TAILIEUCHUNG - Ebook Pharmacology for anaesthesia and intensive care (4/E): Part 2
Part 2 book “Pharmacology for anaesthesia and intensive care” has contents: Sympathomimetics, adrenoceptor antagonists, anti-arrhythmics, sentral nervous system, antiemetics and related drugs, intravenous luids and minerals, drugs afecting coagulation, drugs used in diabetes, and other contents. | SECTION III Cardiovascular drugs 13 Sympathomimetics Physiology Autonomic nervous system he 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 eferent limb controls individual organs and smooth muscle, while its aferent limb relays information (occasionally in somatic nerves) concerning visceral sensation and may result in relex arcs. he 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 relex activity is processed within the spinal cord; and the control of vital functions by baroreceptors is processed within the medulla. he ANS is divided into the parasympathetic and sympathetic nervous systems. Parasympathetic nervous system he parasympathetic nervous system (PNS) is made up of pre- and post-ganglionic ibres. he pre-ganglionic ibres arise from two locations (Figure ): • Cranial nerves (III, VII, IX, X) – which supply the eye, salivary glands, heart, bronchi, upper gastrointestinal tract (to the splenic lexure) and ureters • Sacral ibres (S2, 3, 4) – which supply distal bowel, bladder and genitals. All these ibres synapse within ganglia that are close to, or within, the efector organ. he post-ganglionic neurone releases acetylcholine, which acts via nicotinic receptors. he PNS may be modulated by anticholinergics (see Chapter 19) and anticholinesterases (see Chapter 12). Sympathetic nervous system he sympathetic nervous system (SNS) is also made up of pre- and post-ganglionic ibres. he pre-ganglionic ibres 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 .
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