unit3 nutritionalprocessdigestive_illnesses
DESCRIPTION
The presentation including the illnesses related to the digestive systemTRANSCRIPT
Unit 3 The Nutritional Process
Index
1. Introduction
2. Digestive system
3. Respiratory system
4. Circulatory system
5. Excretory system
1. Introduction
There are 4 system involved in nutrition:Digestive system:
- digestive tract-associated glands
Respiratory system:-respiratory paths-lungs
Circulatory system:-heart-blood-blood vessels
Excretory system:-kidneys-urinary tracts
Products expelled Organ
Carbon dioxide Lungs
Urea, water and salts Kidneys
Faeces Intestin
Substances which enter the organism:
• air• water• foods
Products expelled by the organism (waste products)
2. Digestive system
2.1 Main parts
Gut (digestive tube)
• mouth•pharynx• oesophagus• stomach• small intestine• large intestine
Glands
• salivary glands• liver• pancreas
(it contains amylase)
(it does not contain any enzyme)
(It contains lipase, pancreatic amylase, protease)
SALIVA
BILE
PANCREATIC JUICE
2.2 The digestive processThere are three phases in food processing:
-Digestion (mouth, stomach and small intestine) separation of substances (nutrients) that can be used from the food
-Absorption (small intestine) nutrients pass into thebloodstream
-Expulsion of waste (large intestine) unusable substancesare expelled
PERISTALTIC MOVEMENTS = Movement of food through the digestive tract. It consistson the narrowing of the tube through the contraction of the muscles of the walls,what pushes the food.
2.3 Digestion
A. Types of digestion
Mechanical digestion cutting, crushing food(physical changes)
Chemical digesion substances attack the food and break it down into smaller chemical compounds (nutrients)
B. Stages of digestion
In the mouthmastication and salivation take place
The salivary glands produce saliva, a liquid containing digestive enzymes (which actchemically on the food)
Chemical digestion in the mouth amylase breaks down the starch into maltose
DIGESTION
starch maltoses
DIGESTION
Physical digestionChemical digestion
In the stomach begins gastric digestion(both physical and chemical digestion take place
simultaneously)
Movement of the walls of the stomach Food is mixed with the gastric juices,which contain HCl and enzymes
http://www.youtube.com/watch?v=URHBBE3RKEs = gastric digestion
As a result of gastric digestion, a pulp known as chyme leaves the stomach via the pylorus
First section of the small intestine(duodenum)
Chemical digestion the chyme is mixed with
intestinal juices. They come from
• the walls of the duodenum
• the liver produces bile
• the pancreas produces pancreatic juice
The result is called chyle
2.4 Absorption (in the jejunum and illeon)
The digested food (nutrients) passes into the
bloodstream through the intestine’s walls.
The walls of the intestine are filled with intestinal hairs (deep folds in the wall and manyblood vessels) this increases the efficiency of absorption considerably.
• Functions
• water and some ions pass into the bloodstream (absorption ofwater and ions)
• faeces are released through the anus
2.5 Large intestine
Leftovers and water arrive to the largeintestine.
Page 65, activities 1 and 3
http://www.youtube.com/watch?v=IxNpXO8gGFM&feature=related = digestion and absorption
2.6 Some illnesses
Cavities destruction of teeth due to attacks from the bacteria which live in the mouth
Gastritis inflammation of the walls of the stomach. It makes digestion difficult.
Gastroenteritis caused by a virus or bacteria, producing vomits, fever or diarrhoea.