GI Physiology Study Guide

Flashcards covering key concepts from GI Physiology.

What are the main roles of the digestive system?

breaks down food

absorbs nutrients

eliminates waste

What makes up the alimentary canal?

mouth

pharynx

esophagus

stomach

small intestine

large intestine

anus

What are the accessory organs?

teeth

tongue

salivary glands

gallbladder

liver

pancreas

What are the four layers of the digestive tract, in order from inner to outer?

Mucosa, Submucosa, Muscularis Externa, and Serosa

What is found inside the mucosa?

epithelium

lamina propria

muscularis mucosa

What is found inside the submucosa?

connective tissue

glands

submucosal arteries

submucosal (Meissner’s) nerve plexus

What is found inside the muscularis externa?

inner circular muscle layer

outer longitudinal muscle layer

myenteric (Auerbach’s) plexus between

What makes up the serosa?

epithelium (mesothelium)

connective tissue

What does the enteric nervous system control?

digestive activities

gets input from the parasympathetic and sympathetic nervous system

What is the function of the submucosal plexus?

The submucosal plexus regulates intestinal function, including secretion and blood flow.

How does the ENS coordinate digestion?

The ENS coordinates peristalsis and local reflexes while the CNS manages broader reflex activities.

What is the purpose of sphincters in the digestive tract?

Sphincters regulate the flow of food and prevent backflow in the digestive system.

What are the main ingredients in saliva?

Saliva primarily consists of water, salivary amylase, lingual lipase, enzymes, and electrolytes.

What is the role of gastric acid in digestion?

Gastric acid assists in protein digestion and maintains the acidic environment essential for enzyme activity.

How is pepsinogen activated?

Pepsinogen is activated into pepsin in the acidic conditions of the stomach.

What triggers gastric secretion during the intestinal phase?

The intestinal phase of gastric secretion is triggered by partially digested proteins and amino acids in the small intestine.

Name the pancreatic zymogens.

They include trypsinogen, chymotrypsinogen, and procarboxypeptidase.

What is the function of trypsinogen?

Trypsinogen is converted to trypsin, which helps digest proteins in the small intestine.

What happens as we age concerning the digestive system?

Aging can lead to reduced mucus, decreased muscle tone, and increased susceptibility to digestive issues.

Where is bile produced?

Bile is produced in the liver and stored in the gallbladder.

What does the large intestine do in terms of digestion?

The large intestine absorbs water and electrolytes, and houses beneficial gut bacteria while forming stool.

What is the Migrating Motor Complex (MMC)?

The MMC is a pattern of electrical activity in the gastrointestinal tract that occurs during fasting.

How is salivary secretion controlled?

Salivary secretion is regulated by the autonomic nervous system, with parasympathetic control producing watery saliva.

What protects the stomach from its own acid?

The stomach is protected by a mucus layer, tight junctions between cells, and frequent cell replacement.

What is the importance of fiber in the diet?

Dietary fiber aids in digestion, helps maintain regular bowel movements, and supports gut health.

What role does the tongue play in digestion?

The tongue aids in manipulating food, tasting, and initiating swallowing.

What is the primary function of the esophagus?

The esophagus transports food from the mouth to the stomach through peristaltic movements.

How do gallbladder and liver interact?

The gallbladder stores bile produced by the liver and releases it into the small intestine to aid in digestion.

What types of digestive enzymes does the pancreas produce?

The pancreas produces enzymes such as amylase for carbohydrates, lipase for fats, and proteases for proteins.

What is the effect of excess alcohol consumption on digestion?

Excess alcohol can lead to digestive problems including inflammation, pancreatitis, and liver disease.

How do stomach ulcers develop?

Stomach ulcers develop from long-term use of NSAIDs, excessive alcohol, or infection with Helicobacter pylori bacteria.

What causes heartburn?

Heartburn is caused by acid reflux, when stomach acid flows back into the esophagus due to weakened sphincters.

How does the body absorb nutrients from food?

Nutrients are absorbed primarily through the wall of the small intestine via villi and microvilli projections.

What is the significance of gastric bypass surgery?

Gastric bypass surgery aids in severe obesity by reducing the stomach size and altering nutrient absorption.

What happens to undigested food in the large intestine?

Undigested food is fermented by bacteria and then formed into feces for elimination.

Define bolus in the context of digestion.

A bolus is a soft mass of chewed food that is ready to be swallowed.

What enzymes are involved in carbohydrate digestion?

Amylase in saliva and pancreatic amylase in the small intestine break down carbohydrates into simple sugars.

What are probiotics and their role in digestion?

Probiotics are beneficial bacteria that promote a healthy gut microbiome and aid digestion.

What is the role of the rectum?

The rectum stores feces until they are ready to be expelled from the body.

What dietary practices can improve gut health?

Eating a balanced diet rich in fiber, fermented foods, and maintaining hydration can improve gut health.

How do enzymes lower activation energy in digestion?

Enzymes lower the activation energy needed for chemical reactions, facilitating digestion at lower temperatures.

What is the main purpose of digestion?

The primary purpose of digestion is to convert food into energy and nutrients that the body can utilize.

What does bile do in the digestive process?

Bile emulsifies fats to aid in their digestion and absorption in the small intestine.

How does chronic stress affect digestion?

Chronic stress can disrupt digestive functions, leading to conditions like IBS and general gastrointestinal discomfort.

What can happen if there is an imbalance of gut bacteria?

An imbalance can lead to digestive disorders, inflammation, and increased risk of infections or diseases.

Why is chewing food important?

Chewing breaks down food into smaller pieces, aiding in digestion and increasing the surface area for enzymes to work.

What nutrients are absorbed in the large intestine?

The large intestine absorbs water, electrolytes, and some vitamins produced by gut bacteria.

Describe the role of the pancreas in maintaining blood sugar levels.

The pancreas produces insulin and glucagon to regulate blood sugar levels after eating or during fasting.

What is enteritis?

Enteritis is inflammation of the small intestine, often causing diarrhea and abdominal pain.

What is the purpose of the gallbladder?

The gallbladder stores and concentrates bile between meals to aid in fat digestion when needed.

How does the digestive system vary among different animals?

Different animals have varying digestive systems adapted to their diets, like herbivores having longer intestines for plant matter digestion.

How does hydration influence digestion?

Proper hydration is essential for digestion, as fluids help dissolve and transport nutrients, and prevent constipation.

What are the signs of a healthy digestive system?

Signs include regular bowel movements, comfort during digestion, and a balanced diet without bloating or discomfort.

What role does the pharynx play in digestion?

The pharynx is a muscular tube that connects the mouth to the esophagus, aiding in the swallowing process.

What dietary component is essential for the function of digestive enzymes?

Many digestive enzymes require minerals such as zinc and magnesium to function optimally.

What is dysphagia?

Dysphagia is a medical term for difficulty swallowing food or liquids.

How can one prevent constipation?

Constipation can be prevented by consuming adequate fiber, drinking plenty of fluids, and exercising regularly.

What changes occur in digestion as one ages?

Aging often results in slowed digestion, decreased enzyme production, and increased gastrointestinal discomfort.

What effect does physical activity have on digestion?

Physical activity can stimulate digestive functions and help in maintaining regular bowel movements.

How can food intolerances affect the digestive system?

Food intolerances can lead to digestive discomfort, gas, bloating, and sometimes diarrhea.

What is the function of intestinal villi?

Intestinal villi increase the surface area for absorption of nutrients in the small intestine.

What are common signs of digestive disorders?

Signs include bloating, gas, cramps, changes in bowel habits, and unexplained weight gain or loss.

How does the digestive system interact with the immune system?

The digestive system houses a significant portion of the immune system, helping to defend against pathogens and support overall health.

What is celiac disease?

Celiac disease is an autoimmune disorder where ingestion of gluten leads to damage in the small intestine.

What role does the stomach play in the digestion of protein?

The stomach produces pepsin, an enzyme that begins the breakdown of proteins into smaller peptides.

What is the role of bicarbonate secreted by the pancreas?

Bicarbonate neutralizes stomach acid in the small intestine, creating an optimal environment for digestive enzymes to function.

What contributes to the formation of gallstones?

Gallstones are caused by an imbalance in the substances that make up bile, often leading to cholesterol crystallization.

What lifestyle changes can support digestive health?

Regular exercise, a balanced diet, stress management, and adequate hydration contribute to better digestive health.

What symptoms indicate lactose intolerance?

Symptoms include bloating, gas, diarrhea, and abdominal pain after consuming dairy products.

What is the role of gastric mucosa?

The gastric mucosa protects the stomach lining from acid and mechanically processes ingested food.

How is lipid digestion different from carbohydrate digestion?

Lipid digestion primarily occurs in the small intestine with bile acids and lipases, whereas carbohydrates are mostly digested in the mouth and small intestine.

What is icterus?

Icterus is the medical term for jaundice, which is the yellowing of the skin and eyes due to high bilirubin levels.

How does a balanced microbiome impact digestion?

A balanced microbiome supports efficient digestion, nutrient absorption, and a robust immune response against pathogens.