STRUCTURAL AND FUNCTIONAL ORGANIZATION OF THE DIGESTIVE SYSTEM Flashcards
What are two groups of organs make up the digestive system
1) Gastrointestinal tract / Alimentary canal
(2) Accessory digestive organs
Accessory digestive organs do what, and what are the organs?
(a) Organs that aid in digestion
(b) Teeth, tongue, salivary glands, liver, gallbladder, and pancreas
Gastrointestinal tract / Alimentary canal does what and what are the organs?
(a) A continuous tube that extends from the mouth to the anus
(b) Mouth, pharynx, esophagus, stomach, small intestine, and large intestine
What group of the digestive system?
A continuous tube that extends from the mouth to the anus
Gastrointestinal tract / Alimentary canal
What group of the digestive system?
Organs that aid in digestion
Acessory digestive organs
What group of the digestive system?
Teeth, tongue, salivary glands, liver, gallbladder, and pancreas
Accessory digestive organs
What group of the digestive system?
Mouth, pharynx, esophagus, stomach, small intestine, and large intestine
Gastrointestinal tract / Alimentary canal
The abdomen is traditionally divided into what three regions
- Intrathoracic
- True abdomen
- Retroperitoneal abdomen
What region of the abdomen?
lies behind the thoracic and true portions. It is separated by
the retroperitoneal membrane from the other.
retroperitoneal abdomen
What region of the abdomen?
Contains the large and small intestines, a portion of the liver, and the bladder. In females, the uterus, fallopian tubes, and ovaries are considered part of the pelvic portion of the true abdomen
true abdomen
What region of the abdomen?
Enclosed by lower ribs and immediately distal to the diaphragm
intrathoracic
What region of the abdomen contains these?
(a) Liver (Solid)
(b) Gallbladder (Solid but contained)
(c) Spleen (Solid)
(d) Stomach (Hollow)
(e) Transverse Colon (hollow)
Intrathoracic
What region of the abdomen contains these?
(a) Small Intestines
(b) Large Intestines
(c) Liver, lower portions
(d) Bladder
(e) Female: Uterus, Fallopian Tubes, and Ovaries
True Abdomen
What region of the abdomen contains these?
(a) Kidneys
(b) Urters
(c) Pancreas
(d) Posterior Duodenum
(e) Ascending and Descending Colon
(f) Inferior Vena Cava
retroperitoneal abdomen
What are the six basic functions of digestion
(1) Ingestion
2) Secretion
(3) Mixing and Propulsion
(4) Digestion
(5) Absorption
(6) Defecation
What basic fx of digestion?
elimination of materials not absorbed by our body indigestion
Defecation
What basic fx of digestion?
taking in food and liquid through the mouth
Ingestion
What basic fx of digestion?
cells lining GI tract produces water, acid, buffers and enzymes to aid digestion
Secretion
What basic fx of digestion?
mechanical and chemical process that breaks down the food we ingest
Digestion
What basic fx of digestion?
continuous contraction and relaxation moving food along the GI tract.
Mixing and Propulsion
What basic fx of digestion?
small molecules produced in digestion moved into spaces to be used by cells
Absorption
Serosa: Made up of two sub layers
________ – outermost layer around the organs of the GI tract.
________ – lines the walls of the abdominal cavity.
Visceral peritoneum
Parietal peritoneum
What is the “fatty apron” that drapes over the transverse colon and small
Greater omentum
What binds the small intestine to the posterior abdominal wall
mesentery
______ is the innermost lining of the GI tract in direct contact with the substances passing through.
Mucosa
What is made up of areolar connective tissues that bind the mucosa to the muscularis. Contains blood and lymphatic vessels which absorb food molecules as they
are broken down.
Submucosa
_________ contains skeletal (voluntary) muscles and smooth (involuntary) muscles
Muscularis
Serosa is made up of how many layers?
2
There are three pairs of salivary glands
_________ located inferior and anterior to the ears between the skin and the masseter muscle.
_________ located medial and partly inferior to the mandible in the floor of the mouth.
_________ beneath the tongue and superior to the submandibular glands
Parotid
Submandibular
Sublingual
Upper esophageal sphincter - composed of what type of muscle?
Skeletal
Lower esophageal sphincter - composed of what type of muscle?
smooth muscle
______ functions to transport food along its path while mixing it with mucous
esophagus
Phases of swallowing
________ Bolus forced into the oropharynx by the movement of the tongue upward and backward against the palate.
________ Begins when the bolus is in the oropharynx. Breathing is temporarily interrupted. The soft palate and uvula move upward to close off the nasopharynx. The epiglottis seals off the larynx. The upper esophageal sphincter relaxes and the bolus moves into the esophagus
________ 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 esophageal sphincter relaxes and the bolus moves into the stomach.
Voluntary
Pharyngeal
Esophageal
What organ?
J-shaped organ of the GI tract, serves as a reservoir and mixing chamber for food, and aids in digestion.
stomach
What are the main regions of the stomach?
cardia, fundus, body and pylorus
The stomach extends from the end of the _______ to the tip of the _______
esophagus to the tip duodenum
What is the most elastic part of the GI tract?
STomach
Gastric gland cells are exocrine cells that secrete 3 types of contents that combine to create gastric juice:
- _______ secrete mucous
- _______ secrete pepsinogen
- _______ Secrete Hydrochloric acid (HCl) which helps convert pepsinogen into pepsin (active digestive enzyme)
- _______ Gastrin is secreted into the bloodstream by these cells in the pyloric antrum of the stomach.
- Mucous neck cells
- Chief cells
- Parietal cells
- G Cell
The PH of the stomach is ….
*2 (TG)
or
1.5-3.5 (Slides)
______ is a thick liquid with the consistency of pea soup in the stomach that is made up of gastric juices and macerated food particles
Chyme
The pancreas has what functions
endocrine and exocrine
There are specialized areas within the pancreas called
islets of Langerhans
The islets of Langerhans are made up of different type of cells that make hormones.
-The commonest ones are the _____ that produces _____
beta cells, which produce insulin
is a hormone that is produced by the alpha cells, found in the islets of Langerhans
Glucagon
Glucagon’s role in the body is to
prevent blood glucose levels dropping too low
______ is one of the most important accessory organs within the Gastrointestinal system. This organ has an exocrine function within the Gastrointestinal system
Pancreas
_______ (pH: 7.1-8.2)- a clear, colorless liquid made up of three enzymes that consists mostly of water, some salts, and sodium bicarbonate
Pancreatic juice
Pancreatic juice contains
_______ -protein digesting.
(a) Proteins: Broken down by enzymes into amino acids, dipeptides and tripeptides
_______- starch (carbohydrate) digesting
(a) Carbohydrates: Broken down by enzymes and absorbed as monosaccharides
______ - triglyceride (fat) digesting
(a) Triglycerides (fats): Broken down by enzymes and absorbed as monoglycerides and fatty acids
Trypsin and chymotrypsin
Pancreatic amylase
Pancreatic lipase
_______ second largest organ in the body located just below the diaphragm, mostly on the right side of the body
Liver
What organ is responsible for these fx
(1) Carbohydrate metabolism
(2) Lipid metabolism
(3) Protein metabolism
(4) Processing of drugs and hormones
(5) Excretion of bilirubin
(6) Storage of vitamins and minerals
(7) Activation of vitamin D
Liver
What are the major functional cells of the liver that perform metabolic, secretory and endocrine functions.
Hepatocytes
What part of the liver
A pear-shaped sac that hangs from the inferior margin of the liver.
(1) Stores bile to be released into the small intestine.
(2) Aids in chemical digestion, especially digestion of fats.
gallbladder
Duct system of the Liver and Gallbladder
_______ duct Bile and waste created in the liver are passed into the hepatic ducts
Left and right hepatic duct
Duct system of the Liver and Gallbladder
Bile produced in the gallbladder is secreted through the _____ duct
Cystic Duct
Duct system of the Liver and Gallbladder
The left and right hepatic duct form with the cystic duct to create
the ________ .
Common Bile Duct
Duct system of the Liver and Gallbladder
The common bile duct forms with the pancreatic duct to form
the ______ duct
hepatopancreatic duct
Duct system of the Liver and Gallbladder
______ The muscular valve that controls the passage of contents from the hepatopancreatic duct into the duodenum
Sphincter of Oddi
______ is the segment in the GI system that comes after the stomach
Small intestine
Intestinal glands contain 3 types of endocrine cells that secrete hormones into the bloodstream:
_____ Secrete the hormone Secretin, which stimulates the secretion of pancreatic juice.
_____ Secrete Cholecystokinin, which regulates gastric emptying, stimulates bile and pancreatic juice secretion, causes relaxation of the Sphincter of Oddi, and the feeling of satiety (feeling full to satisfaction).
_____ Secrete glucose-dependent insulinotropic peptide (GIP), which stimulates the release of insulin
S Cells
CCK Cells
K Cells
The small intestine is divided into three different segments:
____ Attaches to the pyloric sphincter of the stomach
____ Middle section of small intestine.
____ Attaches to the large intestine at the ileocecal sphincter/valve
Duodenum
Jejunum
Ileum
What part of the small intestine?
______absorbs remaining, nutrients, B12, and bile salts. Bile salts are recycled to the liver and gallbladder for reuse
The ilium
What part of the small intestine?
Predominant function of this is the absorption of sugars, amino acids, and fatty acids
Jejunum
What part of the small intestine?
Significant landmark of the this is the ligament of Trietz, which connects at the duodenal-jejunal flexure and serves to secure those segments to the posterior wall. The ligament of Trietz is the line of demarcation that denotes upper G.I. bleeds (above the ligament) and lower G.I. bleeds (below the ligament).
Duodenum
______ is the line of demarcation that denotes upper G.I. bleeds (above the ligament) and lower G.I. bleeds (below the ligament).
The ligament of Trietz
Most of the digestion and absorption events occur where
Small intestine
What type of digestion
via segmentation and peristalsis
Mechanical
What type of digestion
via pancreatic enzymes, bile and intestinal juice
Chemical
This defines what?
Nutrients are broken down into their simplest form which can be absorbed. These molecules are then absorbed by the microvilli and villi. The nutrients then diffuse from the villi to the bloodstream, and finally to the liver for use by the body
Absorption
Foods and nutrients are absorbed in their simplest (broken down) forms which are:
1) Monosaccharides
2) Amino acids, dipeptides and tripeptides
3) Monoglycerides and fatty acids
4) Ions and water.
5) Vitamins A, D, E and K.
The last part of the GI tract
The large intestine
The large intestine has four regions
(1) – First segment of the large intestine. The appendix attaches here.
(2) – Broken down into ascending, transverse, descending and sigmoid portions.
(3) – Connects the sigmoid colon to the anus.
(4) – last 2-3 cm of the rectum consisting of internal (involuntary) and external (voluntary) sphincters
(1) Cecum
(2) Colon
(3) Rectum
(4) Anal canal
The large intestine functions to:
(1) Complete absorption – absorbs water, electrolytes and vitamins.
(2) Absorbs certain vitamins produced by healthy gut bacteria – vitamins B and
K. These are needed for normal metabolism.
(3) Forms feces (unabsorbed digested material) to be expelled from the body
What part of the large intestine
Connects the sigmoid colon to the anus.
Rectum
What is unabsorbed digested material
feces
What phase of digestion
The smell, sight, sound or thought of food activates neural centers in the brain stimulating the salivary glands to secrete saliva and the gastric glands to secrete gastric juice.
Cephalic
What phase of digestion
Starts when food enters the stomach. Gastrin is released promoting the release of gastric juice which increases the mobility of the stomach, relaxes the pyloric sphincter and promotes gastric emptying
Gastric
What phase of digestion
Starts when food enters the small intestine. Inhibitory effects slow gastric emptying and excitatory effects stimulate the secretion of pancreatic juices to aid in absorption and digestion
Intestinal
What is secreted into the bloodstream by G cells in the pyloric
antrum of the stomach.
and is the major hormonal regulator of HCL secretion.
Gastrin
_____ is necessary for the absorption of Vitamin B12 in the Small Intestines
Intrinsic Factor (IF)
What is in the about 1 -2 inches in the into the anal canal
Dentate Line
