Structural and Functional Organization of the Digestive System Flashcards
What two groups of organs make up the digestive system?
GI tract/Alimentary
and
Accessory Organs
What is included in the GI/alimentary tract?
mouth, pharynx, esophagus, stomach, small and large intestine
What is included in the accessory digestive organs?
teeth, tongue, salivary glands, liver, gallbladder, and pancreas
Three regions of the abdomen:
intrathoracic
true abdomen
retroperitoneal
organs of the intrathoracic region:
liver (solid) gallbladder (solid but contained) spleen (solid) Stomach (hollow) Transverse Colon (hollow)
organs in the true abdomen:
small and large intestine
liver, lower portions
bladder
FEMALE: uterus, fallopian tubes, ovaries
What are the six functions of digestion?
Ingestion Secretion Mixing and propulsion Absorption Digestion Defecation
What are the 4 distinct layers of GI tissue?
Mucosa
Submucosa
Muscularis
Serosa
The serosa is made up of two sub layers, what are they?
Visceral peritoneum
Parietal peritoneum
What is the “fatty apron” that drapes over the traverse colon and small intestine?
greater omentum
What binds the intestine to the posterior abdominal wall?
Mesentery
This function of digestions involves cells lining GI tracts produce water, acid, buffers and enzymes to aid digestions
Secretion
This basic function of digestion involves mechanical and chemical process that breaks down the food we ingest
Digestion
this basic function of digestion is when small molecules produced in digestion move into spaces to be used by cells
absorption
this basic function of digestion is when elimination of materials happens of materials not absorbed by our body in indigestion.
defecation
what are the four distinct layers that form the gastrointestinal tract?
mucosa
submucosa
muscularis
serosa
this layer of the GI tract is the innermost lining of the GI tract that is in direct contact with the substances passing through:
Mucosa
this layer of the GI tract is made up of areolar connective tissue that bind the mucosa to the muscularis. It contains blood and lymphatic vessels which absorb food molecules.
Submucosa
this layer of the GI tract is made up of skeletal and smooth (involuntary) muscle:
Muscularis
This layer of the GI tract is made up of TWO sub layers
Serosa
What are the two sublayers of the Serosa?
Visceral peritoneum- (outerlayer around the organs of GI)
Parietal peritoneum - lines the wall of the abdominal cavity
What is the greater omentum?
fatty apron that drapes over the transverse colon and small intenstine
this binds the small intestine to the posterior abdominal wall:
mesentery
What are the three pairs of salivary glands?
Parotid
Submandibular
Sublingual
how do salivary glands function?
99.5% water and .5% solutes
contain lysozomes that kill bacteria
salivary amylase begins digestions of starches
lubricate foods.
This accessory digestive organ is made up of skeletal muscle, maneuvers food, and forces it to the back of the mouth?
tounge
what is the fold of mucous membrane called in the midline underneath the tounge that limits the tongues posterior movement?
frenulum
Three branches of the pharynx
nasopharynx
oropharynx
laryngopharynx
which branch of the pharynx helps propel food into the esophagus via muscular contraction?
laryngopharynx
what type of tissue lines the esophagus?
stratified squamous epithelium
Which of the esophagus’ sphincters is composed of skeletal muscle, and is therefore voluntary?
Upper Esophageal sphincter
three phases of swallowing?
Voluntary
Pharyngeal
Esophageal
In this phase of swallowing, breathing is temporarily interrupted. Soft palate, uvula close off nasopharynx and epiglottis seals larynx.
Pharyngeal
What are the muscle contractions that move food through the GI tract called?
peristalsis
What is the PH range of the stomach?
1.5-3.5
What is the most elastic part of the GI tract?
the stomach
how many liters of food can the stomach stretch to accomadate?
6.4 Liters
what are the four main regions of the stomach
cadia, fundus, body, and pylorus
What type of cells are Gastric gland cells?
exocrine cells that excrete contents that combine to create gastric juice
Which cells release pepsinogen?
Chief Cells
What do the parietal cells excrete?
Hydrochloric acid (HCL) which converts pepsinogen into pepsin
and
Intrinsic Factor.
what is secreted by the G cells in the pyloric antrum of the stomach?
Gastrin
What is necessary for the absorption of B12 in the Small intesine?
IF
What do we call the thick liquid with the consistency of pea soup in the stomach that is made up of gastric juices and macerated food particles:
Chyme
Endocrine functions of the pancreas:
Islets of Langerhans made up of beta cells, which make insulin and alpha cells that make glucagon (prevents blood glucose from dropping too low)
Exocrine functions of the pancreas:
Chemical digestions is achieved through secretions passing through pancreatic duct, joining common bile duct to form hepatopancreatic duct. secretions pass though the hepatopancreatic duct through the sphincter of Oddi into the duodenum.
What is the pH of pancreatic juice?
71.-8.2
what is pancreatic juice?
a clear, colorless liquid made up of enzymes that consist mostly of water, some salts, and sodium bicarbonate
name some of the enzymes in pancreatic juice:
trypsin and chymotrypsin- protein digesting
pancreatic amylase- starch digesting
pancreatic lipase- fat digesting
ribonuclease- nucleic acid digesting
What is the liver responsible for?
metabolizing carbs, fats, and protein processing drugs and hormones excretion of bilirubin vitamin and mineral storage Vitamin D activation
what is the bile pigment that is one end product of heme catabolism, responsible for the brown color in human feces:
stercobilin.
What are the major functional cells of the liver that perform metabolic, secretory, and endocrine functions?
hepatocytes.
What is the name for the pear shaped sac that hangs from the inferior margins of the liver?
the gallbladder
What stores bile to be released into the small intestine and aids in the chemical digestion of fats, acting as an emulsifier?
gallbladder
The bile produced by the liver are passed into which ducts?
left and right hepatic ducts.
the bile produced by the gallbladder is secreted through which duct?
cystic duct
what is the duct called where the hepatic ducts and the cystic duct converge?
common bile duct
the common bile duct forms with the pancreatic duct to form __________ ?
the hepatopancreatic duct
what is the muscular valve that controls the passage of contents from the hepatopancreatic duct into the duodenum?
Sphincter of Oddi
what are the 3 types of endocrine cells that secrete hormones that are contained in the intestinal glands?
S cells
CCK cells
K cells
These endocrine cells in the intestinal glands secrete which hormone that stimulates secretion of pancreatic juice?
S cells, secretin
What is cholecystokinin and which cells secrete it?
regulates gastric emptying, stimulates bile and pancreatic juice secretion, relaxes sphincter of Oddi, and the feeling of satiety.
Secreted by CCK cells
What hormone stimulates the release of insulin and which cells in the intestinal glands secret it?
glucose dependent insolinotropic peptide (GIP), secreted by K cells
What part of the intestine attaches to the pyloric sphincter of the stomach?
Duodenum
what is the line of demarcation between upper GI bleeds and lower GI bleeds?
ligament of Trietz
where is the ligament of Trietz located?
connects at duodenal-jejunal flexure and secures those segments to the posterior wall.
The predominant function of this segment of the small intestine is the absorption of sugars, amino acids, and fatty acids:
Jejunum
where does Ileum attach to the large intestine?
ileocecal sphincter/valve
this segment of the small intestine absorbs remaining nutrient’s, b12, and bile salts. (the bile salts are recycled into the liver and gallbladder)
Ileum.
Where do most of the digestion and absorption phases of digestion occur?
small intestine
Four regions of the large intestine?
Cecum
Colon
Rectum
Anal Canal
what part of the large intestine does the appendix attach?
cecum
how is the colon broken down?
ascending, transverse, descending, and sigmoid portions
what connects the sigmoid to the anus?
Rectum
what is the last 2-3 cm of the rectum consisting of internal (involuntary) and external (voluntary) sphincters
anal canal
function of the large intestine:
complete absorption, complete absorption of vitamins (b and k) produced by gut bacteria. Forms feces.
This phase of digestion involves the smell, sight, sound, or thought of food, activating neural centers in the brain stimulating salivary glands….
cephalic
this phase of digestion is when gastrin is released promoting the release of gastric juice which increases the mobility of the stomach, relaxing pyloric sphincter and gastric emptying?
gasric
this phase of digestion is when inhibitory effects slow gastric emptying, and excitatory effects stimulate secretion of pancreatic juices to aid in absorption and digestion?
intestinal
