Chapter 16 The Autonomic Nervous System 1 Efferent pathways and ganglia in ANS divisions Jordan Garvey o Effectors o Pathway Smooth muscle Cardiac muscle Glands ANS controls visceral organs i e blood vessels CV GI urinary bladder 2 neurons and one synapse Spinal Cord Autonomic Ganglion Autonomic Ganglion Effector organ is stimulated or inhibited depends on NTs Unconscious regulation o Location of Synapse Paravertebral Chain close to vertebral bodies of spinal column thoracic cavity organs use this Collateral Ganglia for organs in abdominal cavity 2 ANS anatomy Parasympathetic and Sympathetic Pathways to the adrenal medulla o Sympathetic Short preganglionic neuron long postganglionic neuron T1 L2 thoracolumbar division Paravertebral ganglia chain 1st ganglia set Thoracic organs use this Collateral ganglia 2nd ganglia set Abdominal organs use this T5 L2 Increase heart rate and inhibit digestion Preganglionic secretes ACh Postganglionic produces and secretes NE and E this is the only one that is different o Sympathetic Pathway Catecholamines stimulate thoracic NE and E stimulate heart Catecholamines inhibit abdominal NE and E inhibit abdominal organs o Parasympathetic Long presynaptic neuron short postsynaptic neuron This leaves from cranial region brainstem to sacral division S2 S4 The Vagus Nerve leaves from the cervical division from medulla and goes to the heart stomach pancreas and liver gallbladder Decrease heart rate and allow digestion Preganglionic secretes ACh Postganglionic secretes ACh Ventricles and Blood Vessels don t have parasympathetic innervation o Parasympathetic Pathway Soma is in Medulla and secretes Ach to ganglion Ach in postganglionic fiber to effector organ Parasympathetic inhibits thoracic ACh inhibits heart Parasympathetic stimulates abdominal ACh stimulates abdominal organs 1 3 Visceral reflexes o Visceral organs are innervated by sympathetic and parasympathetic fibers o Parasympathetic reflex lowers heart rate o Sympathetic reflex increases heart rate fight or flight Jordan Garvey 4 ANS physiology Neurotransmitters NT and receptors the effects of drugs are not included o The autonomic nervous system is controlled by the hypothalamus o Catecholamines can be NTs and hormones o Pink tissue in adrenal medulla produces Epinephrine and Norepinephrine This is why the adrenal medulla secretes catecholamines into the blood Results in increased sympathetic activity to organs and parasympathetic activity decreases o Neurotransmitter effect can be excitatory or inhibitory depending upon the receptor type o There is NO parasympathetic innervation on Blood Vessels so increasing parasympathetic won t change BV diameter BP o Ventricles and Blood vessels don t have parasympathetic innervation 5 NTs secreted by preganglionic and postganglionic autonomic neurons o Acetylcholine is released by preganglionic neurons in both divisions o ACh is released by Parasympathetic postganglionic neurons o NE E are released by Sympathetic postganglionic neurons 80 NE and 20 E secreted by sympathetic post 20 NE and 80 E are secreted by Adrenal medulla into the blood stream adrenergic 6 The inhibitory and stimulatory effects of catecholamines and Ach on the effector organs o Postganglionic sympathetic neurons secrete catecholamines E NE Catecholamines stimulate the thoracic cavity i e increase HR and inhibit the abdominal cavity o Postganglionic parasympathetic neurons secrete only ACh ACh on the thoracic cavity is inhibitory i e slows HR and stimulates the abdominal cavity 2 Chapter 18 The Endocrine System 1 The endocrine system an overview Jordan Garvey a A collection of glands that secrete hormones directly into the circulatory system to be carried toward a distant target organ b The endocrine system is an information signal system like the nervous system 2 The chemistry of hormones classification based on chemical structure a Hormones are chemical substances secreted by endocrine cells into the blood Receptors are proteins molecules to which a particular hormone binds strongly b Amino acid based hormones amines and proteins These act on plasma membrane receptors Examples Insulin Glucagon c Steroids synthesized from cholesterol Sex organs and adrenal medulla These act on intracellular receptors to directly activate genes 3 Mechanisms of hormones general no details hormones that have receptors in the cell membrane or the nucleus b Location of receptor a Hormones are bound to transporter protein b c they are NOT water soluble On target cell a hormone can stimulate synthesis of proteins or regulatory molecules i ii In the membrane for protein and AAs Catecholamines These have a faster effect Inside of the cell for Sterols These are produced and secreted in two places adrenal cortex and sex organs c Chemical nature affecting action i Water soluble membrane receptors messenger Protein production ii Lipid soluble to directly activate genes all AA based hormones except thyroid These act on the plasma 1 Adenylate Cyclase is activated This allows ATP to be converted to cAMP 2nd 2 cAMP is in charge of hormones final effect it activates other enzymes steroid and thyroid hormones These act on intracellular receptors 1 Receptor will be in cytoplasm or nucleus 2 Sterol hormone combines with the 1st receptor to for steroid receptor complex 3 Steroid receptor complex will bind in the DNA to form a protein 4 Interaction of hormones at target cells synergistic and antagonic hormones a Synergism more than one hormone produces the same effects on a target cell I e Epinephrine GH Cortisol Glucagon and ACTH all raise blood glucose b Antagonism one or more hormones opposes the action of another hormone I e insulin lowers blood glucose and Glucagon raises blood glucose c Hormones circulate to all tissues but only activate cells referred to as target cells d Target Cell Activation depends on 1 Blood levels of the hormone free or bound steroid and thyroid 2 Relative number of receptors on target cell 3 Affinity of those receptors for the hormone 5 Control of hormone release humoral neural and hormonal stimuli 3 Jordan Garvey a A hormone can produce a hormone A NT can produce a hormone Chemical substances can produce hormones b Humoral Stimuli hormones c Neural Stimuli d Hormonal Stimuli i Changing levels of ions and nutrients in the blood directly stimulate secretion of ii This is a chemical substance that is not a hormone i e high glucose stimulating B cells of pancreas to secrete insulin OR declining Ca2
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