digestive System

Digestive Tract

organs essentially form a continuous tube that includes the oral cavity (mouth), pharynx, esophagus, stomach, small intestine, large intestine, anal canal and ends at the anus

Accessory Digestive Organ

are connected to the GI tract and typically develop as outgrowths from the tract (liver, gallbladder, pancreases and salivary glands)

Mouth (oral cavity)

is the initial site of mechanical digestion (via mastication) and chemical digestion (via an enzyme in saliva)

Pharynx

common space used by both the respiratory and digestive system

Esophagus

is a tubular passageway for swallowed materials being conducted from the pharynx to the stomach

Stomach

is a muscular, J-shaped sac that occupies the left upper quadrant of the abdomen, immediately inferior to the diaphragm

Small Intestine

consists of three specific segments: duodenum, jejunum, and the ileum. Most nutrients are absorb here

Large Intestine

absorbs most of the water and ions from the remaining digested materials

Anus

waste is eliminated from here

Functions of the Digestive System

-Ingestion

-Mastication

-Secretion.

-Digestion

-Absorption

-Elimination

Peristalsis

is the process of muscular contraction that form ripples along part of the GI tract and forces material to move further along tract

Mass Movement

powerful, sustained contrition of large intestine that propel undigested waste towards the rectum, preparing if for defecation

Segmentation

a type of muscular movement that mixes intestinal contents, facilitating digestion and nutrient absorption

Labia (Lips)

largely orbicularis muscle and covered with keratinized stratified squamous epithelium

Cheeks

largely buccinator muscle, helps maintain food within the mouth, guiding it between teeth for chewing and assisting with swallowing

Hard Palate

palatine and maxilla bone makes it up. Covered in dense connective tissue and nonkeratinized stratified squamous epithelium

Soft Palate

skeletal muscles and nonkeratinized stratified squamous epithelium

teeth

are responsible for mastication (break down) first part of the mechanical digestion process

Incisors

shaped like a chisel and having a single root. They are designed for slicing or cutting into food (anteriorly)

Canines

(posterolateral to incisors) which have a pointed tip for puncturing and tearing food

Premolars

located posterolateral to the canines and anterior to the molars. They have a flat crown that are used to crush and grind ingested materials

Molars

are thickest and most posteriorly placed teeth. They have large, broad, flat crowns used for grinding and crushing ingested materials

Palatine Tonsils

located at the back of the throat, near the entrance of the digestive and respiratory tract

Tongue

is an accessory digestive organ that is formed primarily from skeletal muscle and covered with stratified squamous epithelium

Uvula

preventing food and liquids from entering the nasal cavity during swallowing

Saliva

moistens food so it moves more easily through your esophagus into your stomach the enzymes in it helps break down food

Parotid

major salivary glands in the digestive system, producing serous saliva located in front of and below each ear

Submandibular

plays a crucial role in digestion by producing saliva, which contains amylase and enzyme that helps break down starches, located under the jawbone

Sublingual

produce saliva that plays a crucial role in the initial stages of digestion and oral health

Pharynx break down

-Nasopharynx

-Oropharynx

-Laryngopharynx

Esophagus

is a tubular passageway for swallowed materials being conducted from the pharynx to the stomach

Esophageal Hiatus

inferior region of the esophagus connecting the stomach by passing through an opening in the diaphragm

Superior Esophageal Sphincter

is a contracted ring of circular skeletal muscle at the superior end of the esophagus It is the area where the esophagus and the pharynx meet

Inferior Esophageal Sphincter

is a contracted ring of circular smooth muscle at the inferior end of the esophagus. This sphincter isn’t strong enough alone to prevent materials from refluxing back into the esophagus

Cardiac Orifice

the internal opening where the cardia meets the esophagus

Cardia

is the small, narrow, superior entryway into the stomach lumen from the esophagus

Fundus

is the dome-shaped region lateral and superior to the esophageal connection with the stomach. It’s superior surface contacts the diaphram

Pyloric Orifice

It’s opening into the duodenum of the small intestine

Longitudinal

an outer layer of muscle in the gastrointestinal tract, running along the length of the digestive system (moves food through the digestive tract via peristalsis)

Circular

move food along and mixes with digestive juices, arranged in circular pattern within the walls of the digestive tract, helps with segmentation and peristalsis

Oblique

muscle layer in the stomach is crucial for food churning and mechanical digestion

Rugea/Gastric Folds

They are seen only when stomach is empty, allowing the stomach to expand greatly when it fills and then returns to its normal J-shape when it empties

Gastric Pits

tiny indentations in the stomach lining that open into gastric glands. These pits are lined with specialized cells that produce and release digestive secretion, including acid and enzymes

Gastric Glands

tubular structure within the lining of the stomach that produce and secretes gastric juice, a mixture containing Hydrochloric acid, enzymes, and mucus

Mucous Cells

these cells produce an acidic mucin that differs structurally and functionally from the mucin secreted by the surface mucous cells

Parietal Cells

are located primarily in the proximal and middle parts of the gastric gland. Hydrochloric Acid secreted across the parietal cells vast internalized surface helps denature proteins to facilitate chemical digestion

Chief Cells

are housed primarily in the distal part of the gastric glands. These cells produce pepsinogen into the stomach which produces pepsin which chemical digests and denatures proteins

Duodenum

forms the initial or first segment of the small intestine

Jejunum

middle region of the small intestine, primary region within the small intestine for chemical digestion and nutrient absorption

Ileum

is the final region

Circular Folds

the mucosal and submucosal tunics

Villi

When circular folds are viewed at the microscopic level, smaller fingerlike projections of mucosa only

Microvilli

increases the absorptive surface area even further

Lacteals

located within the villi of small intestine, responsible for absorbing and transporting dietary fats and fat-soluble vitamins

How many lobes does the liver have

4 Lobes

Liver Functions

-Detoxification

-Phagocytosis

-Production of bile

Biliary Apparatus

is a network of thin ducts that carry bile from the liver and gallbladder to the duodenum

Left and Right Hepatic Duct

the left and right lobes of the liver drain bile into them

Common Hepatic Duct

the right and left hepatic duct merge to form it

Common Bile Duct

the cystic duct and common hepatic duct form it

Cystic Duct

is attached to the common hepatic duct and carries bile to and from the gallbladder

Gallbladder

concentrates bile produced by the liver and stores this concentrate until it is needed for digestion

Gallstones

high concentration of certain materials in the bile may lead to them

Pancreatic Duct

transporting pancreatic juices from the pancreas to the duodenum

Secretion

Insulin and Pancreatic Juice

Pancreatic Juice

breaks down fats, proteins and carbohydrates

Ileocecal Valve

a sphincter muscle located at the end of the small intestine (ilium) where it connects to the beginning of the large intestine (cecum)

Cecum

absorbs water and electrolytes from undigested food waste and mixing it with mucus to form feces

Vermiform Appendix

no longer serves a major function in digestion

Ascending colon

originates at the ileocecal valve and extends superiorly from the superior edge of the cecum along the right lateral border of the abdominal cavity

Transverse Colon

originates at the right colic flexure and curves slightly anteriorly as it projects horizontally across the anterior region of the abdominal cavity

Descending Colon

is retroperitoneal and found along the left side of the