Introduction To Endocrine W3 Flashcards
Following ingestion, carbohydrates, proteins and fats are broken down into their component parts …
– Monosaccharides (predominantly glucose)
– Amino acids
– Fatty acids
What is controlled by hormones
Control of absorption, use, storage and therefore circulating levels
And control of appetite
Brain uses ho much glucose a day
120g
Blood glucose if maintained at around…..
5mM
(3.4-5.8mM)
Energy stores - glycogen
Storage of glucose In liver and skeletal muscles
Easily avaliable but of limited size (1%stores 190g which lasts 1 day)
Essential for stores of glucose for brain
Synthesis - glycogenesis (makes glycogen)
Breakdown - glycogenolysis (break glycogen)
Energy stores - fat
Major store of energy - most efficient as get more energy from fat
Triglycerides are stored in adipose tissue
Synthesis - lipogenesis
Breakdown - lipolysis
Adipose tissue
connective tissue, but it’s also an interactive organ in your endocrine system
Energy stores - protein
Stored in skeletal muscles
Source of glucose for brain if necessary
Some aminos can be converted to glucose - gluconeogenesis
Breakdown - proteolysis
proteolysis
breakdown of proteins and peptides into smaller peptides or amino acids and occurs through hydrolysis of a peptide bond by enzymes called proteolytic enzymes, proteinases, proteases, or peptidases.
gluconeogenesis
process of making glucose (sugar) from its own breakdown products or from the breakdown products of lipids (fats) or proteins.
lipogenesis
the synthesis of fatty acids from nonlipid precursors
lipolysis
metabolic process through which triacylglycerols (TAGs) break down via hydrolysis into their constituent molecules: glycerol and free fatty acids
glycogenesis
process of synthesizing glycogen from glucose, primarily occurring in the liver and muscle tissues
glycogenolysis
breakdown of glycogen to form glucose
Important hormones in fuel metabolism
Insulin
Glucagon
Cortisol
Adrenaline
Growth Hormone
Somatostatin
Pancreatic polypeptide
Amylin
GLP-1
Fuel metabolism - insulin
The major hormone of fuel metabolism.
The most important regulator of blood glucose (only hormone that can decrease blood glucose).
Secreted from β-cells in the Islets of Langahans of endocrine pancreas
Fuel metabolism - glucagon
antagonistic to insulin.
Secreted from α-cells in the Islets of Langerhans of endocrine pancreas
Fuel metabolism - cortisol
glucocorticoid (adrenal cortex) increasing energy sources as part
of the stress response
Fuel metabolism - adrenaline
increases blood glucose and fatty acids. Secreted from
adrenal medulla
Fuel metabolism - growth hormone
Can elevate blood glucose and fatty acids.
Major effect is protein synthesis in muscle. Secreted from anterior pituitary
Fuel metabolism - somatostatin
Inhibits digestion and absorption.
Inhibits secretion of pancreatic hormones. Secreted from δ-cells (D-cells) of endocrine pancreas in response to raised glucose or amino acids
Fuel metabolism - pancreatic polypeptide
Appetite reduction.
Secreted from F-cells (aka PP cells) of endocrine pancreas in response to raised amino acids.
Fuel metabolism - amylin
delays gastric emptying. Secreted from β-cells
Fuel metabolism - GLP-1
Released from the ileum in response to food (L-cells).
Increases glucose-dependent insulin secretion.
Also slows the rate of absorption in the GIT and induces satiety
