All of the following are organs of the digestive system except

A. emulsification

B. excretion

C. absorption

D. peristalsis

Emulsification is a process by which large fat globules are broken down into smaller droplets. This process is facilitated by substances called emulsifiers, with bile being one of the most common emulsifiers in the human body.

A. coenzymes

B. auxins

C. hormones

D. neurotransmitters

A) coenzymes

- Correct: Some vitamins function as coenzymes, which are molecules that assist enzymes in their catalytic activity. Coenzymes work together with enzymes to facilitate various biochemical reactions in the body. For example, certain B vitamins (such as thiamine, riboflavin, and niacin) act as coenzymes in energy metabolism, while vitamin K acts as a coenzyme in blood clotting. Without these essential vitamins, many metabolic processes in the body would be impaired, leading to various health problems.

B) auxins

- Incorrect: Auxins are plant hormones that regulate plant growth and development. They are not vitamins and do not function as coenzymes in biochemical reactions in organisms.

C) hormones

- Incorrect: Hormones are signaling molecules that regulate various physiological processes in organisms. While some vitamins may indirectly influence hormone production or function, they do not function primarily as hormones themselves.

D) neurotransmitters

- Incorrect: Neurotransmitters are chemical messengers that transmit signals between nerve cells (neurons) in the nervous system. They are not vitamins and do not function as coenzymes in biochemical reactions in organisms.

A. stomach

B. gall bladder

C. villi

D. lacteals

B) gall bladder

- Correct: Bile, which aids in the emulsification of fats in the small intestine, is stored and concentrated in the gall bladder before being released into the small intestine. When fatty foods enter the small intestine, the gall bladder contracts and releases bile into the duodenum (the first part of the small intestine). Bile helps to break down large fat globules into smaller droplets, a process known as emulsification, which increases the surface area for the action of digestive enzymes, such as lipase, facilitating the digestion and absorption of fats.

A) stomach

- Incorrect: Bile is not released from the stomach. The stomach primarily secretes gastric juices containing hydrochloric acid and pepsinogen to aid in the digestion of proteins.

C) villi

- Incorrect: Villi are finger-like projections in the lining of the small intestine that increase its surface area for nutrient absorption but do not release bile.

D) lacteals

- Incorrect: Lacteals are lymphatic vessels found in the villi of the small intestine that absorb dietary fats and fat-soluble vitamins. They do not release bile.

A. absorbed food is toxic to the body

B. absorbed food stimulates reproduction

C. absorbed food is the raw material for metabolism

D. absorbed food aids in respiration

C) absorbed food is the raw material for metabolism

- Correct: The digestion of food and subsequent absorption into the bloodstream are essential processes because absorbed food molecules serve as the raw material for metabolism. Once nutrients from food are absorbed into the bloodstream, they are transported to cells throughout the body where they are used for various metabolic processes. Carbohydrates are broken down into glucose, which is used for energy production. Proteins are broken down into amino acids, which are used for building and repairing tissues, as well as for synthesizing enzymes and hormones. Fats are broken down into fatty acids and glycerol, which are used for energy production and for building cell membranes and certain hormones. Overall, absorbed food molecules provide the necessary energy and building blocks for cellular activities, growth, and maintenance of the body.

A) absorbed food is toxic to the body

- Incorrect: Absorbed food is not inherently toxic to the body. In fact, nutrients obtained from food are essential for the body's survival and proper functioning. However, certain substances in food may be harmful if absorbed in excessive amounts, such as certain vitamins or minerals. Generally, the body has mechanisms to regulate nutrient absorption and maintain homeostasis.

B) absorbed food stimulates reproduction

- Incorrect: While proper nutrition is important for overall health and fertility, absorbed food does not directly stimulate reproduction. Reproduction is regulated by various hormones and physiological processes within the body.

D) absorbed food aids in respiration

- Incorrect: While nutrients obtained from food are used by cells for energy production through respiration, absorbed food itself does not directly aid in respiration. Respiration is a complex physiological process that involves the exchange of gases (oxygen and carbon dioxide) in the lungs and cellular respiration within cells to produce energy.

A. glucose

B. protein

C. starch

D. oxygen

B) protein

- Correct: After an organism consumes meat, the organic molecules present in the meat, such as amino acids and lipids, are broken down through the process of digestion. These molecules are then absorbed into the bloodstream and transported to various cells throughout the body. In the cells, these molecules are used as building blocks for synthesizing new proteins. Proteins are essential macromolecules involved in numerous cellular functions, including structural support, enzymatic activity, and regulation of cellular processes. Therefore, many of the organic molecules originally contained in the meat would be found in newly formed molecules of protein within the organism's cells.

A) glucose

- Incorrect: Glucose is a simple sugar that is primarily derived from the digestion of carbohydrates. While some amino acids obtained from the digestion of protein can be converted into glucose through gluconeogenesis, the majority of amino acids are used for protein synthesis, not glucose production.

C) starch

- Incorrect: Starch is a complex carbohydrate found in plants. It is not typically present in meat, and it is not directly synthesized from the organic molecules obtained from meat consumption.

D) oxygen

- Incorrect: Oxygen is a gas essential for cellular respiration but is not synthesized from the organic molecules obtained from meat consumption. Oxygen is mainly obtained through breathing and is used in cellular respiration to generate ATP, the energy currency of the cell.

A. They form proteins needed in the stomach.

B. They form the acids that break down food.

C. They change food substances into molecules that can pass into the bloodstream and cells.

D. They change food materials into wastes that can be passed out of the body.

C) They change food substances into molecules that can pass into the bloodstream and cells.

- Correct: Digestive enzymes secreted by the pancreas play a crucial role in breaking down complex food molecules into smaller, absorbable molecules that can pass through the walls of the small intestine and into the bloodstream. These smaller molecules include carbohydrates broken down into simple sugars, proteins broken down into amino acids, and fats broken down into fatty acids and glycerol. Once these molecules are absorbed into the bloodstream, they can be transported to cells throughout the body to provide energy and support various metabolic processes.

A) They form proteins needed in the stomach.

- Incorrect: Digestive enzymes do not form proteins needed in the stomach. Proteins are broken down into amino acids by digestive enzymes, but the enzymes themselves do not form proteins.

B) They form the acids that break down food.

- Incorrect: Digestive enzymes do not form acids. Acids such as hydrochloric acid are secreted by the stomach and aid in the breakdown of food, particularly proteins, but they are not formed by pancreatic enzymes.

D) They change food materials into wastes that can be passed out of the body.

- Incorrect: While digestive enzymes help break down food materials, their primary function is to convert these materials into absorbable molecules rather than wastes. The conversion of food into waste products occurs primarily through processes in the digestive tract and is facilitated by enzymes as part of digestion, but it is not the direct role of pancreatic enzymes.

A. liver and pancreas

B. glomerulus and villi

C. esophagus and alveoli

D. gallbladder and pharynx

A) liver and pancreas

- Correct: The liver and pancreas both secrete chemicals that are utilized for the completion of digestion within the small intestine. The liver produces bile, which is stored in the gallbladder and released into the small intestine to aid in the emulsification and digestion of fats. The pancreas secretes pancreatic enzymes (such as amylase, lipase, and proteases) into the small intestine to further break down carbohydrates, fats, and proteins into smaller molecules that can be absorbed.

B) glomerulus and villi

- Incorrect: The glomerulus is a part of the kidney involved in the filtration of blood, and villi are finger-like projections in the small intestine that increase surface area for absorption. While villi play a role in absorption within the small intestine, they do not secrete chemicals for digestion. The glomerulus is not involved in digestion.

C) esophagus and alveoli

- Incorrect: The esophagus is involved in swallowing and does not secrete chemicals for digestion. Alveoli are air sacs in the lungs where gas exchange occurs during respiration and are not involved in digestion.

D) gallbladder and pharynx

- Incorrect: The gallbladder stores bile produced by the liver but does not secrete chemicals directly into the small intestine. The pharynx is involved in swallowing and does not secrete chemicals for digestion.

A. by enzyme action that begins in the mouth and ends in the

B. esophagus

C. stomach

D. small intestine

C) small intestine

- Correct: Chemical digestion in humans is a complex process involving various enzymes acting on different nutrients. While digestion does begin in the mouth with the action of enzymes like salivary amylase on carbohydrates, the majority of chemical digestion occurs in the small intestine. Enzymes secreted by the pancreas (such as pancreatic amylase, lipase, and proteases) and the small intestine itself (such as maltase, sucrase, lactase, and peptidases) break down carbohydrates, fats, and proteins into smaller molecules. Additionally, bile salts produced by the liver and stored in the gallbladder aid in the emulsification and digestion of fats in the small intestine. Therefore, chemical digestion largely concludes in the small intestine before nutrients are absorbed into the bloodstream.

A) esophagus

- Incorrect: The esophagus is primarily involved in the mechanical process of swallowing, which pushes food down into the stomach. While some minor enzymatic activity may occur due to saliva coating the food during swallowing, significant chemical digestion does not occur in the esophagus.

B) stomach

- Incorrect: While the stomach does play a role in chemical digestion, particularly in the breakdown of proteins by the enzyme pepsin and the denaturation of proteins by hydrochloric acid, the majority of chemical digestion occurs in the small intestine. The stomach mainly serves to mechanically churn food and begin the process of protein digestion.

D) gallbladder

- Incorrect: The gallbladder stores and releases bile produced by the liver, which aids in the emulsification and digestion of fats in the small intestine. However, the gallbladder itself is not directly involved in chemical digestion, and the majority of digestive enzymes are not secreted or stored in the gallbladder.

A. salivary amylase

B. protease

C. hydrochloric acid

D. bile

Protease enzymes are responsible for breaking down proteins in our food into amino acids. Then different enzymes join amino acids together to form new proteins needed by the body for growth and repair. Protease enzymes are produced in pancreas.

A. meat and eggs

B. fruits and vegetables

C. minerals and milk

D. water and vitamins

B) fruits and vegetables

- Correct: Fruits and vegetables contain the greatest amounts of sugars and starches in the human diet. Both fruits and vegetables are rich sources of carbohydrates, including natural sugars, fiber, and starches. These carbohydrates provide a readily available source of energy for the body. Examples of fruits with natural sugars include apples, bananas, and grapes, while starch-containing vegetables include potatoes, corn, and peas.

A) meat and eggs

- Incorrect: Meat and eggs are primarily sources of proteins and fats, not sugars and starches. They contain minimal amounts of carbohydrates.

C) minerals and milk

- Incorrect: Minerals are inorganic compounds essential for various physiological functions, and milk is a source of proteins, fats, and carbohydrates (mainly lactose, a sugar). While milk contains some sugars, fruits and vegetables typically contribute more significant amounts of sugars and starches to the diet.

D) water and vitamins

- Incorrect: Water and vitamins are essential components of the diet, but they do not contain sugars and starches. Water is a vital component for hydration, and vitamins are organic compounds required for various biochemical processes in the body.