Dental plaque is a biofilm or mass of bacteria that grows on surfaces within the mouth. It is a sticky colorless deposit at first, but when it forms tartar, it is brown or pale yellow, it is found between the teeth, on the front of teeth, behind teeth, on chewing surfaces, along the gumline, or below the gumline cervical margins. Dental plaque is known as microbial plaque, oral biofilm, dental biofilm, dental plaque biofilm or bacterial plaque biofilm. Bacterial plaque is one of the major causes for dental gum disease. Progression and build-up of dental plaque can give rise to tooth decay – the localised destruction of the tissues of the tooth by acid produced from the bacterial degradation of fermentable sugar – and periodontal problems such as gingivitis and periodontitis. Plaque control and removal can be achieved with correct daily or twice-daily tooth brushing and use of interdental aids such as dental floss and interdental brushes. Oral hygiene is important as dental biofilms may become acidic causing demineralization of the teeth or harden into dental calculus.
Calculus cannot be removed through tooth brushing or with interdental aids, but only through professional cleaning. Dental plaque is a biofilm that attaches to tooth surfaces and prosthetic appliances if left undisturbed. Understanding the formation and characteristics of plaque helps in its control. An acquired pellicle is a layer of saliva, composed of glycoproteins and forms shortly after cleaning of the teeth or exposure of new teeth. Bacteria attach to the pellicle layer, form micro-colonies, mature on the tooth, which can result in oral diseases; the following table provides a more detailed explanation of biofilm formation: Different types of bacteria are present in the mouth. These bacteria, as well as leukocytes, neutrophils and lymphocytes, are part of the normal oral cavity and contribute to the individual's health. 80–90% of the weight of plaque is water. While 70% of the dry weight is bacteria, the remaining 30% consists of polysaccharides and glycoproteins; the bulk of the microorganisms that form the biofilm are Streptococcus mutans and other anaerobes, though the precise composition varies by location in the mouth.
Examples of such anaerobes include actinobacteria. S. mutans and other anaerobes are the initial colonisers of the tooth surface, play a major role in the establishment of the early biofilm community. These microorganisms all occur present in the oral cavity and are harmless. However, failure to remove plaque by regular tooth-brushing allows them to proliferate unchecked and thereby build up in a thick layer, which can by virtue of their ordinary metabolism cause any of various dental diseases for the host; those microorganisms nearest the tooth surface obtain energy by fermenting dietary sucrose. The bacterial equilibrium position varies at different stages of formation. Below is a summary of the bacteria that may be present during the phases of plaque maturation: Early biofilm: Gram-positive cocci Older biofilm: increased numbers of filaments and fusiforms 4–9 days undisturbed: more complex flora with rods, filamentous forms 7–14 days: Vibrio species, more Gram-negative organisms Dental plaque is considered a biofilm adhered to the tooth surface.
It is a meticulously formed microbial community, organised to a particular structure and function. Plaque is rich in species, given the fact that about 1000 different bacterial species have been recognised using modern techniques. A clean tooth surface would be colonised by salivary pellicles, which acts as an adhesive; this allows the first bacteria to attach to the tooth colonise and grow. After some growth of early colonisers, the biofilm becomes more compliant to other species of bacteria, known as late colonisers. Streptococcus species Eikenella spp. Haemophilus spp. Prevotella spp. Priopionibacterium spp. Capnocytophaga spp. Veil- lonella spp. A. actino- mycetemcomitans Prevotella intermedia Eubacterium spp. Treponema spp. Porphyromonas gingivalis. Fusobacterium nucleatum is found between the late colonisers, linking them together; some salivary components are crucial for plaques ecosystem, such as salivary alpha-amylase which plays a role in binding and adhesion. Proline-rich rich proteins and statherins are involved in the formation of plaque.
Supragingival biofilm is dental plaque that forms above the gums, is the first kind of plaque to form after the brushing of the teeth. It forms in between the teeth, in the pits and grooves of the teeth and along the gums, it is made up of aerobic bacteria, meaning these bacteria need oxygen to survive. If plaque remains on the tooth for a longer period of time, anaerobic bacteria begin to grow in this plaque. Subgingival biofilm is plaque, located under the gums, it occurs after the formation of the supragingival biofilm by a downward growth of the bacteria from above the gums to below. This plaque is made up of anaerobic bacteria, meaning that these bacteria will only survive if there is no oxygen; as this plaque attaches in a pocket under the gums, they are not exposed to oxygen in the mouth and will therefore thrive if not removed. The extracellular matrix contains long-chain polysaccharides and lipids; the most common reasons for ecosystem disruption are the ecological factors discussed in the environment section.
The bacteria that exhibit the most fit plasticity for the cha
Osmotic pressure is the minimum pressure which needs to be applied to a solution to prevent the inward flow of its pure solvent across a semipermeable membrane. It is defined as the measure of the tendency of a solution to take in pure solvent by osmosis. Potential osmotic pressure is the maximum osmotic pressure that could develop in a solution if it were separated from its pure solvent by a semipermeable membrane. Osmosis occurs when two solutions, containing different concentration of solute, are separated by a selectively permeable membrane. Solvent molecules pass preferentially through the membrane from the low-concentration solution to the solution with higher solute concentration; the transfer of solvent molecules will continue. Jacobus van't Hoff found a quantitative relationship between osmotic pressure and solute concentration, expressed in the following equation. Π = i C R T where Π is osmotic pressure, i is the dimensionless van't Hoff index, C is the molar concentration of solute, R is the ideal gas constant, T is the temperature in kelvins.
This formula applies when the solute concentration is sufficiently low that the solution can be treated as an ideal solution. The proportionality to concentration means. Note the similarity of this formula to the ideal gas law in the form p = n V R T = c gas R T where n is the total number of moles of gas molecules in the volume V, n/V is the molar concentration of gas molecules. Harmon Northrop Morse and Frazer showed that the equation applied to more concentrated solutions if the unit of concentration was molal rather than molar. For more concentrated solutions the van't Hoff equation can be extended as a power series in solute concentration, C. To a first approximation, Π = Π 0 + A C 2 where Π 0 is the ideal pressure and A is an empirical parameter; the value of the parameter A can be used to calculate Pitzer parameters. Empirical parameters are used to quantify the behaviour of solutions of ionic and non-ionic solutes which are not ideal solutions in the thermodynamic sense; the Pfeffer cell was developed for the measurement of osmotic pressure.
Osmotic pressure measurement may be used for the determination of molecular weights. Osmotic pressure is an important factor affecting cells. Osmoregulation is the homeostasis mechanism of an organism to reach balance in osmotic pressure. Hypertonicity is the presence of a solution. Hypotonicity is the presence of a solution. Isotonicity is the presence of a solution; when a biological cell is in a hypotonic environment, the cell interior accumulates water, water flows across the cell membrane into the cell, causing it to expand. In plant cells, the cell wall restricts the expansion, resulting in pressure on the cell wall from within called turgor pressure. Turgor pressure allows herbaceous plants to stand upright, it is the determining factor for how plants regulate the aperture of their stomata. In animal cells excessive osmotic pressure can result in cytolysis. Osmotic pressure is the basis of filtering, a process used in water purification; the water to be purified is placed in a chamber and put under an amount of pressure greater than the osmotic pressure exerted by the water and the solutes dissolved in it.
Part of the chamber opens to a differentially permeable membrane that lets water molecules through, but not the solute particles. The osmotic pressure of ocean water is about 27 atm. Reverse osmosis desalinates fresh water from ocean salt water. Consider the system at the point when it has reached equilibrium; the condition for this is that the chemical potential of the solvent on both sides of the membrane is equal. The compartment containing the pure solvent has a chemical potential of μ 0, where p is the pressure. On the other side, in the compartment containing the solute, the chemical potential of the solvent depends on the mole fraction of the solvent, 0 < x v < 1. Besides, this compartment can assume a different pressure, p ′. We can therefore write the chemical potential of the solvent as μ v. If we write p ′ = p + Π, the balance of the chemical potential is therefore: μ v 0 = μ v. Here, the difference in pressure of the two compartments Π ≡ p ′ − p is defined as the osmotic pressure exerted by the solutes.
Holding the pressure, the addition of solute decreases the chemical potential
In chemistry, a colloid is a mixture in which one substance of microscopically dispersed insoluble particles is suspended throughout another substance. Sometimes the dispersed substance alone is called the colloid. Unlike a solution, whose solute and solvent constitute only one phase, a colloid has a dispersed phase and a continuous phase. To qualify as a colloid, the mixture must be one that does not settle or would take a long time to settle appreciably; the dispersed-phase particles have a diameter between 1 and 1000 nanometers. Such particles are easily visible in an optical microscope, although at the smaller size range, an ultramicroscope or an electron microscope may be required. Homogeneous mixtures with a dispersed phase in this size range may be called colloidal aerosols, colloidal emulsions, colloidal foams, colloidal dispersions, or hydrosols; the dispersed-phase particles or droplets are affected by the surface chemistry present in the colloid. Some colloids are translucent because of the Tyndall effect, the scattering of light by particles in the colloid.
Other colloids may have a slight color. Colloidal suspensions are the subject of colloid science; this field of study was introduced in 1845 by Italian chemist Francesco Selmi and further investigated since 1861 by Scottish scientist Thomas Graham. Because the size of the dispersed phase may be difficult to measure, because colloids have the appearance of solutions, colloids are sometimes identified and characterized by their physico-chemical and transport properties. For example, if a colloid consists of a solid phase dispersed in a liquid, the solid particles will not diffuse through a membrane, whereas with a true solution the dissolved ions or molecules will diffuse through a membrane; because of the size exclusion, the colloidal particles are unable to pass through the pores of an ultrafiltration membrane with a size smaller than their own dimension. The smaller the size of the pore of the ultrafiltration membrane, the lower the concentration of the dispersed colloidal particles remaining in the ultrafiltered liquid.
The measured value of the concentration of a dissolved species will thus depend on the experimental conditions applied to separate it from the colloidal particles dispersed in the liquid. This is important for solubility studies of hydrolyzed species such as Al, Eu, Am, Cm, or organic matter complexing these species. Colloids can be classified as follows: Based on the nature of interaction between the dispersed phase and the dispersion medium, colloids can be classified as: Hydrophilic colloids: The colloid particles are attracted toward water, they are called reversible sols. Hydrophobic colloids: These are opposite in nature to hydrophilic colloids; the colloid particles are repelled by water. They are called irreversible sols. In some cases, a colloid suspension can be considered a homogeneous mixture; this is because the distinction between "dissolved" and "particulate" matter can be sometimes a matter of approach, which affects whether or not it is homogeneous or heterogeneous. The following forces play an important role in the interaction of colloid particles: Excluded volume repulsion: This refers to the impossibility of any overlap between hard particles.
Electrostatic interaction: Colloidal particles carry an electrical charge and therefore attract or repel each other. The charge of both the continuous and the dispersed phase, as well as the mobility of the phases are factors affecting this interaction. Van der Waals forces: This is due to interaction between two dipoles that are either permanent or induced. If the particles do not have a permanent dipole, fluctuations of the electron density gives rise to a temporary dipole in a particle; this temporary dipole induces a dipole in particles nearby. The temporary dipole and the induced dipoles are attracted to each other; this is known as van der Waals force, is always present, is short-range, is attractive. Entropic forces: According to the second law of thermodynamics, a system progresses to a state in which entropy is maximized; this can result in effective forces between hard spheres. Steric forces between polymer-covered surfaces or in solutions containing non-adsorbing polymer can modulate interparticle forces, producing an additional steric repulsive force or an attractive depletion force between them.
Such an effect is searched for with tailor-made superplasticizers developed to increase the workability of concrete and to reduce its water content. There are two principal ways of preparation of colloids: Dispersion of large particles or droplets to the colloidal dimensions by milling, spraying, or application of shear. Condensation of small dissolved molecules into larger colloidal particles by precipitation, condensation, or redox reactions; such processes are used in the preparation of colloidal gold. The stability of a colloidal system is defined by particles remaining suspended in solution at equilibrium. Stability is hindered by aggregation and sedimentation phenomena, which are driven by the colloid's tendency to reduce surface energy. Reducing the interfacial tension will stabilize the colloidal system by reducing this driving force. Aggregation is due to the sum of the interaction forces between particles. If attractive forces (such as van der Waals for
Eye drops are saline-containing drops used as an ocular route to administer. Depending on the condition being treated, they may contain steroids, sympathomimetics, beta receptor blockers, parasympathomimetics, parasympatholytics, nonsteroidal anti-inflammatory drugs, antifungal, or topical anesthetics. Eye drops sometimes do not have medications in them and are only lubricating and tear-replacing solutions. Eye drops have less of a risk of side effects than do oral medicines, such risk can be minimized by occluding the lacrimal punctum, for a short while after instilling drops. Eye drops are used for stopping itching and redness of the eyes. Although most bottles of eye drops contain preservatives to inhibit contamination once opened, these will not prevent contamination indefinitely. Ophthamologists recommend disposing of bottles no longer than four weeks after opening. Eye drops that contain no preservatives are packaged in single-use tubes. Dispensers oversize the drops. Different pharmacological classes of eye drops can be recognized by patients by their different colored tops.
For instance the tops to dilating drops are a different color than anti-allergy drops. Eyes drops sometimes do not have medications in them and are only lubricating and tear-replacing solutions. There is a wide variety of artificial tear eye drops that provide different surface healing strategies. One can find bicarbonate ions, hypotonicity and non-preserved types, they all act differently and therefore, one may have to try different artificial tears to find the one that works the best. Steroid and antibiotic eye drops are used to treat eye infections, they have prophylactic properties and are used to prevent infections after eye surgeries. They should be used for the entire time prescribed without interruptions; the infection may relapse. Eye drops used in managing glaucoma help the eye's fluid to drain better and decrease the amount of fluid made by the eye which decreases eye pressure, they are classified by their active ingredient and they include: prostaglandin analogs, beta blockers, alpha agonists, carbonic anhydrase inhibitors.
There are combination drugs available for those patients who require more than one type of medication. Some eye drops may contain histamine antagonists or nonsteroidal anti-inflammatory drug, which suppress the optical mast cell responses to allergens including aerosolized dust particles. Antibiotic eye drops are prescribed when conjunctivitis is caused by bacteria but not when it is caused by a virus. In the case of allergic conjunctivitis, artificial tears can help dilute irritating allergens present in the tear film; these make the eye's pupil widen to maximum, to let an optometrist have the best view inside the eyeball behind the iris. Afterwards in sunny weather they can cause dazzling and photophobia until the effect of the mydriatic has worn off. In Russia, Tropicamide, a mydriatic eye drop, is used to some degree as an inexpensive recreational drug. Like other anticholinergics, when taken recreationally, tropicamide acts as a deliriant. According to one reporter, when injected intravenously, as is most the case, the drug "brings on suicidal feelings."
Syringe designed saline drops are distributed in modern needle-exchange programmes as they can be used efficiently either by injection or ophthalmic route of administer, compared to intravenous use. Steroid and antibiotic eye drops may cause stinging for one or two minutes when first used and if stinging continues, medical advice should be sought. One should tell their doctor if vision changes occur or if they experience persistent sore throat, easy bleeding or bruising when using drops with chloramphenicol. One should be aware of symptoms of an allergic reaction, such as: rash, swelling and trouble breathing. Prostaglandin analogs may cause changes in iris color and eyelid skin, growth of eyelashes, blurred vision, eye redness and burning. Beta blockers' side effects include low blood pressure, reduced pulse rate, shortness of breath, in rare occasions, reduced libido and depression. Alpha agonists can cause burning or stinging, headache, dry mouth and nose, they have a higher likelihood of allergic reaction.
Carbonic anhydrase inhibitors may cause stinging and eye discomfort. Lubricant eye drops may cause some side effects and one should consult a doctor if pain in the eye or changes in vision occur. Furthermore, when redness occurs but lasts more than 3 days, one should consult a doctor. Eye droppers are used in watercolor painting. Artificial tears Carboxymethyl cellulose Mydriasis Refractive error Tetrahydrozoline hydrochloride Visine
Red blood cell
Red blood cells known as RBCs, red cells, red blood corpuscles, erythroid cells or erythrocytes, are the most common type of blood cell and the vertebrate's principal means of delivering oxygen to the body tissues—via blood flow through the circulatory system. RBCs take up oxygen in the lungs, or gills of fish, release it into tissues while squeezing through the body's capillaries; the cytoplasm of erythrocytes is rich in hemoglobin, an iron-containing biomolecule that can bind oxygen and is responsible for the red color of the cells and the blood. The cell membrane is composed of proteins and lipids, this structure provides properties essential for physiological cell function such as deformability and stability while traversing the circulatory system and the capillary network. In humans, mature red blood cells are oval biconcave disks, they lack most organelles, in order to accommodate maximum space for hemoglobin. 2.4 million new erythrocytes are produced per second in human adults. The cells develop in the bone marrow and circulate for about 100–120 days in the body before their components are recycled by macrophages.
Each circulation takes about 60 seconds. A quarter of the cells in the human body are red blood cells. Nearly half of the blood's volume is red blood cells. Packed red blood cells are red blood cells that have been donated and stored in a blood bank for blood transfusion. All vertebrates, including all mammals and humans, have red blood cells. Red blood cells are cells present in blood; the only known vertebrates without red blood cells are the crocodile icefish. While they no longer use hemoglobin, remnants of hemoglobin genes can be found in their genome. Vertebrate red blood cells consist of hemoglobin, a complex metalloprotein containing heme groups whose iron atoms temporarily bind to oxygen molecules in the lungs or gills and release them throughout the body. Oxygen can diffuse through the red blood cell's cell membrane. Hemoglobin in the red blood cells carries some of the waste product carbon dioxide back from the tissues. Myoglobin, a compound related to hemoglobin, acts to store oxygen in muscle cells.
The color of red blood cells is due to the heme group of hemoglobin. The blood plasma alone is straw-colored, but the red blood cells change color depending on the state of the hemoglobin: when combined with oxygen the resulting oxyhemoglobin is scarlet, when oxygen has been released the resulting deoxyhemoglobin is of a dark red burgundy color. However, blood can appear bluish when seen through skin. Pulse oximetry takes advantage of the hemoglobin color change to directly measure the arterial blood oxygen saturation using colorimetric techniques. Hemoglobin has a high affinity for carbon monoxide, forming carboxyhemoglobin, a bright red in color. Flushed, confused patients with a saturation reading of 100% on pulse oximetry are sometimes found to be suffering from carbon monoxide poisoning. Having oxygen-carrying proteins inside specialized cells was an important step in the evolution of vertebrates as it allows for less viscous blood, higher concentrations of oxygen, better diffusion of oxygen from the blood to the tissues.
The size of red blood cells varies among vertebrate species. The red blood cells of mammals are shaped as biconcave disks: flattened and depressed in the center, with a dumbbell-shaped cross section, a torus-shaped rim on the edge of the disk; this shape allows for a high surface-area-to-volume ratio to facilitate diffusion of gases. However, there are some exceptions concerning shape in the artiodactyl order, which displays a wide variety of bizarre red blood cell morphologies: small and ovaloid cells in llamas and camels, tiny spherical cells in mouse deer, cells which assume fusiform, lanceolate and irregularly polygonal and other angular forms in red deer and wapiti. Members of this order have evolved a mode of red blood cell development different from the mammalian norm. Overall, mammalian red blood cells are remarkably flexible and deformable so as to squeeze through tiny capillaries, as well as to maximize their apposing surface by assuming a cigar shape, where they efficiently release their oxygen load.
Red blood cells in mammals are unique amongst vertebrates. Red blood cells of mammals cells have nuclei during early phases of erythropoiesis, but extrude them during development as they mature; the red blood cells without nuclei, called reticulocytes, subsequently lose all other cellular organelles such as their mitochondria, Golgi apparatus and endoplasmic reticulum. The spleen acts as a reservoir of red blood cells. In some other mammals such as dogs and horses, the spl
A health system sometimes referred to as health care system or as healthcare system, is the organization of people and resources that deliver health care services to meet the health needs of target populations. There is a wide variety of health systems around the world, with as many histories and organizational structures as there are nations. Implicitly, nations must design and develop health systems in accordance with their needs and resources, although common elements in all health systems are primary healthcare and public health measures. In some countries, health system planning is distributed among market participants. In others, there is a concerted effort among governments, trade unions, religious organizations, or other co-ordinated bodies to deliver planned health care services targeted to the populations they serve. However, health care planning has been described as evolutionary rather than revolutionary; the World Health Organization, the directing and coordinating authority for health within the United Nations system, is promoting a goal of universal health care: to ensure that all people obtain the health services they need without suffering financial hardship when paying for them.
According to WHO, healthcare systems' goals are good health for the citizens, responsiveness to the expectations of the population, fair means of funding operations. Progress towards them depends on how systems carry out four vital functions: provision of health care services, resource generation and stewardship. Other dimensions for the evaluation of health systems include quality, efficiency and equity, they have been described in the United States as "the five C's": Cost, Consistency and Chronic Illness. Continuity of health care is a major goal. Health system has been defined with a reductionist perspective, for example reducing it to healthcare system. In many publications, for example, both expressions are used interchangeably; some authors have developed arguments to expand the concept of health systems, indicating additional dimensions that should be considered: Health systems should not be expressed in terms of their components only, but of their interrelationships. The World Health Organization defines health systems as follows: A health system consists of all organizations and actions whose primary intent is to promote, restore or maintain health.
This includes efforts to influence determinants of health as well as more direct health-improving activities. A health system is therefore more than the pyramid of publicly owned facilities that deliver personal health services, it includes, for example, a mother caring for a sick child at home. It includes inter-sectoral action by health staff, for example, encouraging the ministry of education to promote female education, a well known determinant of better health. Healthcare providers are individuals providing healthcare services. Individuals including health professionals and allied health professions can be self-employed or working as an employee in a hospital, clinic, or other health care institution, whether government operated, private for-profit, or private not-for-profit, they may work outside of direct patient care such as in a government health department or other agency, medical laboratory, or health training institution. Examples of health workers are doctors, midwives, paramedics, medical laboratory technologists, psychologists, chiropractors, community health workers, traditional medicine practitioners, others.
There are five primary methods of funding health systems: general taxation to the state, county or municipality national health insurance voluntary or private health insurance out-of-pocket payments donations to charitiesMost countries' systems feature a mix of all five models. One study based on data from the OECD concluded that all types of health care finance "are compatible with" an efficient health system; the study found no relationship between financing and cost control. The term health insurance is used to describe a form of insurance that pays for medical expenses, it is sometimes used more broadly to include insurance covering disability or long-term nursing or custodial care needs. It may be provided from private insurance companies, it may be purchased by individual consumers. In each case premiums or taxes protect the insured from unexpected health care expenses. By estimating the overall cost of health care expenses, a routine finance structure can be developed, ensuring that money is available to pay for the health care benefits specified in the insurance agreement.
The benefit is administered by a government agency, a non-profit health fund or a
Polysaccharides are polymeric carbohydrate molecules composed of long chains of monosaccharide units bound together by glycosidic linkages, on hydrolysis give the constituent monosaccharides or oligosaccharides. They range in structure from linear to branched. Examples include storage polysaccharides such as starch and glycogen, structural polysaccharides such as cellulose and chitin. Polysaccharides are quite heterogeneous, containing slight modifications of the repeating unit. Depending on the structure, these macromolecules can have distinct properties from their monosaccharide building blocks, they may be amorphous or insoluble in water. When all the monosaccharides in a polysaccharide are the same type, the polysaccharide is called a homopolysaccharide or homoglycan, but when more than one type of monosaccharide is present they are called heteropolysaccharides or heteroglycans. Natural saccharides are of simple carbohydrates called monosaccharides with general formula n where n is three or more.
Examples of monosaccharides are glucose and glyceraldehyde. Polysaccharides, have a general formula of Cxy where x is a large number between 200 and 2500; when the repeating units in the polymer backbone are six-carbon monosaccharides, as is the case, the general formula simplifies to n, where 40≤n≤3000. As a rule of thumb, polysaccharides contain more than ten monosaccharide units, whereas oligosaccharides contain three to ten monosaccharide units. Polysaccharides are an important class of biological polymers, their function in living organisms is either structure- or storage-related. Starch is used as a storage polysaccharide in plants, being found in the form of both amylose and the branched amylopectin. In animals, the structurally similar glucose polymer is the more densely branched glycogen, sometimes called "animal starch". Glycogen's properties allow it to be metabolized more which suits the active lives of moving animals. Cellulose and chitin are examples of structural polysaccharides.
Cellulose is used in the cell walls of plants and other organisms, is said to be the most abundant organic molecule on Earth. It has many uses such as a significant role in the paper and textile industries, is used as a feedstock for the production of rayon, cellulose acetate and nitrocellulose. Chitin has nitrogen-containing side branches, increasing its strength, it is found in the cell walls of some fungi. It has multiple uses, including surgical threads. Polysaccharides include callose or laminarin, xylan, mannan and galactomannan. Nutrition polysaccharides are common sources of energy. Many organisms can break down starches into glucose; these carbohydrate types can be metabolized by some protists. Ruminants and termites, for example, use microorganisms to process cellulose. Though these complex polysaccharides are not digestible, they provide important dietary elements for humans. Called dietary fiber, these carbohydrates enhance digestion among other benefits; the main action of dietary fiber is to change the nature of the contents of the gastrointestinal tract, to change how other nutrients and chemicals are absorbed.
Soluble fiber binds to bile acids in the small intestine, making them less to enter the body. Soluble fiber attenuates the absorption of sugar, reduces sugar response after eating, normalizes blood lipid levels and, once fermented in the colon, produces short-chain fatty acids as byproducts with wide-ranging physiological activities. Although insoluble fiber is associated with reduced diabetes risk, the mechanism by which this occurs is unknown. Not yet formally proposed as an essential macronutrient, dietary fiber is regarded as important for the diet, with regulatory authorities in many developed countries recommending increases in fiber intake. Starch is a glucose polymer, it is made up of a mixture of amylopectin. Amylose consists of a linear chain of several hundred glucose molecules and Amylopectin is a branched molecule made of several thousand glucose units. Starches are insoluble in water, they can be digested by breaking the alpha-linkages. Both humans and other animals have amylases, so they can digest starches.
Potato, rice and maize are major sources of starch in the human diet. The formations of starches are the ways. Glycogen serves as the secondary long-term energy storage in animal and fungal cells, with the primary energy stores being held in adipose tissue. Glycogen is made by the liver and the muscles, but can be made by glycogenesis within the brain and stomach. Glycogen is analogous to starch, a glucose polymer in plants, is sometimes referred to as animal starch, having a similar structure to amylopectin but more extensively branched and compact than starch. Glycogen is a polymer of α glycosidic bonds linked, with α-linked branches. Glycogen is found in the form of granules in the cytosol/cytoplasm in many cell types, plays an important role in the glucose cycle. Glycogen forms an energy reserve that can be mobilized to meet a sudden need for glucose, but one, less compact and more available a