Human Body Organization and Digestive System Review

Vocabulary flashcards covering human body structure, digestive system anatomy, stomach enzymes and secretions, sphincters, accessory digestive organs, and cellular absorption mechanisms based on lecture notes.

Cell

The smallest unit of the body that absorbs nutrients, uses energy, grows, performs body functions, and excretes waste.

Epithelial tissue

A type of tissue that covers body surfaces.

Connective tissue

A type of tissue that supports and connects different parts of the body.

Muscle tissue

A type of tissue responsible for movement.

Nervous tissue

A type of tissue that sends impulses throughout the body.

Organ

A structure formed by combining different tissues to perform specific body functions.

Organ system

A group of several organs working together, such as the digestive, nervous, cardiovascular, and endocrine systems.

GI tract (alimentary tract)

A long, hollow, muscular tube approximately $15\,\text{ft}$ long through which food travels, including the mouth, esophagus, stomach, small intestine, large intestine, rectum, and anus.

Bolus

A mixture of food and saliva formed in the mouth during chewing.

Lysozyme

An enzyme found in saliva that kills bacteria.

Epiglottis

A flap that prevents food from entering the trachea and helps direct it into the esophagus.

Peristalsis

The squeezing and contracting of muscles that pushes food through the GI tract.

Chyme

A liquid mixture of food and gastric juice leaving the stomach.

Pepsinogen

An inactive protein-digesting enzyme secreted in the stomach that is activated into pepsin by hydrochloric acid (HCl).

Pepsin

An active stomach enzyme that digests protein.

Gastrin

A hormone that stimulates the release of hydrochloric acid (HCl) and pepsinogen in the stomach.

Lower esophageal sphincter

A sphincter located between the esophagus and stomach that prevents stomach contents from moving backward, avoiding heartburn or GERD.

Pyloric sphincter

A sphincter between the stomach and small intestine that controls the movement of chyme into the small intestine.

Small intestine

The major site of digestion and absorption in the GI tract, consisting of the duodenum, jejunum, and ileum.

Villi

Finger-like projections on the surface of the small intestine that increase surface area for nutrient absorption.

Microvilli

Fine projections located on villi that further increase the surface area for nutrient absorption.

Bile

A substance produced by the liver and stored in the gallbladder that aids in fat digestion.

Bicarbonate

A component of pancreatic juice that neutralizes acidic stomach chyme.

Passive diffusion

A method of absorption where substances move from high to low concentration without requiring energy.

Facilitated diffusion

A method of absorption where substances move from high to low concentration using a carrier protein without requiring energy.

Active transport

A method of absorption where substances move from low to high concentration, requiring energy in the form of ATP.

Endocytosis

An absorption process where a cell takes in substances, categorized into phagocytosis for solids and pinocytosis for liquids.