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Flashcards in Endocrine energy regulation Deck (39)
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1

What other hormones apart from insulin and glucagon can influence glucose homeostasis

Epinephrine
Cortisol
Growth hormone
Thyroid hormone
Secretin
Cholecystokinin

2

What is the only hormone that lowers bood glucose

Insulin

3

What receptors are stimulated by insulin and which by glucagon/epinephrine

Insulin- RTK

Glucagon, epinephrine ->GPCR

4

how endocrine portion of pancreas in called

Islets of langernas

5

what is secreted by acinar and duct cells? to what portion of paracrine they are referred?

What cells are founf in islets of langerhans and what they secrete

6

where glucagon, somatostatin and pancreatic polypeptide are produced apart from pancreas?

Gastrointestinal mucosa

7

What is morphology of islets of Langerhans

islets highly vascularized (5 to 10 x blood flow of exocrine pancreas)
v blood first supplies centrally located B cells i.e. detects glucose levels
v then blood travels to more peripheral A and D cells i.e. exposed to insulin secreted by B cells

8

how islet cell hormones interact between each other?

9

How glucagon and insulin are produced?

10

what are nutrients, gastrointestinal hormones, hormones and autonomic nerves which control the release of insulin form beta cells

11

major factors controlling insulin secretion

epinephrine through alpha receptors

12

what nutrients, GI hormones, hormones and nerves control release of glucagon

13

What is the longest nerve in our body

Vagus nerve, number 10

14

what is the functional of vagus nerve

v Acts as a sensory neuron and
as a motor neuron (providing
and receiving signals from
peripheral organs)


v Main neuronal coordinator of
appetite control, digestion
and metabolism


v Release of acetylcholine
(cholinergic) in the pancreas
stimulates insulin release

15

how insulin get released from beta cells

  1. v Uptake of glucose by the type 2 facilitative glucose transporter (Glut 2)
  2.  Aerobic glycolysis and increase of the ATP/ADP ratio.
  3.  Inhibition of ATP-sensitive K+ channels → reduction of K+ efflux → membrane depolarization
  4. Opening of voltage gated Ca2+ channels (VDCC)
  5. Increased intracellular Ca2+ triggers exocytosis of insulin containing granules
  6. Opening of Ca2+ activated potassium channels (K-Ca), leading to the repolarization of the membrane (resetting)
  7. Metabolic coupling factors generated during glucose metabolism facilitate exocytosis and/or proinsulin synthesis (amplification pathway). Examples are plasma FFA (stimulates exocytosis via G-protein receptor) and intracellularly formed succinate.
  8.  Glucagon-like peptide 1 (GLP-1 from intestine) or related peptides bind to GLP-1 receptors and trigger cAMP production. It potentiates the amplification pathway, ion channels and exocytosis

16

what is happeing with glucose metabolism overall after meal and when fasting

17

what is normal glucose level during fasting , after meal and when glycosuria

v Serum glucose in the fasting stage 3-5 mM
v Rise to 7 mM after meal (glycosuria if exceeding 10 mM)

18

anabolic effects of insulin

synthesis of protein, lipid and glycogen and
inhibition of their degradation (usage of glucose)

v Insulin promotes cell growth. It is essential for normal growth and
development

19

Key target tissues of insulin

Insulin promotes glucose uptake in muscle and adipose tissue
by increasing the Glut 4 transporters on the cell surface

and cardiac muscle

20

is insulin stopped to be secreted ever?

Insulin is continuously secreted to enable peripheral tissues to uptake glucose

21

Glucose supresses ___ (hormone) secretion

GH, which reduces glucose uptake and increases lypolysis 

22

where glut2,glut 3, glut 4 is found and their specifics

23

how facilitated uptake via glut 2 is maintained

The concentration gradient of (non-phosphorylated) glucose

24

insulin receptor-> ___ pathway->glut 4 is brought to the surface

PI3K pathway

25

glucagon functions through which GPCR

adenylyl cyclase and PKA

26

how glucagon increases glucose blood concentration

it induces phosphorylase-> increased glycogenolysis

27

does glucagon affect muscles?

No, because msucles do not have glucagon receptors

28

compare glucagon, GLP-1, GLP2

29

Name functions of insulin on liver, muscle and adipose tissue

30

what viruses cacn destroy beta cells

Enterovirus, Rotavirus, Mumpsvirus and Cytomegalovirus