Gastrointestinal Digestive System Anatomy 1 — Questions and Answers
Question 1: Which organ is primarily responsible for nutrient absorption?
- Stomach
- Small intestine (Correct answer)
- Large intestine
- Esophagus
Correct answer: Small intestine
The small intestine is the primary site for the absorption of nutrients from digested food. Its inner surface is lined with villi and microvilli, which greatly increase the surface area available for efficient absorption of carbohydrates, proteins, fats, vitamins, and minerals into the bloodstream. While digestion begins elsewhere, absorption is maximized here.
Question 2: What is the primary function of the large intestine?
- Absorption of nutrients
- Secretion of digestive enzymes
- Absorption of water and electrolytes (Correct answer)
- Production of bile
Correct answer: Absorption of water and electrolytes
The large intestine's primary function is to absorb water and electrolytes from the remaining indigestible food matter. This process helps to solidify the waste material, forming feces, before it is eliminated from the body. It also houses beneficial bacteria that produce certain vitamins.
Question 3: Which enzyme is responsible for breaking down proteins in the stomach?
- Amylase
- Pepsin (Correct answer)
- Lipase
- Lactase
Correct answer: Pepsin
Pepsin is the primary enzyme responsible for breaking down proteins in the stomach. It is secreted in an inactive form called pepsinogen, which is then activated by hydrochloric acid in the stomach. Once active, pepsin cleaves proteins into smaller polypeptides, initiating their digestion.
Question 4: Which structure prevents food from entering the trachea during swallowing?
- Uvula
- Esophagus
- Epiglottis (Correct answer)
- Pharynx
Correct answer: Epiglottis
The epiglottis is a leaf-shaped flap of cartilage located at the base of the tongue. During swallowing, it folds down to cover the opening of the larynx and trachea. This crucial action prevents food and liquids from entering the respiratory tract, directing them instead into the esophagus.
Question 5: What is the primary function of bile in digestion?
- Breaks down carbohydrates
- Neutralizes stomach acid
- Emulsifies fats (Correct answer)
- Stimulates protein digestion
Correct answer: Emulsifies fats
Bile, produced by the liver and stored in the gallbladder, contains bile salts that act as emulsifiers. Emulsification is the process of breaking down large fat globules into smaller droplets. This increases the surface area of the fats, making them more accessible for digestion by lipase enzymes in the small intestine.
Question 6: Which part of the stomach connects to the small intestine?
- Fundus
- Body
- Pylorus (Correct answer)
- Cardia
Correct answer: Pylorus
The pylorus is the narrow, distal part of the stomach that connects to the duodenum, the first section of the small intestine. It contains the pyloric sphincter, a muscular valve that regulates the emptying of chyme (partially digested food) from the stomach into the small intestine. This controlled release ensures proper digestion and absorption.
Gastrointestinal Digestive System Anatomy 1
Which organ is primarily responsible for nutrient absorption?