UNIT 8: Digestion and metabolism

Which of the following can cause an increase in insulin levels? Check all that apply.

-Increased amino acid levels in plasma -GIP -Increased parasympathetic output -Increased blood glucose levels

Match the term on the left with the description on the right. Note that there are more descriptions than terms given so you will have to eliminate those that don't apply to any of the terms!

-Secretion: This refers to the movement of solutes from the intracellular fluid to either the lumen, blood or interstitial fluid -Gall bladder: This organ stores bicarbonate and bile salts. -Pyloric sphincter: This is a ring of smooth muscle between the stomach and the duodenum -Leptin: This hormone acts as a long-term appetite regulator and is released from fat cells -Amylase: This enzyme converts starch into glucose and is secreted by the salivary glands and the pancreas. -Absorption: This refers to the movement of solutes from the lumen to the blood -Lacteal: Chylomicrons are picked up by this structure -Secretin: This hormone is secreted in response to acidic chyme and acts as an enterogastrone -GIP: This hormone has receptors in the beta cells of the Islets of Langerhans -Cortisol: This hormone is secreted in response to increased levels of ACTH -Glycogenesis: This is an anabolic process for storing glucose -Ghrelin: This is a short-term appetite regulator whose release depends on gastric stretch -Liver: This organ synthesizes bicarbonate and bile salts. -Exocrine pancreas: These cells secrete zymogens into the pancreatic duct -Hypoglycemia: Abnormally low blood sugar -Glucagon: This hormone prevents hypoglycemia -Beta cells of the pancreas: These cells secrete a hormone that causes insertion of glucose transporters into cell membranes when it binds with its receptors -Cholecystokinin: This hormone is an appetite regulator that is secreted in response to amino and fatty acids in the intestinal chyme -Insulin: This hormone prevents hyperglycemia -Gastrin: This hormone causes contraction of the lower esophageal sphincter

Match the letters on the diagram to the correct description

A: Increased blood glucose B: Glucagon C: Insulin D: Decreased blood glucose

Which statement is true about the role of cortisol in a catabolic state?

ACTH binds with receptors in the adrenal cortex, stimulating the synthesis and release of cortisol, which then causes glycogenolysis to occur.

Which statement is true about nutrient absorption in the duodenum?

Absorption of glucose and amino acids involves the use of ATP. (Both glucose and amino acids are absorbed by secondary active transport which relies on a sodium gradient created using ATP.)

Here is one more review question before we put these concepts together. Which statement is true about aldosterone secretion?

Aldosterone is secreted when low renal blood pressure activates the RAAS pathway and causes increased reabsorption of sodium from the distal tubule of the nephron and from the colon.

Which of the following would cause excessive proteolysis or "muscle wasting"?

An increase in cortisol secretion, causing a catabolic state.

Which statement about regulation of the digestive process is correct?

Beta cells of the pancreas have receptors for GIP which produce insulin when stimulated, causing a decrease in levels of blood glucose.

Let's do a review question. Which drawing indicates the correct direction of water movement? The density of "dots" corresponds to the solute concentration, and the "membrane" between the squares is only permeable to water.

D (less dots arrow pointing to o into more concentrated blue dots-lots)

Which statement is true about fed state metabolism?

During the fed state, glycogen is produced by glycogenesis, primarily influenced by insulin.

Which statement about signaling is FALSE?

Exocrine signals are hormones which are secreted into the blood.

Which statement is true about chemical digestion?

Fatty acids, the products of digestion by lipases, are absorbed into intestinal cells by simple diffusion.

Which statement is true about regulation of blood glucose levels?

Glucagon release, stimulated by a decrease in blood glucose levels, normally prevents hypoglycemia.

Which statement correctly describes how glucose is absorbed by intestinal cells?

Glucose is absorbed into intestinal cells by secondary active transport and exits those cells toward the blood by facilitated diffusion.

What is the disturbance to homeostasis caused by the glucagonoma?

Hyperglycemia

Diarrhea (watery feces) can be caused by:

Ingestion of solutes that cannot be absorbed because these solutes remain in the lumen and reduce the solute concentration gradient

Which statement about the regulation of blood sugar is correct?

Insulin release, stimulated by an increase in blood glucose levels, normally prevents hyperglycemia.

Which statement is true about regulation of blood glucose levels?

Insulin release, stimulated by an increase in blood glucose levels, normally prevents hyperglycemia.

Question 101 / 1 pts Which statement is true about the role of the autonomic nervous system in controlling the digestive process?

Parasympathetic neurons or the smell of food can activate the cephalic phase of digestion, leading to increased gastric secretions.

Which statement is true about regulation of digestion?

Parasympathetic neurons or the smell of food can activate the cephalic phase of digestion, leading to increased gastric secretions.

Which statement is true about the gastric phase of digestion?

Parietal cells in the stomach release hydrochloric acid which converts pepsinogen to pepsin.*

Which is true about the regulation of blood sugar?

Regulation of blood sugar is under antagonistic control because glucagon causes an increase in blood sugar levels, and insulin opposes its effect causing a decrease in blood sugar levels.

Which is the correct description of the pathway leading to the secretion of cortisol?

Secretion of CRH from the hypothalamus leads to secretion of ACTH from the anterior pituitary which leads to secretion of cortisol from the adrenal cortex.

Which statement is true about chemical digestion?

Simple sugars, the products of digestion by amylase, are absorbed into intestinal cells by secondary active transport.

Which statement is true about the role of the pancreas?

The endocrine cells of the pancreas secrete insulin and glucagon into the blood. (Insulin and glucagon are both hormones which are endocrine signals, which by definition, travel through the blood before they reach their receptors)

Which statement is true about the relationship between the liver and the gall bladder?

The liver makes bile salts and bicarbonate which are then stored in the gall bladder and released into the common bile duct under the influence of cholecystokinin.

In patients with uncontrolled diabetes mellitus, high blood glucose results in high levels of glucose in the filtrate of the nephron. What happens when abnormally elevated levels of filtered glucose levels "saturate" the transporters in the nephrons?

Urine volume increases because less water is reabsorbed due to the decreased concentration gradient causes by more glucose than normal in the filtrate. (Hypergylcemia reduces the solute concentration gradient between the lumen where the filtrate is, and the inside of the cells.)

What type of cell releases glucagon?

alpha cells

What chronic condition might arise as a result of the disturbance to homeostasis caused by the glucagonoma?

diabetes mellitus

The greatest percentage of water absorption occurs in the

duodenum

What hormone is released in response to hypoglycemia?

glucagon

During the fasted state, glucose is produced by:

glycogenolysis, primarily influenced by glucagon.

Which is the correct relationship between calcium levels, myosin kinase activity and contraction of smooth muscle?

increased Ca++ leads to increased myosin kinase leads to increased contraction.

Diarrhea (watery feces) can be caused by:

ingestion of solutes that cannot be absorbed.

What hormone would need to be upregulated in response to the disturbance to homeostasis caused by the glucagonoma?

insulin

Glucose is absorbed into intestinal cells by_______ and exits those cells toward the blood by _______.

secondary active transport; facilitated diffusion.