ANAPHY LEC - DIGESTIVE SYSTEM

Digestion

Breakdown of ingested food

Absorption

Passage of nutrients into the blood

Metabolism

Production of cellular energy (ATP)

Alimentary canal

Continuous coiled hollow tube of the digestive system through which food directly passes

Accessory digestive organs

Group of digestive organs that assist in digestion but through which food does not actually pass

Salivary glands

Accessory organ that produces saliva containing amylase to start digesting carbohydrates in the mouth

Liver

Accessory organ that produces bile to emulsify fats

Emulsification

Process of breaking large fat droplets into smaller ones for easier digestion

Gallbladder

Accessory organ that stores and releases bile into the small intestine

Pancreas

Accessory organ that produces digestive enzymes and bicarbonate to neutralize stomach acid

Teeth

Accessory organs responsible for mechanically breaking down food into smaller pieces

Mastication

Mechanical process of chewing food

Tongue

Accessory organ that helps in mixing food with saliva, tasting, and initiating swallowing

Lips (Labia)

Anatomical structures that protect the anterior opening of the mouth

Cheeks

Structures forming the lateral walls of the oral cavity

Hard palate

Structure forming the anterior roof of the mouth

Soft palate

Structure forming the posterior roof of the mouth

Uvula

Fleshy projection hanging from the soft palate that helps close off the nasopharynx during swallowing

Vestibule

Space between the lips externally and the teeth and gums internally

Oral cavity

Area inside the mouth contained within the teeth

Lingual frenulum

Hyoid and styloid processes of the skull, along with this specific membrane/fold

Tonsils (Palatine and Lingual tonsils)

Lymphoid structures containing immune cells like phagocytes located in the oral cavity region

Nasopharynx

Part of the pharynx located superiority that is NOT part of the digestive system

Oropharynx

Region of the pharynx located directly posterior to the oral cavity

Laryngopharynx

Region of the pharynx located below the oropharynx that connects directly to the esophagus

Peristalsis

Alternating contractions of muscle layers that propel food through the digestive tract

Longitudinal inner layer and Circular outer layer

The two muscle layers responsible for peristalsis in the pharynx

Esophagus

Organ conducting food from the pharynx through the diaphragm to the stomach

Mucosa

Innermost, moist membrane layer lining the lumen of alimentary canal organs

Lamina propria

Small layer of connective tissue found within the mucosa layer

Submucosa

Layer of the alimentary canal wall located just beneath the mucosa, composed of soft dense connective tissue with blood vessels, nerve endings, and lymphatics

Submucosa (Meissner’s) plexus

Nerve plexus located within the submucosa layer

Muscularis externa

Muscle layer of the alimentary canal consisting of inner circular and outer longitudinal layers responsible for propulsion and mixing

Myenteric (Auerbach’s) plexus

Nerve plexus located within the Muscularis externa layer

Serosa

Outermost layer of the alimentary canal wall, also known as the visceral peritoneum

Adventitia

Connective tissue structure that anchors alimentary canal organs to surrounding structures (replacing serosa in certain areas)

Gastroesophageal sphincter (or Lower Esophageal Sphincter)

Sphincter through which food enters the stomach from the esophagus

Pylorus

Funnel-shaped terminal end of the stomach

Pyloric sphincter

Sphincter through which food empties from the stomach into the small intestine

Cardiac region (cardia), Fundus, Body, and Pylorus

The four main anatomical regions of the stomach

Rugae

Internal folds of the gastric mucosa that allow the stomach to expand

Lesser curvature and Greater curvature

The two external curved margins of the stomach

Lesser omentum

Layer of peritoneum that attaches the liver to the lesser curvature of the stomach.

Greater omentum

Layer of peritoneum that attaches the greater curvature to the posterior body wall and contains fat to cushion abdominal organs.

Stomach

Primary organ acting as a storage tank for food and the initial site of chemical protein breakdown.

Chyme

Processed food delivered from the stomach into the small intestine.

Simple columnar epithelium

Specific type of epithelial tissue lining the stomach mucosa.

Mucous neck cells

Specialized cells of the stomach mucosa that produce a sticky alkaline mucus.

Gastric glands

Glands of the stomach that secrete gastric juice.

Chief cells

Cells of the gastric glands that produce protein-digesting enzymes known as pepsinogens.

Parietal cells

Cells of the gastric glands that produce protein-digesting enzymes known as pepsinogens.

Endocrine cells

Endocrine cells of the stomach mucosa that produce gastrin.

Mucus

Protective substance produced by tall, column-shaped cells that prevents the stomach from digesting itself.

Gastric pits

Pits in the stomach lining formed by folded mucosa.

Small intestine

The body's major digestive organ and primary site of nutrient absorption into the blood.

Small intestine

Muscular tube extending from the pyloric sphincter to the ileocecal valve

Messengers

Structure from the posterior abdominal wall that suspends the small intestine.

Duodenum

First subdivision of the small intestine attached to the stomach and curving around the head of the pancreas.

Jejunum

Middle subdivision of the small intestine that attaches anteriorly to the duodenum.

Ileum

Terminal subdivision of the small intestine extending from the jejunum to the large intestine.

Pancreas

Accessory organ that produces pancreatic juice containing enzymes for carbohydrates, proteins, and fats, along with an alkaline content to neutralize acidic chyme.

Liver

Organ that produces bile for lipid absorption and provides alkaline content.

Villi

Fingerlike structures formed by the mucosa of the small intestine that greatly increase surface area.

Microvilli

Small projections of the plasma membrane found on absorptive cells of the small intestine.

Lacteals

Specialized lymphatic capillaries located inside villi responsible for absorbing fats.

Blood capillaries

Responsible for absorbing general nutrients such as glucose, amino acids, and water-soluble vitamins.

Circular folds (plicae circulares)

Deep folds of the mucosa and submucosa in the small intestine that do not disappear when filled with food.

Peyer’s patches

Collections of lymphatic tissue located in the submucosa of the small intestine.

Pancreatic amylase

Pancreatic enzyme responsible for helping complete the digestion of starch.

Lipase

Pancreatic enzyme responsible for major fat digestion.

Nucleases

Pancreatic enzymes responsible for digesting nucleic acids.

Active transport

Cellular transport mechanism by which most nutrient substances are absorbed through cell membranes in the small intestine.

Diffusion

Cellular transport mechanism by which lipids are absorbed.

Hepatic portal vein

Specialized blood vessel transporting absorbed nutrients from the digestive tract directly to the liver.

Peristalsis

Major means of moving food through the small intestine, acting as alternating waves of contraction.

Segmental movements / Segmentation

Movements in the small intestine that mix chyme with digestive juices and aid in propelling food by moving materials back and forth.

Large intestine

Intestinal organ that is larger in diameter but shorter in length than the small intestine, framing the internal abdomen.

Cecum

Saclike first part of the large intestine.

Appendix

Accumulation of lymphatic tissue hanging from the cecum that sometimes becomes inflamed.

Colon

Main, longer sections of the large intestine collectively referred to by this term.

Ascending, transverse, descending, and S-shaped sigmoidal colons

The four main subdivisions or sections of the colon.

Anus

Terminal external body opening of the alimentary canal.

Goblet cells

Specialized cells in the large intestine that produce mucus to act as a lubricant.

Resident bacteria / Microbiota

Resident microorganisms in the large intestine that digest remaining nutrients, produce some vitamins K and B, and release gases.

Mass movements

Slow, powerful movements occurring three to four times per day in the large intestine.

Defecation reflex

Reflex triggered by the presence of feces in the rectum.

Parotid glands

Salivary glands located anterior to the ears.

Saliva

Component of saliva containing salivary amylase that begins starch digestion and dissolves chemicals so they can be tasted.

Deciduous (baby or milk) teeth

Set of 20 baby or milk teeth fully formed by age two

Permanent teeth

Set of teeth consisting of up to 32 teeth that replace deciduous teeth between the ages of 6 and 12.

Incisors, canines, premolars, and molars

The four classifications of human teeth.

Crown

Exposed part of a tooth covered by outer enamel, dentin, and a pulp cavity.

Neck

Region of a tooth in contact with the gum that connects the crown to the root.

Root

Region of a tooth attached to bone via the periodontal membrane and containing root canals for blood vessels and nerves.

Insulin and glucagons

Endocrine products produced by the pancreas to regulate blood sugar levels.

Liver

Largest gland in the body, located on the right side under the diaphragm and suspended by the falciform ligament.

Bile pigment / Bilirubin

Pigment found in bile derived mostly from the breakdown of hemoglobin

Gallbladder

Small sac found in the hollow fossa of the liver that stores bile and can develop blockages from stones.

Ingestion

The initial process of getting food into the mouth

Mechanical digestion

Digestive process involving the mixing of food in the mouth by the tongue, churning of food in the stomach, and segmentation in the small intestine.