Brainscape's Knowledge GenomeTM

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


See full index

Endocrine Physiology 2 > Blood Glucose Hormones > Flashcards

Blood Glucose Hormones Flashcards

1
Q

what are the hormones that raise blood glucose?

A

glucagon
cortisol
catecholamines (epinephrine, norepinephrine)
growth hormone

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

What are the hormones that lower blood glucose?

A

insulin

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

what cells secrete insulin?

A

beta cells in core of pancreatic islets of langerhans

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

what cells secrete glucagon?

A

alpha cells on the edges of pancreatic islet of langerhans

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

what cells secrete somatostatin?

A

delta cells in pancreatic islet of langerhans

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

describe the structure of insulin

A

contains an alpha and beta chain held together by two S-S bridges.

A chain contains six membered ring

entire molecule except for carboxyl end of B is required for biological action

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

insulin is conserved across species

A

ok

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

describe the biosynthesis of insulin

A

synthesized in beta cells.

preproinsulin has a signal sequence cleaved off, forming proinsulin.

proinsulin is cleaved of C-peptide to form insulin

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

how do you measure endogenous insulin production

A

measure amount of C-peptide

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

describe how beta cells sense blood glucose

A

glucose is transported into beta cells via GLUT2, and glucokinase converts it into glucose-6-phosphate

this begins glucose metabolism, which increases the ATP/ADP ratio, which inhibits ATP-sensitive K channels. This depolarizes the membrane and activates voltage gated Ca channels, leading to exocytosis of insulin

leads to increase in insulin production, secretion, storage, and beta cell proliferation

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

how do amino acids affect insulin secretion?

A

esp arginine

increase insulin secretion, especially in combo w/ glucose

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

how do ketones affect insulin secretion

A

stimulate insulin release

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

why is glucose through the gut more effective than through IV

A

b/c it stimulates glucagon-like-peptide 1, which stimulates insulin release

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

what are the effects of catecholamines on insulin release?

A

depends what receptors they use

a-receptors- more common- result in inhibition of insulin release

b-receptors- less common- results in stimulation of insulin release

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

what is the effect of somatostatin release?

A

potent inhibitor of insulin and glucagon release

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

insulin degradation

A

insulin half life is only 10 minutes

kidney and liver account for 80% of degradation

17
Q

describe the insulin receptor

A

a tyrosine kinase comprised of
an alpha-beta heterodimer, the alpha portion is the binding unit and the beta unit is a transmembrane effector protein

the complex is ultimately internalized, where insulin is degraded but the receptor is recycled

18
Q

what are the actions of insulin on muscle?

A

glucose uptake- cause GLUT4 receptors to be translocated to membrane

glycogen synthesis- glycogen synthetase is inactive when phosphorylated. insulin activates a phosphatase to remove the P, and inactivates glycogen synthase kinase-3

amino acid uptake

protein synthesis

inhibits proteolysis

19
Q

what are the effects of exercise or anoxia on glucose uptake?

A

these stimuli allow for glucose uptake w/o insulin

20
Q

what are the effects of insulin in adipose tissue?

A

glucose uptake- causes GLUT4 receptors to be translocated to membrane

fat synthesis

lipoprotein lipase synthesis- breaksdown lipoproteins (chylomicrons and VLDL) for uptake into adipose

inhibits HS lipase- breaks down triglyceride inside adipose

glycogen synthesis

AA uptake and protein synthesis

21
Q

effects of insulin on liver

A

stimulates glucokinase and glycogen synthease

stimulation of phosphofructokinase, pyruvate kinase, pyruvate dehydrogenase (glycolytic rate limiting enzymes)

inhibits gluconeogenic enzymes (glucose-6-phosphatase, fructose-1,6-diphasphatase, PPCK, pyruvate carboxylase)

stimulates fatty acid synthesis

22
Q

describe GLUT2

A

the glucose transporter in the liver and pancreas, can handle a wider range of glucose concentration than GLUT4, and so transport is not limited

is not upregulated by insulin

23
Q

where does glucagon exert its effects?

A

liver

24
Q

what factors control secretion of glucagon

A

low blood sugar- primary

amino acids - esp arginine

catecholamines

sympathetic innervation

inhibited by somatostatin

25
Q

where is glucagon secreted into?

A

into portal vein

26
Q

where is glucagon degraded

A

liver- half life of 10 min

27
Q

what are glucagons effects on the liver

A

stimulation of glyconeogenesis- slower than glycogenolysis

stimulation of glycogenolysis- mediated by adenyl cyclase/cAMP/PKA

inhibition of glycogen synthetase

stimulation of hepatic lypolysis

inhibition of fatty acid synthesis

stimulation of hepatic ketogenesis

28
Q

where do catecholamines come from?

A

adrenal medulla- chromaffin granules

29
Q

describe the biosynthesis of catecholamines

A

tyrosine to L-dopa via tyrosine hydroxylase (stimulated by ACTH)

L-dopa to dopamine via A. acid decarboxylase

dopamine to norepinephrine via dopamine b-hydroxylase

norepinephrine to epinephrine via phenylethanolamine (stimulated by cortisol)

30
Q

describe catecholamine synthesis regulation

A

acute- norepinephrine inhibits tyrosine hydroxylase tonically. stimulation relieves this, and also causes release

chronic- results in de novo synthesis of tyrosine hydroxylase

31
Q

major stimulus for release of catecholamines?

A

AcH from preganglionic fibers

32
Q

describe catecholamine removal from the blood

A

short lived

  1. reuptake by storage granules
  2. COMT inactivates them (liver, blood, kidneys)

3 excretion via kidneys

33
Q

describe catecholamine receptors

A

alpha- PIP3- mobilizes calcium

beta- cAMP- major metabolic receptor- higher affinity for epinephrine

34
Q

catecholamine effects in muscle

A

simulation of glycogenolysis + lactate

inhibition of glycogen synthesis and glucose uptake

35
Q

catecholamines effects on adipose

A

stimulation of lipolysis via HSL

36
Q

catecholamines effects on liver

A

stimulation of glycogenolysis

inhibition of glucose oxidation

inhibition of glycogen synthesis

stimulation of gluconeogenesis

stimulatoin of lipolysis

37
Q

glucocorticoids effect

A

stimulates gluconeogenesis in liver

inhibits glucose uptake

promoting glycogen synthesis

stimulating lipolysis via HSL

38
Q

growth hormone effects

A

stimulation of lipolysis via HSL

early- increased glucose uptake

later- decreased glucose uptake

39
Q

somatostatin

A

decreases insulin, glucagon, GH

Endocrine Physiology 2 (6 decks)

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