Animal Nutrition and Digestion

Animals that only eat plants.

Animals that only eat meat.

Animals that eat both plants and meat.

The breakdown of food into smaller molecules that the body can absorb.

Digestion that occurs within a cell, like in amoeba.

A type of cell found in gastric glands that secretes pepsinogen, an inactive form of the enzyme pepsin.

A type of cell found in gastric glands that secretes hydrochloric acid (HCl), which is crucial for digestion.

The process of converting pepsinogen into its active form, pepsin, by hydrochloric acid (HCl).

An inactive form of the enzyme pepsin, secreted by chief cells in the stomach.

A powerful enzyme that breaks down proteins in the stomach after being activated from pepsinogen.

A muscular ring that separates the esophagus from the stomach. It relaxes to allow food to enter the stomach and contracts to prevent food from flowing back into the esophagus.

A flap of cartilage that covers the opening of the trachea during swallowing, preventing food from entering the airway.

The opening of the trachea (windpipe) that allows air to pass into the lungs.

The process of moving food through the digestive tract by waves of muscular contraction.

A sequence of involuntary actions initiated by the presence of food in the pharynx, resulting in the passage of food from the mouth to the stomach.

Enzymes that break down carbohydrates into simpler sugars.

Enzymes that break down proteins into smaller peptides and amino acids.

Enzymes that break down nucleic acids (DNA and RNA) into nucleotides.

Enzymes that break down fats (lipids) into fatty acids and glycerol.

A substance produced by the liver that helps emulsify fats, making them easier to digest.

The first part of the small intestine, where most of the digestion of food occurs.

The last part of the small intestine, where most of the absorption of nutrients occurs.

The complete digestive tract, a continuous tube that extends from the mouth to the anus, responsible for the breakdown of food and absorption of nutrients.

A watery fluid produced in the mouth, primarily composed of water, enzymes, and mucus. It moistens food, aids in swallowing, and begins carbohydrate digestion.

A digestive enzyme present in saliva that breaks down starch into simpler sugars.

The muscular tube that connects the pharynx to the stomach. It propels food through peristaltic contractions.

The sac-like organ located in the upper abdomen, responsible for storing food, mixing it with gastric juices, and partially digesting proteins.

A thick, acidic fluid produced by the stomach lining, containing enzymes (like pepsin) and hydrochloric acid. It breaks down proteins, kills bacteria, and activates pepsin.

A ring of muscle at the base of the stomach, which prevents food from entering the small intestine until it is sufficiently broken down.

A long, coiled tube that continues after the stomach, responsible for most nutrient absorption. It consists of three sections: duodenum, jejunum, and ileum.

A hormone produced by the duodenum that stimulates the pancreas to release digestive enzymes into the small intestine.

A hormone produced by the duodenum that stimulates the pancreas to release sodium bicarbonate (NaHCO3) into the small intestine, which neutralizes acidic chyme from the stomach.

Tiny projections on the surface of villi that further increase the surface area for nutrient absorption.

A network of lymphatic vessels within each villus that absorbs fats.

The first part of the large intestine, responsible for reabsorption of water and formation of feces.

A small, finger-like projection attached to the cecum, with a role in immunity.

Beneficial bacteria residing in the large intestine that aid in digestion and nutrient absorption.

Hydrochloric acid (HCl) is a component of gastric juices, which are secreted by the stomach.

Pepsinogen is an inactive enzyme that's converted into pepsin by acidic conditions (pH 2) found in the stomach.

Pepsin is an active enzyme responsible for breaking down proteins in the stomach. It's activated by the acidic environment.

The combination of gastric juices and partially digested food is called chyme. It moves from the stomach to the small intestine for further digestion.

The cardiac orifice is a valve between the esophagus and the stomach. Backflow of acidic chyme can cause heartburn.

The pyloric sphincter acts as a valve between the stomach and the small intestine, regulating the flow of chyme for optimal digestion.

Salivary amylase is an enzyme secreted in saliva that begins the breakdown of carbohydrates (starch) into smaller sugars.

Pancreatic amylase plays a crucial role in breaking down starches and complex carbohydrates into smaller sugars within the small intestine.

Pepsin, pancreatic trypsin and chymotrypsin are digestive enzymes that breakdown protein into smaller units called peptides.

Pancreatic nucleases are enzymes responsible for breaking down DNA and RNA molecules into smaller units like nucleotides.

Bile salts are produced in the liver and stored in the gallbladder. They help emulsify fats, breaking large fat globules into smaller droplets.

Pancreatic lipase is an enzyme secreted by the pancreas that digests fat droplets into smaller units like glycerol and fatty acids.

Dipeptidases, carboxypeptidase, and aminopeptidase are enzymes that break down small peptides (two or more amino acids) into individual amino acids.

Disaccharidases are enzymes that break down disaccharides like sucrose, lactose, and maltose into monosaccharides.

The pancreas has both endocrine and exocrine functions. Endocrine refers to secreting hormones into the bloodstream, while exocrine refers to secreting substances into ducts, like digestive enzymes.

The breakdown of food into smaller molecules that the body can absorb.

Digestion that occurs within a cell, like in amoeba.

Digestion that occurs in a specific compartment outside of cells, like in the gastrovascular cavity of a hydra.

Animals with simple body plans, like hydra, have a gastrovascular cavity that acts as both a digestive chamber and a circulatory system.

Animals must prevent self-digestion by processing food in compartments so that digestive enzymes only work on food and not on their own tissues.

A single opening serves as both the mouth and anus. Food enters, is digested, and waste exits through the same opening. Common in organisms like jellyfish.

A digestive tube with separate mouth and anus. Food moves in one direction, allowing for specialized compartments for different digestive functions. Found in humans and most animals.

A sac-like cavity found in some animals like jellyfish and hydra, that functions in both digestion and distribution of nutrients. It has a single opening that serves as both the mouth and anus.

The complete digestive tract, a continuous tube that extends from the mouth to the anus, responsible for the breakdown of food and absorption of nutrients.

The process of moving food through the digestive tract by waves of muscular contraction.

A flap of cartilage that covers the opening of the trachea during swallowing, preventing food from entering the airway.

The opening of the trachea (windpipe) that allows air to pass into the lungs.

A thick, acidic fluid produced by the stomach lining, containing enzymes (like pepsin) and hydrochloric acid. It breaks down proteins, kills bacteria, and activates pepsin.

A hormone produced by the duodenum that stimulates the pancreas to release digestive enzymes into the small intestine.

A hormone produced by the duodenum that stimulates the pancreas to release sodium bicarbonate (NaHCO3) into the small intestine, which neutralizes acidic chyme from the stomach.

The first part of the small intestine, where most of the digestion of food occurs.

Tiny projections on the surface of villi that further increase the surface area for nutrient absorption.

A network of lymphatic vessels within each villus that absorbs fats.

CCK is a hormone secreted by the duodenum that stimulates the pancreas to release digestive enzymes into the small intestine. It helps break down fats and proteins.

The villi are finger-like projections that line the small intestine, increasing its surface area for maximum absorption of nutrients.

The large intestine, also known as the colon, is about 1.5 meters long. It reabsorbs water, harbors beneficial bacteria (microflora), and forms feces.

The appendix is a small finger-like projection attached to the colon. While its exact function is still being researched, it's believed to play a role in immunity.

The presence of beneficial microflora, including E. coli, in the large intestine is crucial for digestion. These bacteria contribute to nutrient absorption and vitamin production.

The process of converting pepsinogen into its active form, pepsin, by hydrochloric acid (HCl).

The enzyme pepsin, activated by acid, breaks down proteins in the stomach.

The pyloric sphincter controls the flow of chyme from the stomach to the small intestine.

Mucus protects the stomach lining from the corrosive acid and pepsin.

The backflow of acidic chyme into the esophagus causes pain, commonly known as heartburn.

The pancreas secretes digestive enzymes (proteases, amylases, lipases, nucleases) and bicarbonate into the duodenum.

Enteropeptidase, secreted in the duodenum, converts inactive trypsinogen into active trypsin, which starts a cascade of enzyme activation.

The pancreas produces both hormones (endocrine) and digestive enzymes (exocrine).

Bile, produced in the liver and stored in the gallbladder, emulsifies fats into smaller droplets, making them easier to digest.

Pancreatic lipase breaks down fat droplets into smaller units like glycerol and fatty acids.

Disaccharidases break down disaccharides (like sucrose, lactose, and maltose) into monosaccharides (simple sugars).

Dipeptidases, carboxypeptidase, and aminopeptidase break down small peptides into individual amino acids.

The ileum is the last part of the small intestine, where most of the absorption of nutrients occurs.