Homeostasis

And The Digestive System

The Junk Food We Eat

It's the 21st century and "junk food" has gone global. For better or for worse (mostly worse), junk food is now available all over the world. We see it most everywhere we go -- in grocery and convenience stores, fast-food restaurants, on television -- usually looking very appealing. But just what are the facts about junk food?

Junk Food Facts

1)."Junk food" generally refers to foods that contribute lots of calories but little nutritional value. Of course, what's considered "junk food" depends on whom you ask. Some might say pizza is junk food, for example. But I personally don't think so, since it contributes real food with nutrients, like cheese and tomato sauce. Add whole-wheat or part whole-wheat crust, plus veggies as a topping, and I'd say pizza completely exits the junk food category.


2).One problem with junk foods is that they're low in satiation value -- that is, people don't tend to feel as full when they eat them -- which can lead to overeating. Another problem is that junk food tends to replace other, more nutritious foods. When people drink lots of soda, for example, they are usually not getting plenty of low-fat dairy or other healthful beverages like green tea or orange juice. When they're snacking on chips and cookies, they're usually not loading up on fruits and vegetables



3).Most "junk food" falls into the categories of either "snack food" or "fast food." And then there are things like breakfast cereals. They seem innocent enough, but some of them could definitely be considered "junk food," as they mostly contain sugar or high-fructose corn syrup and white flour or milled corn.

Calories

Popular snack foods are usually commercially prepared and packaged, like chips, cheese puffs, candy bars, snack cakes, and cookies.

The contribution of snack food to the calories we eat should not be underestimated. Between 1977 and 1996, the contribution of snack calories to total calories for American children between 2 and 5 years old increased by 30%, according to an article published in the Chilean medical journal, Revista Medica de Chile.

The Skeletal System

Your Skeletal system is all of the bones in the body and the tissues such as tendons, ligaments and cartilage that connect them.
Your teeth are also considered part of your skeletal system but they are not counted as bones. Your teeth are made of enamel and dentin. Enamel is the strongest substance in your body.

The main job of the skeleton is to provide support for our body. Without your skeleton your body would collapse into a heap. Your skeleton is strong but light. Without bones you'd be just a puddle of skin and guts on the floor.

Your skeleton also helps protect your internal organs and fragile body tissues. The brain, eyes, heart, lungs and spinal cord are all protected by your skeleton. Your cranium(skull) protects your brain and eyes, the ribs protect your heart and lungs and your vertebrae (spine, backbones) protect your spinal cord.

Bones provide the structure for muscles to attach so that our bodies are able to move.Tendons are tough inelastic bands that hold attach muscle to bone.

A typical bone has an outer layer of hard or compact bone, which is very strong, dense and tough. Inside this is a layer of spongy bone, which is like honeycomb, lighter and slightly flexible. In the middle of some bones is jelly-like bone marrow, where new cells are constantly being produced for the blood. Calcium is an important mineral that bone cells need to stay strong so keep drinking that low-fat milk!

Bones are tough and usually don't break even when we have some pretty bad falls. I'm sure you have broken a big stick at one time. When you first try to break the stick it bends a bit but with enough force the stick finally snaps. It is the same with your bones. Bones will bend a little, but if you fall the wrong way from some playground equipment or maybe your bike or skateboard you can break a bone. Doctors call a broken bone a fracture. There are many different types of fractures.

Luckily, bones are made of living cells. When a bone is broken your bone will produce lots of new cells to rebuild the bone. These cells cover both ends of the broken part of the bone and close up the break.

Bones need regular exercise to stay as strong as possible. Walking, jogging, running and other physical activities are important in keeping your bones strong and healthy. Riding your bike, basketball, soccer, gymnastics, baseball, dancing, skateboarding and other activities are all good for your bones. Make sure you wear or use the proper equipment like a helmet, kneepads, shin guards, mats, knee pads, etc... to keep those bones safe.

Strengthen your skeleton by drinking milk and eating other dairy products (like low-fat cheese, frozen yogurt, and ice cream). They all contain calcium, which helps bones harden and become strong.

The Muscular System

The interaction between the skeletal system and the muscular system is so constant that sometimes the two organ systems are referred to as one system--the musculoskeletal system. Skeletal muscles must be attached to something at either end to give them support while they contract. Typically this means each end of a skeletal muscle is attached to a bone. According to Hillendale Health, when a muscle contracts, it brings the two bones closer together. Skeletal muscles are connected to bones via bands of connective tissue called tendons. If a tendon is severed, the muscle no longer has anything to contract against and becomes essentially useless.

The Digestive System

The digestive system is made up of the gastrointestinal (GI) tract—also called the digestive tract—and the liver, pancreas, and gallbladder. The GI tract is a series of hollow organs joined in a long, twisting tube from the mouth to the anus. The hollow organs that make up the GI tract are the mouth, esophagus, stomach, small intestine, large intestine—which includes the rectum—and anus. Food enters the mouth and passes to the anus through the hollow organs of the GI tract. The liver, pancreas, and gallbladder are the solid organs of the digestive system. The digestive system helps the body digest food.

Bacteria in the GI tract, also called gut flora or microbiome, help with digestion. Parts of the nervous and circulatory systems also play roles in the digestive process. Together, a combination of nerves, hormones, bacteria, blood, and the organs of the digestive system completes the complex task of digesting the foods and liquids a person consumes each day.

Digestion is important for breaking down food into nutrients, which the body uses for energy, growth, and cell repair. Food and drink must be changed into smaller molecules of nutrients before the blood absorbs them and carries them to cells throughout the body. The body breaks down nutrients from food and drink into carbohydrates, protein, fats, and vitamins.

Carbohydrates. Carbohydrates are the sugars, starches, and fiber found in many foods. Carbohydrates are called simple or complex, depending on their chemical structure. Simple carbohydrates include sugars found naturally in foods such as fruits, vegetables, milk, and milk products, as well as sugars added during food processing. Complex carbohydrates are starches and fiber found in whole-grain breads and cereals, starchy vegetables, and legumes. The Dietary Guidelines for Americans, 2010, recommends that 45 to 65 percent of total daily calories come from carbohydrates.1

Protein. Foods such as meat, eggs, and beans consist of large molecules of protein that the body digests into smaller molecules called amino acids. The body absorbs amino acids through the small intestine into the blood, which then carries them throughout the body. The Dietary Guidelines for Americans, 2010, recommends that 10 to 35 percent of total daily calories come from protein.1

Fats. Fat molecules are a rich source of energy for the body and help the body absorb vitamins. Oils, such as corn, canola, olive, safflower, soybean, and sunflower, are examples of healthy fats. Butter, shortening, and snack foods are examples of less healthy fats. During digestion, the body breaks down fat molecules into fatty acids and glycerol. The Dietary Guidelines for Americans, 2010, recommends that 20 to 35 percent of total daily calories come from fat.1

Vitamins. Scientists classify vitamins by the fluid in which they dissolve. Water-soluble vitamins include all the B vitamins and vitamin C. Fat-soluble vitamins include vitamins A, D, E, and K. Each vitamin has a different role in the body’s growth and health. The body stores fat-soluble vitamins in the liver and fatty tissues, whereas the body does not easily store water-soluble vitamins and flushes out the extra in the urine. Read more about vitamins on the Office of Dietary Supplements website at www.ods.od.nih.gov External NIH Link.

Homeostsis

Homeostasis or homoeostasis (homeo- + -stasis) is the property of a system in which variables are regulated so that internal conditions remain stable and relatively constant. Examples of homeostasis include the regulation of temperature and the balance between acidity and alkalinity (pH).

Things I learned

  • I learned that junk food generally refers to foods that contribute lots of calories but little nutritional value.
  • I learned that the pancreas is part of the digestive tract
  • I learned that bacteria in the GI tract, also called gut flora or microbiome, help with digestion.