By V. Muntasir. Belhaven College. 2018.
Your body can store some of the micronutrients in its tissues buy ceftin 250mg on line, and draw on those reserves if you fail to consume them in your diet for a few days or weeks purchase 500mg ceftin fast delivery. Some others micronutrients cheap ceftin 500mg line, such as vitamin C and most of the B vitamins discount ceftin 500 mg online, are water-soluble and cannot be stored, so you need to consume them every day or two. Narrow Range of Temperature You have probably seen news stories about athletes who died of heat stroke, or hikers who died of exposure to cold. Such deaths occur because the chemical reactions upon which the body depends can only take place within a narrow range of body temperature, from just below to just above 37°C (98. When body temperature rises well above or drops well below normal, certain proteins (enzymes) that facilitate chemical reactions lose their normal structure and their ability to function and the chemical reactions of metabolism cannot proceed. Adequate water (from the extracellular fluid in the body) is necessary to produce sweat, so adequate fluid intake is essential to balance that loss during the sweat response. Not surprisingly, the sweat response is much less effective in a humid environment because the air is already saturated with water. Thus, the sweat on the skin’s surface is not able to evaporate, and internal body temperature can get dangerously high. The body responds to cold by reducing blood circulation to the extremities, the hands and feet, in order to prevent blood from cooling there and so that the body’s core can stay warm. Even when core body temperature remains stable, however, tissues exposed to severe cold, especially the fingers and toes, can develop frostbite when blood flow to the extremities has been much reduced. This form of tissue damage can be permanent and lead to gangrene, requiring amputation of the affected region. Controlled Hypothermia As you have learned, the body continuously engages in coordinated physiological processes to maintain a stable temperature. Controlled hypothermia is clinically induced hypothermia performed in order to reduce the metabolic rate of an organ or of a person’s entire body. Controlled hypothermia often is used, for example, during open-heart surgery because it decreases the metabolic needs of the brain, heart, and other organs, reducing the risk of damage to them. The heart is cooled further and is maintained at a temperature below 15°C (60°F) for the duration of the surgery. This very cold temperature helps the heart muscle to tolerate its lack of blood supply during the surgery. Some emergency department physicians use controlled hypothermia to reduce damage to the heart in patients who have suffered a cardiac arrest. In the emergency department, the physician induces coma and lowers the patient’s body temperature to approximately 91 degrees. Narrow Range of Atmospheric Pressure Pressure is a force exerted by a substance that is in contact with another substance. If you were suddenly ejected from a space ship above Earth’s atmosphere, you would go from a situation of normal pressure to one of very low pressure. The pressure of the nitrogen gas in your blood would be much higher than the pressure of nitrogen in the space surrounding your body. As a result, the nitrogen gas in your blood would expand, forming bubbles that could block blood vessels and even cause cells to break apart. Your ability to breathe—that is, to take in oxygen and release carbon dioxide—also depends upon a precise atmospheric pressure. Altitude sickness occurs in part because the atmosphere at high altitudes exerts less pressure, reducing the exchange of these gases, and causing shortness of breath, confusion, headache, lethargy, and nausea. Mountain climbers carry oxygen to reduce the effects of both low oxygen levels and low barometric pressure at higher altitudes (Figure 1. This condition affects underwater divers who surface from a deep dive too quickly, and it can affect pilots flying at high altitudes in planes with unpressurized cabins. At high altitude, barometric pressure is much less than on Earth’s surface because pressure is produced by the weight of the column of air above the body pressing down on the body. The very great pressures on divers in deep water are likewise from the weight of a column of water pressing down on the body. This occurs because when pressure of a gas over a liquid is decreased, the amount of gas that can remain dissolved in the liquid also is decreased.
Learn tree of life and finding that the genomes of mice purchase 500 mg ceftin with mastercard, how medicine and science are changing in big frogs cheap 250mg ceftin amex, fish and a slew of other creatures have ways discount 250 mg ceftin amex, and how these changes influence society discount 500 mg ceftin. From metabolism to medicines to agriculture, So why doesn’t your brother look like your the science of genetics affects us every day. In Chapter 3,“Life’s Genetic Tree,” find out how evolution works and how it relates to genetics and medical research. C H A P T E R 1 How Genes Work eople have known for many years that Proteins do many other things, too. When a cell needs Firming up the details took quite some time, more proteins, it uses the manufacturing instruc though. Genetics in the Garden In 1900, three European scientists inde The monk Gregor Mendel first described pendently discovered an obscure research how traits are inherited paper that had been published nearly 35 from one generation to years before. Mendel had studied how pea plants When he crossbred purpleflowered pea plants inherited the two variant forms of easytosee with whiteflowered ones, the next generation had traits. Over Rosalind Franklin, a physical chemist work time, mutations supply the raw material from ing with Maurice Wilkins at King’s College in which new life forms evolve (see Chapter 3, London, was among the first to use this method “Life’s Genetic Tree”). Her experiments plants were bred to each other, some of their off factors, whatever they were, must be physical spring had white flowers. What’s more, the material because they passed from parent to secondgeneration plants displayed the colors in a offspring in a mathematically orderly way. On average, 75 percent of the until many years later, when the other scientists secondgeneration plants had purple flowers and unearthed Mendel’s report, that the factors were 25 percent of the plants had white flowers. Mendel’s mathematical rules of inheritance applied Trying to solve the mystery of the missing color not just to peas, but also to all plants, animals and blooms, Mendel imagined that the reproductive people. The discovery of a quantitative rule for cells of his pea plants might contain discrete inheritance was momentous. It revealed that a “factors,” each of which specified a particular trait, common, general principle governed the growth such as white flowers. Although Franklin did not earn a you know the sequence of nucleotide building share of the prize due to her untimely death at age blocks on one strand, you know the sequence of 38, she is widely recognized as having played a nucleotide building blocks on the other strand: significant role in the discovery. A always matches up with T and C always links The spiral staircaseshaped double to G (see drawing, page 7). But what and groups of genes are packaged tightly into is so beautiful about the structures called chromosomes. Every cell in your discovery of the twisting body except for eggs, sperm and red blood cells ladder structure isn’t just contains a full set of chromosomes in its nucleus. It taught were connected in this way, it would stretch them that the two connected approximately 67 billion miles! P Nucleotide S C 8 National Institute of General Medical Sciences Copycat It’s astounding to think that your body consists of trillions of cells. Each strand becomes cellular spellchecker catches and corrects nearly a pattern, or template, for making a new strand, all of these errors. The trouble is that most of these G C T A drugs do affect normal cells that grow and T A divide frequently, such as cells of the immune system and hair cells. A T G C Most of your cells are called diploid G C A T (“di” means two, and “ploid” refers to sets of A T chromosomes) because they have two sets of chromosomes (23 pairs). Each G C C G G C haploid cell has only one set of 23 chromosomes C G so that at fertilization the math will work out: A T A T A haploid egg cell will combine with a haploid sperm cell to form a diploid cell with the right A T number of chromosomes: 46. Matching chromosomes pair up This creates a mix of new genetic Chromosomes swap material in the offspring’s cells. Her research shows What happens if an egg or a sperm cell gets how, in healthy cells, gluelike protein complexes the wrong number of chromosomes, and how called cohesins release pairs of chromosomes at often does this happen? One of every 18 babies born to women over 45 has three copies of chromosome 13, 18 or 21 instead of the normal two, and this improper balancing can cause trouble. To make her work easier, Amon—like many other basic scientists—studies yeast cells, which separate their chromosomes almost exactly the same way human cells do, except that yeast do it much faster. Cells can look and act differently, and do entirely different jobs, because each cell “turns on,” or expresses, only the genes appropriate for what it needs to do. The New Genetics I How Genes Work 13 The biggest obstacle to learning more But our understanding is improving fast, has been a lack of tools.
After having read the satellite module thoroughly buy generic ceftin 500mg line, the student should attempt to answer all the post-test questions given in the core module generic ceftin 250 mg with amex. Disinfections is a process mainly used as a barrier between the patients and the people about him/ her ceftin 250 mg. Mention the tests required before administering Progress of patients on anti- retroviral therapy for a patient? Mention the tests that are required for monitoring the progress of patients on anti- retroviral therapy order 250mg ceftin. In Ethiopia there are indications that the epidemic has affected a large proportion of the society and that no region or zone in the country is spared. In this module major emphasis is placed on the Epidemiology as well as the prevention and control of the problem. Learning objectives After going through this module all categories of students should at least be able to: 1. Data from blood donors also indicated that this group accounted for a large proportion of infections among the general population. By doing so it substantially reduces the capacity of human body to defend against many of the pathogenic viruses, bacteria, protozoa and fungus. After infection there is a period of asymptomatic carrier sero- negative state, followed by flu -like stage, and then sero-conversion occurs. Minor ones being chronic cough, lymphadenopathy, fungal infections of the mouth and genitalia,herpes infections, neurological abnormalities, cryptococcal meningitis, and others. This modified case definition is simpler, more specific and sensitive, yet requires positive serologic result. Therefore, the control lies on prevention of the infection, which can only be achieved through modification of behavior. Avoid unsafe sexual practices by reducing the number and frequency of sexual contacts, avoiding high-risk practices and using barrier protection such as condoms 2. Reducing transmission through potential drug use (drug injectors) by educating and counseling drug users with regard to risk of sharing needles. Discourage harmful traditional practices such as female genital mutilation, tooth - extraction, venotomy, skin incisions, etc. Follow strict infection prevention rules (disinfections and sterilization) in clinical settings as well as at home 2. In 1989, a sero-epidemiological survey including a representative sample of 6,234 female sex workers in 23 towns of the country aside from Addis Ababa showed a prevalence that ranged from 1. The highest prevalence rates (above20%) were found in large towns situated along the roads leading from Addis Ababa to Asseb, Gondar and Mekele. D After doing so read the core module, do the pre-tests, do the exercises and then go through this satellite module. This system delineates more inclusive definition and classifications that can be used for patient care, health planning, public health strategies, prevention and control activities, and epidemiological studies. Classification into groups is not intended to have prognostic significance or severity of illness designation. In this case the disease ay progress more rapidly, especially in persons with underlying problems, such as chronic diseases, recurrent infections, anemia, malnutrition, closely spaced and repeated pregnancies, malaria and tuberculosis. The “Window Period” of delayed sero-conversion is an important concept for clinicians who are assessing and counseling clients. The clinical signs and symptoms may typically include fever, sweating, headache, migraine, rash, sore throat, muscle and joint pain. This ay be accompanied with generalized lymphadenopathy involving axilliary, occipital, and cervical nodes. There may also be herpes zoster, skin rashes, fungal nail infections, recurrent oral ulcerations, recurrent upper respiratory tract infections and weight loss. Constitutional symptoms-- Weight loss, night sweats, chronic fever (at least 30 days), and /or chronic dearrhea (at least 30 days), fatigue 8. Bacterialinfections-Pneumococcal pneumonia, Streptococcus pnuemonea, Haemophilus influenzea, Pseudomonas aeruginosa ,Staphylococcus aureus, clostridium defficile, Nocardia astroides, Rhodococcus equi,Rochalimaea Quintana 9.
A single unit of light is called a photon buy ceftin 250 mg on-line, which is described in physics as a packet of energy with properties of both a particle and a wave ceftin 250mg visa. The energy of a photon is represented by its wavelength purchase 250 mg ceftin mastercard, with each wavelength of visible light corresponding to a particular color buy ceftin 250 mg line. Wavelengths of electromagnetic radiation longer than 720 nm fall into the infrared range, whereas wavelengths shorter than 380 nm fall into the ultraviolet range. All other colors fall between red and blue at various points along the wavelength This OpenStax book is available for free at http://cnx. Specifically, photons cause some of the double-bonded carbons within the chain to switch from a cis to a trans conformation. Before interacting with a photon, retinal’s flexible double-bonded carbons are in the cis conformation. A photon interacting with the molecule causes the flexible double-bonded carbons to change to the trans- conformation, forming all-trans-retinal, which has a straight hydrocarbon chain (Figure 14. The G protein changes the membrane potential of the photoreceptor cell, which then releases less neurotransmitter into the outer synaptic layer of the retina. Until the retinal molecule is changed back to the 11-cis-retinal shape, the opsin cannot respond to light energy, which is called bleaching. When a large group of photopigments is bleached, the retina will send information as if opposing visual information is being perceived. The photoisomerization is reversed by a series of enzymatic changes so that the retinal responds to more light energy. The three color opsins have peak sensitivities of 564 nm, 534 nm, and 420 nm corresponding roughly to the primary colors of red, green, and blue (Figure 14. The absorbance of rhodopsin in the rods is much more sensitive than in the cone opsins; specifically, rods are sensitive to vision in low light conditions, and cones are sensitive to brighter conditions. In a darkened 620 Chapter 14 | The Somatic Nervous System room, there is not enough light to activate cone opsins, and vision is entirely dependent on rods. The three types of cone opsins, being sensitive to different wavelengths of light, provide us with color vision. By comparing the activity of the three different cones, the brain can extract color information from visual stimuli. For example, a bright blue light that has a wavelength of approximately 450 nm would activate the “red” cones minimally, the “green” cones marginally, and the “blue” cones predominantly. The relative activation of the three different cones is calculated by the brain, which perceives the color as blue. If you think that you can see colors in the dark, it is most likely because your brain knows what color something is and is relying on that memory. This first fiber in the pathway synapses on a thalamic cell that then projects to the visual cortex in the occipital lobe where “seeing,” or visual perception, takes place. This video gives an abbreviated overview of the visual system by concentrating on the pathway from the eyes to the occipital lobe. The video makes the statement (at 0:45) that “specialized cells in the retina called ganglion cells convert the light rays into electrical signals. Spinal Nerves Generally, spinal nerves contain afferent axons from sensory receptors in the periphery, such as from the skin, mixed with efferent axons travelling to the muscles or other effector organs. The dorsal root contains only the axons of sensory neurons, whereas the ventral roots contain only the axons of the motor neurons. Some of the branches will synapse with local neurons in the dorsal root ganglion, posterior (dorsal) horn, or even the anterior (ventral) horn, at the level of the spinal cord where they enter. Other branches will travel a short distance up or down the spine to interact with neurons at other levels of the spinal cord. A branch may also turn into the posterior (dorsal) column of the white matter to connect with the brain.