Digestive Physiology, Hormones, Tissues & Organ Systems

Vocabulary flashcards covering digestive enzymes, gastrointestinal hormones, epithelial tissue types, and major human organ systems.

Salivary Amylase

Enzyme from salivary glands that begins starch digestion in the mouth, converting starch to maltose at neutral pH (~7).

Pepsin

Protein-digesting enzyme secreted in the stomach; works best in acidic conditions (pH ~3) and breaks proteins into peptides.

Pancreatic Amylase

Pancreatic enzyme that continues starch digestion in the small intestine (alkaline pH 7.5–8.5), producing maltose.

Pancreatic Lipase

Pancreatic enzyme that hydrolyzes fats into fatty acids and glycerol in the alkaline small intestine.

Trypsin

Pancreatic protease activated in the small intestine; splits polypeptides into smaller peptides at alkaline pH.

Chymotrypsin

Pancreatic protease acting in the small intestine; cleaves poly- and oligopeptides to amino acids under alkaline conditions.

Carboxypeptidase

Pancreatic enzyme that removes terminal amino acids from peptides in the small intestine (alkaline pH).

Deoxyribonuclease (DNase)

Pancreatic enzyme that digests DNA into nucleotides in the alkaline small intestine.

Ribonuclease (RNase)

Pancreatic enzyme that digests RNA into nucleotides in the alkaline small intestine.

Bile

Liver secretion stored in gallbladder; emulsifies fat globules into smaller droplets in the small intestine (alkaline environment).

Aminopeptidase

Small-intestinal brush-border enzyme that removes amino acids from the amino end of polypeptides.

Tripeptidase

Small-intestinal brush-border enzyme that splits tripeptides into individual amino acids in the small intestine.

Dipeptidase

Small-intestinal brush-border enzyme that hydrolyzes dipeptides to amino acids in the small intestine.

Maltase

Intestinal enzyme that breaks maltose into two glucose molecules in an alkaline environment.

Lactase

Intestinal brush-border enzyme that splits lactose into glucose and galactose.

Sucrase

Intestinal enzyme that hydrolyzes sucrose into glucose and fructose at alkaline pH.

Enterokinase (Enteropeptidase)

Duodenal enzyme that converts trypsinogen to active trypsin, initiating activation of other pancreatic zymogens.

Phosphatases

Intestinal enzymes that remove phosphate groups from nucleotides, sugars, and other molecules for absorption.

Gastrin

Hormone released from the upper stomach in response to proteins; stimulates gastric glands to secrete acid and pepsinogen.

Secretin

Hormone from the small intestine triggered by acidic chyme; prompts pancreas to release bicarbonate-rich juice and enzymes.

Cholecystokinin (CCK)

Small-intestinal hormone released by fat-rich chyme; causes gallbladder contraction and pancreatic enzyme secretion.

Gastric Inhibitory Peptide (GIP)

Intestinal hormone released when fat-rich chyme enters duodenum; inhibits gastric motility and acid secretion.

Simple Squamous Epithelium

Single flat cell layer specialized for filtration, diffusion, and osmosis; lines blood vessels and alveoli.

Simple Cuboidal Epithelium

Single layer of cube-shaped cells for secretion and absorption; found on ovarian surface and kidney tubules.

Simple Columnar Epithelium

Tall single layer that protects, secretes, and absorbs; lines uterus and much of digestive tract.

Pseudostratified Columnar Epithelium

Appears stratified but is a single layer; functions in protection, secretion, and mucus movement in respiratory tract.

Stratified Squamous Epithelium

Multiple cell layers providing protection; forms epidermis, and lines vagina and anal canal.

Digestive System

Organ system that converts food into absorbable nutrients for the body.

Circulatory System

System that transports nutrients, gases, hormones, and wastes through blood and lymph.

Immune System

Defense network protecting the body against pathogens and foreign substances.

Respiratory System

Organs responsible for gas exchange—oxygen intake and carbon-dioxide release.

Excretory System

Removes metabolic wastes and maintains water-salt balance; primarily kidneys and associated structures.

Nervous & Sensory System

Coordinates regulation, control, information processing, and response to stimuli.

Muscular & Skeletal System

Provides body support, protects organs, and enables movement via muscles acting on bones.

Hormonal (Endocrine) System

Glands that secrete hormones to regulate internal environment, growth, and development.

Reproductive System

Organs and glands involved in producing gametes and enabling conception and offspring development.