Structural and Functional Organization of the Digestive System Flashcards
What are the two groups of organs that make up the digestive system?
GI tract/alimentary canal
Accessory digestive organs
What is contained within the GI tract/alimentary canal?
Mouth Pharynx Esophagus Stomach Small and large intestines
What are the accessory digestive organs?
Teeth, tongue, salivary glands, liver, gallbladder, pancreas
What are the 3 regions of the abdomen?
Intrathoracic
-enclosed by lower ribs and immediately distal to the diaphragm
True abdomen
Retroperitoneal abdomen
-lies behind the thoracic and true abdomens. It is separated by the retroperitoneal membrane. It is attached in the posterior of the body.
What is contained within the intrathoracic abdomen?
Liver (solid)
Gallbladder (solid but contained)
Spleen (solid)
Stomach (hollow)
Transverse colon (hollow)
What is contained within the true abdomen?
Small and large intestines
Lower portion of liver
Bladder
FEMALES: uterus, Fallopian tubes, ovaries (considered part of the pelvic portion of the true abdomen)
What is contained within the retroperitoneal abdomen?
Kidneys
Ureters
Pancreas
Posterior duodenum
Ascending and descending colon
Inferior vena cava
What is the pneumonic to remember what substances are absorbed in different parts of the intestines? (Duodenum, Jejunum, Ilium)
I: Iron (duodenum)
FIST: Folate (Jejunum)
BRO: Ilium (Bile/B12)
What are the 6 basic functions of digestion?
Ingestion
Secretion
Mixing and Propulsion
Digestion
Absorption
Defecation
What is: “cells lining the GI tract produce water, acid, buffers and enzymes to aid digestion”
Secretion
Which of the 6 basic functions of digestion involves peristalsis?
Mixing and Propulsion
Define: “continuous contraction and relaxation moving food along the GI tract”
Mixing and Propulsion
Define: “mechanical and chemical process that breaks down the food we ingest”
Digestion
Define: “small molecules produced in digestion moved into spaces used by cells”
Absorption
What are the 4 distinct layers of the lining of the GI tract?
Mucosa
-Innermost lining, has direct contact with contents passing through
Submucosa
-Alveolar connective tissues that bind the mucosa to the muscularis. Contains blood and lymphatic vessels which absorb food molecules.
Muscularis
-Contains skeletal muscle and smooth muscle.
Serosa
-Made up of two sub layers: visceral and parietal peritoneum.
Visceral vs. Parietal Peritoneum
Visceral: outermost layer around the ORGANS of the GI tract.
Parietal: layer that lines the WALLS of the abdominal cavity.
The salivary glands contain what enzyme that helps to kill ___ and protect the mouth from infection and food decay?
Lysozomes that kill bacteria.
Lysozime is the actual enzyme that kills bacteria in the mouth.
This is a fold of mucous membrane in the midline of the mouth that limits movement of the tongue posteriorly.
Frenulum
The pharynx is a funnel shaped tube located in the posterior end of the oral cavity that is lined with what type of muscle?
Skeletal muscle.
What are the 3 branches of the pharynx?
Nasopharynx
-Involved in respiration
Oropharynx
-Located between the nasopharynx and laryngopharynx
Laryngopharnx
-Helps to propel food into the esophagus via muscle contractions
The upper and lower esophageal sphincters contain what types of muscle?
Upper: skeletal
Lower: smooth
What are the 3 phases of swallowing?
Voluntary
-Bolus forced into the oropharynx by the tongue moving upward and backward against the palate.
Pharyngeal
-Begins when the bolus is in the oropharynx. Breathing is temporarily interrupted. The soft palate and uvula close off the nasopharynx and the epiglottis seals off the larynx. The upper esophageal sphincter relaxes and the bolus moves into the esophagus.
Esophageal
-Begins when the bolus moves into the esophagus. Food is pushed through the esophagus via peristalsis. When the bolus reaches the bottom of the esophagus the lower sphincter relaxes and the bolus moves into the stomach.
The environment of the stomach is ___ and has a pH of ___.
The range is ___ to ___.
Acidic.
2.
1.5-3.5
What is a reservoir and mixing chamber for food that aids in digestion?
The stomach.