Lecture #7: Upper Gi Tract & Surgery

What parts are in the oral cavity?

Mouth and pharynx

Salivary glands

Enxymes in salive

What are the three salivary glands?

parotid, submandibular, sublingual

What are the functions of saliva?

- Salivary amylase begins digestion of carbohydrates

• Facilitates swallowing by moistening food

• Mucus provides lubrication

• Antibacterial action

•Lysozyme destroys bacteria

Solvent for molecules that stimulate taste buds

•Aids speech

•Helps keep mouth and teeth clean

·Rich in bicarbonate buffers

True or false: There is two sphincters in the esophagus?

True

How many layers of tissue are there in the walls of the esophagus?

4

What is the lower esophageal sphincter?

- Ring of muscle at stomach/ esophagus juction

- Controls passage of food into stomach

- Prevents acid from flowing back up into esophagus

What are the 4 main regions of the stomach?

1. Cardia

2. Fundus

3. Body

4. Antrum or distal pyloric region

What are the 4 main processes of the GI tract?

1. Mobility

2. Digestion of food particles

3. Secretion of digestive juices and mucus

4. Absorption of nutrient

What are the two types of digestive motility?

propulsive and mixing movements

What are the two functions that mixing movements serve?

Mixing food with digestive juices promotes digestion of foods

Facilitates absoption by exposing all parts of intestinal contents to absorbing surfaces of digestive tract

What is gastric filling?

Involves receptive relaxation

Enchances stomach's ability to accomodate the extra colume of food with little rise in stomach pressure

What is gastric filling triggered by?

Act of eating

What mediates gastric filling?

The vagus nerve

Where does storage take place (digestion)?

Stomach

Where does mixing take place? (digestion)

Antrum of stomach

What controls gastric emptying?

factors in duodenum

Where does a peristaltic contraction originate in the stomach?

A peristaltic contraction originates in the upper fundus and sweeps down toward the pyloric sphincter.

What happens to the peristaltic contraction as it reaches the antrum?

The contraction becomes more vigorous as it reaches the thick-muscled antrum.

What does the strong antral peristaltic contraction do?

It propels the chyme forward.

How does chyme enter the duodenum?

A small portion of chyme is pushed through the partially open pyloric sphincter into the duodenum. The stronger the antral contraction, the more chyme is emptied with each contractile wave.

What happens when the peristaltic contraction reaches the pyloric sphincter?

The sphincter is tightly closed, preventing further emptying

How does gastric mixing occur?

When chyme that was being propelled forward hits the closed pyloric sphincter, it is tossed back into the antrum. This back-and-forth movement mixes the chyme with each peristaltic contraction.

What are the four abdominopelvic quadrants?

The four quadrants are:

RUQ (Right Upper Quadrant)

RLQ (Right Lower Quadrant)

LUQ (Left Upper Quadrant)

LLQ (Left Lower Quadrant)

What are the main segments of the GI tract?

Mouth, pharynx, esophagus, stomach

Small intestine (~3m)

Large intestine (~1.5m)

What four factors in the duodenum regulate gastric emptying?

Fat – Delays emptying to allow digestion in the small intestine.

Acid – Prevents further emptying until neutralized.

Hypertonicity – Prevents emptying when osmolarity rises.

Distension – Prevents emptying when too much chyme is present.

What are the main components of gastric juice?

Water

Mucus

Hydrochloric acid (HCl)

Intrinsic factor

Pepsinogen (enzyme precursor)

Gastric lipase

How does HCl contribute to digestion?

- Activates pepsinogen into pepsin.

- Provides the acidic environment for pepsin activity.

- Denatures proteins, making them easier to digest.

- Kills most ingested bacteria.

What stimulates gastric secretion?

Factors such as the sight, smell, and thought of food and gastrin hormone.

What inhibits gastric secretion?

The presence of chyme in the duodenum and hormones like secretin and CCK.

Name some key gut hormones and their functions.

Gastrin – Stimulates acid secretion.

Secretin – Stimulates bicarbonate secretion to neutralize acid.

Cholecystokinin (CCK) – Stimulates enzyme release and bile secretion.

Why is it important to understand where nutrients are absorbed?

It helps identify potential nutritional deficiencies and digestive disorders.

What are the three phases of gastric secretion?

Cephalic phase – Triggered by the sight, smell, taste, or thought of food.

Gastric phase – Activated by food entering the stomach, stimulating gastrin release.

Intestinal phase – Occurs when chyme enters the duodenum, slowing gastric secretions.

What triggers the cephalic phase of gastric secretion?

The sight, smell, taste, or thought of food, which stimulates the vagus nerve.

What happens during the gastric phase?

Food in the stomach stimulates gastrin release, which promotes acid and enzyme secretion.

What is the purpose of the intestinal phase?

It inhibits gastric secretion to regulate digestion as chyme enters the small intestine.

What are the two main mechanisms that regulate gastric secretion?

Neural regulation – Controlled by the vagus nerve and local reflexes.

Hormonal regulation – Gastrin, secretin, and CCK control acid and enzyme secretion.

How does the vagus nerve affect gastric secretion?

It stimulates gastric juice production during the cephalic phase.

Which hormone stimulates gastric acid secretion?

Gastrin, released in response to food in the stomach.

Which hormones inhibit gastric secretion?

Secretin and cholecystokinin (CCK) slow down acid production when chyme enters the duodenum.

What is cholecytokinin's role?

Gall bladder contraction

Gastrointestinal motility

Pancreatic exocrine secretion

What is secretin's role?

Pancreatic axocrine secretion

What is GIP's role?

Incretin activity

What is motilins role?

Gastrointestinal motility

What is Ghrelin's role?

Hunger

Growth hormone release

What is Gastrin's role?

Acid secretion

What is insulin and glucagon's role?

Glucose homeostasis

What is pancreatic polypeptide's role?

Gastric motility

Satiation

What is Amylin's role?

Glucose homeostasis

Gastric motility

What is GLP-1's role?

Incretin activity

Satiation

What is GLP-2's role?

Gastrointestinal motility and growth

What is oxyntomodulin's role?

Statiation and acid secretion

What is PYY's role?

Satiation

Define Gastritis

inflammation of the mucosal lining of the stomach

Define dyspepsia

indigestion after meals

What are symptoms of dyspepsia?

Bloating, fullness, burping, heart burn, epigastric pain

Define resection

Surgical removal of tissue or organ (cut out)

Define gastrectomy?

surgery to remove part or all of stomach

Define anastomosis?

Surgical connection between 2 tubular structures

Define stricture

Narrowing or stenosis

Define NSAID

Non-steroidal anti-inflammatory drug

Define maldigestion

Breakdown of macronutrients is impaired (inability to access or utilize digestive enzymes i.e pancreatitis or gastric surgery

Define malabsorption

defective mucosal uptake or transport of inadequately digested nutrients

What can oral surgery include?

Surgical resections of tongue, palate or pharynx (typically for malignancy)

True or false: fractures of the jaw related to trauma or accidents can require surgery and immobilization

true

What determines the type of surgery and nutrition therapy needed in jaw fracture patients?

The type of fracture

How does immobilization of a jaw fracture occur?

Fixation of the fracture

Wiring jaw

How does wiring of the jaw impact nutrition

Nutrition is limited to liquid or blenderized diets using a straw or syringe

What is anotehr term for jaw?

Mandible

How can you add extra protein to a blenderized diet?

Dry milk powder/ protein powder

Egg substitutes

Blended meat, cottage cheese, greek yogurt, nutrition supplements

How can you add extra calories to a blenderized diet?

Whole milk, cream, extra butter/ margarine or gravy for savoury foods

Sugar or honey to fruits or sweeter veg

What is GERD?

Reflux of gastric acid into esophagus

That can lead to irritation and inflammation

What can chronic esophagitic lead to?

Ulceration, scarring, stricture and dysphagia (rare)

True or false: GERD can lead to barrett's esophagus

True

What is barrett's esophagus?

Calls in the esophagus are replaced by those similar to the lining of stomach

Can become pre-malignant (lead to adenocarcinoma)

What are symptoms of gerd?

Heart burn, belching, esophageal spasm and dysphagia

What medical conditions are risk factors for GERD?

Obesity

Excess gastric acid

Impaired esophageal clearance (motility disorders)

Delayed gastric emptying

Hiatal Hernia

True or false: the lower esophageal sphincter isn't working properly in people with GERD

True

What are factors that can worsen reflux ?

Alcohol

Tight fitting clothes

Large meals, fatty meals, eating late at night

Certain foods

Smoking

Increased secretion of gastrin, estrogen and progesteron

Medication

What is a hiatal hernia?

an outpouching of a portion of the stomach into the chest through the esophageal hiatus of the diaphragm

What can cause a hiatal hernia?

Intra-abdominal pressure

Increased incidence with age

True or false: hiatal hernias can result ib epigastric discomfort after large, energy dense meals

True

True or false: hiatal hernias do not result in GERD

False they may

What are treatments for hiatal hernias?

Medical nutrition therapy (weight reduction, decreasing meal size)

May require surgery

What are the treatments for GERD?

Medications, behaviour modifications and surgery

What surgery is used for GERD?

Fundoplication procedure

What behaviour modifications can be made to treat gerd?

Life style modifications: Wear loose-fitting clothing, raise head of bed 6 to 9 inches for sleeping, sit upright for meals

Smoking cessation

Wt management if overweight/obese

Dietary modifications

What are the three categories of GERD medications?

Antisecretory drugs

Antacids

Motility agents/ prokinetics

What fo antisecretory drugs do?

Decrease acid secretion

What are the two types of antisecretory drugs? What do they do and which is most effective?

Proton pump inhibitors (PPIs):

- Most effective

- Blocks peirtal cells where acid is produced

Histamine2-receptors antagonist:

- Block histamine receptors

Why do we want to block histamine receptors? (Histamine2-receptors antagonist)

Histamine is important for acid regulation in stomach, blocks them to reduce acids production

What do antacids to?

Neutralize gastric acid

What do motility agents/ prokinetics do?

Enhance gastric emptying

What types of foods are recommended for GERD patients to avoid? (3)

1. Foods irritating sensitized esophagus

2. Gastric acid secretion

3. Foods that lower esophageal sphincter

Why is it important to maintain a healthy weight for GERD management?

Being overweight increases the risk and severity of GERD. Maintaining a healthy weight helps reduce pressure on the stomach and lower esophageal sphincter, preventing acid reflux.

What meal habits should be avoided to manage GERD?

Avoid large meals and snacks, especially in the evening. Do not eat before lying down to prevent acid reflux.

What types of foods and drinks should be avoided with GERD?

Avoid high-fat meals, alcohol, caffeine, acidic foods, and highly spiced foods, as they can trigger or worsen symptoms.

How can meal frequency help with GERD symptoms?

Eating smaller, more frequent meals helps prevent excessive stomach pressure, reducing acid reflux.

What dietary composition is recommended for GERD management?

A healthy diet should be low in fat, with adequate protein and fiber, to support digestion and reduce reflux symptoms.

What dietary changes should be made if GERD causes inflammation?

Consume soft foods and avoid acidic and highly spiced foods to prevent irritation and discomfort.

What is a fundoplication?

Surgical procedure for treatment of reflux esophagitis/ severe GERD