Digestion in fish involves the breakdown of eaten food in to its smaller components which include amino acids, vitamins, fatty acids etc. which can be used for growth and energy. The process of digestion in fish includes:
Mouth --> Pharynx --> Esophagus --> Gizzard --> Stomach --> Intestines --> Rectum
The above structures functions include:
Mouth: Involves mechanically digesting food by chewing with teeth.
pharynx: Receives food from the mouth once food is swallowed.
Esophagus: Carries food from the mouth to the stomach. Gizzard: A muscular pouch behind the stomach of fish which has a thick lining and often contains chitinous plates or teeth that aids in the breakdown of food.
Stomach: Where the digestion of protein begins.
Similarities/Differences
Some similar structures to humans can be found in fish. These structures include:
Mouth: Involves mechanically digesting food by chewing with teeth.
pharynx: Receives food from the mouth once food is swallowed.
Liver: Absorbs nutrients from the small intestine and creates bile which digest fat.
Gall bladder: Stores bile and releases it to digest and absorb fat.
Intestine (fish only have one intestine): Absorbs most of the nutrients from the food eaten (small intestine). Absorbs water (large intestine).
Anus: The end of the of the digestive tract where feces is expelled.
Stomach: Where the digestion of protein begins.
Esophagus: Carries food from the mouth to the stomach.
There is only one different digestive structure that a fish has that humans do not:
Gizzard: A muscular pouch behind the stomach of fish which has a thick lining and often contains chitinous plates or teeth that aids in the breakdown of food.
some different structures that humans have and fish do not include:
Appendix: Unknown function.
Tongue: Aids in mechanical breakdown of food and aids in the swallowing of food.
Pancreas: A gland that makes enzymes for digestion.
Digestion of organic molecules
As humans we need carbohydrates, proteins and fats in order to survive. That's why most of these organic molecules make up most of our diet, but do fish eat all of these organic molecules?
Fish eat all three of these organic molecules but the frequency or amount may vary between species. Depending on where the fish lives plays a major part in its diet. Fish in the amazon river will often eat a variety of plant matter such as fruits and seeds along with meat such as smaller fish or shrimp whereas fish which live in deep parts of the oceans will rely on other species of fish or other smaller deep sea organisms to prey on for a food source as plants are unable to grow at great depths due to the lack of sunlight. In fish, carbohydrates are stored as glycogen that can be mobilized to satisfy energy demands. Carbohydrates are very important for mammals, but are not used efficiently by fish. Things that fish eat that contains carbohydrates would be seeds and nuts. Protein and lipids in a fishes diet can be found in prey such as fish and crustaceans. Like humans, lipids are digested by bile and protein is digested by pepsin. Finger-shaped pouches called pyloric saeca secrete the digestive enzymes needed and also absorb nutrients.
Structure similar to Villi
The structure in fish which is very similar to villi in the human body is the pyloric saeca. The pyloric saeca is the major site of sugar, amino-acid and dipeptide uptake. Caeca of mammals and birds serve as fermentation chambers whereas for fish, caeca are an adaptation to increase gut surface area to absorb more sugar, amino-acid and dipeptides.
Mouth --> Pharynx --> Esophagus --> Gizzard --> Stomach --> Intestines --> Rectum
The above structures functions include:
Mouth: Involves mechanically digesting food by chewing with teeth.
pharynx: Receives food from the mouth once food is swallowed.
Esophagus: Carries food from the mouth to the stomach. Gizzard: A muscular pouch behind the stomach of fish which has a thick lining and often contains chitinous plates or teeth that aids in the breakdown of food.
Stomach: Where the digestion of protein begins.
Similarities/Differences
Some similar structures to humans can be found in fish. These structures include:
Mouth: Involves mechanically digesting food by chewing with teeth.
pharynx: Receives food from the mouth once food is swallowed.
Liver: Absorbs nutrients from the small intestine and creates bile which digest fat.
Gall bladder: Stores bile and releases it to digest and absorb fat.
Intestine (fish only have one intestine): Absorbs most of the nutrients from the food eaten (small intestine). Absorbs water (large intestine).
Anus: The end of the of the digestive tract where feces is expelled.
Stomach: Where the digestion of protein begins.
Esophagus: Carries food from the mouth to the stomach.
There is only one different digestive structure that a fish has that humans do not:
Gizzard: A muscular pouch behind the stomach of fish which has a thick lining and often contains chitinous plates or teeth that aids in the breakdown of food.
some different structures that humans have and fish do not include:
Appendix: Unknown function.
Tongue: Aids in mechanical breakdown of food and aids in the swallowing of food.
Pancreas: A gland that makes enzymes for digestion.
Digestion of organic molecules
As humans we need carbohydrates, proteins and fats in order to survive. That's why most of these organic molecules make up most of our diet, but do fish eat all of these organic molecules?
Fish eat all three of these organic molecules but the frequency or amount may vary between species. Depending on where the fish lives plays a major part in its diet. Fish in the amazon river will often eat a variety of plant matter such as fruits and seeds along with meat such as smaller fish or shrimp whereas fish which live in deep parts of the oceans will rely on other species of fish or other smaller deep sea organisms to prey on for a food source as plants are unable to grow at great depths due to the lack of sunlight. In fish, carbohydrates are stored as glycogen that can be mobilized to satisfy energy demands. Carbohydrates are very important for mammals, but are not used efficiently by fish. Things that fish eat that contains carbohydrates would be seeds and nuts. Protein and lipids in a fishes diet can be found in prey such as fish and crustaceans. Like humans, lipids are digested by bile and protein is digested by pepsin. Finger-shaped pouches called pyloric saeca secrete the digestive enzymes needed and also absorb nutrients.
Structure similar to Villi
The structure in fish which is very similar to villi in the human body is the pyloric saeca. The pyloric saeca is the major site of sugar, amino-acid and dipeptide uptake. Caeca of mammals and birds serve as fermentation chambers whereas for fish, caeca are an adaptation to increase gut surface area to absorb more sugar, amino-acid and dipeptides.