Digestive System Flashcards
Trace path of food through the mouth to the anus
12
Mouth, pharynx, esophagus, stomach, duodenum, jejunum, ileum, acending-transverse-descending colon, rectum
Layers of the stomach from outer to inner
serosa, muscularis, submucosa, mucosa, lumen
What kind of muscle forms the pyloric sphincter?
muscularis externa
Sympathetic and Parasympathetic control over the digestive system
Sympathetic will inhibit digestive function and parasympathetic will stimulate it
Main nerves involved in the function of the digestive tract?
Sympathetic trunk
vagus nerve
greater splanchnic nerve
lesser splanchnic nerve
How do we make sure the air/food enter the correct areas?
2
The soft palate protects the nasopharynx
the epiglottis protects the trachea
What two types of tissue layers make up the muscularis in the lining of the esophagus?
Circular layer and longitudinal layer
Gastroesophageal Reflux disease
GERD
Lower esophageal sphincter is weak and allows stomachs contents to flow back up to the esophogus
Hiatal hernia
Stomach bulges up through lower esophageal spinchter past the diaphragm
What is the underlyng pathology for gastric ulcers?
Breach in the mucosa from acid and pepsin
What are haustra?
Small pockets caused by sacculation in the colon.
When looking inside they are separated by ridges
What are diverticulae?
outpouchings from the colon
Diverticulitis?
Note the haustra
These outpuchings may get inflammed, start bleeding or infected.
Haustra look like the have holes in them
Why do we get excited about colorectal polyps?
They can become malignant
Where would you see most colon cancers?
Distal Large bowel because carcinogens spend more time there than proximally
Why do we do colostomies or ileostomies?
After a tumor or dysfunctional resection These can be permanent or temporary Each will have different discharges Colon to skin Ileum to skin
What is ileus?
When is this often seen?
Cessation of peristalsis
- Small and large bowels fill with air
- seen following surgery, trauma, or obstruction
What is the function of the omentum?
3
Fat deposition
Immune contribution
Protect against infection, tumor,
What does the omentum connect?
2
the stomach to liver for lesser omentum
the greater omentum hangs off greater curvature and connects to the transverse colon
What creates the foramen of winslow?
the lesser omentum
What goes on in the red pulp of the spleen?
3
There are reserves of RBCs there
It removes old RBCs
It contains 50% of the body’s monocytes
What goes on in the white pulp of the spleen?
3
Creates antibodies
Removes WBCs and bacteria coated with antibodies
Its part of the lymph system
What happened in the picture taken during surgery on page 18 of GI slides?
3
Its a ruptured spleen
The spleen is covered by the ribs but it still can be injured by blunt trauma because its very vascular.
This bleeding can be fatal
How are the spleen and liver connected anatomically?
The splenic vein flows into the hepatic portal vein
What is the orientation of the pancreas in the body?
The head lies on/is connected with the duodenum and the tail lies on/connected with the spleen
What are the two main functions of the pancreas?
2
Its part of the digestive system: producing pancreatic juice and digestive enzymes
Its part of the endocrine system: creates insulin, glucagon, and somatosatin (GH)
What happens with cancer at the head of the pancreas?
2
The tumor blocks the bile ducts and the patient turns yellow (jaundice = due to excess bilirubin)
The tumor also blocks pancreatic juices causing severe pain. (could cause ulcers?)
What do gall stones cause?
3
Obstruction
Subsequent bowel changes
Local inflammation
Desrcibe portal hypertension?
Vessels in the liver are blocked due to liver damage so blood cannot flow properly through the liver. As a result high pressure in the portal system develops. This leads to large swollen (dilated) vessels. These vessels can rupture and cause life threatening issues.
What are the main causes of portal hypertension?
2
vessel blockage (portal/heptaic veins) cirrhosis (alcohol/hep C)
Where are three places where the portal and systemic venous systems connect?
Esophagus
Umbilicus
rectum
What is the function of mesentary?
Layer of tissue that attaches the intestines to the chest wall.
Supplies blood, innervation and lymph to the stomach
What structure is the mesentery most associated with?
Small intestine (thin in the jejunum, thick in the ileum)
Main functions of the esophagus?
2
Swallowing food (peristalsis) The upper and lower esophageal sphincters help prevent acid reflux
Where does the esophagus start?
C6, lower border of the cricoid cartilage
Where are the points of constriction in the esophagus?
C6-Junction of the pharynx and esophagus(narrowest part of the esophagus)
Where it delves behind the Aortic arch and main left bronchi (and is pushed slightly to the left)
Where it passes the diaphragm-lower esophageal sphincter
What glands are found in the submucosa of the esophagus?
esophageal glands proper-secrete acid mucin for lubrication
What does the esophageal cardiac glands produce?
neutral mucus that protects the esophagus from acidic gastric juices
Identify the muscle composition of the esophagus?
Mostly smooth muscle
The upper portion contains striated(skeletal muscle) for voluntary swallowing
Longitudinal layers are on the outer portion and circular layers are on the inner portion
What do contractions of the two muscular layers of the esophagus do?
Circular muscle contraction-causes an increase in luminal pressure needed for peristalsis
Longitudinal muscle contraction-causes shortening
Blood supply to the upper esophagus comes from?
inferior thyroid artery
Blood supply to the middle portion of the esophagus comes from?
thoracic aorta
Blood supply to the lower portion of the esophagus comes from?
left gastric artery
Functions of the stomach?
- Churning action of the stomach along with release of pepsin and other enzymes helps break down food into a consistency that is easier for the intestines to digest
- Can temporarily store food
Structure in the stomach you need to know
9
Greater curvature lesser curvature cardia fundus body pyloric antrum pyloric canal pyloric sphincter esophagogastric junction
Function of rugae?
2
Allow for expansion of the stomach. They are folded when its empty and unfolded when its full.
Also increase surface area for absorption of nutrients.
What does the left gastric artery supply blood to?
branch?
lesser curvature
and to lower esophagus via the esophageal brach of the left gastric