SCIENCE
Different Organs of Digestion
Digestion- process of breaking down food into smaller bits. Food is changed mechanically
and chemically in entering the digestive system.
Mechanical Phase – food is changed into smaller pieces by the process of chewing or
MASTICATION
Chemical Phase – Food is softened by digestive juices.
Digestive system Organization
• Alimentary Organs
– Tube within a tube
- Direct Link or path between organs
• Structures
1. Mouth (buccal cavity)
-Teeth mechanically breakdown food into smaller pieces. Tongue mixes food with
saliva(contains amylase which helps breakdown starch or carbohydrates)
-Epiglottis: a flap-like structure at the back of the throat that closes over the
trachea preventing food from entering it. It is located in the pharynx.
-BOLUS: food in our mouth
2. Esophagus
-Approximately 20cm long
-Heartburn: acid from the stomach gets to the esophagus.
-Secretes mucus
-Functions include:
> Moves food from the throat ot the stomach using mucle movement called
PERISTALSIS (wave-like contraction)
3. Stomach
-J-shaped muscular bg that stores food and breaks it down to tiny pieces.
-Acid( HCl) in the stomach kills bacteria
-Mixes food with digesitive juices that contains enzymes to brak down fats and
lipids(molecule of fats)
, -CHYME: food found in the stomach
4. Small Intestine
-7 meters long
-Lining of intestine walls has finger like projections called villi, to increase
surface area
-Nutrients from the food pass into the bloodstream through the small intestine
walls.
-The villi are covered with microvilli which further increases surface area for
absorption
-Organ of complete digestion and absorption
-Consists of: Duodenum, Jejunum, Ileum
-Absorbs:
>80% ingested water
>Minerals
>Proteins
>Vitamins
>Carbohydrates and Lipids
5. Large Intestine (colon)
-1.5 meters long
-Accepts what small intestines don’t absorb
-Absorbs more water
-Concentrates wastes
6. Rectum
-Short term storage which holds feces before it is expelled
-Anus is the exit point of feces
, • Accessory Organs: The glands
-Not part of the path of food, but play a critical role
-Includes: Liver, gallbladder, and Pancreas
1. Liver
-2nd Largest organ
-Produces BILE which helps digest fat
-Filters out toxins and waste including drugs and alcohol and poisons.
2. Gallbladder
-Stores Bile from the liver, releases it into the small intestine
-Fatty diets can cause GALLSTONES
3. Pancreas
-Produces digestive enzymes to digest fats, carbohydrates, and proteins
-Regulates blood sugar by producing insulin
-Functions as both exocrine and endocrine glands
Processes in the Digestive System
INGESTION
• The first step in digestion
• Ingestion is the process of taking in food through the mouth. In vertebrates, the
teeth, saliva, and tongue play important roles in mastication (preparing the food into
bolus)
• While the food is being mechanically broken down, the enzymes in saliva begin to
chemically process the food as well.
• The combined action of these processes modifies the food from large particles to a
soft mass that can be swallowed and can travel the length of the esophagus
DIGESTION AND ABSORPTION
• Digestion is the mechanical and chemical break down of food into small organic
fragments.
• It is important to break down macromolecules into smaller fragments that are of
suitable size for absorption across the digestive epithelium. Large, complex
molecules of proteins, polysaccharides, and lipids must be reduced to simpler
particles such as simple sugar before they can be absorbed by the digestive
epithelial cells
Different Organs of Digestion
Digestion- process of breaking down food into smaller bits. Food is changed mechanically
and chemically in entering the digestive system.
Mechanical Phase – food is changed into smaller pieces by the process of chewing or
MASTICATION
Chemical Phase – Food is softened by digestive juices.
Digestive system Organization
• Alimentary Organs
– Tube within a tube
- Direct Link or path between organs
• Structures
1. Mouth (buccal cavity)
-Teeth mechanically breakdown food into smaller pieces. Tongue mixes food with
saliva(contains amylase which helps breakdown starch or carbohydrates)
-Epiglottis: a flap-like structure at the back of the throat that closes over the
trachea preventing food from entering it. It is located in the pharynx.
-BOLUS: food in our mouth
2. Esophagus
-Approximately 20cm long
-Heartburn: acid from the stomach gets to the esophagus.
-Secretes mucus
-Functions include:
> Moves food from the throat ot the stomach using mucle movement called
PERISTALSIS (wave-like contraction)
3. Stomach
-J-shaped muscular bg that stores food and breaks it down to tiny pieces.
-Acid( HCl) in the stomach kills bacteria
-Mixes food with digesitive juices that contains enzymes to brak down fats and
lipids(molecule of fats)
, -CHYME: food found in the stomach
4. Small Intestine
-7 meters long
-Lining of intestine walls has finger like projections called villi, to increase
surface area
-Nutrients from the food pass into the bloodstream through the small intestine
walls.
-The villi are covered with microvilli which further increases surface area for
absorption
-Organ of complete digestion and absorption
-Consists of: Duodenum, Jejunum, Ileum
-Absorbs:
>80% ingested water
>Minerals
>Proteins
>Vitamins
>Carbohydrates and Lipids
5. Large Intestine (colon)
-1.5 meters long
-Accepts what small intestines don’t absorb
-Absorbs more water
-Concentrates wastes
6. Rectum
-Short term storage which holds feces before it is expelled
-Anus is the exit point of feces
, • Accessory Organs: The glands
-Not part of the path of food, but play a critical role
-Includes: Liver, gallbladder, and Pancreas
1. Liver
-2nd Largest organ
-Produces BILE which helps digest fat
-Filters out toxins and waste including drugs and alcohol and poisons.
2. Gallbladder
-Stores Bile from the liver, releases it into the small intestine
-Fatty diets can cause GALLSTONES
3. Pancreas
-Produces digestive enzymes to digest fats, carbohydrates, and proteins
-Regulates blood sugar by producing insulin
-Functions as both exocrine and endocrine glands
Processes in the Digestive System
INGESTION
• The first step in digestion
• Ingestion is the process of taking in food through the mouth. In vertebrates, the
teeth, saliva, and tongue play important roles in mastication (preparing the food into
bolus)
• While the food is being mechanically broken down, the enzymes in saliva begin to
chemically process the food as well.
• The combined action of these processes modifies the food from large particles to a
soft mass that can be swallowed and can travel the length of the esophagus
DIGESTION AND ABSORPTION
• Digestion is the mechanical and chemical break down of food into small organic
fragments.
• It is important to break down macromolecules into smaller fragments that are of
suitable size for absorption across the digestive epithelium. Large, complex
molecules of proteins, polysaccharides, and lipids must be reduced to simpler
particles such as simple sugar before they can be absorbed by the digestive
epithelial cells
