Lecture 1 - Endocrine control of metabolism and digestion Flashcards
What hormone dominates in the fed state?
Insulin
What does insulin cause?
Causes an increase in:
- ) Glucose oxidation
- ) Glycogen synthesis
- ) Fat synthesis
- )Protein synthesis
What dominates in the fasted state?
glucagon
What does glucagon cause?
Causes an increase in:
- ) Glycogenolysis
- ) Gluconeogenesis
What is the incretin effect?
It is the difference of when glucose is infused in the body either orally or through an IV. Orally the response is much higher and so there is more insulin. This diffrence between the glucose is called the incretin effect.
Step by step of how the blood glucose level decreases?
Hypothalamus - parasympathetic nervous system - B cells in the pancreas release insulin - lowers blood glucose levels
Step by step of how blood glucose levels increase?
Hypothalamus:
- ) sympthetic nervous system to medulla which stimulates adrenal glands and releases adrenaline.
- )hormones released - go to pituitary gland which releases growth horomone and also stimulate the cortex to release cortisol.
- ) a cells in pancreas release glucagon
Role of the thyroid gland in the liver?
- )Regulates lipid homeostasis
2. ) Influences susceptability to obesity and liver steatosis
Role of the thyroid gland in the Pancreas?
- ) Directs pancreas development and function
2. ) Enhances mafa expression in B cells.
Role of the thyroid gland in the hypothalamus?
- ) Regulates the feeding behaviour
2. )Controls energy expenditure
Role of the thyroid gland in the skeletal muscle?
- ) Determines shift from type 1 to type 2 fibers
- ) influences the regeneration process
- ) Increases energy expenditure
Role of the thyroid gland in the BAT (brown adipose tissue)?
- ) regulates adipocytes proliferation and differentiation
2. ) Regulates thermogenesis and UCP1 levels.
Role of the thyroid gland in the WAT (White adipose tissue)?
1.) regulates adipocyte proliferation adn differentiation
What is prader-willi syndrome?
Rare genetic disorder that results in physical, mental and behavioral problems. Constant sense of hunger from the age of 2. Essentially, the hunger center in the brain is disregulated.
What is the normal range of blood glucose levels?
60-90 mg/100ml
What happens to blood glucose levels during rest, moderate intensity exercise and high intensity exercise?
Rest: 80/10/10 - fatty acids/glucose/amino acids
Moderate: 40/50/10
High: 0/100/0
What happens when blood glucose levels are under 60 and under 40 and under 20 mg/100 ml ?
under 60 - Neurological signs like hunger, release of glucagon, epinephrine, cortisol, sweating and trembling. But it is sufficient for the brain.
Under 40 - Lethargy, convulsions, coma
under 20 - permenant brain damage if prolonged and could lead to death.
What does the metabolism do in the fed state?
It is nutrient rich so glucose and amino acids are transported from the intestine to the blood. Also, dietary lipids transported from the lymphatic system to the blood.
The predominant hormone in this stage in insulina dn it stimulates thestorage of fuels and synthesis of proteins.
What does the metabolism do in the early fasting state?
The blood glucose levels frop after several horus after a meal. Hencethe pancreatic hormone is predominating glucagon which mobilises and spares fuel.
What happens in metabolism in prolonged starvation?
In an average 70 kg well fed human, the fuel reserves are about 161,000 kcal. The enrgy needed for a 24 hour period is 1600 kcal to 6000 kcal. Hence, there are sufficent reserves for abotu 1-3 months but the actual glucose reserves are exhausted in less than a day. Problem is that the blood glucose level has to be above 40mg/100 ml.
Priorities in prolonged starvatin?
- ) sufficient glucose for the brain, nervous tissue and RBC
- ) Preserve protein - lipolysis and gluconeogenesis take place instead
- ) 3 days into starvation the brain and heart start to use ketones as furl
- ) Several weeks of starvation - ketone bodies are a major fuel for the brain
- ) Once TAG stores are all usedup, there is increased protein degredation which results in decreased heart, liver and kidney function.
How is the pancreas made up?
There are 2 different sections:
- ) exocrine pancreas - 99% of the gland and Acini and involved in digestion.
- ) endocrine pancreas - 1 % of the gland and made of islets of langerhans. Involved in the control of blood glucose.
What are islets of langerhans?
Group of pancreatic cells that secrete insulina nd glucagon.
How is insulin made and its significance?
Preproinsulin - proinsulin - insulin
use proinsulin as a measure to see how much insulin ahs been secreted into the body because proinsulin releases C chain and so if there is an increase in teh C chain in the body than there is also an increase in insulin in the body.
What is the stimulus for insulin?
Glucose:
increase in glucose in teh body will cause an increase in insulin in the body. This wiill lower the glucose iin the body which will lower the insulin in the body.
islets of langerhans vascularisation?
Highly vascularised as 10 - 15 % of pancreatic blood flow goes there because it monitors blood constituents and release products.
Increase in FFA causes insulin to …?
increase in insulin
Increase in Glucagon causes insulin to …?
increase in insulin
Increase in GH, GIT hormones causes insulin to …?
increase in insulin
Increase in plasma AAs causes insulin to …?
increase in insulin
waht innervates the islets ?
ANS
Steps of insulin secrettion by beta cells?
- ) glucose enters the body
- ) after glycolysis, kreb cycle, etc. ATP increases in the body
- ) depolarisation
- ) calcium enters cell
- ) insulin is secreted
Main types of glucose transporters?
SGLT - sodium-glucose linked transporters
GLUT - facilitated diffusion glucose transporters
Glut 1 ?
it is ubiqutous as it is in red cells and the blood brain barrier. ALways there and its main substrate is glucose which allows to help in basal glucose absorption.
Glut 2 ?
In the liver, interstine, kidney and pancreatic beta cells. Its main substrate is glucose and its physiological function is in glucose absorption in the intestine and kidney.
Glut 3 ?
In the brain and main substrate is glucose. It is involved in neuronal glucose absorption.
Glut 4 ?
In insulin sensitive tissue, makes up 80 % of GLUTS. Involved in insulin mediated glucose uptake and may be related to type 2 diabetes.
Glut 5 ?
In the small intestine and sperm. Main substrate is fructose and is involved in intestinal fructose absorption.
What is so special about glut 10?
It provides a constant low level of glucose to cardiac muscle.
