By A. Eusebio. Southwestern Oklahoma State University.
The somatosensory cortex provides an example in which buy mentax 15mg online, in essence mentax 15mg mastercard, the locations of the somatosensory receptors in the body are mapped onto the somatosensory cortex buy generic mentax 15 mg line. The term homunculus comes from the Latin word for “little man” and refers to a map of the human body that is laid across a portion of the cerebral cortex buy mentax australia. In the somatosensory cortex, the external genitals, feet, and lower legs are represented on the medial face of the gyrus within the longitudinal fissure. As the gyrus curves out of the fissure and along the surface of the parietal lobe, the body map continues through the thighs, hips, trunk, shoulders, arms, and hands. The representation of the body in this topographical map is medial to lateral from the lower to upper body. It is a continuation of the topographical arrangement seen in the dorsal column system, where axons from the lower body are carried in the fasciculus gracilis, whereas axons from the upper body are carried in the fasciculus cuneatus. Also, the head and neck axons running from the trigeminal nuclei to the thalamus run adjacent to the upper body fibers. The connections through the thalamus maintain topography such that the anatomic information is preserved. Note that this correspondence does not result in a perfectly miniature scale version of the body, but rather exaggerates the more sensitive areas of the body, such as the fingers and lower face. Less sensitive areas of the body, such as the shoulders and back, are mapped to smaller areas on the cortex. Likewise, the topographic relationship between the retina and the visual cortex is maintained throughout the visual pathway. The visual field is projected onto the two retinae, as described above, with sorting at the optic chiasm. The right peripheral visual field falls on the medial portion of the right retina and the lateral portion of the left retina. Though the chiasm is helping to sort right and left visual information, superior and inferior visual information is maintained topographically in the visual pathway. Light from the superior visual field falls on the inferior retina, and light from the inferior visual field falls on the superior retina. This topography is maintained such that the superior region of the visual cortex processes the inferior visual field and vice versa. Therefore, the visual field information is inverted and reversed as it enters the visual cortex—up is down, and left is right. However, the cortex processes the visual information such that the final conscious perception of the visual field is correct. The topographic relationship is evident in that information from the foveal region of the retina is processed in the center of the primary visual cortex. Information from the peripheral regions of the retina are correspondingly processed toward the edges of the visual cortex. Similar to the exaggerations in the sensory homunculus of the somatosensory cortex, the foveal-processing area of the visual cortex is disproportionately larger than the areas processing peripheral vision. In an experiment performed in the 1960s, subjects wore prism glasses so that the visual field was inverted before reaching the eye. On the first day of the experiment, subjects would duck when walking up to a table, thinking it was suspended from the ceiling. However, after a few days of acclimation, the subjects behaved as if everything were represented correctly. Therefore, the visual cortex is somewhat flexible in adapting to the information it receives from our eyes (Figure 14. The topography of this image is maintained as the visual information travels through the visual pathway to the cortex. The cortex has been described as having specific regions that are responsible for processing specific information; there is the visual cortex, somatosensory cortex, gustatory cortex, etc. Our perceptions of the various sensory modalities—though distinct in their content—are integrated by the brain so that we experience the world as a continuous whole. In the cerebral cortex, sensory processing begins at the primary sensory cortex, then proceeds to an association area, and finally, into a multimodal integration area. For example, the visual pathway projects from the retinae through the thalamus to the primary visual cortex in the occipital lobe. Because of the overlapping field of view between the two eyes, the brain can begin to estimate the distance of stimuli based on binocular depth cues. Similar to how retinal disparity offers 3-D moviegoers a way to extract 3-D information from the two-dimensional visual field projected onto the retina, the brain can extract information about movement in space by comparing what the two eyes see. If movement of a visual stimulus is leftward in one eye and rightward in the opposite eye, the brain interprets this as movement toward (or away) from the face along the midline. If both eyes see an object moving in the same direction, but at different rates, what would that mean for spatial movement? Two ways in which we can extract depth information from the two-dimensional retinal signal are based on monocular cues and binocular cues, respectively. Monocular depth cues are those that are the result of information within the two- dimensional visual field. Binocular depth cues compare information represented in the two retinae because they do not see the visual field exactly the same. Because of this offset, visual stimuli do not fall on exactly the same spot on both retinae unless we are fixated directly on them and they fall on the fovea of each retina. All other objects in the visual field, either closer or farther away than the fixated object, will fall on different spots on the retina. When vision is fixed on an object in space, closer objects will fall on the lateral retina of each eye, and more distant objects will fall on the medial retina of either eye (Figure 14. This is easily observed by holding a finger up in front of your face as you look at a more distant object. You will see two images of your finger that represent the two disparate images that are falling on either retina. These depth cues, both monocular and binocular, can be exploited to make the brain think there are three dimensions in two-dimensional information. The projected image on the screen is two dimensional, but it has disparate information embedded in it. The 3-D glasses that are available at the theater filter the information so that only one eye sees one version of what is on the screen, and the other eye sees the other version. If you take the glasses off, the image on the screen will have varying amounts of blur because both eyes are seeing both layers of information, and the third dimension will not be evident. Some optical illusions can take advantage of depth cues as well, though those are more often using monocular cues to fool the brain into seeing different parts of the scene as being at different depths. There are two main regions that surround the primary cortex that are usually referred to as areas V2 and V3 (the primary visual cortex is area V1). The visual association regions develop more complex visual perceptions by adding color and motion information. Visual processing has two separate streams of processing: one into the temporal lobe and one into the parietal lobe. Because the ventral stream uses temporal lobe structures, it begins to interact with the non-visual cortex and may be important in visual stimuli becoming part of memories. The dorsal stream locates objects in space and helps in guiding movements of the body in response to visual inputs. The dorsal stream 634 Chapter 14 | The Somatic Nervous System enters the parietal lobe, where it interacts with somatosensory cortical areas that are important for our perception of the body and its movements. A particular sensory deficit that inhibits an important social function of humans is prosopagnosia, or face blindness. The word comes from the Greek words prosopa, that means “faces,” and agnosia, that means “not knowing. However, a person with prosopagnosia cannot recognize the most recognizable people in their respective cultures. They would not recognize the face of a celebrity, an important historical figure, or even a family member like their mother. A study of the brains of people born with the deficit found that a specific region of the brain, the anterior fusiform gyrus of the temporal lobe, is often underdeveloped. This region of the brain is concerned with the recognition of visual stimuli and its possible association with memories. Though the evidence is not yet definitive, this region is likely to be where facial recognition occurs. Though this can be a devastating condition, people who suffer from it can get by—often by using other cues to recognize the people they see.
You should advise her to continue breastfeeding order 15 mg mentax visa, giving her information about the appropriate solutions to relieve the problem buy mentax 15 mg lowest price. At six months mentax 15mg low cost, the mother or caregiver should introduce soft cheap 15 mg mentax mastercard, appropriate foods and continue breastfeeding on demand. The mother has to increase the amount of food the baby eats as the baby grows older, increasing food thickness (density) and variety. It involves the interpretation of anthropometric, biochemical (laboratory), clinical and/or dietary data. Chaltu is also stunted (because the height for age is below the third centile) and she is also underweight (because her weight for age is below the third centile). The underlying cause may be either family food shortage (because many family members have to live off a very small piece of land that is not very fertile), poor childcare by the mother because she has many children to care for or a combination of these factors. The basic cause in this case may be poverty, which is the common basic cause in many of malnourished families. Millions of children die of severe acute malnutrition each year and poor nutrition prevents many children and adults from ever reaching their full mental and physical capacity. For example, children who are malnourished are at risk of stunting, which affects their productivity when they are older; malnutrition also affects their learning ability, school performance and attendance. All of these consequences have a social and economic impact on the community and the country. As a Health Extension Practitioner you can help to minimise the effects of malnutrition in your community. In particular, through good maternal and child health care, you can help promote good feeding practices in families and emphasise the importance of clean water for drinking, cooking and cleaning. You can also support strong family planning services to help families space or limit the number of children they have. Other examples where you will have a role include advocating for basic education for girls as well as boys, encouraging communities to grow a wide range of nutritious foods and to ensure particularly that children and pregnant mothers have the right amount of food they need to be healthy. This means illness is more common and likely to be more severe, and leads to an increase under-ﬁve death rates. You can work with individuals and families and advise on food diversiﬁcation and food fortiﬁcation, which will help to ensure a more healthy diet. The other important aspect of your role is to mobilise communities and work with other development workers in your community to produce of fruit and vegetables using backyard gardens, which will help to improve access to vitamin A-rich foods. You can also support community child health days and use these to ensure a supply of vitamin A capsules and the other necessary materials to supplement people’sdiets. People must also be able to access the food and then make it into something that can be eaten. You will probably have noted that the additional groups vulnerable to acute food insecurity are those affected by sudden shocks like drought or a rise in food prices (look back at Table 8. However, try to choose three that you think are the most important and be ready to discuss the reasons for your choice with your Tutor. Once people sell land or livestock they are putting their futures at risks, so will leave this until they have tried all other coping strategies. This results in poor physical growth, mental development, affecting socioeconomic development. As a Health Extension Practitioner, you need to be aware that children under ﬁve, pregnant women and lactating mothers are particularly at risk because they have increased nutritional needs. You will work with families, taking into consideration the kinds of food they have available, to advise them on the most nutritious diet possible. As far as possible, you should explore local solutions to support children and vulnerable women, as this is likely to lead to a more sustainable approach to rehabilitation. As there is no oedema, Jemila does not have severe acute malnutrition, but you would need to monitor her progress carefully. For example you can talk with the primary caregiver why they think the child has become malnourished. You will be able to provide nutritional advice to the whole family to ensure the malnourished child is given more energy-rich food, as well as more fat and protein in their diet. An important part of the planning includes organising the services in a logical order, from a service where a child is least likely to cry to one that may create some discomfort to a child. This will also help you to control the direction of the ﬂow of clients through the services. If you start the service at the right time, this will help to minimise the time mother and caregivers will have to wait, and promote effective crowd control. His weight for height is also in the ‘moderate acute malnutrition’ range because it is between 70% and 80% of what would be the normal weight for an infant of his age. However you would class Dawit as having ‘severe acute malnutrition’ because he has oedema. Any child who fulﬁls one criterion for severe acute malnutrition (and oedema falls into this category) will be classiﬁed as having severe acute malnutrition. If Dawit had complications however – such as the presence of general danger signs, pneumonia/severe pneumonia, blood in the stool, fever or hypothermia – his classiﬁcation will be ‘severe complicated malnutrition’. This means he needs to be referred to an in-patient facility for stabilisation of his clinical condition. Another indicator that would require Dawit to be referred to an in-patient facility would be if he failed the appetite test. You should recall that in the appetite test, there is a minimum amount of food that the child should take for their weight range. For Dawit, because his weight comes in the range of 4 – 10kg, he needs to take ¼ – ½ofa sachet to pass the appetite test. The mother or caregiver should always use soap and water to wash their hands before feeding the child 193. You will be able to compare the monthly performance of your health post with other health posts and with the standard that is set at your woreda or regional level. You have to record each key indicator for the child and this will help you follow up the child’s progress in the course of the treatment (and remind you which ones you need to check). You would ask the parents or caregiver whether the child has had diarrhoea, vomiting, fever or any other new complaint or problem since the last visit. You should also check whether the child has oedema and ﬁnally, do the appetite test. For a child who was admitted without oedema, the criterion for discharge is when the child reaches its target weight. On discharge from the facility you would need to counsel the mother on feeding and caring for her child at home. If the service exists, you can provide the mother or caregiver with a discharge certiﬁcate and make a referral for the child to the supplementary feeding programme. You can also ask kebele administrators and Gott leaders to use their meetings to pass on key messages. If you plan ahead and anticipate the stocks you need, based on your caseload, this will help ensure you can provide the best possible treatment and care for managing severe malnutrition in your community. There are several stages a person is likely to go through, from a stage of pre-awareness, where they are not even aware of the change they need to make (for example, not knowing about the importance of exclusive breastfeeding, through the intention to make the change, but uncertain how to do this and therefore needing encouragement) through to adopting and maintaining the new behaviour (exclusive breastfeeding) and becoming an advocate of the practice to others in the community. Consumption of vitamin A-rich foods (dark green leafy vegetables, yellow and orange fruits and vegetables) is part of a healthy and balanced diet. They can be used as an opportunity to educate mothers /care givers about nutrition. Mothers are likely to implement the suggested actions or when you do a home visit. You can play an important role in working with other professionals in your community to promote key messages about nutrition. Because it follows a triple A cycle, it has high potential in bringing about behavioural change. The triple A cycle is used in many activities related to nutrition, such as growth monitoring and maternal counselling on child feeding and nutritional surveillance. For example: market days, ‘Debo’, ‘Edir’, ‘Equb’, Coffee Ceremonies ‘Mahiber’ and ‘senbete’. Promotion of food-based approaches to enhance the production and consumption of a wide range of nutritious foods. These include maintaining a healthy life style, eating energy-rich foods, drinking clean water, having regular health checks for weight and taking appropriate medicines. Appropriate complementary foods should be introduced at six months of age with continued breastfeeding. Breastfeeding should stop only when a nutritionally adequate diet without breastmilk can be provided.
It has many pro-inflammatory effects buy discount mentax on line, including platelet activation buy mentax line, increasing vascular permeability purchase discount mentax on-line, bronchial constriction and neutrophil chemotaxis and activation order mentax. This works very well to kill phagocytized pathogens, but also kills the phagocyte and frequently damages surrounding tissue. It denotes a polypeptide signaling molecule produced primarily, but not exclusively, by cells of the immune system with the aim of coordinating the defense functions of many different cell types. Designated chemokines, these are small (8-10 kDa) proteins with a conserved structure of three β-sheets and a C-terminal α-helix. To improve on the bewildering chaos of traditional designations, a unified nomenclature was introduced. The guiding system of chemokine-gradient fields and chemokine receptors enables all cells of the immune system to arrive in the right place at the right time. Cortisol and other glucocorticoids at higher than physiologic concentrations are highly immunosuppressive. Recombinant proteins counteracting specific cytokines can be used to inhibit limited aspects of an immune reaction without exposing the patient to the danger of generalized immune suppression. Receptor activation results in expression of genes, the products of which contribute to defending the organism against infection. Purpose of the molecule: Coordination of a non-adaptive defense reaction on a local and a systemic level. Strategy: Local level: In case an epithelial barrier is breached, it is essential to confine the ensuing bacterial infection to this area. The most dangerous development possible would be the distribution of these pathogens via the blood over the entire organism, a life-threatening complication termed sepsis. This can be prevented by enhancing permeability of the small blood vessels and closing the draining venules by clotting. Driven by blood pressure, which is locally increased by vasodilatation, this creates a slow movement of tissue lymph toward the regional lymph node, taking some of the pathogens with it. At the same time, leukocytes are recruited from the blood to the primary infection area and endothelial cells are instructed to help them pass. Everywhere in the body, the coagulation cascade is kicked off, together with the fibrinolytic cascade, consuming all available clotting factors (disseminated intravascular coagulation) and causing profuse bleeding. This causes fever, the sensation of feeling sick with conservation of energy, but mobilization of energy to produce more defense equipment: plasma proteins and neutrophils. These two effects allow complement components and IgG to reach the source of infection, they facilitate the extravasation of leukocytes and increase the flow to local lymph nodes. Tissue lymph flow carries pathogen antigens --packaged in phagocytes and ohterwise-- into lymph nodes, helping to initiate an adaptive immune response. This process is already in full swing after one or two days, while it takes much longer to produce antibodies. Acute phase peptide hepcidin blocks iron export via ferroportin, a membrane protein expressed in many cell types including macrophages. Iron is a limiting factor for many pathogens (including staphylococci, streptococci, fungi); in fighting them, our organism may therefore gain an advantage by "locking iron away". In chronic inflammation, however, 12 continuing misallocation of iron may result in anemia, as iron remains unavailable not only for pathogens, but also for erythropoiesis. This is probably due to the fact that they are produced in human cells, making their appearance "less unfamiliar" than that of other pathogens. Three types of interferons were originally described, depending on the cell type used for purification: α, β and γ. Type-I-interferons are signaling molecules secreted by virus-infected cells with the aim of slowing or inhibiting virus replication in neighboring cells. This severely restricts replication opportunities for any virus infecting these cells, as it relies on the host cell machinery to produce virus proteins. Additional proteins induced by type I-interferons facilitate the initiation of an adaptive immune response to eventually eliminate the virus. Viral infections would seem like logical indications, but interferons are both expensive and have considerable adverse effects, e. Viruses using this trick have a selective advantage later on, as these cells cannot be identified as infected by cytotoxic T cells (explained in sections 2. The importance of this mechanism has been shown in the early defense against the protozoon Leishmania, which is spread by sand flies. Five alternative types of heavy chains exist (μ, γ, δ, α, ε), giving rise to respectively IgM, IgG, IgD, IgA or IgE. A few technical terms used in immunology: Functionally, an antibody has a variable and a constant region. Antigens include, but are not limited to, polypeptides, carbohydrates, fats, nucleic acids and (less frequently than commonly perceived) synthetic materials. Any non-covalent binding force can be used to establish this contact: electrostatic attraction, hydrogen bonds, Van der Waals- and hydrophobic forces. In most cases, a biological macromolecule contains several independent structures able to elicit an antibody response, so-called antigenic determinants or epitopes. Conversely, two very different macromolecules which by chance share a certain three-dimensional structure may be bound by the same antibody, a phenomenon known as cross-reaction. Antigens recognized by T-lymphocytes are more narrowly restricted: epitopes sensed by T-lymphocytes are linear peptides from 8 to 20 amino acids. If a certain protease is used to digest the Y-formed antibody, three fragments result: two identical fragments termed Fab (fraction antigen binding) and one fragment representing the other end, containing a large part of the constant region. In early experiments, this fraction was successfully crystallized, giving the fragment the name Fc (fraction crystallizable). As this is the "back" end of an antibody, many cells of the immune system have receptors binding 16 to it: so-called Fc-receptors, named for the heavy chain they recognize: Fcγ-R (for IgG), Fcα- R (for IgA), Fcα/µ-R (for IgA and IgM), Fcε-R (for IgE). The affinity of most of these receptors is too low to bind single, free antibodies for longer periods of time. Only after antigen-binding, resulting in larger immune complexes, cooperative binding between several Fc ends and their receptors leads to rapid internalization by phagocytosis, providing a mechanism for rapid antigen clearance. An exception to this rule are mast cells and eosinophils, which also bind free (meaning non-antigen-complexed) IgE via their high- affinity Fc-ε-receptors. After a lag phase of at least five days, which we must survive with the help of innate immunity, B-lymphocyte-derived plasma cells will produce specific antibodies. For example, these may be virus-infected cells exposing viral envelope proteins in their cell membrane. Neutralizing viruses or toxins means studding them from all directions with antibodies, so that they are no longer able to make contact with their receptors. Of course, the protein was not intended to be a virus receptor; it has some physiological function that is quite different. Some bacterial diseases, like tetanus or diphtheria, are not so much caused by the bacteria themselves, but rather by toxins they produce. These bacterial toxins also work by binding and misusing cellular proteins, directing the cells to do something that is in the interest of the bacteria. Vaccinating babies with inactivated versions of these toxins produces neutralizing anti-toxin antibodies. If a child later is infected, it will not even notice, as the disease-causing toxins cannot bind to their receptors: they are neutralized. The Fc portion of these antibodies binds complement component C1q, with further steps unfolding as described in section 1. This is possible only after the antibodies have bound their antigen --formed an immune complex—, modifying their conformation. Antibodies make the process much more efficient: more opsonizing C3b is deposited per bacterial cell, and much faster. With that, erythrocytes become the garbage truck for immune complexes, transporting them to spleen and liver, where phagocytes will take them off their backs. If this transport system is overwhelmed, soluble immune complexes will deposit at sites of filtration, e. It is always the first immunoglobulin coming up in response to an infection, gradually declining afterwards. For that, it can be used to tell apart a recent infection from an old one: an acutely infected patient will have specific IgM, but little or no IgG, while a patient infected long ago will only have IgG. The ability of IgM to activate complement is so strong that a single bound IgM-"crab" functions as a landing platform for C1q. This is different from IgG, where at least two IgG molecules have to bound at a distance allowing C1q to go in between. By its size, IgM is mainly confined to blood plasma; it is simply too big to squeeze through between endothelial cells.