Pancreas Flashcards
What state are nutrients stored?
fed
what state are nutrients oxidized for energy production
fasting
broken down into sugar and is on the metabolic pathway of glycolysis
carbs
stored as glycogen or fat
carbs
broken down into fatty acids and glycerol with the metabolic pathway of Beta-Oxidation
Fats
stored as triglycerides in fat cells
Fats
Broken down into amino acids with the metabolic pathway of transamination
proteins
stored as glycogen or fat
proteins
a critical (and tightly
regulated) source of energy
glucose
the primary energy
substrate of
the brain.
glucose
Which portion of the pancreas is made of acinar and ductal cells
Exocrine portion
Produces and secretes digestive enzymes into intestines via pancreatic duct
Exocrine portion
What part of the pancreas is made of Islets of Langerhans (small
pockets of highly vascularized tissue
distributed throughout)
endocrine portion
Produces and secretes hormones
endocrine portion
What are the 3 cells that the Islets of Langerhans produces
Alpha cells
Beta cells
Delta cells
Released by alpha cells which leads to blood sugar increasing
alpha cell
Released by Beta cells which leads to a blood sugar decrease
insulin
an Anabolic Hormone
(energy storage)
insulin
target tissues of insulin
Target tissues: skeletal muscle, liver, and adipose tissue
increase of glucose uptake in tissues
insulin
increase in glucose storage
insulin
increase of fat synthesis
insulin
increase of protein synthesis
insulin
molecules are
built up to more complex
ones; requires energy
anabolism
What type of hormone is insulin?
Peptide hormone
Acts through Tyrosine Kinase Receptors
Insulin
decreases blood glucose levels by:
* Enhancing uptake of glucose into cells
* Enhancing storage of glucose
insulin
Liver’s role in glucose regulation
- stores glucose by converting it into glycogen (glycogenesis)
- releases glucose to circulation by breaking down glycogen (glycogenolysis)
- produces glucose from amino acids (gluconeogenesis)
Skeletal Muscle’s role in glucose regulation
- Takes up glucose and stores it as glycogen
- Releases glucose from stored glycogen, primarily for muscle contractions
what is adipose tissue’s role in glucose regulation
- Takes up glucose and converts it into triglycerides for storage
- Releases fatty acids from stored triglycerides into circulation Role of Target Tissues in Glucose Regulation
the primary insulin-
regulated glucose
transporter
GLUT4
How does insulin increase glucose uptake?
Glucose transporters (GLUT) move glucose into
the cell and insulin
increases them
How does insulin increase glucose storage?
Glucose can’t be stored; it needs to be converted to glycogen (glycogenesis)
What stimulates the conversion of glucose to glycogen
insulin stimulates the conversion of glucose to glycogen
the main fat storage hormone. It tells adipose tissue to store fat and
prevents stored fat from being broken down
insulin
the most important regulator of insulin secretion
rise in blood glucose
will inhibit further insulin secretion (negative feedback)
decrease in blood glucose
break down
of complex molecules;
releases energy
catabolism
a Catabolic Hormone
(energy utilization)
Glucagon
Effects of Glucagon
increase in glycogen breakdown
increase glucose synthesis
increase fat breakdown
increase protein breakdown
increase formation of ketone bodies
All the effects of glucagon are mediated by
cAMP
Main function of glucagon
oppose actions of insulin
(liberates stored energy / glucose mobilization)
glucagon increase blood glucose levels by
breaking down stored glycogen and new glycogen synthesis
are made when glucose is in short supply. They are made in the liver from the breakdown of fatty acids.
ketones
body doesn’t have enough carbohydrates (glucose) to utilize for energy, so it breaks down fat instead to make ketones
ketosis
the most important regulator of glucagon secretion
A drop in blood glucose
Characterized by elevated (fasting) blood glucose levels
Hyperglycemic
symptoms of diabetes
- Increased thirst (polydipsia)
- Increased appetite (polyphagia)
- Increased need to urinate (polyuria)
insulin-dependent diabetes; caused by destruction of islet cells as a result of an autoimmune reaction to Beta cells (insufficient insulin)
Type I diabetes
non-insulin-dependent diabetes; caused by a defect in insulin
function (insulin not being properly used)
Type II Diabetes
temporary insulin resistance during late pregnancy
gestational diabetes
Caused by autoimmune response in genetically predisposed individuals
Type I Diabetes
Develop antibodies targeting beta
cells leads to
the destruction of beta cells
Insulin is produced, but hyperglycemia
is not corrected due to insulin resistance in target tissues.
Type II Diabetes
Causes of Insulin resistance
- Obesity interfering with signaling
-Lipid accumulation in tissues
-Inflammation
-Insulin receptor desensitization
-High leptin (it inhibits insulin) - Direct dysfunction of insulin receptors (e.g., mutation in receptor)
Type 2 Diabetes: Insulin
Resistance
Insulin resistance combined with minimal insulin secretion triggers
Type II Diabetes
main cause of
insulin resistance
visceral fat
