Brainscape's Knowledge GenomeTM

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


See full index

Endocrine > Pancreas (L10) > Flashcards

Pancreas (L10) Flashcards

1
Q

Endocrine pancreas

A

Three types of cells clustered into the “islets of Langerhans”

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

Endocrine pancreas

A

Three types of cells clustered into the “islets of Langerhans”

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

Histology of the endocrine pancreas

A

“cord” network surrounded by reticular fibers

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

How many islets of Langerhans are there in a typical human?

A

About 1 million

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

Beta cells: product and percentage

A

73-75%; secrete insulin

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

Alpha cells: product and percentage

A

18-20%: secrete glucagon

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

Delta cells: product and percentage

A

4-6%: secrete somatostatin

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

PP cells: product and percentage

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

Arrangement of alpha and beta cells

A

Alpha cells in the mantle surround beta cells in the core

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

Arrangement of alpha and beta cells

A

Alpha cells in the mantle surround beta cells in the core

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

Histology of the endocrine pancreas

A

“cord” network surrounded by reticular fibers

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

How many islets of Langerhans are there in a typical human?

A

About 1 million

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

Beta cells: product and percentage

A

73-75%; secrete insulin

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

Alpha cells: product and percentage

A

18-20%: secrete glucagon

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

Delta cells: product and percentage

A

4-6%: secrete somatostatin

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

What types of glucose receptors are present on beta cells?

A

GLUT2 receptors: low affinity, only active in high concentrations of glucose

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

Epsilon cells: product and percentage

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

Arrangement of alpha and beta cells

A

Alpha cells in the mantle surround beta cells in the core

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

How does blood flow in the islet?

A

From the center outward; venous blood rich in hormone

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

Minor pancreatic hormones

A

Ghrelin, somatostatin, amylin, pancreatic peptide

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

Half life of insulin

A

3-8 minutes

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

Incretins

A

Potentiate insulin release, but are still glucose dependent

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

What is C-peptide used for?

A

Can be measured as a good indicator of pancreatic function due to half life of 35 minutes

24
Q

What is the C-chain necessary for?

A

Proper folding and disulfide linking of the alpha and beta chains

25
Q

Insulin release in response to a meal

A

Amplitude and frequency of insulin release will continue to rise until glucose levels are normalized

26
Q

Once inside the beta cell, what happens to glucose?

A

Phosphorylated by glucokinase

27
Q

Describe what happens when insulin binds its receptor.

A

Insulin binds the alpha subunit and causes autophosphorylation of intracellular beta subunit, which phosphorylates IRSs and activates intracellular signaling cascades

28
Q

Once G6P is created, what happens?

A

The G6P is metabolized and the increased ATP causes closing of potassium channels, which leads to depolarization of the cell

29
Q

Main mediators of insulin’s effects

A

PI3K - metabolic effects

MAPK - mitogenic effects

30
Q

Sulfonylurea drugs

A

There is a SUR binding unit on the potassium channels of beta cells, causing more cell depolarization and increased insulin release

31
Q

Incretins

A

Potentiate insulin release, but are still glucose dependent

32
Q

Catecholamines and insulin release

A

Inhibitory

33
Q

Biphasic glucose release

A

5% of insulin vesicles are docked at the membrane and are released immediately. The other 95% are moved from inside the cell and take longer

34
Q

What type of receptors are insulin receptors?

A

Tyrosine kinase receptors

35
Q

Describe what happens when insulin binds its receptor.

A

Insulin binds the alpha subunit and causes autophosphorylation of intracellular beta subunit

36
Q

What happens after downstream targets of IRSs are activated?

A

GLUT4 is inserted into the cell membrane and cell can take up glucose

37
Q

Main mediators of insulin’s effects

A

PI3K - metabolic effects

MAPK - mitogenic effects

38
Q

Physiologic effects of insulin on the liver

A

Promotes glycogen and triglyceride production; reduces glucose production/output

39
Q

Physiologic effects of insulin on muscle

A

Promotes glycogen and triglyceride production, as well as protein synthesis

40
Q

Stimulators of somatostatin release

A

High fat, high carb meals

41
Q

Components of proglucagon

A

Glucagon-related peptide, glucagon, GLP-1 and GLP-2 (incretins)

42
Q

Processing of proglucagon in the alpha cell

A

GRPP is cleaved and left as inactive peptide; GLP-1 and 2 remain linked and are also inactive

43
Q

Processing of proglucagon in the intestine

A

GRPP stays linked to glucagon and they both remain inactive as glicentin. However, GLP-1 and 2 are cleaved and are active as potentiators of insulin release

44
Q

What stimulates GLP release in the intestines?

A

Carbohydrates

45
Q

Stimulators of glucagon release

A

Low blood glucose levels, protein ingestion, and catecholamines

46
Q

Insulin’s effect on the bifunctional enzyme

A

Insulin dephosphorylates the portion of the enzyme conferring kinase activity, promoting glycolysis

47
Q

Glucagon’s effect on the bifunctional enzyme

A

Glucagon phosphorylates the portion of the enzyme conferring phosphatase activity, promoting gluconeogenesis

48
Q

Somatostatin and insulin

A

Inhibit each other; somatostatin treatment is used in the case of insulin-releasing tumors

49
Q

What does amylin do?

A

It is released with insulin to synergize in the regulation of blood glucose

50
Q

Pathology of amylin

A

Increased in obesity and hypertension, which could aid in destruction of beta cells by forming amyloid

51
Q

Stimulatory functions of ghrelin

A

Stimulates food intake at level of hypothalamus

Stimulates GH release

52
Q

Ghrelin and obesity

A

Inverse relationship between the two

53
Q

Paracrine actions of ghrelin

A

Inhibits insulin release via activation of potassium channels
Decreases intracellular calcium

54
Q

Where is ghrelin produced and released?

A

In the stomach and newly described epsilon cells of the islets of Langerhans

55
Q

Four counterregulatory hormones of insulin

A

Glucagon, GH, cortisol, and catecholamines

56
Q

GH without insulin

A

Has the glucose mobilization effects, but no IGF-1 is released and no cell proliferation effects take place. GH is elevated due to lack of negative feedback

57
Q

Growth hormone and cortisol as counterregulators of insulin

A

Stimulate lipolysis and gluconeogenesis; delayed release (6 hours) to protect against prolonged starvation

Endocrine (11 decks)

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