Digestive System A&P Exam III

What are the general functions of the digestive system?

Ingestion, propulsion, mechanical digestion, chemical digestion, absorption, and elimination.

What is the role of the mucosa in the GI tract?

It consists of epithelial tissue, connective tissue, and smooth muscle, which helps in absorption and secretion.

What are the two main components of the enteric nervous system?

Myenteric Plexus and Submucosal Plexus.

What hormones dominate the postabsorptive state?

Glucagon, epinephrine, cortisol, and growth hormone.

What is the function of the greater omentum?

It acts as a fat storage site and contains immune cells.

What are the components of saliva?

Water, electrolytes, enzymes, mucins, antibacterial compounds, buffers, and metabolic waste products.

What is mumps and what are some common symptoms?

Mumps is a viral infection causing fever, headache, and painful swelling of the parotid glands.

What occurs during the oral phase of deglutition?

The tongue collects and pushes food to the back of the mouth to form a bolus.

What factors can cause acid reflux?

Hiatal hernia, stress, obesity, certain medications, and lifestyle factors like diet.

What is the difference between pylorospasm and pyloric stenosis?

Pylorospasm is intermittent spasms, while pyloric stenosis involves a thickening and narrowing of the pyloric muscle.

What substance do parietal cells secrete?

Hydrochloric acid (HCl) and intrinsic factor.

What are the phases of digestion?

Cephalic, gastric, and intestinal phases.

What is the primary function of intestinal secretions during digestion?

They aid in the digestion and absorption of nutrients.

What enzymes does the pancreas produce and their functions?

Pancreatic amylase (carbohydrates), pancreatic lipase (fats), proteases (proteins), ribonuclease and deoxyribonuclease (nucleic acids).

What is the main function of the large intestine?

Water and electrolyte absorption, storage of feces, fermentation of undigested carbohydrates, and synthesis of certain vitamins.

What is the gastrocolic reflex?

It increases colonic motility in response to stomach filling.

How is glucose regulated in the absorptive state?

Insulin promotes glucose uptake and storage as glycogen.

What is unique about the muscularis in the stomach?

It has three layers: inner oblique, middle circular, and outer longitudinal.

What stimulates bile secretion?

Cholecystokinin (CCK) and secretin, responding to fats in the chyme.

How do the components of pancreatic juice contribute to digestion?

Enzymes such as amylase, lipase, and proteases break down carbohydrates, fats, and proteins, while bicarbonate neutralizes stomach acid.

What is the role of goblet cells in the large intestine?

They secrete mucus to lubricate and protect the intestinal lining.

What are Peyer's patches and where are they located?

They are lymphoid tissues in the ileum that provide immune defense.

How does nutrient absorption differ for lipids compared to carbohydrates?

Lipids are absorbed as micelles into lacteals, while carbohydrates enter blood vessels as monosaccharides.

What characterizes the absorptive state of metabolism?

Occurs during and after meals, focusing on nutrient uptake and storage, primarily regulated by insulin.

What is the absorptive state of metabolism?

The absorptive state occurs during and shortly after eating, focusing on nutrient uptake and storage, primarily regulated by insulin.

What is the postabsorptive state of metabolism?

The postabsorptive state occurs when the digestive system is empty, and the body relies on stored nutrients for energy, primarily regulated by glucagon and other hormones.

glycerol is used for gluconeogenesis during the

postabsorptive phase

How does insulin function in the absorptive state?

Insulin promotes glucose uptake by cells and the conversion of excess glucose into glycogen.

What typically happens to hormone levels during the postabsorptive state?

Hormone levels such as glucagon increase to promote glycogenolysis and gluconeogenesis.

How does the body respond to fasting during the postabsorptive state?

The body shifts from using glucose to utilizing fatty acids and ketones for energy.

What role does glucagon play in the postabsorptive state?

Glucagon stimulates the breakdown of stored glycogen into glucose and promotes gluconeogenesis.

What are the hormones involved in digestion?

Key hormones include gastrin (stimulates acid secretion), cholecystokinin (CCK, stimulates bile release), secretin (stimulates bicarbonate release), and insulin (regulates glucose uptake).

What is the role of gastrin in digestion?

Gastrin triggers the secretion of hydrochloric acid (HCl) from parietal cells in the stomach.

How does cholecystokinin (CCK) contribute to digestion?

CCK stimulates the gallbladder to release bile and the pancreas to release digestive enzymes.

What is the function of secretin?

Secretin stimulates the pancreas to release bicarbonate, neutralizing stomach acid in the small intestine.

What enzymes does saliva contain, and what are their functions?

Salivary amylase (breaks down carbohydrates) and lipase (initiates fat digestion).

Where are pancreatic enzymes produced, and what are their functions?

Produced in the pancreas; they include amylase (carbohydrates), lipase (fats), and proteases (proteins).

What is the effect of pancreatic lipase?

Pancreatic lipase breaks down dietary fats into fatty acids and glycerol.

What role do proteases play in digestion, and where are they produced?

Proteases, produced in the pancreas, digest proteins into smaller peptides and amino acids.

How is bile produced and what is its function?

Bile is produced in the liver and aids in the emulsification of fats for digestion.

What stimulates the release of insulin during digestion?

Rising blood glucose levels after eating stimulate insulin secretion from the pancreas.

What is the enteric nervous system?

The enteric nervous system (ENS) is a complex network of neurons that govern the function of the gastrointestinal tract.

What is the myenteric plexus?

The myenteric plexus, located between the longitudinal and circular muscle layers, controls gastrointestinal motility.

What is the submucosal plexus?

The submucosal plexus, located in the submucosa, regulates enzyme secretion, blood flow, and absorption.

How does the enteric nervous system interact with the central nervous system?

The ENS communicates with the central nervous system via the vagus nerve, integrating gut activity with brain functions.

What types of neurons are found in the enteric nervous system?

The ENS contains sensory neurons, interneurons, and motor neurons, which work together to coordinate digestive processes.

What stimulates glycogenesis?

Glycogenesis is stimulated primarily by insulin, which promotes the uptake of glucose and its conversion to glycogen for storage.

What is glycogenolysis?

Glycogenolysis is the biochemical process of breaking down glycogen into glucose to be used for energy.

What stimulates glycogenolysis?

Glycogenolysis is primarily stimulated by glucagon and epinephrine, which increase glucose availability during fasting or stress.

What is gluconeogenesis?

The production of glucose from non-carbohydrate sources like amino acids and glycerol.

What is glycogenesis?

The process of converting glucose into glycogen for storage.

What is glycogenolysis?

The breakdown of glycogen into glucose.

What is glycogen catabolism?

Similar to glycogenolysis, it refers to the breakdown of glycogen.

What is glycolysis?

The breakdown of glucose to produce energy.

What is the relationship between insulin and the absorptive state?

Insulin primarily regulates the absorptive state by promoting glucose uptake and storage.

Which hormones regulate the postabsorptive state?

The postabsorptive state is regulated by glucagon, epinephrine, cortisol, and growth hormone.

What happens to energy sources during the absorptive state?

Energy sources are primarily derived from absorbed nutrients, with glucose being used for immediate energy and stored as glycogen.

What metabolic processes are emphasized in the postabsorptive state?

During the postabsorptive state, the body emphasizes glycogenolysis and gluconeogenesis to maintain blood glucose levels.

How does glucagon affect energy metabolism in the postabsorptive state?

Glucagon stimulates the liver to convert stored glycogen into glucose, increasing blood glucose levels.

What is the main difference in energy utilization between the absorptive and postabsorptive states?

In the absorptive state, nutrients are utilized for energy; in the postabsorptive state, the body relies on stored nutrients for energy.

the vagus nerve’s role in the digestive system

aids digestion by stimulating gastric juices, regulating stomach and intestine movement, triggering insulin release, signaling hunger and fullness, and promoting muscle relaxation and enzyme release.

the medulla oblongata

plays a key role in autonomic functions, including the regulation of digestive processes. It contains the vagal nuclei