Brainscape's Knowledge GenomeTM

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


See full index

Endocrine System > The Endocrine Pancreas - Part 2 > Flashcards

The Endocrine Pancreas - Part 2 Flashcards

1
Q

What happens if there is more glucagon than insulin?

A

Glucose released into plasma from stores and BG conc. increases
Increased glycogenesis, gluconeogenesis and ketogenesis

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

Describe glucagon

A

Peptide hormone produced by alpha cells of pancreatic islet cells
Glucose mobilizing hormone, acting mainly on the liver

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

What is the plasma half life of glucagon?

A

5-10 mins
Degraded mainly by the liver

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

When is glucagon most active?

A

In post absorptive state

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

What are glucagon receptors?

A

G protein coupled receptors
Linked to adenylate cyclase/cAMP system which when activated phosphorylate specific liver enzymes

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

What is the action of glucagon?

A

Opposes the action of insulin, part of the glucose counter regulatory control system which included epinephrine, cortisol and GH

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

What does phosphorylation of specific liver enzymes result in?

A

Increased glycogenolysis
Increased gluconeogenesis
Formation of ketones from FAs

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

What is glycogenolysis?

A

Breakdown of glycogen to return to glucose

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

How does fasted state metabolism maintain plasma glucose for brain?

A

Liver glycogen becomes glucose
Adipose lipids become free FAs and glycerol that enter blood
Muscle glycogen is used for energy -use FAs and break down proteins into aa
Brain can only use glucose and ketones

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

How are ketone bodies formed?

A

Beta oxidation from free fatty acids

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

What do amino acids stimulate and why is it important?

A

Stimulate glucagon and insulin
If no glucagon stimulation then glucose uptake into cells and lowered BG conc.
Potentially catastrophic for brain - hypoglycaemia
Adaption was for high protein meals

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

What happens if someone consumes a very high protein meal?

A

Amino acids stimulate insulin causing decreased BG conc.
Also stimulates glucagon causing increased BG conc.
This maintains BG conc.

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

Explain glucose sparing for obligatory glucose users

A

In post absorptive state then there is low insulin levels so a large mass of tissue like muscle and fat can not readily access glucose

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

What are some stimuli which promote glucagon release?

A

Low BG conc. (under 5 mM)
High conc. of amino acids
Sympathetic innervation and epinephrine, Beta 2 effects
Cortisol
Stress

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

What stimuli inhibit glucagon release?

A

Glucose
Free fatty acids and ketones
Insulin
Somatostatin

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

What happens if increased parasympathetic innervation on islets cells?

A

Increased insulin and lesser increase of glucagon
Association with anticipatory phase of digestion

17
Q

What happens if increased sympathetic innervation on islets cells?

A

Promotes glucose mobilization
So increased glucagon, epinephrine and inhibition of insulin so brain had enough energy

18
Q

How does epinephrine help control BG conc.?

A

Muscle and liver glycogenolysis
Gluconeogenesis
Lipolysis

19
Q

How does cortisol and GH help control BG conc.?

A

Gluconeogenesis
Inhibition of glucose uptake
Lipolysis
Cortisol only - protein catabolism

20
Q

What is somatostatin?

A

SS is a peptide hormone secreted by D cell of the pancreas
Main pancreatic function is to inhibit activity of GI tract

21
Q

What is another action of somatostatin?

A

Supresses the release of both insulin and glucagon
If SS tumour then can have symptoms of diabetes

22
Q

Describe the effect of exercise on conc. of BG?

A

Entry of glucose into skeletal muscle increases even in absence of insulin
There is insulin independent increase in GLUT4 in muscle membrane
Also increases insulin sensitivity of muscle

23
Q

Explain GLUT4 transporters in active muscle

A

Can migrate to membrane without insulin being present
Exercise causes glucose uptake independent of insulin

24
Q

Describe what happens during starvation

A

Adipose tissue is broken down - fatty acids are released
Most tissues can used FFAs to make energy and liver converts excess to ketones - additional source of energy

25
Q

What happens to the brain after a period of starvation?

A

Brain adapts to be able to use ketones

26
Q

Why does the brain adapt to use ketones as energy source?

A

Serves to save protein breakdown as can become weak and vulnerable to infection
Ketone body uptake is insulin dependant

27
Q

Describe Type I diabetes (IDDM)

A

Inulin dependant diabetes mellitus
Autoimmune destruction of the pancreatic beta cells destroys ability to produce insulin and compromises ability to absorb glucose

28
Q

What are the results of type I diabetes?

A

Absolute need for insulin - insulin injections
Without then develop ketoacidosis, coma and die

29
Q

Describe the breakdown of homeostatic regulation in diabetes

A

Meal increases BG conc. but lack of insulin effect so liver produces more glucose by gluconeogenesis because body thinks its starving - further increase in BG conc.

30
Q

Describe ketoacidosis in type I diabetes

A

Lack of insulin depresses ketone body uptake so build up rapidly in plasma - acidic so create life threatening acidosis with plasma less than 7.1

31
Q

How are ketones detectable?

A

Detectable in urine and produce distinctive acetone smell to breath

32
Q

Describe type II diabetes

A

Non-insulin dependant diabetes mellitus
Peripheral tissues become insensitive to insulin - insulin resistance
Either abnormal insulin response of receptors or reduction in number of receptors

33
Q

What are the beta cells like in type II diabetes?

A

Intact and appear normal
Can sometimes even be hyperinsulinemia

34
Q

What are major contributions to type II diabetes?

A

High sugar and animal fat diet with little exercise

35
Q

Describe the glucose tolerance test in diabetes

A

Type I and type II give raised BG conc.
Type I - inadequate release of insulin
Type II - inadequate tissue response
Patient ingests glucose after fasting BG measures then if elevation after 2 hrs - indictive of diabetes

36
Q

How is mg/dl converted to mM?

A

Ex. 90mg/dl x 100 to make L
900mg/l
MW of glucose is 180
900/180 - 5mM

37
Q

What are some diabetic complications of long term hyperglycaemia?

A

Retinopathy
Neuropathy
Nephropathy
CVD

38
Q

What can hypoglycaemia in type I diabetes cause?

A

Type I on exogeneous insulin
Can lead to permanent brain damage and death in end
Only needs to be over short period to see complications

Endocrine System (23 decks)

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