Recall that the hydrostatic and osmotic pressures of the interstitial fluid are essentially negligible discount singulair 10mg mastercard. At this point order singulair 4mg visa, there is no net change of volume: Fluid moves out of the capillary at the same rate as it moves into the capillary. Considering all capillaries over the course of a day, this can be quite a substantial amount of fluid: Approximately 24 liters per day are filtered, whereas 20. These extremely thin-walled vessels have copious numbers of valves that ensure unidirectional flow through ever-larger lymphatic vessels that eventually drain into the subclavian veins in the neck. In a very real sense, the cardiovascular system engages in resource allocation, because there is not enough blood flow to distribute blood equally to all tissues simultaneously. For example, when an individual is exercising, more blood will be directed to skeletal muscles, the heart, and the lungs. Only the brain receives a more or less constant supply of blood whether you are active, resting, thinking, or engaged in any other activity. Although most of the data appears logical, the values for the distribution of blood to the integument may seem surprising. During exercise, the body distributes more blood to the body surface where it can dissipate the excess heat generated by increased activity into the environment. Systemic Blood Flow During Rest, Mild Exercise, and Maximal Exercise in a Healthy Young Individual Resting Mild exercise Maximal exercise Organ (mL/min) (mL/min) (mL/min) Skeletal muscle 1200 4500 12,500 Heart 250 350 750 Brain 750 750 750 Integument 500 1500 1900 Kidney 1100 900 600 Gastrointestinal 1400 1100 600 Others 600 400 400 (i. The primary regulatory sites include the cardiovascular centers in the brain that control both cardiac and vascular functions. In addition, more generalized neural responses from the limbic system and the autonomic nervous system are factors. The Cardiovascular Centers in the Brain Neurological regulation of blood pressure and flow depends on the cardiovascular centers located in the medulla oblongata. The cardiovascular center contains three distinct paired components: • The cardioaccelerator centers stimulate cardiac function by regulating heart rate and stroke volume via sympathetic stimulation from the cardiac accelerator nerve. The majority of these neurons act via the release of the neurotransmitter norepinephrine from sympathetic neurons. There is also a small population of neurons that control vasodilation in the vessels of the brain and skeletal muscles by relaxing the smooth muscle fibers in the vessel tunics. As noted earlier, arterioles are normally partially constricted: With maximal stimulation, their radius may be reduced to one-half of the resting state. Baroreceptor Reflexes Baroreceptors are specialized stretch receptors located within thin areas of blood vessels and heart chambers that respond to the degree of stretch caused by the presence of blood.
With the exception of somatosensation purchase 10mg singulair mastercard, this list represents the special senses generic 10mg singulair, or those systems of the body that are associated with specific organs such as the tongue or eye. Somatosensation belongs to the general senses, which are those sensory structures that are distributed throughout the body and in the walls of various organs. The special senses are all primarily part of the somatic nervous system in that they are consciously perceived through cerebral processes, though some special senses contribute to autonomic function. The general senses can be divided into somatosensation, which is commonly considered touch, but includes tactile, pressure, vibration, temperature, and pain perception. The general senses also include the visceral senses, which are separate from the somatic nervous system function in that they do not normally rise to the level of conscious perception. The cells that transduce sensory stimuli into the electrochemical signals of the nervous system are classified on the basis of structural or functional aspects of the cells. The structural classifications are either based on the anatomy of the cell that is interacting with the stimulus (free nerve endings, encapsulated endings, or specialized receptor cell), or where the cell is located relative to the stimulus (interoceptor, exteroceptor, proprioceptor). Thirdly, the functional classification is based on how the cell transduces the stimulus into a neural signal. Related to chemoreceptors are osmoreceptors and nociceptors for fluid balance and pain reception, respectively. Mechanoreceptors respond to mechanical stimuli and are the basis for most aspects of somatosensation, as well as being the basis of audition and equilibrium in the inner ear. Thermoreceptors are sensitive to temperature changes, 650 Chapter 14 | The Somatic Nervous System and photoreceptors are sensitive to light energy. The sensory fibers connect to the spinal cord through the dorsal root, which is attached to the dorsal root ganglion. Sensory information from the body that is conveyed through spinal nerves will project to the opposite side of the brain to be processed by the cerebral cortex. The cranial nerves can be strictly sensory fibers, such as the olfactory, optic, and vestibulocochlear nerves, or mixed sensory and motor nerves, such as the trigeminal, facial, glossopharyngeal, and vagus nerves. The cranial nerves are connected to the same side of the brain from which the sensory information originates. This is necessary for all sensory systems to reach the cerebral cortex, except for the olfactory system that is directly connected to the frontal and temporal lobes. The two major tracts in the spinal cord, originating from sensory neurons in the dorsal root ganglia, are the dorsal column system and the spinothalamic tract. The major differences between the two are in the type of information that is relayed to the brain and where the tracts decussate. The dorsal column system primarily carries information about touch and proprioception and crosses the midline in the medulla. The spinothalamic tract is primarily responsible for pain and temperature sensation and crosses the midline in the spinal cord at the level at which it enters. The auditory pathway passes through multiple nuclei in the brain stem in which additional information is extracted from the basic frequency stimuli processed by the cochlea. The vestibular system enters the brain stem and influences activity in the cerebellum, spinal cord, and cerebral cortex.
Q11 Under what conditions does effective treatment of addiction require treatment of co-morbid psychiatric conditions? Is evidence from research findings accessible and understandable to providers generic singulair 10 mg on-line, as well as to policymakers and advocacy groups? Q14 What do you think stands in the way of people getting quality cheap singulair 5mg online, effective treatment and of providers offering quality, effective treatment? Q16 Do you think there should be minimum standards of knowledge, skills and/or training for an individual to provide treatment? Coppola, John, Executive Director, New York Association of Alcoholism and Substance Abuse Providers, Inc. West, Chief Executive Officer and Executive Director, National Association of Drug Court Professionals, National Drug Court Institute Humphreys, PhD, Keith N. The number corresponding to each response option represents the percent, among those responding to the question, that provided the particular response. For each one I mention, please tell me how much of a problem you think it is in your community--a very serious problem, somewhat serious problem, not too much of a problem, or not a problem at all. Now I am going to mention various substances some people may consume and I would like you to tell me what level of use would, in your personal opinion, indicate that a person has a serious problem. To give you an example, some people might say that a person who eats fried foods once a week does not have a problem but if someone eats fried foods several times a day then they do have a serious problem and should seek help to change their diet. Should it be complete abstinence, reduced use, fewer negative consequences from use or the goal should be set by the patient? Suppose someone close to you realized they had a major problem with addiction to alcohol, tobacco, prescription or other drugs, how confident would you be that you knew or could find out where to go or call or send them to get the help they would need: very confident, somewhat confident, not too confident or not at all confident? Would you say you are very confident that you know what treatment for addiction involves, somewhat confident, not too confident, or not at all confident that you know what is really involved when someone gets treatment for addiction? Now I would like to read two views about medicines to treat addictions and have you tell me which one comes closer to your personal point of view. Now I would like to read two views about medicines to treat addictions and have you tell me which one comes closest to your personal point of view. Statement A: It is good news that there are medicines to treat addictions, because addictions are medical conditions that medicine can help. Now I am going to mention some approaches society could take to address the problem of addiction to alcohol, tobacco, prescription and other drugs. For each approach, please tell me how important you think it is--very important, somewhat important, not too important, or not important at all? Are you, yourself, addicted to alcohol, or prescription or other drugs right now, or have you been addicted to them in the past? I know this is a sensitive topic, but let me reassure you that this is for research purposes only and that all your responses will be completely anonymous and confidential. I know this is a sensitive topic, but let me reassure you that this is for research purposes only and that all your responses will be completely anonymous and confidential.
This additional fluid moving toward the lungs increases pulmonary pressure and makes respiration difficult discount 4 mg singulair mastercard. Symptoms include shortness of breath (dyspnea) discount singulair 4 mg, tachycardia, enlarged heart, a widened pulse pressure, and poor weight gain in infants. Treatments include surgical closure (ligation), manual closure using platinum coils or specialized mesh inserted via the femoral artery or vein, or nonsteroidal anti- inflammatory drugs to block the synthesis of prostaglandin E2, which maintains the vessel in an open position. Septal defects are not uncommon in individuals and may be congenital or caused by various disease processes. Tetralogy of Fallot is a congenital condition that may also occur from exposure to unknown environmental factors; it occurs when there is an opening in the interventricular septum caused by blockage of the pulmonary trunk, normally at the pulmonary semilunar valve. This allows blood that is relatively low in oxygen from the right ventricle to flow into the left ventricle and mix with the blood that is relatively high in oxygen. Symptoms include a distinct heart murmur, low blood oxygen percent saturation, dyspnea or difficulty in breathing, polycythemia, broadening (clubbing) of the fingers and toes, and in children, difficulty in feeding or failure to grow and develop. The term “tetralogy” is derived from the four components of the condition, although only three may be present in an individual patient: pulmonary infundibular stenosis (rigidity of the pulmonary valve), overriding aorta (the aorta is shifted above both ventricles), ventricular septal defect (opening), and right ventricular hypertrophy (enlargement of the right ventricle). Other heart defects may also accompany this condition, which is typically confirmed by echocardiography imaging. Normal treatment involves extensive surgical repair, including the use of stents to redirect blood flow and replacement of valves and patches to repair the septal defect, but the condition has a relatively high mortality. Survival rates are currently 75 percent during the first year of life; 60 percent by 4 years of age; 30 percent by 10 years; and 5 percent by 40 years. In the case of severe septal defects, including both tetralogy of Fallot and patent foramen ovale, failure of the heart to develop properly can lead to a condition commonly known as a “blue baby. Septal defects are commonly first detected through auscultation, listening to the chest using a stethoscope. In this case, instead of hearing normal heart sounds attributed to the flow of blood and closing of heart valves, unusual heart sounds may be detected. Right Atrium The right atrium serves as the receiving chamber for blood returning to the heart from the systemic circulation. The two major systemic veins, the superior and inferior venae cavae, and the large coronary vein called the coronary sinus that drains the heart myocardium empty into the right atrium. The superior vena cava drains blood from regions superior to the diaphragm: the head, neck, upper limbs, and the thoracic region. The inferior vena cava drains blood from areas inferior to the diaphragm: the lower limbs and abdominopelvic region of the body. It, too, empties into the posterior portion of the atria, but inferior to the opening of the superior vena cava. Immediately superior and slightly medial to the opening of the inferior vena cava on the posterior surface of the atrium is the opening of the coronary sinus. The majority of the internal heart structures discussed in this and subsequent sections are illustrated in Figure 19. While the bulk of the internal surface of the right atrium is smooth, the depression of the fossa ovalis is medial, and the anterior surface demonstrates prominent ridges of muscle called the pectinate muscles.
The purpose of the portal system of veins is to the liver sinusoids so the liver cells can carry out their functions order singulair 5 mg on-line. For example purchase singulair 5mg free shipping, when food is digested, most of the end products are absorbed from the small intestine into the blood stream and transported to the liver by the portal system. In the liver, these nutrients are processed, stored, and released as needed into the general circulation. Pulse and Blood Pressure Pulse The ventricles pump blood into the arteries regularly about 70 to 80 times a minute. The force of the ventricular contraction starts a wave of increased pressure that begins at the heart and travels along the arteries. This wave, called the pulse, can be felt in any artery that is relatively close to the surface, particularly if the vessel can be pressed down against a bone. At the wrist the radial artery passes over the bone on the thumb side of the forearm, and the pulse is most commonly obtained here. Other vessels sometimes used for obtaining the pulse are the carotid artery in the neck and the dorsalis pedis on the top of the foot. Only if a heart beat is abnormally weak , or if the artery is obstructed, may the beat not be detected as a pule. The pulse is some what faster in small persons than in large persons usually slightly faster in women than in men. During sleep the pulse may slow down to 60 a minute, while during strenuous exercise the rate may go up to well over 100 a minute. Because blood pressure decreases as the blood flows from arteries into capillaries and finally into veins, measurements ordinarily are mde of arterial pressure only. Systolic pressure, which occurs during heart muscle contraction, averages around 120 and is expressed in millimetres of mercury (mm Hg). The Lymphatic System The lymphatic system communicates with the blood circulatory system and is closely associated with it. Lymphatic ducts are ducts that drains different parts of the body and includes: 289 Human Anatomy and Physiology a. A certain amount of this fluid and waste products from the cells is returned to the venous capillaries, but with in the tissue spaces fine capillary vessels known as lymphatic capillaries begin, which help to drain the waste products and water from the interstitial spaces. Also larger sized materials or substances of the result of phagocytosis of pathogenic micro-organisms are drained away in the lymphatic capillaries and vessels. Thymus for processing of T-lymphocytes and hormone (thymosin) secretion to stimulate T-lymphoid tissues. Explain systole and diastole and tell how these phases are related to each other in the four chambers of the heart.
Key Terminology ampule ohpthalimic parentral brand name pharmacokinectics trade name capsule pharmacology transdermal chemical name potentiating toxicity dosage prescription transfusion enteric coated synergistic vial generic name otic z-track infusion tablet 253 Basic Clinical Nursing Skills medication topical Pharmacology is the study of drugs discount 4mg singulair amex. Therapeutic agents are drugs or medications that purchase 4mg singulair with mastercard, when introduced in to living organism, modify the physiologic functions of that organism. Drug Metabolism Drug metabolism in the human body is accomplished in four basic stages: absorption, transportation, biotransformation, and excretion. For a drug to be completely metabolized, it must first be given in sufficient concentration to produce desired effect on body tissues. Route of Absorption Drugs are absorbed by the mucus membranes, the gastro intestinal tract, the respiratory tract, and the skin. The mucus membranes are one of the most rapid and effective routes of absorption because they are highly vascular. The rate of absorption depends on the pH of the stomach’s contents, the food contents in the stomach at the time of ingestion, and the presence of disease conditions. Most of the drug concentrate dissolves in the small intestine where the large 254 Basic Clinical Nursing Skills vascular surface and moderate pH level enhance the process of breaking down the drug. Transportation The second stage of metabolism refers to the way in which a drug is transported from the site of introduction to the site of action. When the body absorbs a drug, a portion of the drug binds to plasma protein and may compete with other drugs for this storage site. As the free drug moves from the circulatory system, it crosses cell membranes to reach its site of action. Lipid-soluble drugs are distributed to and stored in fat and then released slowly in to the bloodstream when drug administration is discontinued. The amount of the drug that is distributed to body tissues depends on the permeability of the membranes and blood supply to the absorption area. Biotransformation:- The third stage of metabolism takes place as the drug, which is a foreign substance in the body; is converted by 255 Basic Clinical Nursing Skills enzymes into a less active and harmless agent that can be easily excreted. Most of this conversion occurs in the liver, although some conversion does take place in the lungs, kidney plasma and intestinal mucosa Excretion:- The final stage in metabolism takes place when the drug is changed in to an inactive form or excreted from the body. The kidneys are the most important route of excretion because they eliminate both the pure drug and the metabolism of the parent drug. During excretion, these two substances are filtered through glomeruli, secreted by the tubules, and either reabsorbed through the tables or directly excreted. Feces, saliva, tears, and mother’s milk Factors Affecting Drug metabolism Many factors affect drug metabolism, including personal attributes, such as body weight, age, and sex, physiologic factors, such as state of health or disease processes, acid-base and fluid and electrolyte balance; permeability; diurnal rhythm; and circulatory capability.
Table 17-1 Breathing Volumes Volume Definition Average value Tidal volume The amount of air moved into or out 500 cc of the lungs in quiet buy singulair 5 mg mastercard, relaxed breathing Vital capacity The volume of air that can be 4800 cc expelled from the lungs by maximum exhalation following maximum inhalation Residual volume The volume of air that remains in the 1200 cc lungs after maximum exhalation Total lung The total volume of air that can be 6000 cc capacity contained in the lungs after maximum inhalation Functional The amount of air remaining in the 2400 cc residual capacity lungs after normal exhalation Regulation of respiration Regulation of respiration is a complex process that must keep pace with moment-to-moment changes in cellular oxygen requirements and carbon dioxide production singulair 4 mg low price. Regulation 305 Human Anatomy and Physiology depends primarily on the respiratory control centers located in the medulla and pons of the brain stem. Respiration is regulated so that the levels of oxygen, corbon dioxide, and acid are kept within certain limits. From the cervical (neck) part of the cord, these nerve fibers continue through the phrenic nerve to the diaphragm. The diaphragm and the other muscles of respiration are voluntary in the sense that they can be regulated by messages from the higher brain centers, notably the cortex. It is possible for a person to deliberately breath more rapidly or more slowly or to hold his breath and not breath at all for a time. Usually we breath without thinking about it, while the respiratory centers in the medulla and pons do the controlling. These receptors are found in structures called the carotid and aortic bodies, as well as out side the medulla of the brain stem. The carotid bodies are located near the bifurcation of the common carotid arteries, while the aortic bodies are located in the aortic arch. These bodies contain many small blood vessels and sensory neurons, which are 306 Human Anatomy and Physiology sensitive to decreases in oxygen supply as well as to + increases in carbon dioxide and acidity (H ). The digestive tract, a continuous passageway beginning at the mouth, where food is taken in, and terminating at the anus, where the solid waste products of digestion are expelled from the body 2. The accessory organ, which are necessary for the digestive process but are not a direct part of the digestive tract. The Walls of the Digestive Tract Although specified for specific tasks in different organs, the wall of the digestive tract, from the esophagus to the anus, is similar in structure throughout. Follow the diagram of the small intestine in Figure 11-1 as we describe the layers of this wall from the innermost to the outermost surface. First is the mucous membrane, so called because its epithelial layer contains many mucus-secreting cells. The layer of connective tissue beneath this, the submucosa, contains blood vessels and some of the nerves that help regulate digestive activity. The inner layer has circular fibers, 311 Human Anatomy and Physiology and the outer layer has longitudinal fibers. The alternate contractions of these muscles create the wavelike movement that propels food through the digestive tract and mixes it with digestive juices. Most of the abdominal organs have an additional layer of serous membrane that is part of the peritoneum. The Peritoneum The abdominal cavity is lined with a thin, shiny serous membrane that also covers most of the abdominal organs (Figure 11-2).