By Y. Zarkos. Lesley University.

    Over-salivation can occur buy accutane 30mg lowest price, for example cheap 10 mg accutane otc, if you are stimulated by the smell of food, but that food is not available for you to eat. During times of stress, such as before speaking in public, sympathetic stimulation takes over, reducing salivation and producing the symptom of dry mouth often associated with anxiety. When you are dehydrated, salivation is reduced, causing the mouth to feel dry and prompting you to take action to quench your thirst. You might notice whether reading about food and salivation right now has had any effect on your production of saliva. Food contains chemicals that stimulate taste receptors on the tongue, which send impulses to the superior and inferior salivatory nuclei in the brain stem. These two nuclei then send back parasympathetic impulses through fibers in the glossopharyngeal and facial nerves, which stimulate salivation. Even after you swallow food, salivation is increased to cleanse the mouth and to water down and neutralize any irritating chemical remnants, such as that hot sauce in your burrito. The Teeth The teeth, or dentes (singular = dens), are organs similar to bones that you use to tear, grind, and otherwise mechanically break down food. Types of Teeth During the course of your lifetime, you have two sets of teeth (one set of teeth is a dentition). The third members of each set of three molars, top and bottom, are commonly referred to as the wisdom teeth, because their eruption is commonly delayed until early adulthood. Anatomy of a Tooth The teeth are secured in the alveolar processes (sockets) of the maxilla and the mandible. Gingivae (commonly called the gums) are soft tissues that line the alveolar processes and surround the necks of the teeth. The two main parts of a tooth are the crown, which is the portion projecting above the gum line, and the root, which is embedded within the maxilla and mandible. Both parts contain an inner pulp cavity, containing loose connective tissue through which run nerves and blood vessels. In the crown of each tooth, the dentin is covered by an outer layer of enamel, the hardest substance in the body (Figure 23. Although enamel protects the underlying dentin and pulp cavity, it is still nonetheless susceptible to mechanical and chemical erosion, or what is known as tooth decay. The most common form, dental caries (cavities) develops when colonies of bacteria feeding on sugars in the mouth release acids that cause soft tissue inflammation and degradation of the calcium crystals of the enamel. Digestive Functions of the Mouth Structure Action Outcome Lips and Confine food Food is chewed evenly during mastication cheeks between teeth Moisten and lubricate the lining of the mouth and pharynx Moisten, soften, and dissolve food Salivary Secrete saliva glands Clean the mouth and teeth Salivary amylase breaks down starch Manipulate food for chewing Tongue’s Move tongue extrinsic sideways, and in Shape food into a bolus muscles and out Manipulate food for swallowing Tongue’s Change tongue Manipulate food for swallowing intrinsic shape muscles Sense food in Nerve impulses from taste buds are conducted to salivary nuclei in the Taste buds mouth and sense brain stem and then to salivary glands, stimulating saliva secretion taste Activated in the stomach Lingual Secrete lingual glands lipase Break down triglycerides into fatty acids and diglycerides Shred and crush Break down solid food into smaller particles for deglutition Teeth food Table 23. It receives food and air from the mouth, and air from the 1104 Chapter 23 | The Digestive System nasal cavities. A short tube of skeletal muscle lined with a mucous membrane, the pharynx runs from the posterior oral and nasal cavities to the opening of the esophagus and larynx. The other two subdivisions, the oropharynx and the laryngopharynx, are used for both breathing and digestion. The oropharynx begins inferior to the nasopharynx and is continuous below with the laryngopharynx (Figure 23. The inferior border of the laryngopharynx connects to the esophagus, whereas the anterior portion connects to the larynx, allowing air to flow into the bronchial tree. During swallowing, the elevator skeletal muscles of the pharynx contract, raising and expanding the pharynx to receive the bolus of food. Once received, these muscles relax and the constrictor muscles of the pharynx contract, forcing the bolus into the esophagus and initiating peristalsis. Usually during swallowing, the soft palate and uvula rise reflexively to close off the entrance to the nasopharynx. At the same time, the larynx is pulled superiorly and the cartilaginous epiglottis, its most superior structure, folds inferiorly, covering the glottis (the opening to the larynx); this process effectively blocks access to the trachea and bronchi. When food enters the trachea, the reaction is to cough, which usually forces the food up and out of the trachea, and back into the pharynx. To enter the abdomen, the esophagus penetrates the diaphragm through an opening called the esophageal hiatus.

    Poisoning with organophosphates is an important cause of morbidity and mortality all over the world discount 20mg accutane overnight delivery. It usually results from: • Occupational exposure as in persons engaged in spraying insecticides 20 mg accutane fast delivery, • Accidental exposure, and 39 • Ingestion of any of these compounds with suicidal intent. Antinicotinics which include ganglion blockers such as hexamethonium, trimethaphan, etc. Antimuscarinics include tertiary amines such as atropine, scopolamine, tropicamide, etc, andquaternary amines such as propantheline, ipratropium, benztropine, etc. Pharmacokinetics Atropine is absorbed completely from all sites of administration except from the skin wall, where absorption is for limited extent; it has good distribution. Sweat Glands: - suppresses sweating 40 Clinical Indications Pre anesthetic medication -to reduce the amount of secretion and to prevent excessive vagal tone due to anesthesia. As antispasmodic in cases of intestinal, biliary, and renal colic Heart block Hyperhidrosis Organophosphate poisonings Side effects • Dryness of the mouth, tachycardia and blurred vision • Retention of urine Contraindications Glaucoma Bladder outlet obstruction. Better for preanesthetic medication because of strong antisecretory and antiemetic action and also brings about amnesia 4. Mydriatic atropine substitutes, this group of drugs have shorter duration of action than atropine and are used locally in the eye; drugs included: Homatropine, Eucatropine etc. Antiseccretory antispasmodic atropine substitutes: - Effective more localized to the Gl. Antiparkinsonian atropine substitute: - drugs like Benztropine, Trihexyphenidyl 4. Catecholamines have a direct action on sympathetic effectors cells through interactions with receptor sites on the cell membrane. The group includes adrenaline, noradrenaline, dopamine, isoprenaline, and dobutamine. They may directly act on the receptors or may indirectly release the physiologic catecholamines- e. Indirect mode of action: their actions are dependent on the release of endogenous catecholamines. Blood Vessels and Blood pressure: constriction of blood vessels in the skin and mucous membranes 42 - Dilatation of skeletal muscle vessels - Adrenaline increases systolic and decreases diastolic blood pressure at low doses but increases both at higher doses - Noradrenaline increases both systolic and diastolic blood pressure 2. Bladder: relaxation of detrusor muscle; contraction of sphincter and trigone muscle 3. Eye: mydriasis; reduction of intraocular pressure in normal and glacucomatous eyes 4. Respiration: Bronchodilatation; relief of congestion; mild stimulation of respiration 5. Metabolic: Increased hepatic glycogenolysis; decreased peripheral glucose intake; increased free fatty acids in the blood (lipolysis) 6. Skeletal muscle: facilitation of neuromuscular transmission and vasodilatation Drugs Acting on the Adrenergic Receptor Subtypes α1 α2 β1 β2 Agonist Phenylephrine Clonidine Dobutamine Salbutamol Methoxamine Oxymetazoline Isoproterenol Terbutaline Terbutaline Isoetharine Antagonist Prazosin Yohimbine Propranolol Propranolol Phentolamine Phentolamine Pindolol Pindolol Phenoxybenzamine Phenoxybenzamine Atenolol Butoxamine Metoprolol Timolol Timolol Adrenaline stimulates all the four receptor subtypes. Noradrenaline stimulates both alpha receptors and beta1 but has very poor affinity for beta2 receptors. It is therefore ineffective when given orally and should be given intramuscularly or subcutaneous. Intravenous injection is highly dangerous and is likely to precipitate ventricular fibrillation. The drug may how ever, be given by nebulizer for inhalation when its relaxing effect on the bronchi is desired or it may be applied topically to mucus membranes to produce vasoconstriction. Because of the extensive metabolism of the drug in liver, little is excreted unchanged in the urine. Pharmacodynamics Adrenaline directly stimulates all the adrenergic receptors both and brings about effects of sympathetic nerve stimulation. Its action may be divided in to two, depending on the type of receptor stimulated.

    Stillbirth and Perinatal Death Perinatal period is the early postnatal period relating to the birth discount accutane 5mg visa, statistically it includes the period up to 7 days after birth purchase 20mg accutane with visa. In pregnant women anywhere between 2 - 15% have birth weights of greater than 4000 grams (4 Kg, 8 lb 13 oz). Vertex Presentation (cephalic presentation) where the fetus head is the presenting part, most common and safest birth position. Each topic summary is designed for use in conjunction with the relevant didactic lecture given during the rotation. Original and Review Articles – Original, and review articles are provided for residents who seek a more comprehensive understanding of a topic. We recognize that residency is a busy time, but we hope that you will take the time to read articles relevant to the management of your patients. In order to facilitate learning at many levels, several other educational opportunities are available. Tutorials – These are 20-30 minute sessions offered during the rotation that will provide the resident with hands on experience (e. The goal of morning rounds is to develop treatment plans that can be defended by the best available scientific evidence. In addition, morning rounds are an opportunity for residents to test their knowledge, gauge their progress in critical care education, and recognize the limits of the current medical practice. The faculty and fellows of Boston University Pulmonary and Critical Care section hope that you enjoy your rotation in the medical intensive care unit. Management and Optimal Timing of Tracheostomy / Literature Chapters on Cardiopulmonary Critical Care G. During respiration air is humidified reducing atmospheric pressure by 47mmHg to 713mmHg so the maximal inspired partial pressure of oxygen is 149mmHg. Hemoglobin has 4 binding sites for oxygen, and if all are occupied then the oxygen capacity would be saturated. With a normal cardiac output of 5 l/min, the delivery of oxygen to the tissues at rest is approximately 1000 ml/min: a huge physiologic reserve. Dissolved in blood - Dissolved oxygen follows Henry’s law – the amount of oxygen dissolved is proportional to the partial pressure. If this was the only source of oxygen, then with a normal cardiac output of 5L/min, oxygen delivery would only be 15 ml/min. Fick equation: This is computed by determining the amount of oxygen that has been lost between the arterial side and the venous side and multiplying by the cardiac output. Only marginal increases in oxygen content occur with saturations above 88-90% so this should be your goal. Remember: short-term risk of low oxygen is greater than short-term risk of administering too much oxygen. Oxygen Toxicity: Initial concern for oxygen toxicity came from the discovery that therapeutic oxygen causes blindness in premature babies with respiratory distress syndrome. The performance of a particular device depends: 1) flow rate of gas out of the device, and 2) inspiratory flow rate created by the patient. In the ideal device, gas flow exceeds the patient’s peak inspiratory flow so as not to entrain air from the atmosphere. Nasal cannula: The premise behind nasal cannula is to use the dead space of the nasopharynx as a reservoir for oxygen. There are a couple of problems with nasal cannula: 1) they need to be positioned at the nares, 2) effectiveness is influenced by the pattern of breathing - there appears to be little difference whether the patient is a mouth or a nose breather, but it is important that the patient exhale through their mouth. Initiating Mechanical ventilation Aim: Provide adequate ventilation and oxygenation without inducing barotrauma/volutrauma. Unstable hemodynamics: Hypotension is common after intubation–probably multi- factorial including pre–intubation hypovolemia which is increased by peri-intubation 8 analgesia and anesthesia, immediate effects of positive pressure ventilation on venous return; acidosis (hyperventilate pre-intubation). Agitation: Don’t forget that if paralytic agent has been use ensure patient also receives an anxiolytic/anmesic agent like benzodiazepine. Pressure Control Ventilation (see below) Uses Square Pressure wave form-hypothetically allows for recruitment of alveolar gas exchange units by maintaining inspiratory pressures for longer periods. Turning patient to prone position results in recruitment of previously collapsed alveoli- The majority of patients respond within 30 minutes. Protein-rich fluid escapes into the alveolar space and interstitium leading to impaired lung compliance and gas exchange. Clinically: • Patients usually develop syndrome 4-48 hours after precipitant injury, and may persist for days to weeks.

    Life processes: The following are the important life processes of humans: Metabolism: includes catabolism and anabolism that provides energy and body’s structural and functional components Excitability: Ability to sense changes in and around us cheap accutane 40mg amex. Conductivity: ability to carry the effects of stimulus from part of a cell to another discount accutane 20mg mastercard. The human body contains organic compounds such as lipids, proteins, carbohydrates and nucleic acids. The lipids are important forms of storage fuel in addition to providing insulation of the body as a whole or essential component in the structure of plasma membranes, myelin and other membranes. Proteins serve as the structural basis for all enzymes, contractile muscle proteins, connective tissue, such as collagen and elastin and in addition as a fuel (about 15%), or precursor for carbohydrate in the process of gluconeogenesis. Ingested glucose is converted to glycogen and stored in the liver, muscle and adipose tissue. Components of Body System System Components Circulation Heart, blood vessels, blood Digestive system Mouth, pharynx, esophagus, stomach, small & large ` intestine, salivary glands, pancreas liver, and gallbladder Respiratory system Nose, pharynx, larynx, trachea, bronchi, lungs Urinary system Kidneys, ureters, urinary bladder, urethra Skeletal system Bones, cartilage, joints Muscle system Skeletal muscle Integumentary system Skin, hair, nails Immune system Leukocytes, thymus, bone marrow, tonsils, adenoids, `` lymph nodes, spleen, appendix, gut-associated lymphoid ` tissue, skin-associated lymphoid tissue muscosa ` associated lymphoid tissue Nervous system Brain, spinal cord, peripheral nervous system. Large part of physiology is concerned with regulation mechanisms that act to maintain the constancy of the internal environment. The structure and chemical 6 reactions of living organisms are sensitive to the chemical and physical conditions within and around cells. For multicellular organisms, the surrounding fluid is the interstitial fluid: a component of the extracellular fluid. The intracellular fluid has a high concentration of potassium and low concentration of + - ++ + Na Cl , Mg , and Ca. Body temperature is very crucial for intracellular physiological processes; enzymatic events need a very narrow range of temperature, within the physiological range of temperature compatible with life, cooler temperature favors preservations of cellular structure but slows the rate of chemical reactions carried out by cells. The higher temperature enhances chemical reactions, but may also disrupt the structure of the proteins and other macromolecules within cells. The production of energy for cellular activities requires oxygen and nutrients reaching the cell interior and carbon dioxide and other chemical wastes products be transferred to the environment. Extensive exchange between cells and immediate surroundings, interstitial fluid, occurs by diffusion based on a concentration gradient. Diffusion causes adequate movement of dissolved nutrients, gases and metabolic end products to meet the active needs of the cell, if the distance is short. For the efficiency of diffusion, the diameter of individual cells is usually not more than a few tenths of a millimeter. In the circulatory system, blood rapidly moves between the respiratory system, where gases are exchanged; the kidney where wastes and excess of fluid and solutes are excreted; and the digestive system where nutrients are absorbed. These substances are rapidly transported by blood flow overcoming the diffusion limit on large body size. By maintaining a relatively constant internal environment, multicellular organisms are able to live freely in changing external environment. Responses tend to oppose the change and restore the variable to its set point value. All organ systems have regulatory processes for maintaining a delicate balance in a dynamic steady state. If external environment stresses are very severe beyond the homeostatic processes, the balance can be overwhelmed. Prolonged exposure to cold may lead to an intolerable reduction in the body temperature. Exercise in very hot environment, may result in fluid depletion and an increase in the core temperature, resulting in heat stroke. The cells are much adapted to a regulated core temperature that even a few degree of temperature variations may have fatal consequences. Without clothes and proper protection humans can tolerate only a narrow differences between body temperature and environmental temperature. Factors homeostatically maintained include: • Concentration of nutrient molecules • Concentration of oxygen and carbondioxide • Concentration of waste products • pH • Temperature • Concentration of water, salt, and other electrolytes • Volume (fluids), osmolality, and pressure Homeostasis is essential for survival of cells in that : • Cells need homeostasis for their own survival and for performing specialized function essential to survival of the whole body. Nervous System: Information from the external environment relayed through the nervous system. Nervous system acts through electrical signals to control rapid responses for higher functions e.

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