The endocrine pancreas 1 and 2 Flashcards
2 ‘theories’ (pathways) that control energy intake etc
glucostatic theory
lipostatic theory
glucostatic theory
food intake is determined by blood glucose
lipostatic theory
food intake is determined by fat stores (as fat stores increase, drive to eat decreases)
3 categories of energy output
cellular work
mechanical work
heat loss
anabolic pathways
build up
net effect is synthesis of large molecules from smaller ones, usually for storage purposes
catabolic pathways
break down
net effect is degradation of large molecules into smaller ones, releasing energy for work
after eating, we enter the ……. state where ingested nutrients supply energy needs of the body and excess is stored
this is the ………. phase
absorptive
anabolic
between meals and overnight the pool of nutrients in the plasma decreases and we enter a …………. state where we rely on body stores to provide energy
this is the ……. phase
post-absorptive
catabolic
most cells can use fats, carbohydrates or protein for energy, but the brain can only use
glucose
except in extreme starvation
blood glucose is maintained by synthesising glucose from ……….. (………….) or amino acids (…………..)
glycogen
(glycogenolysis)
(gluconeogenesis)
what is the normal range of blood glucose?
4.2-6.3mM
hypoglycaemia occurs when blood glucose is less than what?
3mM
glucose is maintained over a tight range due to the actions of two key endocrine hormones produced in the pancreas:
insulin
glucagon
99% of the pancreas operates as an ……. gland
exocrine
only 1% of the pancreas has ……… function
endocrine
alpha cells produce
glucagon
beta cells produce
insulin
gamma cells produce
somatostatin
F cells produce
pancreatic polypeptide
insulin is synthesised as a large preprohormone called
preproinsulin
preproinsulin gets converted into ……… in the ………
proinsulin
ER
proinsulin is cleaved into ……. and ………..
insulin
c-peptide
Most cells use glucose as their energy source during the absorptive state. Any excess is stored as ………….. in liver and muscle, and as ………… in liver and adipose tissue.
glycogen
triacylglycerols (TAG)
fatty acids are stored in the form of triglycerides in ……. ……. and the ……….
adipose tissue
liver
the liver takes up glucose by ……… transporters, which are ………. dependent
GLUT2
insulin
insulin increases ……..synthesis in muscle and liver
glycogen
insulin increases …… ……. uptake into muscle
amino acid
4 main stimuli that inhibit insulin release
low BG
somatostatin
sympathetic alpha effects
stress (eg hypoxia)
vagal activity increases or decreases insulin release?
increases
what kind of hormone is glucagon?
peptide
glucagon has a plasma half life of 5-10minutes and is degraded mainly by the….
liver
the primary function of glucagon
to raise blood glucose
it is a mobilising hormone
what hormone primarily opposes the actions of insulin?
glucagon
glucagon is most active in which state?
post-absorptive
Glucagon receptors are G-protein coupled receptors linked to the adenylate cyclase/cAMP system which when activated phosphorylate specific liver enzymes resulting in:
3.
increased glycogenolysis
increased gluconeogenesis
formation of ketones from fatty acids
Glucagon release is relatively constant although secretion increases dramatically when [BG] < …….. mM
5.6
normal blood glucose in mM is between ……. and ……….
4.2 - 6.3 mM
What are also a potent stimulus for glucagon secretion?
amino acids
5 main stimulti that promote glucagon release
low BG
high AA
sympathetic innervation (epinephrine)
cortisol
stress (exercise, infection)
4 stimuli that inhibit glucagon release
glucose
free fatty acids and ketones
insulin
somatostatin
increased parasympathetic activity (vagus) leads to …….. insulin and to a lesser extent ……… glucagon, in association with the anticipatory phase of digestion.
increased
increased
increased sympathetic activation promotes glucose mobilization leads to …….. glucagon, ……… epinephrine and INHIBITION of insulin, all appropriate for fight or flight response.
increased
increased
somatostatin is secreted by what type of cells?
and also the ……
D cells
hypothalamus
somatomedian C is also known as
IGF-1
the main PANCREATIC action of somatostatin is to …
inhibit activity in the GI tract
slows down the absorption of nutrients
somatostatin is NOT a counter-regulatory hormone in the control of blood glucose but it does strongly suppresses the release of both ……. and ………. in a paracrine fashion.
insulin
glucagon
in the loss of control of BG in diabetes - patients will produce large volumes of what?
sweet tasting urine
type 1 diabetes is the autoimmune destruction of the pancreatic beta cells which destroys their ability to produce ……. and seriously compromises patients ability to absorb …. from the plasma
insulin
glucose
ketoacidosis in diabetes
When nutrients are scarce, body relies on stores for energy – when adipose tissue is broken down …… …….. are released. FFA’s can be readily used by most tissues to produce energy and liver will convert excess to ……. …….. which provides an additional source for muscle and brain!
fatty acids
ketone bodies
ketoacidosis in diabetes:
in poorly controlled insulin-dependent diabetes a lack of insulin depresses ….. …… uptake. They build up rapidly in the plasma and because they are acidic create life threatening acidosis (ketoacidosis or ketosis) with plasma pH < 7.1. Death will occur within hours if untreated.
ketone body
what is the first line of treatment for T2DM?
metformin
what does metformin do?
inhibits hepatic gluconeogenesis and antagonises action of glucagon
Sulphonylureas are a class of drug which act to
close the KATP in beta cells and therefore stimulate Ca2+ entry and insulin secretion.
Patient ingests glucose load after fasting [BG] measured. [BG] will normally return to fasting levels within an hour, elevation after 2 hours is indicative of …..
diabetes
the entry of insulin into …… …….. is increased during exercise
skeletal muscle
exercise increases the ……. ……. of muscle and causes an insulin-independent increased in …….. ……… incorporated into the muscles membrane
insulin sensitivity
GLUT4 transporters
when adipose tissues are broken down - what is released?
fatty acids
