Animal and Human Digestive System Structures
Nutrition: Different Structures
- Snakes: They have a specialized adaptation of their oral equipment. Their fangs are hollow and connected to the venom gland, a modified salivary gland. The poison is used to immobilize prey.
- Butterflies: They have highly specialized mouthparts that enable them to extract nectar from flowers.
- Sharks: Their teeth grow continuously. As teeth are worn, new rows form.
- Hippos: They spend all day in the water, gathered in groups of up to 150 individuals, and disperse to feed on herbs on land.
- Condors: They are the largest birds of prey. Their diet consists of carrion.
- Tiofaga: Bird-eating fish.
- Porifera (e.g., Sponges): They feed when water passes through their pores, trapping particles. Phagocytes capture and digest organic particles; the rest is eliminated.
- Coelenterata (e.g., Jellyfish, Corals): They have a gastrovascular cavity and perform extracellular digestion. They do not have a complete digestive system.
Invertebrate Digestive Structures
- Echinoderms: Sea stars are carnivorous. They evert their stomachs onto their prey, digest it externally, and then retract their stomachs.
- Arthropods: These are invertebrates with jointed legs, such as arachnids.
- Digestive Systems of Herbivores: These are generally larger than those of carnivores. They have specialized teeth for grinding plant material.
- Hippopotamus Digestion: They have a compartmentalized stomach but do not ruminate. Digestion is slower and helps to digest glucose.
- Cow Digestion: Cows eat food and then regurgitate it to chew it again. They are ruminant herbivores.
- Birds: Their digestive tract is adapted to their diet. It is divided into a crop and a gizzard.
Human Digestion
Small intestine: Duodenum, common bile duct, pancreatic duct, jejunum, ileum.
Food: The process by which nutrients enter the body. Food is digested throughout the digestive system, and unabsorbed materials are discarded.
Digestive System Function
- Marinate and digest food.
- Produce enzymes that degrade substances.
- Complete the degradation processes.
- Transport nutrients into the blood.
- Eliminate substances that were not absorbed.
Difference Between Mechanical and Chemical Digestion: Mechanical digestion depends on muscle movement and the movements of the organ walls. Chemical digestion involves enzymes and cofactors.
Enzymes in the Digestive System: Enzymes are proteins that act as biological catalysts. They have specific actions and are affected by temperature and acidity.
- Chemical Action: Enzymes
- Mechanical Action: Peristalsis
Small Intestine: Through the intestinal villi, cells absorb amino acids, sugars, fatty acids, glycerol, water, vitamins, and minerals. It transforms chyme into chyle.
Large Intestine: Absorbs water, synthesizes vitamins, forms feces, and produces gases.
Bile: Emulsifies fats, transforming them into droplets so that enzymes can act on them.
Liver: Produces bile, stores and distributes it, and processes digestion products.
Chyme: The mass that passes from the stomach into the duodenum through the pylorus.
Stages: Chewing, swallowing, muscle contractions, stomach digestion.
Completion of Digestion: Proteins are broken down into amino acids, carbohydrates into monosaccharides, and fats into fatty acids and glycerol. These pass through the portal system to the liver and then via the hepatic vein throughout the body.
What is Food? Everything that is consumed to provide nutrition, energy, and matter.
Principles of Nutrition
We Need: Minerals, vitamins, proteins, fluids, lipids, carbohydrates, and water.
- Proteins: Formed by amino acids containing carbon, hydrogen, oxygen, and nitrogen (CHON).
- Carbohydrates: A source of quick energy, found mostly in the plant kingdom.
- Vitamins: Losing 20% of water can lead to death. 70% of our body is water, and we lose about 2.5 liters per day.
- Trans Fats: A type of unsaturated fat found mainly in industrialized foods.