyperpolarize depending on where light is shone in the receptive field. • • • On center, off-surround Off-center, on-surround When an image is projected on to the retina, it is analyzed by many, many ganglion cells • By analyzing the input from the On-center and off-center ganglia, the visual cortex detects contours, borders, and edges. • • • Cortical cells are organized to process info about Lines, orientation, color, binocular processing. We perceive particular images based on several clues that are provided to the brain. • • • PNS: Efferent Division Communication link by which CNS controls activities of muscles and glands. Two divisions of PNS • • • • • • • • • • • • • • • Autonomic nervous system (ANS) Involuntary branch of PNS Innervates cardiac muscle SM Most exocrine glands Some endocrine glands Adipose tissue Somatic nervous system Subject to voluntary control Innervates skeletal muscle ANS- extends form CNS to an innervated organ Two neuron chain Preganglion fiber (synapse with cell body of second neuron) Postganglionic fiber (innervates effector organs) ANS- sympathetic system dominates in emergency or stressful (flight-or-fight) situations • • • • • Promotes responses that prepare body for strenuous physical activity Parasympathetic system dominates in quiet, relaxed (rest-and-digest sitiuations) Promote body maintenance activities such as digestion. PNS somatic nervous system Consists of axons or motor neurons that originate in spinal cord or brain stem and terminate on skeletal muscle. • • Motor neuron releases NT, Ach, which stimulates muscle contraction. Motor neurons are final common pathway by which various regions of CNS exert control over skeletal muscle contraction. • Motor neurons are final common pathway by which various regions of CNS exert control over skeletal muscle activity. • These areas of CNS include spinal cord, motor regions of cortex, basal nuclei, cerebellum, a...
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This note was uploaded on 09/23/2010 for the course NPB 8746546 taught by Professor Goldberg during the Spring '10 term at UC Davis.
- Spring '10