Integration Of META Flashcards
Protein, polysaccharide and lipids are broken down into what building blocks and the later broken down to
Amino acid, glucose, Glycerol &fatty acids
BB later broken down to acetyl group of acetyl coA I. E glucose–pyruvate– acetyl coA (common degradation products)
common degradation products) is then converted to?
Catabolism converts common degradation products via citric cycle yo NH3, water and co2
Polysaccharide under goes oxidative phosphorilation
Metabolic pathway is highly consrved
Catabolism typically involves _____ while anabolism involves_______
Oxidation and is energy yielding
Reduction and requires energy
Both simultaneously occurs
Highly regulated and may occur in different compartments
Cata and ana
Catabolism and anabolism must differ in at least one step for it to be independently regulated
During anabolism reducing power is usually provided by___
Nadph
Oxidative reaction of catabolism involves____ often as _____ which are transferred in _____ reactions from substrate to _____
Release of reducing equivalents often as hydride ions
To NAD
What are the four major organ that play a role in fuel metabolism
Liver adipose muscle and brain
Insulin
binds to specific, high-affinity receptors in the cell
membrane of
most tissues like
Liver, muscle and adipose
Glucose
transport in some tissues
, such as
,
increases in the
presence of insulin.
skeletal muscle and adipocytes
Other tissues such as,
do not require
insulin for glucose
uptake
hepatocytes, erythrocytes,
and cells of the nervous
system,
intestinal
mucosa, renal tubules, and cornea
Vessicles fuse to form an organnel called
Endosome
How dies insulin increase glucose uptake
STIMULATION OF INSULIN SECRETION is done by?
Insulin secretion by the β cells
of the islets of Langerhans of the pancreas is closely
coordinated with the release of glucagon by pancreatic α cells
the pancreas adjusts the levels of insulin and glucagon to make sure that the liver doesn’t produce more glucose than the body needs and that the glucose is being used efficiently by other cells in the body.
Insulin secretion is increased by:
Glucose
AA
Gastrointestinal hormones
What gastrointestinal hormones cause increase in insulin and they are also called
Cholecystokinin & gastric inhibitory peptide increase insulin levels in response to oral glucose
Incretins
gastric inhibitory peptide is also called
Glucose dependent insulinotropic peptide
INHIBITION OF INSULIN SECRETION
during periods of stress (for example, fever or
infection and
or deperession
Hunger
These effects are mediated by epinephrine secreted by adrenal medulla
Release of epinephrine is controlled by NS
Epinephrine has
a direct effect on energy metabolism, causing a rapid
mobilization
of
energy-yielding fuels, including glucose from the
liver (produced by
Glycogenolysis or gluconeogenesis and free fatty acids from adipose tissue
epinephrine can override the normal glucose-stimulated release of
insulin.
T or F
Thus, in emergency situations, the sympathetic nervous system
largely replaces the plasma glucose concentration as
the controlling influence over β-cell secretion.
Insulin effects on metabolism
Carbohydrates
Promotes it’s storage in liver, muscle & adipose
Effects of insulin on liver & muscle
Increase glycogen synthesis
In muscle & adipose
insulin increases glucose uptake by increasing
the
number of glucose transporters (
GLUT-4) in the cell membrane
intravenous administration of insulin thus causes an
immediate
decrease
in the concentration of blood gluc
In liver, insulin decreases the production of glucose through the
inhibition of glycogenolysis and gluconeogenesis
administration of insulin,causes a
significant
reduction in the release of fatty acids
Effects on lipid metabolism:
Increased
triacylglycerol synthesis:
the liver, insulin promotes the conversion of glucose into triacylglycerols, contributing to the storage of excess glucose as fat.
Insulin enhances the activity of lipoprotein lipase, an enzyme in adipose tissue that breaks down circulating triglycerides into free fatty acids and glycerol.
It provides the substrate glycerol 3-phosphate for the synthesis of triacylglycerols (fat molecules)
In liver, insulin promotes
the conversion
of glucose to
triacylglycerols
Insulin Effects on protein synthesis
In most tissues, insulin stimulates the entry of amino acids into cells, and
protein synthesis.
What hormones oppos the action of insulin
And are called “counter-regulatory hormones
Glucagon, along with epinephrine, cortisol
, and growth hormone
Most importantly
, glucagon acts to maintain blood glucose levels by
activation of hepatic glycogenolysis
and gluc
glucagon secretion is increased by:
Low blood glucose
AA increase
Epinephrine & nor epinephrine(sympathetic innervation of the pancreas
Amino acids:
Amino acids derived from a meal containing
protein
2.
stimulate the release of both glucagon and insulin. The
glucagon
effectively
prevents hypoglycemia that would otherwise occur as
a
result
of increased insulin secretion that occurs after a protein meal
INHIBITION OF GLUCAGON SECRETION
significantly decreased by elevated blood glucose and
by insulin.
Metabolic effects of glucagon
Effects
on carbohydrate metabolism
The intravenous
administration of
1.
glucagon leads to an immediate rise in blood glucose.
This results
from an
increase in the breakdown of liver (not muscle
) glycogen
and an increase
in
gluconeogenesis
Effects
on lipid metabolism
Glucagon activates lipolysis in adipose
. The
2.
free fatty acids released are taken up by liver and
oxidized to
acetyl
coenzyme A, which is used in ketone
body synthesis
.
Effects
on protein metabolism
Glucagon increases uptake
of amino
3.
acids by the liver, resulting in increased availability
of carbon
skeletons
for gluconeogenesis. As a consequence
, plasma levels of amino acids are
decreased.
glucagon is a hormone that helps the liver take in amino acids, which are the building blocks of proteins. When the liver takes in these amino acids, it can use them to create new glucose molecules through a process called gluconeogenesis. As a result, the levels of amino acids in the bloodstream decrease because they are being taken up by the liver for this process.
Hypoglycemia is characterized by:
central nervous system (CNS) symptoms, including confusion, aberrant behavior or coma
a simultaneous blood glucose= or less than 40 mg/dl
ptoms being resolved within minutes following the
administration
of glucose.
Hypoglycemia
is a medical emergency because
the CNS has an absolute
requirement for a continuous
supply of bloodborne
glucose to serve as
fuel for energy metabolism.
Transient hypoglycemia can cause cerebral dysfunction, whereas severe,
prolonged hypoglycemia
causes brain
It is, therefore, not surprising that the body has multiple overlapping
mechanisms to prevent or
correct hypoglycemia
.
