The Human Digestive System Quiz

Nutrition Overview

• Nutrition defines how organisms acquire food.
• Autotrophic nutrition: Organisms produce their own food.
• Heterotrophic nutrition: Organisms depend on consuming others for food.

Alimentary Canal

• Another name for the alimentary canal is the gut.
• Major functions of food include energy provision, cell growth and repair, and defense mechanisms.

Stages of Human Nutrition

• Five stages include ingestion, digestion, absorption, assimilation, and egestion.

Types of Digestion

• Physical digestion: Breaks down food from large to small pieces; occurs in the mouth, stomach, and esophagus.
• Chemical digestion: Breaks down food into simpler nutrients using enzymes and acids; primarily occurs in the mouth, stomach, and duodenum.

Dental Anatomy

• Human dental formula: I 2/2, C 1/1, PM 2/2, M 3/3.
• Amylase is the enzyme in the mouth that converts starch to maltose.

Digestive Environment

• Mouth has a pH range of 7-8; stomach pH ranges from 2-3.

Peristalsis and Muscle Types

• Peristalsis involves the alternating contraction and relaxation of alimentary canal muscles facilitating food movement.
• Involuntary muscles line the alimentary canal, stimulated by fiber.
• Food exiting the mouth is called bolus.

Stomach Functionality

• The epiglottis prevents food from entering the trachea during swallowing.
• Gastric juice incorporates hydrochloric acid, pepsinogen, and mucous.
• Hydrochloric acid functions to kill bacteria and activate pepsin, while mucous protects the stomach lining.

Digestion Products

• Physical digestion in the stomach churns food into a liquid called chyme.

Small Intestine Structure

• The small intestine is composed of two parts: ileum and duodenum.
• Digestion primarily occurs in the duodenum.

Nutrient Absorption

• The ileum's adaptations include length for absorption efficiency, villi and microvilli for increased surface area, and abundant capillaries for nutrient transfer to blood.

Accessory Organs

• The pancreas aids digestion through hormone (insulin) production and digestive enzyme secretion.
• The liver produces bile, breaks down old blood cells, stores fat-soluble vitamins and glycogen, produces cholesterol, and deaminates unnecessary proteins.

Bile and Large Intestine

• Bile is stored in the gallbladder and functions to emulsify fats and neutralize stomach acid.
• Components of the large intestine include the colon, caecum, appendix, rectum, and anus.
• The rectum is where feces are stored; functions of the large intestine include reabsorbing water and absorbing B vitamins.

Digestive Disorders

• Stomach ulcers cause burning pain in the abdomen as a common symptom.