Body Systems

Circulatory System

Digestive System

Circulatory System

On average, your body has about 5 liters of blood continually traveling through it by way of the circulatory system. The heart, the lungs, and the blood vessels work together to form the circle part of the circulatory system. The pumping of the heart forces the blood on its journey.

Parts of the Circulatory System

The circulatory System is divided into three major parts:

• The Heart

• The Blood

• The Blood Vessels

The Heart

• But the heart muscle is special because of what it does. The heart sends blood around your body. The blood provides your body with the oxygen and nutrients it needs. It also carries away waste.

• Your heart is sort of like a pump, or two pumps in one. The right side of your heart receives blood from the body and pumps it to the lungs. The left side of the heart does the exact opposite: It receives blood from the lungs and pumps it out to the body.

Anatomy of the heart

Your arteries carry blood away from the heart. Oxygenated blood is pumped out of the heart through the body's main artery — the aorta. Arteries that branch off the aorta transport blood throughout the body, supplying tissues with oxygen and nutrients.

Your veins carry blood back toward the heart. Tiny vessels called capillaries in organs and tissues of the body deliver deoxygenated blood into small veins called venules, which join to form veins. Blood flows through the veins to the body's two main veins (called the vena cavae), which deliver the blood back into the heart.

Blood Vessels

Major Veins and Arteries

Circulation and Lungs

1. Oxygen-poor blood (shown in blue) flows from the body into the right atrium.

2. Blood flows through the right atrium into the right ventricle.3. The right ventricle pumps the blood to the lungs, where the blood

releases waste gases and picks up oxygen.4. The newly oxygen-rich blood (shown in red) returns to the heart and

enters the left atrium.5. Blood flows through the left atrium into the left ventricle.6. The left ventricle pumps the oxygen-rich blood to all parts of the

body.

• blood movement

• blood movement in heart

• circulation in different animals (The Vertebrate Circulatorium )

• http://www.nhlbi.nih.gov/health/dci/Diseases/hhw/hhw_electrical.html

Digestive System

Chewing

When food is being chewed, saliva is squirted into the mouth. Saliva helps to soften the food. It contains an enzyme that helps break down the starch in the food.

SwallowingWhen you swallow a small ball of mushed-up food or liquids, a special

flap called the epiglottis (say: eh-pih-glah-tiss) flops down over the opening of your windpipe to make sure the food enters the esophagus and not the windpipe.

Esophagus

The food is moved along the small intestine in a squeezing motion known as peristalsis. This motion is much the same as squeezing a tube of toothpaste. All of this movement causes the noise when we say our stomach is "growling."

Stomach

The stomach is a sac shaped like a "j" and is about eight inches long. In the stomach, food is mixed with acids. The muscles in the stomach move, which helps break down the food. The stomach is protected from the acid by a lining. From the stomach, the food pulp is sent to the small intestine. Food leaves the stomach a little bit at a time.

Other “players” in breaking down food

• Liver

• Pancreas

• Gallbladder

Liver

The liver processes and distributes nutrients. The liver creates bile, which is important in chemically breaking down the food in the small intestine. It also processes damaged red blood cells and stores vitamins A and D. This organ is also where alcohol, drugs, bacteria and old blood cells are broken down and removed from the body.

Pancreas

The pancreas is an elongated gland that is below the stomach. The pancreas produces pancreatic juice. The pancreas makes enzymes which are released into the small intestine to break down the food. The enzymes neutralize the hydrochloric acid from the stomach and stimulates the liver into producing bile and secretes insulin which transports sugar.

Gallbladder

The gallbladder is a small sac on the underside of the right lobe of the liver. When there is no food in the small intestine bile from the liver is sent to the gall bladder where it is stored in a concentrated form, to be released when food enters the digestive tract.

Small Intestine(1) the duodenum, a receiving area for chemicals

and partially digested food from the stomach

(2) the jejunum, where most of the nutrients are absorbed into the blood

(3) the ileum, where the remaining nutrients are absorbed before moving into the large intestine.

Absorption

Lining the small intestine are millions of fingers called villi. These absorb the chemicals that we need from the food into the body. It is at this point the food is actually in the body.

Appendix

• The appendix has no function in modern humans; however it is believed to have been part of the digestive system in our primitive ancestors.

Large Intestine

• Waste products and food that are not absorbed in the small intestine pass into the large intestine. This waste material is called feces. The large intestine is only five feet long but is larger in diameter than the small intestine. The large intestine includes the colon.

• In the large intestine, feces are formed from water, undigested food and bacteria. Water is absorbed back into the body so the waste material becomes more solid as it travels through the colon. It may take as long as twenty hours for food to pass completely through the large intestine.

A meal may take up to three days to pass through your digestive system. It spends about three hours in your stomach.

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