On average generic slimex 15 mg with amex, about 34 to 36 mol- Aerobic Mitochondria Carbon dioxide ecules of ATP can be formed aerobi- and water 34–36 ATP cally per glucose molecule—quite an increase over anaerobic metabolism quality slimex 15mg. METABOLISM purchase slimex 15mg without prescription, NUTRITION purchase slimex 10mg without prescription, AND BODY TEMPERATURE ✦ 409 During the aerobic steps of cellular respiration, the Checkpoint 20-2 What name is given to the series of cellular re- cells form carbon dioxide, which then must be trans- actions that releases energy from nutrients? In addition, water is formed by the combination of oxygen with the hydrogen Metabolic Rate Metabolic rate refers to the rate at that is removed from nutrient molecules. Note that enzymes are re- Metabolic rate is high in children and adolescents and de- quired as catalysts in all the reactions of cellular respira- creases with age. Glycerol and fatty acids (from fat digestion) Box 20-1 A Closer Look Calorie Counting: Estimating Daily Energy NeedsCalorie Counting: Estimating Daily Energy Needs asal energy requirements for a day can be estimated with a The equation to calculate total energy needs for a day is: Bsimple formula. These 11 amino acids are described for energy, but they enter the breakdown process at dif- as nonessential because they need not be taken in as food ferent points. The remaining 9 amino acids cannot be Fat in the diet yields more than twice as much energy made by the body and therefore must be taken in as part as do protein and carbohydrate (e. Note that ing”); fat yields 9 kcal of energy per gram, whereas pro- some nonessential amino acids may become essential tein and carbohydrate each yield 4 kcal per gram. Calo- under certain conditions, as during extreme physical ries that are ingested in excess of need are converted to fat stress, or in certain hereditary metabolic diseases. Therefore, when one needs more proteins than are supplied in the diet, they must be obtained from body sub- Minerals and Vitamins stance, such as muscle tissue or plasma proteins. Drawing In addition to needing fats, proteins, and carbohydrates, on these resources becomes dangerous when needs are ex- the body requires minerals and vitamins. Fats and carbohydrates are described as “protein Minerals are chemical elements needed for body struc- sparing,” because they are used for energy before proteins ture, fluid balance, and such activities as muscle contrac- are and thus spare proteins for the synthesis of necessary tion, nerve impulse conduction, and blood clotting. Essential Amino Acids Eleven of the 20 amino acids The water-soluble vitamins are the B vitamins and vi- needed to build proteins can be synthesized internally by tamin C. They de- Asparagine ah-SPAR-ah-jene Leucine LU-sene fend against the harmful effects of Aspartic acid ah-SPAR-tik AH-sid Lysine LI-sene free radicals, highly reactive and un- Cysteine SIS-teh-ene Methionine meh-THI-o-nene stable molecules produced from oxy- Glutamic acid glu-TAM-ik AH-sid Phenylalanine fen-il-AL-ah-nene Glutamine GLU-tah-mene Threonine THRE-o-nene gen in the normal course of metabo- Glycine GLY-sene Tryptophan TRIP-to-fane lism (and also from UV radiation, air Proline PRO-lene Valine VA-lene pollution and tobacco smoke). Carbohydrates in the diet should be mainly complex, nat- urally occurring carbohydrates, and simple sugars should Checkpoint 20-5 Both vitamins and minerals are needed in be kept to a minimum. However, they boost pancre- The relative amounts of carbohydrates, fats and proteins atic insulin output, and as a result, they cause blood glu- that should be in the daily diet vary somewhat with the cose levels to rise and fall rapidly. Typical recommendations for the number of steady glucose levels, which normally range from approx- calories derived each day from the three types of food are imately 85 to125 mg/dL throughout the day. Note, however, that the glycemic It is important to realize that the type as well as the effect of a food also depends on when it is eaten during the amount of each is a factor in good health. Box 20-2 • Health Maintenance Dietary Fiber: Bulking UpDietary Fiber: Bulking Up ietary fiber is best known for its ability to improve bowel ◗ Whole grain breads, cereals, pasta, and brown rice. If your diet lacks fiber, try adding the following foods over a period of several weeks: METABOLISM, NUTRITION, AND BODY TEMPERATURE ✦ 413 Foods high in fiber, such as whole grains, fruits, and ture, such as butter and lard. Diets Fats high in saturated fats are associated with a higher than normal incidence of cancer, heart disease, and cardiovas- Fats are subdivided into saturated and unsaturated forms cular problems, although the relation between these fac- based on their chemical structure. These are listed on food labels as par- are from animal sources and are solid at room tempera- tially hydrogenated (HI-dro-jen-a-ted) vegetable oils and are found in baked goods, processed peanut butter, veg- Saturated Unsaturated etable shortening, and solid margarine. Evidence shows fatty acid fatty acid that components of hydrogenated fats, known as trans- (stearic acid) (linoleic acid) fatty acids, may be just as harmful, if not more so, than natural saturated fats and should be avoided. HO O HO O C C Proteins H C H H C H Because proteins, unlike carbohydrates and fats, are not H H stored in special reserves, protein foods should be taken C H C H in on a regular basis, with attention to obtaining the es- H C H H C H sential amino acids. Table 20-5 demon- strates the principles of combining two foods, legumes H C H C H and grains, to supply essential amino acids that might be missing in one food or the other. Traditional ethnic diets H C H C H reflect these healthy combinations, for example, beans with corn or rice in Mexican dishes or chickpeas and H C H H C H lentils with wheat in Middle Eastern fare. Most fatty acids contain the maximum numbers of hydrogen atoms agree, however, that children, elderly people, pregnant and attached to carbons and no double bonds between carbon lactating women, and teenagers, who often do not get atoms. Consumed at a more rapid rate, alcohol enters the ture) developed a pyramid to represent the quantities of bloodstream and affects many cells, notably in the brain.
For Surgery can be used for many purposes in cancer example slimex 10 mg for sale, if the tumor is very large or has spread to therapy 15mg slimex mastercard. Since cancer usually spreads via the lymphatic Radiation uses high-energy rays to kill cancer cells discount slimex 15mg with mastercard. For example order slimex 10mg amex, 40% of peo- external form, the radiation comes from a machine that ple with a colon disease, called ulcerative colitis, ulti- aims the rays at the tumor. Rather than live with the known as brachytherapy), radioactive material is sealed fear of developing colon cancer, these people may in needles, seeds, or wires and placed directly in or near choose to have their colons removed in order to reduce the tumor. The side effects of detect cancer cells that have spread and are circulating in this immunotherapy are variable but include flu-like the body. Chemotherapy is based on the principle that symptoms, weakness, loss of appetite, and skin rash. Chemotherapeutic drugs can be injected into a vein, the Bone marrow failure is a complication of chemother- muscle, or the skin or they may be taken by mouth. When high dose chemotherapy is used, this failure is When chemotherapy is used before surgery, it is anticipated. Bone marrow transplantation (BMT) or known as primary chemotherapy or “neoadjuvant peripheral stem cell transplantation (PSCT) are tech- chemotherapy. The more common use of chemotherapy is provide healthy stem cells for the patient. Chemotherapy can also be used in conjunction a patient to undergo very aggressive treatment for their with radiation therapy. Patients who receive BMT or PSCT have an The side effects of chemotherapy vary but can increased risk of infection, bleeding, and other side include susceptibility to infections, fatigue, poor appetite, effects due to the chemotherapy and radiation. This complica- fertility can be a long-term side effect in some patients tion occurs when the donated marrow reacts against a who undergo chemotherapy. It can occur any time after the trans- GALE ENCYCLOPEDIA OF GENETIC DISORDERS 197 plant. Drugs may be given to reduce the risk of graft-ver- effective against breast cancer and is now thought to be sus-host disease and to treat the problem if it occurs. Similarly, retinoids derived from vitamin A are being tested for Hormone therapy their ability to slow the progression or prevent head and neck cancers. Hormone therapy is used to fight certain cancers that depend on hormones for their growth. Drugs can be used to block the production of hormones or change the way Prognosis they work. Additionally, organs that produce hormones Most cancers are curable if detected and treated at may be removed. The five-year survival rate for all The use of alternative therapies must be carefully consid- cancers combined is 59%. This means that 59% of peo- ered because some of these unproven treatments may ple with cancer are expected to be alive five years after have life-threatening side effects. These people may be free of cancer one uses alternative therapy, they may lose the opportu- or they may be undergoing treatment. The American Cancer Society recom- five-year survival rate does not account for differences in mends that anyone considering alternative or comple- detection methods, types of treatments, additional ill- mentary therapy consult a health care team. Prevention Resources According to experts from leading universities in the BOOKS United States, a person can reduce the chances of getting American Cancer Society. What You Really Need to Know about Cancer: A Comprehensive Guide for Patients and Their • Exercising vigorously for at least 20 minutes every day Families. Informed Decisions: The Complete Book of Cancer Diagnosis, Treatment and Recovery. Certain drugs that are currently being used for treat- American Foundation for Urologic Disease, Inc. Office of Communications, 31 still not known precisely how this change in the genetic Center Dr. Johns Hopkins Cardiofaciocutaneous syndrome can sometimes be Hospital, Weinberg Building, Room 2242, 401 North confused with another genetic syndrome, Noonan syn- Broadway, Baltimore, MD 21231-2410.
Although such a view might have accurately described the function of early electrical circuits buy discount slimex 15 mg line, ﬁndings in modern neuroscience have turned nearly every aspect of that view on its head with regard to how the mind-brain functions order 15 mg slimex. During the course of the evolution of life over the last 4 billion years cheap slimex 10 mg, selective pressures have shaped living organisms at nearly all levels of analysis – from the genomic and protein levels purchase slimex 10 mg on-line, to the levels of biochemical and neural networks, to the level of the survival- and reproductive-related behavior of individuals and groups within a spe- cies. An inﬁnite number of strictly psychological models could describe a given behavioral process, such as how a rodent selects a morsel of food, grasps it, and brings it to its mouth. However, a correct psychological model for how the rodent © 2005 by Taylor & Francis Group. DEVISING TASK ANALYSES BASED ON CURRENT UNDERSTANDINGS OF NEURAL PROCESSING In this chapter, we describe ﬁve principles that sketch the beginnings of a more nuanced conception of how sensorimotor behaviors are learned and performed, based on new ﬁndings from neuroscience. Although most of the principles we will describe apply to all species with nervous systems, we will focus on the rat for several reasons. First, rats are a good mammalian exemplar, because the earliest mammals of approx- imately 175 million years ago resembled rats in their size and their heavy reliance on olfaction and somatosensory perception. Also, most of the hypoth- esized early-mammal and current-rodent neuroanatomy and neurochemistry have been conserved throughout the mammalian radiation. For instance, all mammals including rats have primary and secondary somatosensory, auditory, and visual areas23 that are neocortical in their layer structure1 (i. Further- more, they all have three-layered olfactory cortices; a highly similar limbic system; 175 MYA Non-Mammalian Other Hadrocodium Monotremes Archaic Marsupials Placentals Cynodont Mammaliforms (new mammal) Therians Place of the new mammal on the mammalian family tree Cynodont Ancestry (source: Dr. Additionally, there is exten- sive homology across rats and other mammals in terms of cytoarchitecture, cytochemistry, and the roles played by different neurotransmitters and neuromodu- lators. In this chapter, we will illustrate the ﬁve principles using data from all levels of the rat nervous system, from the sensory periphery and spinal level to higher cognitive levels. Most of our sensory examples will come from the somatosensory modality, although we will discuss other sensory modalities when they illustrate a point well. PRINCIPLE I: SENSORY AND MOTOR PROCESSING ARE CONSTANTLY INFLUENCING ONE ANOTHER A common view of information ﬂow through the mammalian nervous system is ﬁrst, sensory information ascends through sensory thalamic relay nuclei (for all modalities except olfaction, where information ﬂows directly to the cortex); next, this informa- tion undergoes multiple transformations as it proceeds through various cortical areas processed via lateral layer V connections; and ﬁnally, the transformed information descends via multiple motor system tracts to control muscular output. At the behav- ioral level, this translates into task analyses of the data-in, transfer-function-per- formed, data out logic described in the introduction. NON-HIERARCHICAL VIEWS OF SENSORIMOTOR PROCESSING However, a closer examination of mammalian brain anatomy suggests that this picture is not only oversimpliﬁed, but fundamentally wrong. At all levels of the neuraxis including the spinal cord, ascending sensory information and descending motor information inﬂuence each other. Older neuroanatomical and neurophysio- logical data suggested that this was the case; e. However, newer neuroanatomical data demonstrate that this is an ever present theme in the structure and function of neural systems. For instance, outputs from the basal ganglia, once thought to be a motor learning structure, project to layer I of all primary sensory cortical areas,27 likely inﬂuencing the processing of all cortical cells with dendrites extending into layer I. Data such as these indicate that sensory and motor areas are continuously interacting via multiple, parallel looping structures. Likewise, all sen- sory thalamic relay nuclei including the ventroposterior lateral thalamus (VPI) (pro- cessing somatosensory information), the medial geniculate thalamus (MGN) (pro- cessing auditory information) and the lateral geniculate thalamus (LGN) (processing visual data) receive axon collaterals of layer V efferents from primary motor cortex (M1) and the premotor cortex. Thus, descending motor commands appear able to modulate or even drive thalamic sensory processing. The constant interaction of sensory and motor data streams is manifest in mam- malian behavior in myriad instances. For example, the strength of an odor modulates snifﬁng intensity, even on the ﬁrst sniff of the odor. For instance, while recording single units from the digit-wrist area of caudal M1 and the magnocellular red nucleus as rats perform this task, we have found that many neurons in both areas that code the overt arm-movement phases are strongly modulated by olfactory information taken in during the ﬁnal sniff of the food target just prior to lifting the paw12 (Figure 7. In fact, the caudal M1 in rats is distinguished by having layer IV somatosensory inputs,5 whereas most motor regions in mammals lack layer IV sensory inputs. Correspondingly, we have found that many rat M1 units are partic- ularly active during phases of the reaching task in which somatosensory information is being evaluated, such as lifting the paw off the ground, brushing the paw against M1 cell, FINAL SNIFF mRN cell, FINAL SNIFF sig001c sig019a 80 20 60 15 40 10 20 5 0 0 -1 -0. The percentages below each graph show the proportion of single units recorded in each area that displayed such signiﬁcant modulation on the ﬁnal sniff.
Free-radicals can In short-term memory loss slimex 10 mg visa, patients can remember their damage the blood-brain barrier buy slimex 15 mg with visa, a membrane that sepa- childhood and past events but fail to remember events rates the circulating blood and the brain order 10mg slimex with amex. In long-term barrier may not be able to prevent toxic chemicals from memory loss slimex 15mg with mastercard, patients are unable to recall events in the entering the brain. Daily exposure to toxic chemicals Diagnosis such as alcohol, tobacco, and illicit drugs (heroine, co- To find the underlying cause of memory loss, your caine, and amphetamines) destroys brain cells at a physician will obtain a detailed medical history, which rapid rate. Other environmental toxins, such as lead and documents the pattern, symptoms, and types of memory mercury, can penetrate the blood-brain barrier. He or she will also inquire about contributing fac- side the brain, these heavy metals kill nerve cells. A routine helps explain why exposure to heavy metals has been physical and detailed neuropsychological examination linked to memory and learning problems in children. In Even though aluminum is not considered a heavy addition, he or she will order several diagnostic tests. Tests used to pinpoint the exact cause of memory loss may include neuroimaging; electroencephalography • Central nervous system (CNS) infections and inflam- (EEG) for patients with seizures; blood, cerebrospinal mation of the brain. Emotional or physical stress stimulates the re- function is the Mini-Mental Status Examination, or lease of stress hormones such as cortisol and adrena- MMSE, which is also known as the Folstein. Constant exposure to stress hormones results in Available neuroimaging techniques include computed nerve-cell death and memory loss. A CT many tasks or worry about too many things at the same scan can detect structural abnormalities, such as brain tu- time, the brain is overloaded with information and can- mors or lesions. Therefore, if a person associated with aging or degenerative diseases, an MRI, is trying to remember a lot of information, he or she PET, or SPECT test can be run. Nerve cells require glucose (sugar) to doctor pinpoint the exact cause of the memory loss. If there is not enough glucose in the scan is especially useful in that it allows the doctor to track blood, nerve cells starve and die. Excessively low and record which memory centers are stimulated in live, blood sugar can send a person into shock and/or into a working brain tissue while a person is functioning. Prolonged seizures, such as in patients with • Avoid eating foods that contain such additives as artifi- epilepsy, can cause significant memory loss. Extreme emotional trauma accumulate in the body and become toxic, causing has been associated with sudden amnesia. Women often report a significant decrease in memory function immediately following menopause. GALE ENCYCLOPEDIA OF ALTERNATIVE MEDICINE 2 1319 • Drink only filtered water to avoid toxic chemicals in for its ability to improve memory function. Therefore, it can • Eat a low-fat, high-fiber diet with emphasis on fresh slow down memory loss associated with normal aging fruits and vegetables. Antiox- that ginkgo helps improve thinking and concentration idants also protect and support brain function. Protein is necessary to maintain • Gotu kola (Centella asiatica: 70 mg taken twice daily). Studies have shown that ginseng can improve risk of strokes, blood clotting, and heart attacks. Be- cause ginseng may elevate blood pressure, patients Nutritional supplements with heart disease or high blood pressure should con- The following nutritional supplements may help re- sult with their doctor before using this herb. Studies have shown that India that is used in Ayurvedic medicine and Japanese acetylcarnitine can improve memory function in the el- medicine as a nerve tonic and treatment for insomnia. Brahmi, which is sometimes called bacopa in Western countries, contains two compounds known as • Phosphatidylserine (100 mg three times per day). It is thought that these chemicals phatidylserine probably works by lowering stress hor- help to prevent memory loss by improving the efficien- mone levels and increasing the availability of acetyl- cy of impulse transmission between nerve cells in the choline. An Australian study published in 2002 reported tion in patients suffering from age-related memory loss. Flaxseed oil (1 tablespoon per day) and fish oil capsules are good sources of omega-3 fatty acids. Patients need to be given effective antimi- crobial treatment immediately to save them from death, Herbal therapy significant brain damage, and profound memory loss.
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