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Monday, December 21, 2009

Week 7 reflection

Digestive Juices

The digestive juices are the secretions of the digestive tract that break down food. They include saliva,gastric juice, pancreatic juice,bile,and intestinal juice.The digestive juices are secreted by different organs, it varies widely in chemical composition, and each play different roles in the digestive process.Each is constantly produced by the body in small amounts, but the presence of food as it passes through the digestive tract causes increased production and secretion.

Where does digestion begin in?

Digestion begins in the mouth, where the mechanical action of the teeth and tongue and the chemical action of saliva begin to break down food. Saliva is produced by the salivary glands in the mouth.Upon being swallowed, food heads to the stomach, where it is bathed in gastric juice, the second of the digestive juices. Gastric juice is a nearly colorless, strongly acidic liquid secreted by the gastric glands. Its active food-dissolving ingredients are the digestive enzymes pepsin and rennin, which break down proteins, and hydrochloric acid. Gastric juice also contains mucus to protect the stomach lining from being dissolved by the acid.

Sunday, December 6, 2009

Week 6 reflection


Digestion is the mechanical and chemical breaking down of food into smaller components, to a form that can be absorbed, for instance, into a blood stream. Digestion is a form of catabolism; a break-down of macro food molecules to smaller ones.
Digestion imammals, food enters the mouth, being chewed by teeth, with chemical processing beginning with chemicals in the saliva from the salivary glands. Then it travels down the esophagus into the stomach, where acid both kills most contaminating microorganisms and begins mechanical break down of some food, and chemical alteration of some. After some time, the results go through the small intestine, through the large intestine, and are excreted during defecation.

Why is digestion important?

When you eat foods—such as bread, meat, and vegetables—they are not in a form that the body can use as nourishment. Food and drink must be changed into smaller molecules of nutrients before they can be absorbed into the blood and carried to cells throughout the body. Digestion is the process by which food and drink are broken down into their smallest parts so the body can use them to build and nourish cells and to provide energy for your activities in daily life.

How is food digested?

Digestion involves mixing food with digestive juices, moving it through the digestive tract, and breaking down large molecules of food into smaller molecules. Digestion begins in the mouth, when you chew and swallow,through the stomach and is completed in the small intestine.

Week 5 reflection

Definitions of digestion:
  1. The process of decomposing organic matter (as in sewage) by bacteria or by chemical action or heat
  2. The organic process by which food is converted into substances that can be absorbed into the body
  3. learning and coming to understand ideas and information; "his appetite for facts was better than his digestion" 
  4. In alchemy, Digestion is a process in which gentle heat is applied to a substance over a period of several weeks.
  5. Digestion is the mechanical and chemical breaking down of food into smaller components, to a form that can be absorbed, for instance, by a blood ...
  6. Digestive - relating to or having the power to cause or promote digestion; "digestive juices"; "a digestive enzyme"; "digestive ferment" 
  7.  The process the body uses to break down food into simple substances for energy, growth and cell repair.
  8. The biochemical decomposition of organic matter, resulting in partial gasification, liquefaction, and mineralization of pollutants.
  9. The process in which digested food is broken down into molecules that are usable by cells.
  10. Process in which food is broken down by the stomach and small intestine and absorbed by the body.
  11. The process of breaking down food into its molecular and chemical components so that these nutrient molecules can cross plasma membranes.
  12. The breaking down of food into forms the body can use.
  13. The process by which larger molecules of food substance are broken down mechanically and chemically into smaller molecules that can be absorbed.
  14. An ulcer refers to a sore on the lining of the stomach or duodenum, which is the beginning of the small intestine.
  15. Either in the presence of oxygen (aerobic) or in an oxygen-depleted atmosphere (anaerobic), digestion is the process in which microbes digest biogenic carbonaceous materials and emit any number of energetic, inert gases and liquids.

Saturday, November 28, 2009

Week 4 reflection

This is what I have learnt

Main components of the digestive tract:

  1. Oral cavity(mouth)
  2. Esophagus
  3. Stomach
  4. Small intestine
  5. Large intestine
  6. Rectum and anus
Esophagus

The esophagus is a straight muscular tube which connects the oral cavity to the stomach.

Stomach

The stomach is a very muscular organ in which acid secretions(Digestive enzymes) contribute to the digestion of food.

Small intestine

The small intestine is the main site of absorption of digested food. The small intestine is specialized for the completion of the digestion processes and the subsequent absorption of the digestion produce.

Large intestine

It is characterized by many tubular intestinal glands with large numbers of goblet cells. This is sometimes described as a glandular epithelium. The large intestine is the site of water absorption and is also the site of formations of the feces.

Appendix

The appendix is a blind ended tube with the basic histological structure of the large intestine. The lumen is usually fairly narrow and irregular.





Monday, November 16, 2009

Week 3 reflection

How to balance our food intake and amount of activity?

The amount of energy,we need will depend on factors like body size,gender,age,occupation and activity.
  • Body size: A larger person uses more energy to maintain bodily processes than a smaller person.
  • Gender: Men tend to have a larger body mass than a women. Therefore, men needs more energy than women.
  • Age: We need more energy during periods of growth. For example,teenagers need a lot of energy because they are growing.
  • Occupation: More physically demanding work requires more energy. An athlete needs more energy than a clerk.
High-nutrients foods contain very few calories and have high nurtritive value. They include fruits and vegetables,non-fat dairy products,lean meat and meat alternatives such as eggs and tofu.

Low-nutrients foods provide a great source of calories but are low in nutritive value. They are not considered to be healthy. These foods generally belong to the fats,sugars and salt group of the Healthy Diet Pyramid.
















Low-energy foods provide our bodies with small amounts of energy.

Balancing energy intake with energy needs

            When the energy intake is more than what we need, the excess energy is converted to fats and stored in our bodies. This will lead to an increase in body mass. If such eating habits are maintained,obesity will occur.
             If the energy intake is less than what our bodies need,our bodies will break down sotred body fats to release the energy required. This will result in weight loss.
             Energy balance occurs when the energy intake matches the amount of energy our bodies need. This will help maintain our body weight.

Friday, November 13, 2009

Week 2 reflection

What is Fibre?

Fibre is made up of a number of complex carbohydrates. There are two types of fibre,insoluble fibre and soluble fibre. There are no calories,vitamins or minerals in fibre and is not digested when we eat it.

Which food can it be found in?

Fibre is only found in the cell walls of plants. Food found in meats,fish and diary products contains no fibre at all.

What is the function of Fibre?

Fibre is an essential part of bowel function. When fibre passes through the bowel,its absorbs a lot of water,so it increases the amount of waste. It also causes the waste to be softer and increases the speed and ease in which it passes through the bowel.

Why is fibre important?

A fibre rich diet has many health benefits. It reduces the risk of bowel problem like:

  1. Constipation
  2. Piles(Haemorrhoids)
  3. Diverticular disease
  4. Cancer of the colon
Also, soluble fibre helps to stabilize blood sugar levels because it slows down blood cholesterol levels, which would help reduce the risk of heart disease. Fibre also helps you to feel full so it would help those who hope to control their diet,so as to lose weigh.

Good source of fibre:

All plant-base food contains fibre, although some more than the others. Good source of are fruit,vegetables, wholegrain rice and pasta,wholemeal bread,many breakfast cereals,nuts,seeds and bran.

Particularly good sources of fibre are bran,vegetable,beans and oats

Sunday, November 8, 2009

Week 1 reflection

This week i found out that the main nutrients consists of:
  1. Carbohydrates
  2. Fats
  3. Proteins
  4. Vitamins
  5. Minerals
 Carbohydrates

               Carbohydrates are energy-giving nutrients. Our bodies use the carbohydrates to produce the energy that we use to function properly.
 
               Carbohydrate consists of sugars and starchs. Rice,potatoes,wheat,noodles and sugar are such examples.
               If we eat more food containing carbohydrates than necessary for our bodies, the excess carbohydrates would then be turned in to fat and stored on our bodies. Over time, if we continue eating more carbohydrates than necessary, this would then lead to weight gain and obesity.

 Fats

              Fats are a good source if energy. They provide out bodies with more energy than the same amount of carbohydrates do. The layer of fats would also provide us with a layer if insulation and prevent heat loss from our bodies, they also provide our bodies with protection for our organs.
              We obtain fats by eating food from either plants or animals such as olive oil,corn oil,meat,butter,cheese and lard which contains fats. If we include too much fatty food in our diet, this maybe contribute to obesity.

 Proteins

              We need proteins for our body to grow,heal and production of cells. If our carbohydrate intake and fat intake are not enough, our body may take proteins as a source of energy. Food like meat,fish,milk and eggs are animals sources of proteins. Plant sources of plant include beans and soya beans products.
              Too little proteins can lead to a deficiency disease called kwashiorkor. Some symptoms of protein deficiency include apathy,distended belly,swollen legs,stunted growth and flaky skin. Over time, people who suffer from protein deficiency may get weaker and die if left untreated. However, too much proteins in our diet can lead to obesity and loss of calcium from our bodies

Vitamins

              Vitamins protect our bodies from diseases and keep our bodies functioning. Vitamins are only needed by over bodies in small amounts.
               A lack of any vitamin can result in vitamin deficiency diseases and cause problems. We can eat both animals and plants to obtain the vitamins we need.

Minerals

Minerals help us stay healthy and function well. We require minerals in small amounts. Usually, we obtain enough minerals by eating a variety of food in correct amounts. Minerals include sodium,iron and calcium.
  • Sodium helps the muscles and nerves to function properly.It is an important part of the blood and other fluids in our bodies. Sodium also helps to maintain the fluid balance in out bodies. Sodium is part of salt. Salt is found in large quantities in processed food as it is a good preservative. Lack of sodium can cause tiredness and muscle cramps. Too much sodium can cause hypertension. People who suffer form hypertension suffer from high blood pressure. They can also suffer from dizziness and headaches.
  • Iron is needed in our bodies to form red blood cells. Red blood cells carry oxygen in our bodies. Liver,kidneys and dark-green vegetables can provide good sources of iron. Lack of iron can cause anaemia. People who suffer from it experience a lack of breath and feel weak and tired.
  • Calcium is needed to form bones and teeth. Milk,cheese,fish and green vegetables abd rich calcium sources. A lack of calcium results in weak and brittle bones. Brittle bones break very easily and may not support our weigh of our bodies
 

My Learning Targets

My Learning Targets are :
  1. What are the nutrients
  2. How does fibre get digested
  3. How to balance our food intake and amount of activity
  4. What are the digestive systems consists of and what is the function of each of them?
  5. To know what is digestion
  6. How is food digested and broken down by the body?
  7. What are food in the digestive system digested by?
  8. What the energy of foods does for us