the digestive system - fatimaphysed.weebly.com · the functions of the digestive system take food...
TRANSCRIPT
Learning Objectives
To state the function of the digestive system.
To describe the structure and workings of the digestive system.
To describe the effects of physical activity on the digestive system.
What makes up the digestive system.
The digestive system or alimentary canal
starts at the mouth and ends at the anus
and includes the pharynx, esophagus,
stomach, small intestine and large
intestine.
The functions of the Digestive System
Take food into the body through the mouth.(Ingestion)
Break food down into smaller particles to be used by the body. (Digestion)
Pass the digested food to the bloodstream.(Absorption)
Eliminate the undigested waste from the body.(Excretion).
Digestion
Digestion is the breakdown of complex food
particles into smaller units so that they can
be used by the body.
How does Digestion Occur?
*THE MOUTH
The digestive process begins in
the mouth. The food is chewed by the
teeth and mixes with saliva. The enzyme,
amylase starts to break down the starch.
The food is swallowed and enters the
stomach via the esophagus.
*THE STOMACH In the stomach the food is churned by
that organ’s strong muscular wall and mixes with other enzymes and is further broken down. The food is now in a liquid form called chyme.
* THE SMALL INTESTINE The liquid food enters the small
intestine and mixes with more enzymes to complete the digestive process. The nutrients are small enough to pass through the walls of the small intestines, into the blood. They are carried away to the liver and other body parts to be processed, stored and distributed as they are needed in the body.The small intestine is divided into three parts. The duodenum, jejunum and the lleum.
*THE LARGE INTESTINES
The remaining undigested waste enters the large intestine where any useful substances such as water and minerals are absorbed through its walls and into the blood. The only thing left is faeces.
*THE RECTUM AND ANUS
The faeces move to the rectum which is at the end of the large intestine where it passes through the anus, and out of the body.
Organs that aid in Digestion
*THE LIVER
This is a large internal organ in that
weighs between 1.4 –1.6 kg and is responsible
for
• The production of bile to aid digestion
• Storage of digested food which can be used to
provide energy
• Stores vitamins
• Removes waste products
Organs that aid in Digestion
*THE PANCREAS
It is a long gland about 15cm long
which produces digestive juices.
*THE GALLBLADDER
This stores bile fluid which passes
to the duodenum to break down fats
What are the nutrients absorbed during digestion?
Food provides us with energy which we need to work and play, as well as the raw materials to build new cells. During the digestive process our bodies absorb:
• Carbohydrates
• Protein
• Fats
• Vitamins
• Water and Mineral salts
Nutrients Uses Foods
Carbohydrates Provides us with
energy.
Bread, potatoes,
rice, sugar, fruits
and vegetables
Proteins Building and
repairing our
bodies
Meat, eggs,
beans.
Fats A rich source of
energy
Butter and oil
Vitamins Keeping our body
healthy
Fruits and fish
Water and Mineral
Salts
These are vital to
proper functioning
of our bodies,
They are found in
most of the foods
we eat.