Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

ENDOCRINOLOGY - BRS > 1a Glucose Homeostasis > Flashcards

1a Glucose Homeostasis Flashcards

1
Q

What is significantly impaired when glucose concentration falls below normal levels?

A

Cerebral function

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

What bodily system is glucose particularly important for?

A

The functioning of the central nervous system

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

What is hypoglycemia?

A

Blood glucose concentration levels fall below a normal levels

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

What can happen is blood glucose Concentration falls below 2mmol/L

A

Unconsciousness, coma and ultimately death

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

What does persistent hyperglycemia result in?

A

Diabetes mellitus type II

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What hormones act against hypoglycemia? - 4

A

Glucagon
Cortisol
Growth hormone
Catecholamines

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

What is the most prevalent form of diabetes?

A

Type 2 diabetes mellitus

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

What are the three types of diabetes

A

Type 1 DM
Type 2 DM
maturity onset diabetes of the young

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

state the cell types found in the pancreas - 2

A

Islets of Langerhans
Exocrine acinar cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is meant by the pancreas having retroperitoneal structure?

A

Has a peritoneum on the anterior side only

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the small clumps of cells in the pancreas called?

A

Islets of Langerhans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are exocrine acinar cells?

A

Cells that generate exocrine secretions

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

What are the three types of islet cells?

A

alpha, beta and delta cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the alpha cells involved with?

A

Glucagon secretion

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

What are the beta cells in the islets of langerhans involved with?

A

Insulin secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the delta cells in the islet of langerhans involved with?

A

Somatostatin secretion

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

What do the gap junctions between the cells of the islets of Langerhans allow?

A

They allow small molecules to pass directly between cells - paracrine communication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the purpose of the tight junctions between the cells of the islets of langerhans?

A

Create small intercellular spaces

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

What effect does somatostatin have on the insulin and glucagon?

A

inhibitory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What type of communication is found between the islet cells?

A

Paracrine communication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does insulin do?

A

Stimulates growth and development and reduces blood glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What increased effect does insulin secreted from the beta cells have on the liver? - 5

A

Increased:
- Glycolysis
- Glycogenesis
- Glucose transport into cells via GLUT 4
- amino acid transport
- lipogenesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Where is GLUT 4 predominantly expressed?

A

Adipocytes and skeletal muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

When blood glucose is high, what is released?

A

Insulin from the beta cells as well as some glucagon from the alpha cells to ensure that hypoglycaemia doesn’t occur

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
How does somatostatin affect the release of insulin from beta cells when there is a rise in blood glucose?
inhibits the release of insulin
26
How does glucagon affect the release of insulin from beta cells when there is a rise in blood glucose?
stimulates release of insulin
27
state the impact of insulin on: amino acid transport protein synthesis lipogenesis?
Increases amino acid transport, protein synthesis and lipogenesis
28
What is released when blood glucose levels are lowered?
Alpha cells release glucagon
29
What affect does glucagon have? - 5
INCREASED: - gluconeogenesis - lipolysis - blood glucose - amino acid transport to the liver - hepatic glycogenolysis
30
Is GLUT 2 insulin sensitive?
No
31
What is the main glucose sensor?
Glucokinase (hexokinase as IV)
32
What is GLUT 2’s affinity for glucose, and what does this mean?
LOW affinity for glucose => moves glucose into liver cell in proportion to plasma glucose levels
33
Does glucose 6 phosphate inhibit glucokinase?
No
34
Why do glucose 6 phosphate levels give a good indication of glucose levels as well?
Glucose to glucose 6 phosphate is a continual conversion by glucokinase therefore the amount of glucose present is equal to glucose 6 phosphate
35
What intrabodily changes lead to insulin release
The ATP produced from glycolysis inhibits the potassium ion channels, meaning K+ remains in the beta cells therefore, there is an intracellular influx of Ca2+ which triggers the insulin to be released from the beta cells
36
What is meant by a graded response of insulin production?
Insulin isn’t released in an all or nothing manner, continually released when needed and the amount released changes over time
37
What is pro insulin cleaved into?
insulin and C-peptide
38
What happens to C peptide levels after a big meal?
Increase
39
What happen to someone’s C peptide levels when a person with type 1 diabetes eats a meal?
They are low - this is because C peptide levels are only a measure of endogenous insulin, and doesn’t include the insulin which they have injected following the meal
40
What is the difference between oral and intravenous glucose in terms of plasma insulin production? And what is this effect called?
Oral is significantly higher - incretin effect
41
Transcription of what gene produced Glucagon like peptide 1?
Pro-glucagon gene
42
Where is glucagon like peptide found?
In the gut
43
What is the effect of glucagon like peptide 1?
Stimulated insulin and suppresses glucagon
44
What effect does glucagon like peptide1 do to us?
Increases feeling of fullness
45
Why does GLP1 have a short half life?
Rapidly degraded by enzymes dipeptidyl peptidase 4
46
What is GLP1 used in the treatment of?
Diabetes mellitus
47
What is meant by the first phase insulin release?
This is following a meal, when a diabetics insulin levels do increase slightly, but much less than a healthy individuals, and stay elevated
48
How does the insulin receptor work?
1. Insulin binds to alpha subunit 2. Causes a confirmation change in the tyrosine kinase domain of the beta sun unit 3. This causes the movement of GLUT 4 from intracellular space to cell membrane so glucose can be absorbed
49
What part of the insulin receptor does insulin initially bind to?
Extracellular domain - alpha subunit
50
What percentage of the pancreas gland is involved in exocrine secretions?
98%
51
Where may you find insulin receptors?
Liver, muscle and fat
52
What is the incretin effect?
When the production of plasma insulin is greater following giving oral glucose to patients rather than IV
53
impact of insulin on lipolysis
decreases
54
why do we see an increase in amino acid transport to the liver by glucagon?
amino acid metabolites are used as substrates in gluconeogenesis to produce glucose
55
How do PNS activity affect the secretion of insulin when there is a rise in blood glucose?
stimulates the release of insulin
56
How do SNS activity affect the secretion of insulin when there is a rise in blood glucose?
inhibits secretion of insulin via alpha cells
57
relationship between insulin and glucagon
insulin inhibits glucagon release
58
is GLUT-4 insulin sensitive and what is its glucose affinity?
YES, and has high glucose affinity
59
link between insulin and GLUT-4
insulin stimulates the uptake of glucose by GLUT-4
60
what does glucokinase serve as in beta-cells?
a glucose sensor
61
What is the main difference in the actions of hexokinase I and hexokinase IV?
Hexokinase IV is not subject to -ve feedback from Glucose-6-P
62
Describe the process by which insulin is released from the beta cells after blood glucose increases?
1. Glucose transported into beta cell by GLUT-2 (which is NOT insulin sensitive and has a low glucose affinity) 2. Glucose in the cell undergoes glycolysis by Glucokinase (hexokinase IV) to produce ATP (Rate-Limiting Step) 3. ATP inhibits the K+ efflux pump so K+ remains intracellularly and builds up in the cell, this relative increase leads to **membrane depolarisation 4. This opens Ca2+ voltage gated channels leading to Ca2+ influx which promotes secretion of stored insulin in beta cell
63
In what form is insulin stored in the body
proinsulin
64
Why is measuring endogenous c-peptide a good indicator for insulin?
c-peptide can be stable for up to half an hour when samples sent to lab
65
A person with Type 1 diabetes mellitus eats a Big Mac meal, do you expect their C-Peptide levels to be high or low?
low
66
What is the gastrointestinal incretin effect?
GI hormones enhance insulin secretion so when glucose is ingested orally there's higher plasma insulin in oral vs IV even though plasma glucose is the same
67
What is Glucagon like peptide-1 (GLP-1)?
gut hormone
68
What is GLP-1 secreted in response to?
Secreted in response to nutrients in gut
69
What effects does GLP-1 have on the INSULIN secreted by the islets of langerhans?
stimulates insulin
70
What effects does GLP-1 have on the GLUCAGON secreted by the islets of langerhans?
suppresses glucagon
71
link between GLP-1 and Type II diabetes
T2 diabetics have low GLP-1
72
link between GLP-1 and Type II diabetes
T2 diabetics have low GLP-1
73
How does the insulin receptor work when insulin binds? (3)
1. Insulin binds to the extracellular domain of insulin receptor at the alpha subunit 2. This causes a conformational change in the tyrosine kinase domains of the beta-subunits 3. This enables GLUT4 transport from intracellular into the membrane
74
What is the first phase insulin release (FPIR) in normal people vs those with T2DM?
normal people => marked increase in insulin after IV glucose challenge and then blood gluc goes down and thus so does insulin T2DM this response is blunted so it's not just that our cells are resistant to insulin, but also beta cells can't produce enough insulin to counteract glucose load after working hard for a long time
75
What is the first phase insulin release (FPIR) in normal people vs those with T2DM?
normal people => marked increase in insulin after IV glucose challenge and then blood gluc goes down and thus so does insulin T2DM this response is blunted so it's not just that our cells are resistant to insulin, but also beta cells can't produce enough insulin to counteract glucose load after working hard for a long time
76
What is the first phase insulin release (FPIR) in normal people vs those with T2DM?
normal people => marked increase in insulin after IV glucose challenge and then blood gluc goes down and thus so does insulin T2DM this response is blunted so it's not just that our cells are resistant to insulin, but also beta cells can't produce enough insulin to counteract glucose load after working hard for a long time

ENDOCRINOLOGY - BRS (21 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions