Our Bodies - The Circulatory System

Our Bodies - The Circulatory System

The circulatory system transports nutrients and waste around the body in the blood. The heart pumps the blood through the arteries and veins, around the body.

The arteries take the blood, full of oxygen away from the heart. The veins take the blood back to the heart to be pumped to the lungs to get more oxygen.
The capillaries are small and have thin walls to let the food and oxygen pass through to the muscles and to let the waste from the body pass back into the blood.

The circulatory system is made up of the heart and blood vessels known as arteries and veins. The heart pumps blood throughout your body through the blood vessels. Blood delivers oxygen and nutrients to cells and carries away carbon dioxide and other waste materials.
SEE : Our Bodies - Human Organ Systems

Our Bodies - The Excretory System

Our Bodies - The Excretory System

The Excretory System removes waste materials from the body. some of the waste is poisonous. Waste is filtered out of the blood by the kidneys and passes out of the body as urine.

The Kidneys are a pair of organs that remove water and other waste products from the blood. These waste products pass through the bladder and leave the body in urine.
SEE : Our Bodies - Human Organ Systems

Our Bodies - The Respiratory System

Our Bodies - The Respiratory system

The Respiratory system takes in oxygen from the air we breathe and removes the carbon dioxide from our bodies.

• The air enters through the lungs when the rib muscles and diaphragm move.
• Oxygen is absorbed into the blood system. 
• The lungs are big air sacs. They absorb gasses from the air.
• Inhaling is breathing in. Exhaling is breathing out.
• The diaphragm is a muscle that controls breathing. The diaphragm moves down to make the ribs move out. The space in the lungs gets bigger and air rushes in to fill the bigger space. When the diaphragm moves up the ribs move back and the space is smaller, so the air rushes out. While the air is in the lungs, some of the oxygen gets into the blood stream and carbon dioxide leaves the blood and goes into the air.

Your respiratory system helps your body take oxygen from the air. The respiratory system is made up of your nose, mouth, trachea, lungs, and diaphragm.
SEE : Our Bodies - Human Organ Systems

Our Bodies - The Digestive System

Our Bodies - The Digestive System

The digestive system breaks down the food so it can be absorbed into the body for energy and growth. Digestion takes place in the mouth, the esophagus, stomach, and intestines. The digested food is absorbed into the blood system.

- Digestion starts in the mouth. The teeth crush the food and digestive chemicals in the saliva start to attack the food and break it down.
- The food goes down the esophagus into the stomach.
- In the stomach, enzymes mix with the food and take out the protein. Hydrochloric acid kills the bacteria and helps and helps the enzymes break down the food.
- In the small intestine, enzymes from the pancreas take out more protein, carbohydrates , and fats. Some food nutrients pass through the walls of the stomach and into the blood that takes it around the body.
- In the large intestine, water is absorbed.
- In the rectum, fiber is stored. The body cannot use the fiber so it leaves the body through the anus as waste.
Your digestive  system is made up of many important organs that work together to digest the food you eat. It also helps your body absorb all the nutrients that the food contains. Nutrients are substances that keep you healthy and give you energy.
SEE : Our Bodies - Human Organ Systems

Our Bodies - Human Organ Systems

Our Bodies - Human Organ Systems

An organ system is a group of organs working together. There are ten major organ systems in the human body.

 

1.The digestive system.
2.The respiratory system
3.The excretory system
4.The circulatory system
5.The reproductive system
6.The nervous system
7.The gland system
8.The skeletal system
9.The muscular system
10.The immune system

Food Chains, Food Webs and Food Pyramids

Food Chains, Food Webs and Food Pyramids

A food chain is a linear sequence of links in a food web starting from species that are called producers in the web and ends at species that are called decomposers in the web.
A food chain also shows how the organisms are related with each other by the food they eat. Below show how food energy moves from producers to tertiary consumers.

Food webs show that animals in a community eat more than one thing. Food webs are made up of many food chains.

Food pyramids - when an animal is at the top of the food chain, it is rarely if ever eaten by another animal.
Humans, eagles and lions are examples of animals found at the top of a food chain or food pyramid.
A food pyramid is similar to a food chain, except a pyramid also shows the number or total biomass of plants and animals. Biomass is the dry mass of the organisms in a food pyramid. It measures how much the plants and animals in a food chain would weigh if they were dried out, leaving only biological material.