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(BQ) Part 2 book "Pharmacology for anaesthesia and intensive care" presents the following contents: Cardiovascular drugs (Sympathomimetics, adrenoceptor antagonists, anti-arrhythmics ,.), other important drugs (central nervous system, antiemetics and related drugs, drugs acting on the gut, intravenous fluids and minerals,.). | SECTION III Cardiovascular drugs 13 Sympathomimetics Physiology Autonomic nervous system The autonomic nervous system ANS is a complex system of neurones that controls the body s internal milieu. It is not under voluntary control and is anatomically distinct from the somatic nervous system. Its efferent limb controls individual organs and smooth muscle while its afferent limb relays information occasionally in somatic nerves concerning visceral sensation and may result in reflex arcs. The hypothalamus is the central point of integration of the ANS but is itself under the control of the neocortex. However not all autonomic activity involves the hypothalamus locally the gut coordinates its secretions some reflex activity is processed within the spinal cord and the control of vital functions by baroreceptors is processed within the medulla. The ANS is divided into the parasympathetic and sympathetic nervous systems. Parasympathetic nervous system The parasympathetic nervous system PNS is made up of pre- and post-ganglionic fibres. The pre-ganglionic fibres arise from two locations Figure 13.1 Cranial nerves III VII IX X - which supply the eye salivary glands heart bronchi upper gastrointestinal tract to the splenic flexure and ureters Sacral fibres S2 3 4 - which supply distal bowel bladder and genitals. All these fibres synapse within ganglia that are close to or within the effector organ. The post-ganglionic neurone releases acetylcholine which acts via nicotinic receptors. The PNS may be modulated by anticholinergics see Chapter 19 and anticholinesterases see Chapter 12 . Sympathetic nervous system The sympathetic nervous system SNS is also made up of pre- and post-ganglionic fibres. The pre-ganglionic fibres arise within the lateral horns of the spinal cord at the thoracic and upper lumbar levels T1-L2 and pass into the anterior primary rami and via the white rami communicans into the sympathetic chain or ganglia where they may either synapse at that or an .
