A blog that can help with essays regarding some health and social or Health science topics.
Copyright by Marcel Dekker. Our ancestors in their quest for food must have attempted to eat a variety of foods of both plant and animal origin and soon recognized that there were harmful as well as beneficial consequences associated with the consumption of such material.
In terms of archaeological findings, primitive agriculture may have developed as early as — B. The selection of only a handful of plant species for domestication and cultivation by the nomadic human is certainly not a chance occurrence.
It must predate agriculture P5 and m2 homeostatis at least some thousands of years. Its enormous complexity is further illustrated by the plus species of the estimatedspecies of plants documented in the annals of botany and plant sciences that have been used historically in some form to feed humans Deshpande, ; Borlaug, ; Wittwer, Fewer than are used currently worldwide in organized agriculture.
Among these, at least different species are grown in sufficient quantities to enter the world trade. In contrast, Wittwer suggests, today some 24 crops essentially stand between people and starvation. In approximate order of importance these crops are rice, wheat, corn, potato, barley, sweet potato, cassava, soybean, oat, sorghum, millet, sugarcane, sugar beet, rye, peanut, field bean, chick- Copyright by Marcel Dekker.
Although cereals with nine species and legumes with eight constitute the preponderance of the global food production, together they constitute only 0.
Present-day humans, no doubt, have diversified the uses of important economic plants greatly.
They, however, have added relatively little to this list of basic staples. Domestication of only such a few plant species as human food sources is truly one of the most extraordinary stories of our history. Beginning only by collecting, the gathering peoples perhaps accidentally?
Our experience throughout history has thus taught us much about how to prevent injury from consuming natural products as foods. We now know which products not to eat under any circumstances, which can be eaten under some circumstances, and how to process certain other products to render them safe for consumption.
History has thus taught us how to classify all substances in two classes: Traditionally, the term food was used for those materials that were beneficial and essential for the functioning of human body. Substances that were distinctly harmful to the body were classified as poisons. This concept involving the division of chemicals into two categories has persisted to the present day.
It readily places certain biological and botanical and, in fact, all distinctly harmful chemicals into a category that is accorded due respect. Loomishowever, suggested that such a classification, in a strictly scientific sense, is not warranted, primarily because a strict line of demarcation classifying and separating the beneficial and harmful chemicals cannot be drawn and because the degree of harmfulness of any compound is essentially related to the amount consumed.
The right dose differentiates a poison and a remedy. As a corollary, it is also true that there is no chemical that cannot be used safely by limiting the dose or exposure. Our daily lives are still shaped by our acceptance of numerous acceptable risks.
Nearly everything we consume, including salt, sugar, starch, fat, protein, some minerals and vitamins, and even water, has a harmful effect when consumed in high enough concentration. However, this does not necessarily mean that the substance is hazardous to human beings.
Toxic compounds in our foods, medicines, and environment—though they should indeed be minimized—are inevitable hazards of living. This does not always happen under the usual dietary conditions. We consume many toxic substances in our normal diet every day without showing any signs of intoxification.
This is probably because natural toxicants usually exert their effects only when they are consumed under special conditions or when there are other potentiating substances present. Also, the concentration of these compounds occurring naturally in the food is often so low that the item must be consumed in usually unrealistically large amounts every day for a prolonged period for intoxification to occur.In addition, the surface area of lungs (about 50– m2) is some 50 times the area of skin.
Because of its unpreventable contact with contaminated air, the respiratory system has also developed numerous mechanisms to avoid many airborne substances. Particles can be trapped in the upper respiratory or nasopharyngeal region. SESSION 5 THE CONCEPT OF HOMEOSTASIS HOMEOSTASIS PHYSIOLOGICAL PSYCHOLOGICAL AND SOCIAL Many factors contribute to the development of substance use dependency.
One of those factors is a physiological Unit 5 P5- Explain the Concept Homeostasis with Reference to the Control of Heart Rate, Breathing Rate, Body. M2 Explain the probable homeostatic responses to changes in the internal environment following the consumption of a healthy meal.
Homeostasis: Homeostasis is the maintenance of a constant internal environment. MicrosoftInternetExplorer achieves M2, P6, D1 and D2 of assignment 5- homoeostasis work is marked and passed by teacher Preview 1 out of 11 pages share via Facebook Twitter Report abuse.
P5 Explain the concept of Homeostasis. Full transcript.
More presentations by laura mullen Copy of Cardiovascular System. Copy of Energy law & transformation. Copy of AOM- Btec National Sport- Energy A Prezi on the Energy Systems in the body. More prezis by author Popular presentations.