UCF Anatomy Block 3 Study Guide: Key Terms & Definitions

Regarding surface anatomy, what are the nine regions of the abdomen?

Right hypochondriac region

Right lumbar region

Right iliac region

Epigastric region

Umbilical region

Hypogastric region

Left hypochondriac region

Left lumbar region

Left iliac region

What are the lateral group muscles?

External abdominal oblique, internal abdominal oblique, transverse abdominal

What are the innervations of the lateral group muscles?

6 lower intercostal nerves and L1

What are the medial group muscles?

Rectus abdominis, pyramidalis

What is the origin of the inguinal ligament?

External abdominal oblique muscle

Lowest portion of the aponeurosis

What are the innervations of the medial group muscles?

6 lower intercostal nerves and L1

What is the origin of the cremaster muscle?

The caudal and lowest part of the internal abdominal oblique

What is the innervation of the cremaster muscle?

Genital branch of the genitofemoral nerve (ONLY in genetic males)

What is the clinical significance of the cremasteric reflex?

Is NOT a pathology, it is utilized to our advantage.

If an individual has had a traumatic accident and the testes become twisted (called torsion of the testis), or if there is a mass in the testis and we want to see how invasive that can be, if you palpate the upper portion of the thigh, that will cause a contraction of the cremaster muscle and you can feel that. If you put your hands on the cremaster muscle and palpate the upper thigh, you can feel it contracting. That tells you you've got both sensory and motor innervation from the genitofemoral nerve that is appropriate. If you've had a traumatic event or a mass, you can manipulate the reflex and find out if you have normal innervation.

What is the location of the rectus sheath?

Surrounding the rectus abdominis both anteriorly and posteriorly

External obliques go anterior, internal obliques and transversus abdominis go posterior

What are the contents of the rectus sheath?

Rectus abdominis muscle

Inferior and superior epigastric vessels

Intercostal nerves (5 lower ones), including the subcostal nerve

What is the importance of the rectus sheath?

Holds major abdominal structures

What are the contents of the inguinal canal for the male?

Spermatic cord

What are the contents of the inguinal canal for the female?

Round ligament of the uterus and lymphatics

What is cryptorchidism?

Testis fails to descend

What is the clinical significance of cryptorchidism?

We need to act on this very quickly. In humans, where we have pendulous testes, the testes are very temperature sensitive. They are held 5 to 7° cooler than the rest of the body. If they're inside the body, they don't like to be held at 98.6° or higher. We would need to remove the testes, as long as they are normally developed. If they are left in the abdominal cavity, the tissue can become corrupted and turn into cancer. Typically, we act right when the baby is born.

What is hydrocele of the cord?

Process vaginalis fails to close after testes have descended; fluid forms around the spermatic cord

What is the clinical significance of hydrocele of the cord?

Fluid forms around the spermatic cord

What are the contents of the spermatic cord?

Ductus (vas) defrens

Testicular artery, artery of the ductus deferens, and cremaster artery

Pampiniform plexus

Autonomic nerve fibers

Genital branch of the genitofemoral nerve

Lymphatics

Cremaster muscle

What is the difference between a direct and indirect inguinal hernia?

Direct inguinal hernia:

You can palpate the mass and it is super soft; it is just a loop of intestine. You can even push it back in.

Generally does not require surgery. May put the patient on bed rest or put them into a binding (brace), sometimes it can heal. A doctor might want to do the surgery, depending on the patient they may put a mesh.

Indirect inguinal hernia:

Always requires surgery

Comes through the abdominal wall inside the spermatic cord, so surgery will be required to pull the loop of intestine back out and let it freely into the abdominal cavity.

What are the unique characteristics of an indirect inguinal hernia?

Lateral to epigastric vessels

Passes through the inguinal canal (inside the spermatic cord)

High risk of strangulation/infarct

Congenital and acquired

In younger people

Bigger in size

What are the unique characteristics of a direct inguinal hernia?

Medial to epigastric vessels

Don't pass through the inguinal canal (parallels spermatic cord)

Low risk of strangulation/infarct

Are almost always acquired

Middle age man (over 40 y)

Smaller in size

Occurs within Hesselbach's triangle

Which organs are categorized as intraperitoneal?

Have a mesentery and are completely covered by the peritoneum. Includes these organs, found in the abdominal peritoneal cavity:

Stomach, small intestine (jejunum, ileum, some of the superior part of the duodenum), spleen, liver, gallbladder, cecum with vermiform appendix (portions of variable size may be retroperitoneal), large intestine (transverse and sigmoid colons)

Which organs are categorized as retroperitoneal?

Not covered in visceral peritoneum because they're not inside of the peritoneal cavity or sac. Either have no mesentery or lost it during development. Includes these organs:

Primarily: kidneys, suprarenal glands, uterine cervix

Secondarily: Dudodenum (descending, horizontal, ascending), ascending and descending colon, pancreas, rectum (upper 2/3)

What is the lesser sac?

A diverticulum of the peritoneal cavity to the left side and posterior to the stomach

What is the clinical significance of the epiploic foramen?

This is the site of internal herniation and strangulation of part of the intestine into the lesser sac

Surgery should be done from the other side (into the sac), not touching the porta hepatis

The cystic artery of the gall bladder can be reached through this foramen

What is the epiploic foramen?

The opening to the lesser sac, beneath the portal triad

What is the clinical significance of the lesser sac?

This is the site of internal herniation and strangulation of part of the intestine into the lesser sac

Surgery should be done from the other side (into the sac), not touching the porta hepatis

The cystic artery of the gall bladder can be reached through the epiploic foramen

What is the importance of the greater omentum?

Policeman of the abdomen

Has 4 layers

Prevents the visceral peritoneum to adhere to the parietal peritoneum

Has considerable mobility and moves by peristaltic movements of the viscera

Contains fat and lymphocytes and other immune cells to protect against infection or inflammatory conditions in the abdominal cavity; is often called the abdominal policeman

Moves towards the inflamed or infected area (e.g. the appendicitis)

Protects abdominal organs against injury and acts as an insulator against loss of body heat

What is the clinical significance of the peritoneal spaces and compartments?

Can get an increase in fluid in the abdomen, post-operatively, we can see it's just a consequence or a side effect of inhaled anesthetic, we can get an increase in serous fluid production in the abdomen. Not a big deal, but it can sit in the subphrenic space and cause it to be irritated. In a patient in the elderly population, this can lead to development of respiratory problems in a post operative environment from this type of condition. This is why we want you up and moving. Adhesions form, move that fluid around, and it can become an irritant.

Peritonitis, ascites, paracentesis

What is peritonitis?

The inflammation (accompanied by pain) of the peritoneum following an abdominal injury, i.e., from a stab wound or a perforated appendicitis

What is ascites?

Abnormal accumulation of fluid in the abdominal cavity, commonly seen in liver cirrhosis

What is paracentesis?

Puncturing the peritoneal cavity for aspiration of the fluid

What structures/organs belong to the foregut?

Esophagus and stomach down to the 2nd part of the duodenum, including liver, biliary system, gall bladder, and pancreas

What structures/organs belong to the midgut?

Starts from lower half of the 2nd part of the duodenum and jejunum, ileum, colon (cecum, ascending and the right 2/3 of the transverse colon)

What structures/organs belong to the hindgut?

Left 1/3 of the transverse colon, descending colon, sigmoid colon, rectum and upper part of anal canal

What is the innervation of the foregut?

Parasympathetic: Vagus nerve (CN X)

Sympathetic: T5-L2 spinal segments

What is the innervation of the midgut?

Parasympathetic: Vagus nerve (CN X)

Sympathetic: T5-L2 spinal segments

What is the innervation of the hindgut?

Parasympathetic: Pelvic splanchnic nerves (S2, S3, S4)

Sympathetic: T5-L2 spinal segments

What is the blood supply of the foregut?

Celiac trunk

What is the blood supply of the midgut?

Superior mesenteric artery

What is the blood supply of the hindgut?

Inferior mesenteric artery

What is the blood supply of the esophagus?

Upper part (cervical portion): by inferior thyroid artery

Middle part (thoracic portion): by thoracic aorta (4-5 arteries) and from bronchial arteries

Lower part including the abdominal portion: left gastric artery (from Celiac trunk), and inferior phrenic artery (from abdominal aorta)

What is the venous drainage of the esophagus?

Inferior thyroid vein, azygos, hemiazygos, and gastric veins

Gastric veins drain into the portal vein; therefore, this is a link between portal and the systemic circulation (Porto-Caval anastomosis)

What causes esophageal varices in liver cirrhosis?

Gastric veins drain into the portal vein; therefore, this is a link between portal and the systemic circulation (Porto-Caval anastomosis)

What is the clinical significance of esophageal varices?

When the liver is compromised, the blood is really congested because of these huge fibroids in the liver; it prevents blood from flowing through, so it backs up into the portal vein. When this happens, it causes portal hypertension. The portal vein is really dilated and the walls start to be pushed and gap open. This allows blood plasma and formed elements of blood to be pushed into the abdominal cavity; that is ascites. When that happens, it's not just the portal vein that's dilated, it's all the other veins draining into it that are also dilated. if the stomach drains into the portal vein, the stomach will eventually have blood backing into its veins making it congested. In the areas with the porto-canal anastomosis, if the blood is backing up, the blood will also back up into the lower esophagus because it's backing into the gastral vein. However, you could just flip the switch and have the blood drain into the caval system.

What is the histology of the esophagus?

These four layers/tunics will form the walls of every tubal structure in the body, with slight modifications as form follows function. In addition, all tubes are lined with epithelial cells.

Mucosa: stratified non-keratinized squamous epithelium (in Cardia, transitions simple columnar)

Muscularis mucosa

Submucosa

Tunica muscularis: consist of inner circular and outer longitudinal muscular layers

Adventitia serosa

What is the type of epithelium that lines the Gastrointestinal tract from the mouth to the external anal canal?

Oral cavity to esophagus: stratified non-keratinized squamous epithelium

Stomach to upper anal canal: simple columnar

Below the pectinate line: stratified non-keratinized squamous epithelium

What is a diverticulum of the esophagus?

All 3 wall layers protruding to form little pouches

What is the clinical significance of Zenker's diverticulum?

Upper esophagus, dysphagia, and halitosis

Complications: ulceration, bleeding, and inflammation

Therapy: surgery

Food can get trapped in here. It can cause irritation, ulceration, bleeding, inflammation, and infection. Surgery to remove it can fix it.

What is the clinical significance of achalasia (cardiospasm)?

Retrosternal pain, neuromotor disorder of the lower esophageal sphincter (LES), decreased cells in the myenteric plexus (analogous to Hirschprung's disease), dysphagia for solid and liquid, dilated proximal esophagus and aperistalsis, increased LES pressure

Treated in a case-by-case basis; some patients are completely fine but can have moments of something hurting. They will understand that the lower esophageal sphincter has stayed closed. They will need to go to the hospital and have mechanical assistance. The worst scenario is where the lower esophageal sphincter can't open at all. This will need a feeding tube, liquid diet, or eat something soft like apple sauce/jello, and then wait, take a sip of liquid, and wait. We could try stimulation; if this is because of stroke or trauma, we could work with a physical therapist.

What is the clinical significance of Barrett's esophagus?

Columnar cell metaplasia of the squamous epithelium due to acid injury

This is caused by a chemical burn. Lower esophageal sphincter isn't closing as it should. Can cause damage/erosion to tissue, chronic inflammation, etc.

What is the importance of the stomach rugae?

Expands the stomach

What is the importance of the oblique muscle layer of the stomach?

Allows for churning the stomach

What are gastric pits?

Shallow part of the gastric mucosa; all you'll see is mucus cells, same simple columnar epithelium

What are gastric glands?

Deep part of the gastric mucosa; cells become more specialized

What three types of cells would you find in the gastric glands within the body and fundus of the stomach?

Mucoid cells

Chief cells

Parietal cells

What are the functions of mucoid cells?

Secrete mucus to shield the mucosal membrane

What are the functions of chief cells?

Produce pepsinogen

What are the functions of parietal cells?

Produce HCl and intrinsic factor for B-12 absorption in the ileum

What enteroendocrine cell would you find within the gastric glands in the pyloric antrum?

Endocrine cells of mucosa (1.2% of all) mainly in antrum

Gastrin, produced by G cells mainly in pyloric antrum

What is one of the most important enteroendocrine cells we have in the stomach, found in the glands, in the pylorus and the pyloric antrum?

G cells

What is the function of the endocrine cells of mucosa?

Produce histamine, somatostatin, gastrin, serotonin, and prostaglandins

What is the function of the gastrin?

Stimulate acid secretion and growth of parietal cells

What is the blood supply of the stomach?

Celiac trunk branches

Left gastric artery

Common hepatic artery -> right gastric artery

Common hepatic artery -> gastroduodenal artery -> right gastroepiploic artery

Splenic artery -> short gastric arteries and left gastroepiploic artery

What is the venous drainage of the stomach?

Portal vein directly (left and right gastric veins) or indirectly through the splenic vein (the left gastroepiploic vein and short gastric veins)

The right gastroepiploic vein goes to the superior mesenteric vein

What is the innervation of the stomach?

Parasympathetic: Vagus nerve

Sympathetic: Mostly coming from splanchnic (innervating organs) nerves (also from upper lumbar) which synapse in the Celiac ganglion

Postganglionic fibers innervate the stomach to inhibit peristalsis and gastric secretion, and cause pyloric contraction; they also convey pain

What is the clinical significance of gastric ulcers?

Understanding how gastric juices are secreted is essential for treating an unresponsive ulcer.

A gastric/duodenal ulcer can be incompatible with life if we have a perforation, meaning the ulcer erodes all the layers of the wall of the organs and spills the hydrochloric acid and gastric contents into the abdominal cavity. When I am treating an ulcer, first thing I want to do is say, what's going on in the patient's life? Make changes to their life. Or give medication and see if it helps. If not, get more invasive. The rule of thumb is no acid, no ulcer, or highly regulated acid secretion, no ulcer. One of the ways to do that is a vagotomy.

Will focus on a pylorectomy: removes G cells that secrete Gastrin; controls acid secretion

What is a pylorectomy?

Removes G cells that secrete gastrin; controls acid secretion

What is the clinical significance of a vagotomy?

Used to be popular in the US but not anymore. Performed in other countries, going in and cutting the vagus nerve. Not going to cut all areas, but depending on the patent you could completely cut it on the top of the fundus of the stomach. Still going to have mechanical stimulation; when you eat, food will go into the duodenum but it won't be optimal. The consequences of it outweigh the benefits. Controlling neural stimulation to cut the vagus nerve out, but seeing/smelling food will not cause neural secretion of hydrochloric acid. Eliminates the neural stimulation of gastric secretion. Procedure is known to have complication on gastric emptying.

What is the clinical significance of a hemigastrectomy?

Part of the stomach gets removed

Could potentially perform a pylorectomy: Removes G cells that secrete gastrin; controls acid secretion

How are gastric ulcers, vagotomy, and hemigastrectomy connected?

You could perform a vagotomy or hemigastrectomy to deal with gastric ulcers

What is the clinical significance of a sliding hernia?

When abdominal part of the esophagus and cardia and even part of the fundus slide up through the esophageal hiatus. *Regurgitation and heart burn

The stomach pushes up and everything shifts upwards. The esophagus gets pushed up, the cardia gets pushed up, and sometimes the fundus. Puts pressure on the lower esophageal sphincter and pushes it open.

What is the treatment for a sliding hernia?

Surgery:

Reinforces the barrier to reflux that the lower esophageal valve normally provides

In most cases, the operation performed to correct gastroesophageal reflux is a procedure called "fundoplication"

The upper portion of the stomach (the fundus) is wrapped (plicated) around the lower portion of the esophagus and anchored securely below the diaphragm

Radiofrequency treatment:

Using an endoscope supplied by electrodes

Radiofrequency energy causes tiny burns at G-E junction that heal and form scar tissue that actually tightens the weak valve

Case-by-case basis

What is the clinical significance of a paraesophageal hiatal hernia?

Cardia doesn't move but part of the fundus and peritoneum passes through the esophageal hiatus.

*Usually, no regurgitation

Para = beside, so beside the esophagus. The lower part of the esophagus stays in place; the fundus gets slipped up.

What is the treatment for a paraesophageal hiatal hernia?

Surgery:

Reinforces the barrier to reflux that the lower esophageal valve normally provides

In most cases, the operation performed to correct gastroesophageal reflux is a procedure called "fundoplication"

The upper portion of the stomach (the fundus) is wrapped (plicated) around the lower portion of the esophagus and anchored securely below the diaphragm

Radiofrequency treatment:

Using an endoscope supplied by electrodes

Radiofrequency energy causes tiny burns at G-E junction that heal and form scar tissue that actually tightens the weak valve

Case-by-case basis

What is the clinical significance of hypertrophic pyloric stenosis?

Progressive hypertrophy of circular muscles in pyloric sphincter, causing a narrow pyloric lumen which may obstruct food passage

This may happen in male infants (first child usually) which is associated with projectile, non bilious vomiting after feeding; palpation reveals a small knot (olive-sized mass) at the right costal margin

Treatment: longitudinal pyloromyotomy, leaving the mucosa intact

What are the names of the four parts of the duodenum?

1st or superior part

2nd or descending part

What are the characteristics of the four parts of the duodenum?

1st or superior part:

5 cm long, between T12-L1

Anterior to portal vein and common bile duct

Duodenal cap: site of ulcer

2nd or descending part:

All kinds of things happen

7.5 cm long until lower level of L3

Contains the major duodenal papilla, a common opening for the common bile duct and the main pancreatic duct

Within the wall, the sphincter of Oddi is connected to the common dilated opening known as the hepatopancreatic ampulla of Vater

The minor duodenal papilla, superior to the major opening, is an opening of the accessory pancreatic duct

3rd or horizontal part:

10 cm, at L3 level

Anterior to IVC and abdominal aorta

Crossed by superior mesenteric artery and vein anteriorly

4th or amending part:

2.5 cm long

Travels across the midline to the duodenojejunal flexure at the L1-L2

The beginning of the 1st part and part of the 4th part are covered by the peritoneum (have some mobility), the rest of duodenum is not mobile

Function:

Regulates stomach and gallbladder emptying in response to acidic chyme

Secrete Secretin due to high acid and fatty acids in its lumen; Secretin inhibits the gastric acid secretion

Secretes Cholecystokinin, in response to fatty chyme which induces gallbladder contraction

Secretes the Enterogastrone, that inhibits stomach peristalsis

What is the parasympathetic innervation of the digestive tract?

Submucosal plexus of Meissner and myenteric plexus of Auberach

What is the function of the submucosal plexus of Meissner (digestive tract)?

Parasympathetic innervation

Secretomotor function produces mucus for lubrication and facilitates molecule movement

What is the function of the myenteric plexus of Auberach (digestive tract)?

Parasympathetic innervation

Peristaltic movement of smooth muscle

What is the function of the jejunum?

Absorption of the digested food

What is the blood supply of the small intestine?

Superior mesenteric artery, superior mesenteric vein

What is the function of the ileum?

Absorption of the digested food, vitamin B12, and intrinsic factor

What are the characteristics of the jejunum?

Begins at the duodenojejunal junction and is continuous with ileum

About 2/5 of the total length of the small intestine (6-7 m)

Folate is reabsorbed here

1. Lies mostly in the left upper quadrant

2. More vascular

3. Red color

4. Thick wall

5. Long vasa recta

6. Less Arcades

7. Less fat

8. Window in the mesentery

9. No or very few peyer's patches

10. Large and many circular folds (place circulare)

What are the characteristics of the ileum?

Ends at ileocecal junction

About 3/5 of the total length of the small intestine (6-7 m)

Vitamin B12 is reabsorbed here

1. Lies mostly in the right lower quadrant

2. Less vascular

3. Pale pink

4. Thin wall

5. Short vasa recta

6. More arcades

7. More fat

8. No window in the mesentery

9. Many peers patches

10. Low and fewer circular folds

What is the venous drainage of the small intestine?

Superior mesenteric vein

What is the innervation of the small intestine?

Sympathetic:

Splanchnic nerves

- Inhibition of peristalsis and contraction of the ileocecal sphincter and vasoconstriction of vessels

Parasympathetic:

Vagus nerve

- Causes peristalsis and glandular secretion

What is the clinical significance of Meckel's diverticulum?

An ideal out-pocketing typically located within 50-75 cm (40 cm in newborn) of the ileocecal valve

This is a congenital anomaly resulting from persistence of the vitelline (omphalomesenteric) duct. It might free 74% or attached by a cord to the umbilicus

May mimic pain of appendicitis

About half of them cause ulceration, inflammation, and GI bleeding because of the presence of ectopic acid-secreting gastric epithelium; pancreatic tissue may also be present there

Rule of 2's: Occurs in about 2% of children, 2 feet from the ileocecal valve, contain 2 types of ectopic mucosa (gastric and pancreatic), usually occurs at 2 years of age

What is the location of the vermiform appendix?

The posteromedial aspect of the cecum about 2-3 cm below the ileocecal junction

What is the function of the vermiform appendix?

In younger adults it's a lot larger and as we age it gets smaller in length and diameter. We also know that throughout our lives it contains a very large concentration of e-coli. It's thought that because it houses a lot of e-coli, if I have an insult to the large intestine, i.e. diarrhea, stress, diet, because of an infection of some sort, food poisoning, bacterial infection, viral infection, a lot of the e-coli is eliminated and this can easily be re-colonized due to the storage of the appendix. The gut microbiome is super important, a byproduct of the bacteria is vitamin K, which is important for clotting factors. At the end of the day we really don't know what it's there for or what it does; we can speculate, but we're not sure.

What is the clinical significance of an appendicitis, including treatment?

The appendix may be occluded by a fecalith (fetal material stuck inside) or inflammation and edema of the lymphatic tissue leading to acute (acute abdomen) and chronic appendicitis

Pain is preumbilical at T10 dermatome (sympathetic)

Appendectomy using the McBurney's point between umbilicus and right anterior superior iliac spine (junction between right 1/3 and mid 1/3)

The iliohypogastric nerve should be saved, if not, muscle weakness and direct inguinal hernia may result

The stages:

1. Early appendicitis

2. Appendiceal distention

3. Irritation of the lining of the abdominal and pelvic cavities

4. Perforation

What is the blood supply of the colon?

Branches of the superior and inferior mesenteric arteries

Marginal Artery of Drummond is an anastomosis of the superior and inferior mesenteric arteries. It is an important anastomosis if a portion of the arteries is blocked.

What is the overall function of the duodenum?

Digestion and absorption of food

What is the venous drainage of the colon?

Colic veins -> superior mesenteric veins -> portal vein

What is the clinical significance of the pectinate line of the anal canal?

Separation of the upper and lower anal canal; innervation, drainage, and blood supply change between the upper and lower anal canal

What is the pectinate line of the anal canal?

The inferior comb shaped limit of the anal valves

Separation of the upper and lower anal canal

What is the blood supply of the rectum and anus?

Superior rectal artery: the final branch of the inferior mesenteric artery supplies the superior part of the rectum

Middle rectal artery: from the internal iliac artery supplies the middle

Inferior rectal artery: a branch of the internal pudendal a.

What is the portocaval anastomosis?

Abdominal organs and structures either drain their blood directly into the IVC or indirectly by draining the portal vein and then through the liver for "filtering"