Odborné texty
1 Hospital and wards
2 Human body
3 Musculoskeletal system
4 Circulatory system
5 Digestive system
6 Respiratory system
7 Urinary system
8 Nervous system
9 Reproductive system
10 Integumentary system
11 Vitamins
12 Help your heart
13 What is a hayfever
14 HIV
15 Smoking
16 Exercise
17 Eat variety of food
18 Surgery
19 Are you happy
20 Anxiety, depression
21 Nursing career
22 Admission
23 Nursing process
24 Physical health
25 Florence Nightingale
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5 A/ THE DIGESTIVE SYSTEM
The function of the digestive system is to digest food, absorb nutrients into the blood and eliminate any solid wastes. It is composed of a group of organs that form a tube to carry food from the mouth to the anus and several accessory organs that aid in digestion.
Three processes must occur to convert food into a form that can be used by the body: digestion, absorption and metabolism. The digestion process takes 12 to 48 hours, depending upon the type and quantity of food consumed. There are two types of digestion: mechanical and chemical. Mechanical changes in the food involve breaking relatively large pieces into very small and changing solid food into liquid form, but they cannot completely prepare food for use in the body. Chemical digestion begins with the addition of the enzyme ptyalin to the food. Digestion is complete when nutrients have been reduced to their simplest form. The products of digestion must be absorbed before they can be used by the body. Metabolism is the process, by which the body uses nutrients for energy and the building of body tissue. Two processes are involved in metabolism: anabolism and catabolism.
What is the function of the digestive system?
What types of digestion do you know?
Try to describe the mechanical digestion.
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