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StuDocu is not sponsored or endorsed by any college or universityChapter 15 - The Autonomic Nervous SystemHuman Anatomy And Physiology II (College of Staten Island CUNY)StuDocu is not sponsored or endorsed by any college or universityChapter 15 - The Autonomic Nervous SystemHuman Anatomy And Physiology II (College of Staten Island CUNY)Downloaded by Katya Zamolodchikova ([email protected])lOMoARcPSD|4395810
Chapter 15 - The Autonomic Nervous System and Visceral Reflexesautonomic means “self-governed”;otheautonomic nervous system (ANS)is independent of our willautonomic nervous system (ANS)regulates fundamental states and life processes such asoheart rate,oBP, andobody temperatureWalter Cannon coined the terms“homeostasis”and the“flight-or-fight”ohededicated his career to the study of the ANSofound that animals without ANS cannot survive on their own (must be kept warm and stress-free)1Downloaded by Katya Zamolodchikova ([email protected])lOMoARcPSD|4395810
15.1 - General Properties of the Autonomic Nervous Systemautonomic nervous system (ANS)- a motor nervous system that controlsoglands,ocardiac muscle, andosmooth muscleautonomic nervous system (ANS)is also calledvisceral motor systemprimary target organs of the ANSoviscera of thoracic and abdominal cavitiesosome structures of the body wallcutaneous blood vesselssweat glandspiloerector musclesANScarries out actionsinvoluntarily:without our conscious intent or awarenessovisceral effectors do not depend on the ANS to function; only to adjust their activity to thebody’s changing needsodenervation hypersensitivity- exaggerated response of cardiac and smooth muscle ifautonomic nerves are severed2Downloaded by Katya Zamolodchikova ([email protected])lOMoARcPSD|4395810
Visceral Reflexesvisceral reflexes- unconscious, automatic, stereotyped responses to stimulation involving visceralreceptors and effectors and somewhat slower responsesvisceral reflex arcoreceptors -nerve endings that detect stretch, tissue damage, blood chemicals, body temperature,and other internal stimulioafferent neurons -leading to the CNSointerneurons -in the CNSoefferent neurons -carry motor signals away from the CNSoeffectors -that make adjustmentsANS modifies effector activitybaroreflex:o(1) high blood pressure detected by arterial stretch receptors;o(2) afferent neuron carries signal to CNS;o(3) efferent signals on vagus nerve of ANS travel to the heart;o(4) heart then slows, reducing blood pressureExample of homeostatic negative feedback loop - baroreflex3Downloaded by Katya Zamolodchikova ([email protected])lOMoARcPSD|4395810
Divisions of the ANS2 divisions innervate same target organomay have cooperative or contrasting effectoprepares body for physical activity: exercise, trauma, arousal, competition, anger, or fearincreases heart rate, BP, airflow, blood glucose levels, etc.reduces blood flow to the skin and digestive tractsympathetic divisionoprepares body for physical activity: exercise, trauma, arousal, competition, anger, or fearincreases heart rate, BP, airflow, blood glucose levels, etc.

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Katya Zamolodchikova

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