Human Digestive Tract and Plant Transport System

A comprehensive set of vocabulary flashcards covering the human digestive system, accessory organs, common gastrointestinal disorders, and the plant transport system based on the lecture notes.

Digestive tract

Also known as the gastrointestinal tract, the specific path food follows in the body from the mouth to the anus where food is broken down into smaller and simpler substances.

Digestion

The process of breaking down food into smaller and simpler substances that the body can easily absorb; it involves both mechanical and chemical processes.

Mechanical digestion

The physical breakdown of food into smaller pieces through activities such as biting, chewing, and churning.

Chemical digestion

The breakdown of large and complex food molecules into simpler ones with the help of enzymes that speed up chemical reactions.

Ingestion

The process of taking in food by eating or drinking, occurring at the mouth or oral cavity.

Salivary amylase

A digestive enzyme produced by the salivary glands that initiates the chemical digestion of starch by breaking it down into maltose.

Maltose

A simple carbohydrate formed when salivary amylase breaks down starch.

Teeth

Structures responsible for chewing; human adults typically have $32$ while children have $20$ or fewer.

Incisors and canines

Types of teeth used specifically for cutting and tearing food.

Premolars and molars

Types of teeth with large surface areas ideal for chewing and grinding food.

Enamel

A layer of calcium phosphate that covers the dentin of a tooth and enables the chewing of hard food.

Taste buds

Clusters of receptor cells on the tongue's papillae that mediate the five basic taste sensations: bitter, salty, sour, sweet, and umami.

Pharynx

A $12$ to $14$-centimeter muscular tube, commonly called the throat, that serves as a passageway for both food and air.

Epiglottis

A flap of tissue located in front of the larynx that automatically covers the entrance to the larynx during swallowing to prevent food from entering the respiratory tract.

Esophagus

A $25$-centimeter long tube composed of smooth muscles that carries food from the pharynx to the stomach.

Peristalsis

Wavelike muscular contractions that propel food through the esophagus and throughout the digestive tract.

Sphincter

A ringlike band of muscle that controls the size of an opening in the body, such as the upper esophageal or pyloric valves.

Stomach

A J-shaped, $20$-centimeter long, expandable organ that receives food from the esophagus and consists of the cardia, fundus, body, and pylorus.

Rugae

Folds in the stomach lining that increase surface area to accommodate food.

Gastric juice

A digestive fluid composed of hydrochloric acid ($HCl$) and enzymes like pepsin and lipase.

Pepsin

An enzyme in gastric juice that breaks down proteins into amino acids and peptides.

Chyme

An extremely acidic semiliquid mass ($pH$ of $2$ to $4$) formed when partially digested food mixes with gastric juice.

Small intestine

The longest part of the digestive tract, measuring $5$ to $7$ meters, where final digestion and partial absorption occur; it consists of the duodenum, jejunum, and ileum.

Villi

Microscopic, fingerlike projections in the small intestine that increase surface area for nutrient absorption.

Absorption

The process where nutrients from food pass through the intestinal wall into the blood to be transported throughout the body.

Large intestine

A $2$-meter long organ, also called the colon, that absorbs water and salts from undigested food.

Egestion

Also known as defecation, the process where undigested food (feces) is expelled from the body through the anus.

Bile

An alkaline fluid ($pH$ of $7$ to $8$) produced by the liver and stored in the gallbladder that aids in the emulsification of fats.

Emulsification

The process of breaking down large fat molecules into tiny fat droplets to aid digestion by pancreatic lipase.

Assimilation

The process in which absorbed nutrients are distributed by the circulatory system to all parts of the body for use by cells.

Gastroesophageal reflux disease (GERD)

A disorder where stomach acid enters the esophagus, commonly causing heartburn.

Marasmus

A type of severe malnutrition common in children that causes low energy levels, weight loss, and stomach infections due to overall lack of nutrients.

Kwashiorkor

A form of malnutrition caused by severe protein deficiency, typically occurring in infants and toddlers after being weaned.

Gastroenterologist

A physician who specializes in the diagnosis and treatment of diseases affecting the digestive system or gastrointestinal tract.

Taproot system

A root system characterized by a massive main root with few tiny lateral branching roots, found in plants like carrots and radishes.

Fibrous root system

A root system consisting of numerous branching roots of the same size growing from a central point, common in monocot plants like grasses.

Xylem

Plant vascular tissue that transports water and minerals from the roots to the leaves and other organs.

Phloem

Plant vascular tissue that transports the soluble products of photosynthesis from the leaves to other parts of the plant.

Transpiration

The loss of water from the body of plants through the leaves, which helps cool the plant and provides the force to raise water up the stems.

Cuticle

A waxy substance, also called cutin, that covers the outer epidermis of leaves to protect against excessive water loss.