Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIOL 432 Final > Glucose Regulation > Flashcards

Glucose Regulation Flashcards

1
Q

Where are glucagon receptors mainly expressed?

A
  • in liver and kidney
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which cell types have insulin receptors (that are focused on for this course)?

A
  • liver, muscle and adipose

- plus insulin regulates self in pancreas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How is blood glucose under control? Why is it controlled?

A
  • under extremely tight control

- because glucose main energy source for cells to use

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How does insulin and how does glucagon affect blood glucose?

A
  • insulin decreases blood glucose

- glucagon increases blood glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

When do pancreatic hormones work together?

A
  • to regulate blood glucose after meals and in between meals
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What hormones are from the pancreatic islets? What are the other two important blood glucose regulation hormones?

A
  • insulin, glucagon, somatostatin

- glucagon-like peptide-I and gastric inhibitory peptide (aka glucose-dependent insulinotropic peptide)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are glucagon-like peptide-I and gastric inhibitory peptide? What is their function?

A
  • both incretins

- proteins that amplify insulin effects and are secreted by cells of the small intestine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What cells does the pancreas contain?

A
  • islets of langerhans
  • B cells: insulin (center)
  • A cells: glucagon (periphery)
  • D cells: somatostatin (periphery)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How is insulin involved in paracrine feedback?

A
  • activates beta cells (insulin producers) and inhibits alpha cells (glucagon producers)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How is glucagon involved in paracrine feedback?

A
  • activates alpha cells, activates beta cells, activates delta cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How is somatostatin involved in paracrine feedback?

A
  • inhibits alpha cells, inhibits beta cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Where is GLP-I made and why is this interesting?

A
  • made in intestine

- same precursor as glucagon but very different function!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How is GLP-I involved in paracrine feedback?

A
  • acts on pancreas as potent stimulator insulin transcription and release after meals
  • decreases secretion glucagon
  • acts on other tissues as well as pancreas
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How is GIP involved in paracrine feedback?

A
  • amplifies insulin effects

- secreted by cells of the small intestine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is hypoglycemia? What are the symptoms?

A
  • if blood suar levels drop too low
  • potentially fatal
  • loss of consciousness, brain damage, lethal coma
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is hyperglycemia? What are the symptoms?

A
  • short term: appetite suppressed

- long-term: chronic health problems associated with diabetes mellitus (eye, kidney, heat disease, nerve damage)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is diabetes mellitus? What are the two types?

A
  • deficiency in secretion or action of insulin
  • Type I: no insulin
  • Type II: insulin resistant
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How is type I diabetes mellitus treated?

A
  • used to use pork and beef but more expensive and unsafe

- now human insulin made in host bacteria factory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Cell surface receptors control gene expression by which pathways?

A
  • MAPK, PKC, PI3K
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How does phosphorylation occur and what does it result in?

A
  • occurs in a chain reaction

- activates transcription factors that bind DNA and activate or repress transcription of genes into proteins

21
Q

What pathways stimulate insulin secretion?

A
  • calcium at voltage-gated calcium channel (VGCC)

- GLP-1 acting on GPCR

22
Q

What pathway stumulates insulin synthesis?

A
  • insulin at redeptor tyrosine kinase plus glucose sensor that transports glucose into cell
23
Q

How long does it take to synthesize insulin?

A
  • takes >1hr

- insulin stored for immediate release in response to food

24
Q

What is required to release insulin?

A
  • calcium (from mitochondria and voltage gated calcium channel stimulated by glucose)
25
Q

What is required to link blood glucose levels to insulin secretion?

A
  • glucose “sensor” mechanism
  • metabolic coupling to potassium channels to control plasma membrane potential
  • voltage dependent calcium channels
26
Q

Where are insulin containing granules found?

A
  • reserve pool and a readily released pool
27
Q

What factors mediate insulin release?

A
  • aa from food
  • glucose from food
  • incretins: proteins that amplify insulin effects (GLP-1 and GIP)
28
Q

After release how long does insulin last? How is it removed from circulation?

A
  • 3-5 minutes

- degraded by insulinases in liver, kidney, placenta

29
Q

What are the steps in insulin release from B cell?

A
  1. glucose from meal
  2. a) increase ATP, cAMP/PKA signalling blocks K+ channel (cell depolarized)
  3. b) GIP and GLP-I act to increase cAMP/PKA (potentiates other steps)
  4. voltage sensitive calcium channel opens, influx
  5. increase calcium and increase in cAMP/PKA causes insulin release
  6. increase of calcium opens K-Ca channel that repolarizes the cell
30
Q

What are growth factor receptors also known as?

A
  • tyrosine kinase receptors
31
Q

What is IGF-I?

A
  • major player in GH axis
  • produced in liver
  • negative feedback on GH
  • protein synthesis and cell proliferation
  • insulin family and same receptor type
32
Q

What is IGF-II?

A
  • fetal growth hormone
  • in liver
  • mediates GH effects
  • insulin family too
33
Q

What is insulin implicates for?

A
  • implicated for carb metabolism

- implicated for fetal growth

34
Q

What kind of receptor does insulin use?

A
  • growth factor receptor dimer (made with S-S bridges)
  • enzyme tyrosine kinase is a part of receptor
  • binds extracellularly
35
Q

What does insulin binding result in?

A
  • adds phosphate to substrates that recruit other proteins (signaling complexes)
  • adds phosphate to proteins that also kinases (phosphorylation cascades)
36
Q

What do we share our hormone ancestry with?

A
  • sea squirts!

- insulin and IGF

37
Q

How do genes evolve through gene duplication?

A
  • gene doubles
  • can than mutate one gene to acquire new function without messing up the organism
  • IGF-1 to IGF-II
38
Q

What are GLUTs?

A
  • important for transporting glucose into the cell

- different ones on membranes of different cell types in different tissues

39
Q

What are some of insulins effects?

A
  • metabolic storage hormone
  • increase cell growth
  • critical for fetal growth
  • directly suppresses glucagon transcription
40
Q

What does insulin store as a metabolic storage hormone?

A
  • glycogen to store glucose
  • triglyceride to store fat
  • protein synthesis to store amino acids
41
Q

How does insulin increase cell growth?

A
  • via growth factor receptor (tyrosine kinase receptor)
42
Q

How does insulin suppress glucagon transcription?

A
  • glucagon gene has an insulin response element
43
Q

What are the two pathways following growth factor receptor with tyrosine kinase?

A
  • mitogenic (growth via MAPK)

- metabolic (store food after a meal via PI3K/PKB) (also known as Akt pathway)

44
Q

What are the effects of the PI3K/PKB pathway on the liver?

A
  • decrease gluconeogenesis
  • increase glyogenesis
  • decrease glycogenolysis
45
Q

What are the effects of the PI3K/PKB pathway on the muscle?

A
  • increase glucose transport
  • increase glycogenesis
  • increase protein synthesis
46
Q

What are the effects of the PI3K/PKB pathway on the pancreas?

A
  • increase b-cell growth

- increase insulin secretion

47
Q

What are the effects of the PI3K/PKB pathway on the adipocytes?

A
  • increase glucose transport
  • increase protein synthesis
  • increase lipogenesis
  • decrease lipolysis
48
Q

How are insulin receptors downregulated?

A
  • receptor desensitized by internalization once insulin bound - endosomes to lysosomes, acidification and degraded
  • downregulated if chronic insulin

BIOL 432 Final (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions