Digestive System Notes

Comprehensive vocabulary flashcards covering large intestine anatomy, accessory organs of digestion, body habitus, swallowing dynamics, contrast media characteristics, and upper GI/esophageal radiographic procedures.

Large Intestine Primary Function

Reabsorbs water from remaining chyme, forms and stores feces until defecation, and has little or no digestive function.

Large Intestine Caliber

Measures approximately $2\frac{1}{2}\text{ inches}$ in diameter.

Large Intestine Length

Measures approximately $5\text{--}6\text{ feet}$ ($1.5\text{ m}$) in total length.

Large Intestine Origin

Begins at the ileocecal junction where the ileum joins the cecum.

Cecum Structural Form

A dilated, pouchlike structure that hangs inferior to the ileocecal opening.

Cecum Length and Quadrant

Comprises the first $2.5\text{ inches}$ of the large intestine, located in the right lower quadrant ($RLQ$).

Vermiform Appendix Classification

An accessory organ of uncertain physiological function that communicates directly with the cecum.

Vermiform Appendix Dimensions

Measures approximately $8\text{--}10\text{ cm}$ in length.

Ascending Colon

The retroperitoneal segment of the colon coursing superiorly along the right abdominal flank.

Right Colic Flexure Location

The sharp bend between the ascending colon and transverse colon situated on the right side.

Hepatic Flexure

An alternate clinical designation for the right colic flexure.

Transverse Colon Mobility and Length

The longest and most mobile division of the large intestine, spanning between both colic flexures.

Transverse Colon Sagging

Frequently sags inferiorly below the level of the stomach.

Left Colic Flexure Location

The acute turn between the transverse colon and descending colon situated on the left side.

Splenic Flexure

An alternate anatomical name for the left colic flexure.

Descending Colon Course

The colon segment extending inferiorly along the left abdominal side down toward the iliac crest.

Sigmoid Colon Geometry

An S-shaped tubular segment that joins the descending colon to the rectum.

Rectum Segment Length

The terminal $6\text{ inches}$ of the large intestine.

Rectum Sacral Alignment

Closely follows the anteroposterior curvature of the sacrum and coccyx.

Rectum Distal Termination

Terminates approximately $2\text{ inches}$ distal to the tip of the coccyx.

Anal Canal Length

The final $1\text{ inch}$ ($3\text{ cm}$) constricted segment of the digestive tract.

Anus

The external termination and orifice of the anal canal.

Rectal and Anal Canal Curvatures

Possesses $2$ distinct anteroposterior curves that must guide safe insertion of an enema tip.

Enema Tip Insertion Precaution

Must be directed anterosuperiorly and then posterosuperiorly to match the two normal anteroposterior curves.

Large Intestine Mucous Glands

Glandular structures that secrete lubricating mucus to coat feces during formation.

Taeniae Coli

Three distinct longitudinal smooth muscle bands extending the length of the colon.

Haustra

Pouch-like sacculations along the colon produced by circular muscular contractions.

Liver Abdominal Location

Occupies the right hypochondriac region and parts of the epigastric region directly under the diaphragm.

Liver Skeletal Protection

Largely shielded and bordered externally by the thoracic rib cage.

Falciform Ligament

The peritoneal fold dividing the liver into larger right and smaller left primary lobes.

Liver Left Lobe Proportion

Accounts for approximately $1/6$ of total hepatic volume.

Liver Right Lobe Proportion

Accounts for approximately $5/6$ of total hepatic volume.

Caudate Lobe

A minor hepatic lobe situated on the posterosuperior surface of the liver.

Quadrate Lobe

A minor hepatic lobe situated on the inferoposterior surface of the liver.

Daily Hepatic Bile Output

Produces approximately $1\text{--}3\text{ pints}$ of bile per day.

Bile Waste Elimination Role

Provides an excretory route for bilirubin and breakdown products of red blood cell destruction.

Bile Digestive Action

Emulsifies and promotes the assimilation of dietary fats within the small intestine.

Bile Canaliculi

Microscopic channels receiving initial biliary secretions directly from hepatocytes.

Common Hepatic Duct Formation

Formed by the convergence of the right and left hepatic ducts.

Cystic Duct

The bidirectional conduit connecting the gallbladder neck to the common hepatic duct.

Common Bile Duct Formation

Formed by the junction of the common hepatic duct and the cystic duct.

Ampulla of Vater

The confluence where the common bile duct and pancreatic duct join before emptying into the duodenum.

Hepatopancreatic Ampulla

The official anatomical name for the ampulla of Vater.

Sphincter of Oddi

The circular smooth muscle sphincter surrounding the hepatopancreatic ampulla.

Major Duodenal Papilla

The mucosal elevation in the descending duodenum where the ampulla of Vater opens.

Gallbladder Interdigestive Role

Receives and stores bile between meals when the sphincter of Oddi is closed.

Gallbladder Bile Concentration

Concentrates stored bile through active mucosal absorption of its water content.

Gallbladder Digestive Evacuation

Contracts its muscular wall during digestion to evacuate stored bile into the duodenum.

Cholecystokinin (CCK)

The intestinal hormone stimulating muscular contraction and emptying of the gallbladder.

Pancreas Physical Characteristics

A grayish-pink gland measuring $12\text{--}15\text{ cm}$ in total length.

Pancreatic Head Location

Nestled within the C-loop of the descending duodenum.

Pancreatic Body Location

Extends horizontally and transversely posterior to the stomach.

Pancreatic Tail Location

Tapers laterally across the abdomen to touch the hilum of the spleen.

Dual Pancreatic Classification

Functions simultaneously as an exocrine digestive gland and an endocrine regulatory gland.

Pancreatic Exocrine Product

Pancreatic juice containing digestive enzymes targeting proteins, fats, and carbohydrates.

Pancreatic Acini Cells

The exocrine secretory units that produce digestive enzymes.

Islets of Langerhans

The endocrine clusters that secrete hormones directly into the circulation.

Pancreatic Alpha Cells

Endocrine cells that synthesize and secrete glucagon.

Pancreatic Beta Cells

Endocrine cells that synthesize and secrete insulin.

Glucagon Physiological Role

Elevates circulating blood glucose levels by triggering hepatic glycogenolysis.

Insulin Physiological Role

Reduces circulating blood glucose levels by facilitating cellular uptake and glycogenesis.

Main Pancreatic Duct

Also called the duct of Wirsung, it joins the common bile duct at the hepatopancreatic ampulla.

Accessory Pancreatic Duct

The duct of Santorini, which opens independently into the duodenum superior to the major papilla.

Hypersthenic Habitus Prevalence

Found in approximately $5\%$ of the population.

Hypersthenic Stomach Position

Lies high, transverse, and almost horizontal within the abdominal cavity.

Asthenic Habitus Prevalence

Found in approximately $10\%$ of the population.

Asthenic Stomach Position

Lies vertically, low in the abdomen, extending down near or into the pelvis.

Sthenic Habitus Prevalence

Found in approximately $50\%$ of individuals.

Hyposthenic Habitus Prevalence

Found in approximately $35\%$ of individuals.

Combined Sthenic and Hyposthenic Frequency

Accounts for $85\%$ of the general population.

Modified Barium Swallow Study (MBSS)

A dynamic fluoroscopic examination evaluating the soft palate, pharynx, and larynx during swallowing.

Swallowing Dysfunction Study

An alternate clinical term for the Modified Barium Swallow Study.

MBSS Patient Examination Posture

Performed with the patient seated upright.

MBSS Fluoroscopy Frame Rate

Recorded dynamically at $30\text{ frames per second}$.

Deglutition Definition

The rapid and highly coordinated muscular act of swallowing.

Deglutition Middle Tongue Action

Depresses downward to collect and organize the ingested bolus.

Deglutition Tongue Base Action

Forms a central groove and elevates against the palate to propel the bolus into the pharynx.

Deglutition Laryngeal Movement

Elevates superiorly and moves anteriorly beneath the base of the tongue.

Deglutition Epiglottic Function

Deflects the divided bolus laterally toward the piriform recesses, sealing the airway entrance.

MBSS Radiologic Technologist Role

Prepares the suite, shields the patient, assists handling, and positions the fluoroscopy tower.

MBSS Speech Therapist Contrast Administration

Administers graduated contrast consistencies using spoons, cups, and straws.

MBSS Speech Therapist Guidance

Provides compensatory swallowing instructions and directs maneuvers such as the chin tuck.

Chin Tuck Maneuver Purpose

Narrows the laryngeal vestibule to improve airway protection against aspiration.

MBSS Radiologist Responsibilities

Controls the fluoroscopy pedal, evaluates bolus flow in real time, and dictates diagnostic findings.

Standard MBSS Radiographic View

True lateral projection, often the sole view utilized during the procedure.

MBSS Lateral Shoulder Positioning

Shoulders depressed maximally to prevent superimposition over the pharynx and upper esophagus.

MBSS Radiation Field Boundaries

Collimated from the external auditory meatus ($EAM$) down to the jugular notch.

Peristalsis Definition

Involuntary waves of smooth muscle contraction propelling luminal contents toward the rectum.

Gastric Peristaltic Rate

Typically occurs at $3\text{--}4\text{ waves per minute}$ within the stomach.

Average Gastric Emptying Duration

Averages approximately $2\text{--}3\text{ hours}$ for a standard meal.

Barium Arrival at Ileocecal Valve (Initial Bolus)

Reaches the ileocecal valve in approximately $2\text{--}3\text{ hours}$ post-ingestion.

Barium Arrival at Ileocecal Valve (Final Bolus)

Clears into the ileocecal valve in approximately $4\text{--}5\text{ hours}$ post-ingestion.

Barium Transit Time to Rectum

Usually traverses the entire large intestine and reaches the rectum within $24\text{ hours}$.

Alimentary Tract Examination Modalities

Combines dynamic fluoroscopic observation with high-resolution static overhead radiography.

Fluoroscopy GI Advantage

Enables dynamic real-time assessment of motility, peristalsis, and detailed mucosal coating.

Radiographer GI Suite Preparation

Verifies table footboard, ensures recording devices function, and mixes appropriate contrast suspensions.

GI Scout Radiograph Purpose

Evaluates patient bowel preparation, technical exposure factors, and pre-existing radiopacities.

Barium Sulfate Chemical Nature

A completely water-insoluble radiopaque crystalline salt of metallic barium.

Barium Sulfate Suspension Medium

Mixed with plain water to form a colloidal suspension rather than a chemical solution.

Variables Affecting Barium Transit Speed

Suspending vehicle, liquid temperature, suspension viscosity, and individual patient motility.