Learning Goals:
The respiratory system carries oxygen to & removes carbon dioxide from the blood.
The circulatory system transports dissolved gases & nutrients through the body.
The digestive system breaks down food, absorbs nutrients & eliminates solid waste.
Organ systems working together carry out important tasks in the body.
Success Criteria:
I can...
...label the parts of the respiratory, circulatory & digestive systems.
...follow the path through each system.
...explain how the systems work together.
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As we have already seen, there are numerous organ systems found in the human body (and the bodies of other animals). Over the next few lessons, we will be taking a look at three of them: the digestive system, the circulatory system and the respiratory system.
Let's begin with the digestive system.
The digestion process begins in the mouth, which uses the teeth and tongue to break down food mechanically. The salivary glands produce saliva, which begins to break down the food chemically.
The food passes into the esophagus, which is a tube that uses peristalsis (muscular contractions) to push the food down to the stomach.
The stomach has two jobs: to hold the food and churn it to further the digestion process. The stomach lining produces acid and enzymes, which further break down the food chemically.
The contents of the stomach empty into the small intestine, which is 6 m long and fairly narrow. Most digestion occurs here, allowing nutrients to diffuse through the wall of the small intestine into the bloodstream.
The large intestine is 1.5 m long and larger in diameter. The large intestine absorbs water from indigestible food.
The remaining solid matter is condensed in the rectum and then passes out through the anus as waste, known as feces.
There are three accessory organs that contribute to the digestion process, although food never passes through them. The liver, pancreas and gall bladder all produce digestive enzymes, which are delivered to the digestive tract where they mix with the partially digested food.
Let's make like a system and digest some more info - click here.
