Endocrine pancreas

Question 1

What is metabolism?

Answer 1

Sum of all chemical reactions in the body

Includes anabolic (synthesis of large molecules) and catabolic (breakdown of large molecules) processes.

Question 2

Define anabolic metabolism.

Answer 2

Large molecules synthesized from smaller ones. Fed metabolism that occurs immediately following a meal

Question 3

Define catabolic metabolism.

Answer 3

Breakdown of large molecules into smaller ones.
Fasted metabolism state that is usually 3-4 hours following a meal

Question 4

What is the basal metabolic rate (BMR)?

Answer 4

An individual’s energy expenditure when resting, at comfortable temperature, and fasted.

Question 5

What metabolic state is characterized by using glucose for energy?

Answer 5

Fed (absorptive) state.

Question 6

What metabolic state is characterized by using glucose and fat for energy?

Answer 6

Fasted (postabsorptive) state.

Question 7

List the metabolic processes occurring in the fed state.

Answer 7

glycogenesis: creating glycogen from glucose

Lipogenesis: anabolic state where fatty acid are converted into triglycerides

Protein synthesis: amino acids to proteins (muscles

Question 8

List the metabolic processes occurring in the fasted state.

Answer 8

Glycogenolysis: breakdown of glycogen in the liver and muscles into glucose and then into ATP via glycolysis

Lipolysis: catabolic breakdown of triglycerides in adipose tissue into fatty acids and ATP

Protein degradation: protein in muscles breakdown into amino acids

Question 9

Gluconeogenesis

Answer 9

making new glucose through the fast state by non-carbohydrate substrates such as glycerol and amino acids

Question 10

What transports glucose into cells?

Answer 10

Glucose transporters (GLUT).

There are two main GLUT transporters- GLUT2 and GLUT4 transporters

Question 11

Where is GLUT 2 primarily found?

Answer 11

Liver and pancreas

Question 12

what is the primary role of GLUT 2 transporter

Answer 12

it transports glucose and insulin secretion

Question 13

Where is GLUT 4 primarily found?

Answer 13

Adipose tissue, skeletal muscle.

Question 14

What is the primary role of GLUT 4 transporter

Answer 14

storage of glucose and getting glucose into skeletal muscles- with the help of insulin

Question 15

What is the relationship between insulin and glucagon?

Answer 15

There are antagonistic to one another

Question 16

What is the role of insulin in metabolism?

Answer 16

Reduces blood glucose and promotes formation of glycogen, fat, and protein.

it moves glucose out of the bloodstream and into the cell

Question 17

What happens to glucagon levels immediately following a meal

Answer 17

in the fasted states glucagon levels are high to promote the breakdown of stored energy sources, however after a meal when glucose begins to rise as well as insulin, glucagon bill drop

Question 18

What happens to insulin levels immediately following a meal

Answer 18

insulin levels will rise with glucose levels and push glucose into the cells. When enough glucose is pushed into the cell and out of the bloodstream, insulin levels will start to drop

Question 19

What is the dominant hormone of the fed state?

Answer 19

insulin (anabolic)

Question 20

What is the primary role of insulin

Answer 20

increases glucose oxidation, glycogen synthesis, fat synthesis, and protein synthesis

Question 21

What type of receptor does insulin bind to?

Answer 21

Receptor tyrosine kinase.

Question 22

What is the primary stimulus for insulin secretion?

Answer 22

Glucose.

Question 23

Mechanism of Insulin Action- GLUT 4 transporters

Answer 23

1. insulin will bind to tyrosine kinase receptor- activating kinase
2. receptor phosphorylates insulin-receptor substrates (IRS) which stimulates secondary pathways
3. second messenger pathways alter protein synthesis and existing protein- here GLUT4 receptors will be created and translocate to the plasma membrane via exocytosis where glucose can move into the cell via facilitated diffusion

Question 24

Where are GLUT 4 transporters found?

Answer 24

in muscle and adipose tissue

Question 25

What does glucose do for muscle tissues and adipose tissue

Answer 25

for muscle tissues, it is used for immediate metabolic use- during exercise GLUT 4 can go to the plasma membrane without insulin For adipose tissues, glucose is stored and will eventually be turned into fat

Question 26

What are the differences between Glut 4 and GLUT 2 transporters

Answer 26

GLUT 4 transporters are dependent on insulin, meaning that they need insulin to move to the plasma membrane and they are found on muscle and adipose tissue GLUT 2 transporters are independent of insulin and act on liver cells

Question 27

Mechanism of Action- GLUT 2 Transporters

Answer 27

GLUT 2 receptors are bound to the plasma membrane even when insulin is not present. in the liver, there is presence of glucose on the inside In the presence of insulin- it will activate hexokinase, which phosphorylates glucose into glucose 6 phosphate this phosphorylation will maintain a high glucose concentration on the outside of the cell, indirectly increasing glucose uptake by liver

Question 28

effects of insulin

Answer 28

increase glucose transport into insulin-sensitive cells activates enzymes involved in glycogenesis, lipogenesis, and protein synthesis inhibits enzymes for glycogenolysis, gluconeogenesis, and lipolysis increases uptake of amino acids into muscle and protein synthesis promote lipogenesis and inhibits oxidation enhance cell proliferation

Question 29

What stimulates insulin release

Answer 29

glucose in the blood will bind to transporter which will increase ATP ATP will cause K channels to close, causing the cell to depolarize, opening calcium channels that will will cause the release of insulin in vesicles

Question 30

What are incretin hormones?

Answer 30

GIP-1 GLP-1.

Question 31

Why is there more insulin secreted when glucose is in intestine

Answer 31

because of incretin hormones

Question 32

What is the role of GLP-1?

Answer 32

Stimulates insulin secretion and increases beta cell mass. this is done when it travels through the bloodstream to the pancreas and binds to G-coupled receptor after it is bound, adenyl cyclase will cause increase cAMP and exchange protein activated by Adenyl cyclase (EPAC) which will cause increase of calcium

Question 33

What are stimulators and inhibitors of insulin?

Answer 33

Stimulators: increased glucose intestinal hormones- GIP-1 GLP1 amino acids parasympathetic nervous system Inhibitors: sympathetic nervous system (fight or flight)

Question 34

What stimulates glucagon secretion?

Answer 34

* Decreased plasma glucose * Increased plasma amino acids * Sympathetic nervous system.

Question 35

Glucagon

Answer 35

secreted by pancreatic alpha cells

Question 36

What effects do glucagon have on the body

Answer 36

increase breakdown of glycogen (glycogenolysis) creates new glucose (gluconeogenesis)

Question 37

What is the primary function of glucagon?

Answer 37

Prevents hypoglycemia (too little glucose)

Question 38

How does glucagon prevent hypoglycaemia?

Answer 38

in the fasting state, glucagon triggers activation of a cascade sequence that will breakdown down glucose-1-phosphate into glucose

Question 39

Stimulators and inhibitors of glucagon

Answer 39

stimulators: decreased glucose increased amino acids- protein ingestion enhances glucagon and insulin release, allowing cells to store glucose without severely dropping blood glucose level sympathetic nervous system Inhibitors: GLP1

Question 40

True or False: Type 1 diabetes is often treated with insulin injections.

Answer 40

True.

Question 41

Type 1 diabetes

Answer 41

insulin dependant diabetes where insulin secretion is reduced or absent

Question 42

Type 2 diabetes

Answer 42

non-insulin dependant there is a defect in insulin secretion and target cell responsiveness to insulin is reduced

Question 43

What characterizes uncontrolled Type 1 diabetes?

Answer 43

No insulin production means no GLUT 4 transporters, decreasing glucose uptake to muscle and adipose- causes hyperglycaemia (high blood sugar) and decrease in glucose utilization will cause the body to sense starvation which causes liver to breakdown glycogen in to glucose in protein metabolism; increase in protein breakdown and tissue loss in fat metabolism: increase in fat breakdown and decrease in fat storage causing weight loss leads to hyperglycemia high blood sugar gets filtered into the kidney and we urinate lots of glucose and water- leads to low blood volume, which can can cause ADH secretion Increase in osmolarity no insulin which means you can't use glucose for fuel, use fats which release ketones (acidic) as biproduce can result in acidosis blood volume and blood pressure decreases, as well as urine acidification and hyperkalemia which can lead to coma and death

Question 44

Fill in the blank: GLP-1 helps to stimulate further _______.

Answer 44

insulin release.

Question 45

What is the role of the sympathetic nervous system in insulin secretion?

Answer 45

Inhibition.

Question 46

What happens to glucose levels in the blood during fasting?

Answer 46

They decrease, prompting glucagon release.

Question 47

What is the treatment approach for Type 2 diabetes?

Answer 47

* Diet * Exercise * Oral hypoglycemics * Sometimes insulin injections.

Question 48

how can sulfonylureas help treat type 2 diabetes

Answer 48

they can also close K channels leading to further release of insulin

Question 49

How can GLP1 treat type 2 diabetes

Answer 49

help beta cell proliferation and prevent apoptosis reduce gastric emptying- stomach slows glucose being released in bloodstream which can also reduce appetite

Question 50

What other therapeutic affects do GLP1 have on the body

Answer 50

it can reduce cardiovascular complications such as myocardial infarction some neurological diseases such as Alzheimers and Parkinson's as well as neuropsychiatric disorders like substance use disorders and compulsive behaviours