The digestive process

We need to take in food for our body to function. Food travels through the different organs of the digestive system.

In this process it is broken down small parts called nutrients that our body can absorb.

Digestion is the process that enables us to obtain nutrients from the food we eat.

The digestive system

The digestion system is a long tube that starts in the mouth and ends in the anus.

1. Digestion begins when we chew food in our mouth and mix it with saliva.2. This mixture goes down the oesophagus to the stomach.3. In the stomach it mixes with gastric juices.4. Next the mixtures passes into the small intestine as a thick liquid. Here,

nutrients are absorbed and pass into the blood.5. Any undigested food and waste continue on to the large intestine, where

water is absorbed and faeces are formed.6. Finally faeces are excreted through the anus.

We need air

Oxygen is a gas found in the air we breathe. Breathing is when our bodies obtain oxygen from the air and release carbon dioxide.

The respiratory system is the group of organs that carry out the function of breathing.

The respiratory system

1. When we breathe in, air enters the body through the nose or mouth.2. Then it travels down a long tube called the trachea.3. Next, it continues through two pipes called the bronchi to the lungs.4. In the lungs, oxygen passes from the air into the blood.5. Finally, we breathe out to expel carbon dioxide.

Blood vessels

Blood vessels are hollow tubes that are distributed throughout our body and circulated our blood.

There are three types:

Arteries and veins are thick. Arteries carry blood away from the heart to other organs. Veins carry blood back to the heart.

Capillaries connect veins and arteries. They are thin and weak.

Blood Circulation

Blood is continuously moving inside our body. This movement is called blood circulation. Blood circulation is the process by which blood flows to distribute oxygen and nutrients to different parts of the body and carries away waste substances.

The circulatory system is formed by:

Blood: a red liquid which transport substances. Blood vessels: arteries, veins and capillaries. The heart: an organ made of muscles. The heart is connected to the

blood vessels and pumps blood through them to all parts of the body.

Excretion

Our body produces waste substances. Blood collects waste and has to be cleaned.

Excretion is the process in which blood is cleaned and waste substances are eliminated. The excretory system is responsible for this process.

The kidneys are the organs that filter blood. They produce urine, which is a mixture of waste substances and water.

Urine is stored in the bladder until it is expelled from the body.