Abdomen: organs

2 incisors, 1 canine, 2 molars

Deciduous set of teeth includes

2 incisors, 1 canine, 2 premolars, 3 molars (3rd is the wisdom tooth)

Deciduous set of teeth are replaced by adult teeth containing

Enamel

Cementin

Dentin

-acellular, mineralized tissues that are fairly resistant

Specialized minerals that contribute to the teeth

Outer layer of crown

Enamel

Lines the alveolar bone (tooth sockets, aka ligament for the tooth)

Cementum

Found deep to enamel and cementum. Makes up bulk of tooth.

Dentin

Occur when prolonged exposure to bacterial enzymes demineralize the enamel, cementum, and dentin, creating carries

Typically, the gingiva (gums) cover the tooth below the crown. If the gingiva pulls away it exposes the dentin, which is softer than the enamel and is eroded more quickly

Cavities

Skeletal

Keratinized stratified squamous

The tongue consists of ____ muscles covered by ____ epithelium that resists abrasion during chewing

Specialized structures on the tongue surface

-filiform

-fungiform

-circumvalate

-foliate

Papillae

Sharp extensions that cover most of the tongue. NO TASTE BUDS

Filiform papillae

Little pale dots on the surface of the tongue that have taste buds.

Fungiform papillae

Large circular papillae near the posterior 1/3 of tongue. Have taste buds and secretory glands.

Much larger than other papillae, marks where the anterior and posterior tongue meets

Circumvalate papillae

Longitudinal folds on the lateral aspect of the tongue. Have taste buds and secretory glands.

Foliate papillae

Have sensory cells that contact the outside environment through a small pore.

Sensory cells turn over after ~10 days. Nerve bundles are often visible coming from the taste buds

Taste buds

Epithelium

1

Lamina propria

2

Muscularis mucosae

3

Submucosa

4

Submucosal glands

5

Circular muscularis externa

6

Longitudinal muscularis externa

7

Adventitia/serosa

8

Portion of gut tube in contact with the external environment (innermost layer of generic gut tube).

-Extracts nutrients from food

-protects the body from pathogens.

Mucosa

epithelium (1) - stratified squamous or simple columnar (absorbs food and moves it to LP)

lamina propria (2) - loose connective tissue (WBC screen for pathogens here)

muscularis mucosae (3) - smooth muscle (does some work, but not as much as muscularis externa)

3 layers of the mucosa

Portion of the gut tube superficial to the muscularis mucosae. Contains:

-large vessels (arteries, veins, lymph)

-submucosal ganglia: nerve cells

-submucosal glands

-large lymph nodules.

Submucosa

Contains two layers of smooth muscle that move contents in the gut tube. Most important for doing work

-inner circular layer

-myenteric ganglia: nerve cells

-outer longitudinal layer.

Muscularis externa

Outermost layer of gut tube.

Adventitia is loose connective tissue that anchors gut to nearby tissues.

Serosa is thin connective tissue with simple squamous epithelium that secretes fluid to lubricate the gut tube and other structures in the abdominopelvic cavity, which keeps bowel mobile and prevents irritation that could lead to adhesions

Adventitia/serosa

esophagus, upper esophageal sphincter

Bolus of food passes from the pharynx to the _____ through the ____ which keeps it closed.

Mucosa: nonkeratinized startified squamous epithelium, lamina propria, muscularis mucosa

Submucosa

Muscularis externa: inner circular layer, outer longitudinal layer, transition from skeletal (upper 1/3) to smooth muscle (lower 1/3)

Layers of the esophagus

lower esophageal sphincter

keep acidic gastric contents out of the esophagus

gastroesophageal reflux disease (GERD).

After the bolus passes through the esophagus it reaches the _______, which functions to ______. Dysfunction can lead to ______

The lower esophageal sphincter is compressed by muscles of the diaphragm

As the esophagus enters the abdomen...

There is a stark shift between stratified squamous epithelium of the esophagus and the simple columnar (but highly folded) epithelium of the stomach

Gastroesophageal junction

Due to prolonged GERD, causes metaplasia of the esophagus: mucosa of the esophagus takes on the appearance and function of the cardiac region of the stomach (esophagus becomes columnar epi).

It also leads to increased risk of adenocarcinoma, a type of esophageal cancer

Barrett's esophagus

part of the peritoneum attached to the greater curvature of the stomach and down covering the intestines

mobile and will migrate around the abdomen to wall off areas of inflammation or infection. It will sometimes leave adhesions between itself and the abdominal wall

greater omentum

muscularis externa, hydrochloric acid

The stomach digests food mechanically using the ______ and chemically with ______.

Folds in the stomach wall that facilitate it's expansion

Rugae

Cardia, fundus, body, pyloris

Four regions of the stomach

Parts of the stomach that create mucus to protect the stomach from the low pH

Cardia and pyloris function

Digestive

Fundus and body function

Outermost protective layer of the stomach, covering 3 layers of smooth muscle

-outermost is longitudinal (greater and lesser curvature)

-middle is circular

-innermost is oblique

Tunica serosa

circular, pyloric sphincter

The middle layer of the stomach is ______ and thickens considerably at the pyloric region to form the ______ which regulates release of food into the duodenum.

Chief cells

Parietal cells

Cells found only in the stomach (in body/fundus)

mucous-producing goblet cells surrounding gastric pits to protect the stomach

Cells found in the simple columnar epithelium of the cardia and pylorus

Cells of the stomach that produce HCl to make the stomach acidic. They also release intrinsic factor which helps absorb Vitamin B12 (in ilium) - assist in digestion

Parietal cells

Cells of the stomach that release precursors of digestive enzymes pepsin, renin, and lipase.

Chief cells

Caused by increased secretion of HCl that erodes the stomach's mucosa, submucosa, and even muscularis externa. Causes:

-over production of gastrin causing excessive HCl secretion

-long term NSAID use

-infection with H. pylori which can survive acidic environment and destroy epithelial lining

Gastric ulcers

-raises the pH of food as it exits the pyloric sphincter.

-adds bile from the liver and digestive enzymes from the pancreas

-absorbs nutrients.

Roughly 6-7 meters long.

Function of small intestine

Duodenum (20-25cm)

jejunum (2/5 of length)

ileum (3/5 of length)

3 parts of the small intestine

Surface area

Macroscopic Plicae circularis (circular folds)

Microscopic villi

Super microscopic microvilli

To insure that nutrients are absorbed efficiently, there is a tremendous increase of _____ in the small intestine via _____, _____, and ______

Folds in the lumen of the small intestine

Pilcae circularis

Folds of mucosa with a lymphatic duct in the core called a lacteal

On the pilcae circularis

Villi

Seen on the surface of the actual absorptive cells of the small intestine

Microvilli

A disease in which the body mounts an immune response to a protein in gluten. Inflammation damages villi leading to blunt, shortened villi with a large infiltration of lymphocytes in the mucosa. Can lead to malabsorption.

Celiac disease

First part of the small intestine that receives gastric contents and neutralizes their acidity and also controls the release of pancreatic enzymes and bile into the digestive tract.

Function of duodenum

Part of the submucosa in the duodenum that secretes mucus and bicarbonate to raise the pH to protect the remaining digestive tract and activate pancreatic enzymes.

Duodenal glands (Brunner's glands)

pyloric

duodenum

The _____ region of the stomach releases gastric content into the first part of the small intestine, the _____.

superior, descending, inferior, ascending

4 sections of the duodenum

Portion of the duodenum that receives gastric content (blue)

Superior duodenum

Portion of the duodenum that receives common bile duct from the liver and pancreas - hepatopancreatic ampulla!! (green)

Descending duodenum

Portion of the duodenum that passes posterior to the superior mesenteric vessels (red)

Inferior duodenum

Portion of the duodenum anchored by suspensory ligament and becomes the jejunum there after (yellow)

Ascending duodenum

Extension of the right diaphragmatic crura and is and important surgical landmark. Thereafter continues as the jejunum.

suspensory ligament (ligament of the duodenum/Trietz)

Jejunum

1

Mesentery of small intestine

2

4th part of duodenum

3

Left upper quadrant, under the greater omentum

Jejunum is located in the

Right lower quadrant, under the greater omentum

Ileum is located in the

Branches of the superior mesenteric artery

Jejunal artery: less complex arcades (loops), long vasa recta

Ileal artery: complex arcades, short vasa recta

Jejunum/ileum blood supply

-second portion of the small intestine, 2/5th length-

"typical" small intestine

-Villi are broad and often have a visible lacteal.

Unlike the duodenum (duodenal glands) and ileum (peyer's patches), there are no special structures in the submucosa

Jejunum function

Intestinal veins

Proteins and carbohydrates generally travel through ______ and are then transported to the liver.

lacteals

lymphatic ducts

left subclavian vein

Fatty molecules tend to get absorbed by ______ which transport them through _____ bypassing the liver until they reach the _____.

-third portion of the small intestine, 3/5 of its length

-similar to the jejunum except that it contains large lymph nodules in the lamina propria - peyer's patches.

Ileum function

-large lymph nodules in the lamina propria (submucosa) of the ileum

-major component of our immune maintenance over the normaflora of the gut and response to infection

Peyer's patches

-needed for proper red blood cell production

-parietal cells (stomach) secrete intrinsic factor, which allows VB12 to get absorbed in ileum

Vitamin B12

Vitamin B12 deficency

Pernicious anemia

Careless removal of the stomach or ileum can result in ______ deficiency, which can then lead to ______

At terminal end of the ileum is a thickening (not a true sphincter) of the muscularis externa

Prevents release of the food bolus into the large intestine unless relaxed

-can have a papillary form or labial form

Ileocecal valve

May result in the ileum folding into the colon (cecum) - intussusception

Ileocecal valve dysfunction

Tenia coli (longitudinal muscles of colon)

1

Ileocecal valve

2

Cecum

3

Vermiform appendix

4

Orifice of vermiform appendix

5

Ileum

6

Receives the bolus from the ileum and and recovers water and electrolytes from it. Feces then passes through the anal canal.

Large intestine

Cecum (with appendix), colon, rectum, anorectal junction, anal canal

Portions of the large intestine

Extension of the cecum. Has a narrow lumen and a large number of lymphatic nodules.

If the opening is blocked by feces or lymphatics it will become inflamed, rupture will cause GI contents being released into peritoneal cavity

May function as a reservoir to replenish intestinal normaflora

-suspended by a tiny mesentery that carries it's blood supply

-many variations in location

Appendix

ileum

cecum

ascending colon

The _____ is suspended by a mesentery but the _____ and _____ are not.

Pain in RLQ with appendicitis caused by swelling or infection of the appendix, which irritates the parietal peritoneum nearby.

This turns the dull and diffuse abdominal pain to become sharp and well-localized pain

McBurney's point

right lower quadrant

The cecum is located in the

right upper quadrant

The ascending colon ascends to the

Transverse colon

right colic (hepatic) flexture

The ascending colon becomes the _____ at the ______.

mesentery

left upper quadrant

The transverse colon has a _____ and stretches across to the _____

descending colon

left colic (splenic) flexture

The transverse colon turns into the _______ at the _________

Left lower quadrant

sigmoid colon

The descending colon moves into the _______ and becomes the _______

mesentery

left lower quadrant

The sigmoid colon has a _____ but tends to stay in the ______

rectum

The sigmoid colon loses its mesentery as it becomes the _______ within the pelvis.

3 longitudinal muscles that move food through the colon and pinch off sacs, haustra, that can be seen macroscopically

Tenia coli

peristaltic activity of the circular and longitudinal muscles creates visible compartments, haustra, in the length of the large intestine. As the feces moves along, it passes into the rectum where it is stored prior to defecation

Movement of feces through large intestine

Abnormal side pockets in the intestinal wall due to weak spots in lumen of large intestine. Can become inflamed.

Diverticula

Occur when proliferating masses grow into lumen of the large intestine

Polyps