Physio Exam 3 - Exam 3 Chapter 11 Peripheral Nervous...

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Exam 3 Chapter 11 Peripheral Nervous System: Efferent Division Processed commands from CNS to peripheral tissue to affect responses 2 divisions: autonomic and somatic Autonomic Smooth muscle cells, cardiac muscle, glands, adipose, epithelial Processes can occur or be mediated without conscious thought Automatic Involuntary 2 neurons (preganglionic and postganglionic) Tonic activity (basal rate) o Increase o Decrease Vegetative system: functioning in absence of higher brain function ACh or NE released Axons have varicosities at their terminals o Varicosities: bulges that interact directly with effector tissue that have stored NT that can be released when stimulated to activate the muscle o Diffuse release allows for stimulation of wide SA of tissue at the same time Excitatory or Inhibitory at target cell Somatic Skeletal muscle; motor movement Voluntary: needs input from 1 neuron Excitatory activation Ach released Axons only (release of NT) Excitatory at target cell (activation) 2 Divisions of ANS
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Sympathetic o Fight or Flight o Ex. Heart speeds up, BV dilate, liver produces glucose (digestion is not a priority, blood moves away from GI to skeletal muscle) o Mediated through hypothalamus o Control of blood flow Parasympathetic o Rest or Digest o Ex. Digestion Figure 11-3 ANS works with endocrine and behavioral system Homeostatic control centers collect sensory info o Hypothalamus: temperature control, water balance, eating behaviors o Pons: urinary bladder control, secondary respiratory center, blood pressure control o Medulla: respiratory center o Ex. Baroreceptor reflex: monitors pressure in major systemic arterioles BP decreases, less stimulation of baroreceptors, less sensory info going to medulla and pons modify output from ANS to change and send out signals to heart (causes changes in strength and rate) and SMC (vasodilation, etc.) to bring BP back to homeostasis Motor output from hypothalamus and brain stem create autonomic, endocrine, and behavioral responses o Ex. Eating, drinking, temperature control (getting out of heat) Sensory info integrated in cerebral cortex and limbic system creates emotions o Ex. Blushing Spinal reflexes occur without info from brain but can be influenced by descending pathways o Ex. Urination Figure 11-2 Hypotrophic hormones control secretion of anterior pituitary hormones. The hypothalamus secretes neurohormones from posterior pituitary. Autonomic neurons also control hormone release from peripheral endocrine cells (ex. Beta cells in the pancreas) Emotional responses mediated through limbic system can influence autonomic responses.
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o Ex. Blushing (vasodilation), fainting, sweating, urination (mediated in absence of higher neurons) o Emotional responses all alter ANS output. Antagonistic control of the ANS
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Physio Exam 3 - Exam 3 Chapter 11 Peripheral Nervous...

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