Lecture 1 - Endocrine control of metabolism and digestion

Question 1

What hormone dominates in the fed state?

Answer 1

Insulin

Question 2

What does insulin cause?

Answer 2

Causes an increase in:

1. ) Glucose oxidation
2. ) Glycogen synthesis
3. ) Fat synthesis
4. )Protein synthesis

Question 3

What dominates in the fasted state?

Answer 3

glucagon

Question 4

What does glucagon cause?

Answer 4

Causes an increase in:

1. ) Glycogenolysis
2. ) Gluconeogenesis

Question 5

What is the incretin effect?

Answer 5

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.

Question 6

Step by step of how the blood glucose level decreases?

Answer 6

Hypothalamus - parasympathetic nervous system - B cells in the pancreas release insulin - lowers blood glucose levels

Question 7

Step by step of how blood glucose levels increase?

Answer 7

Hypothalamus:

1. ) sympthetic nervous system to medulla which stimulates adrenal glands and releases adrenaline.
2. )hormones released - go to pituitary gland which releases growth horomone and also stimulate the cortex to release cortisol.
3. ) a cells in pancreas release glucagon

Question 8

Role of the thyroid gland in the liver?

Answer 8

1. )Regulates lipid homeostasis

2. ) Influences susceptability to obesity and liver steatosis

Question 9

Role of the thyroid gland in the Pancreas?

Answer 9

1. ) Directs pancreas development and function

2. ) Enhances mafa expression in B cells.

Question 10

Role of the thyroid gland in the hypothalamus?

Answer 10

1. ) Regulates the feeding behaviour

2. )Controls energy expenditure

Question 11

Role of the thyroid gland in the skeletal muscle?

Answer 11

1. ) Determines shift from type 1 to type 2 fibers
2. ) influences the regeneration process
3. ) Increases energy expenditure

Question 12

Role of the thyroid gland in the BAT (brown adipose tissue)?

Answer 12

1. ) regulates adipocytes proliferation and differentiation

2. ) Regulates thermogenesis and UCP1 levels.

Question 13

Role of the thyroid gland in the WAT (White adipose tissue)?

Answer 13

1.) regulates adipocyte proliferation adn differentiation

Question 14

What is prader-willi syndrome?

Answer 14

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.

Question 15

What is the normal range of blood glucose levels?

Answer 15

60-90 mg/100ml

Question 16

What happens to blood glucose levels during rest, moderate intensity exercise and high intensity exercise?

Answer 16

Rest: 80/10/10 - fatty acids/glucose/amino acids
Moderate: 40/50/10
High: 0/100/0

Question 17

What happens when blood glucose levels are under 60 and under 40 and under 20 mg/100 ml ?

Answer 17

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.

Question 18

What does the metabolism do in the fed state?

Answer 18

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.

Question 19

What does the metabolism do in the early fasting state?

Answer 19

The blood glucose levels frop after several horus after a meal. Hencethe pancreatic hormone is predominating glucagon which mobilises and spares fuel.

Question 20

What happens in metabolism in prolonged starvation?

Answer 20

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.

Question 21

Priorities in prolonged starvatin?

Answer 21

1. ) sufficient glucose for the brain, nervous tissue and RBC
2. ) Preserve protein - lipolysis and gluconeogenesis take place instead
3. ) 3 days into starvation the brain and heart start to use ketones as furl
4. ) Several weeks of starvation - ketone bodies are a major fuel for the brain
5. ) Once TAG stores are all usedup, there is increased protein degredation which results in decreased heart, liver and kidney function.

Question 22

How is the pancreas made up?

Answer 22

There are 2 different sections:

1. ) exocrine pancreas - 99% of the gland and Acini and involved in digestion.
2. ) endocrine pancreas - 1 % of the gland and made of islets of langerhans. Involved in the control of blood glucose.

Question 23

What are islets of langerhans?

Answer 23

Group of pancreatic cells that secrete insulina nd glucagon.

Question 24

How is insulin made and its significance?

Answer 24

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.

Question 25

What is the stimulus for insulin?

Answer 25

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.

Question 26

islets of langerhans vascularisation?

Answer 26

Highly vascularised as 10 - 15 % of pancreatic blood flow goes there because it monitors blood constituents and release products.

Question 27

Increase in FFA causes insulin to …?

Answer 27

increase in insulin

Question 28

Increase in Glucagon causes insulin to …?

Answer 28

increase in insulin

Question 29

Increase in GH, GIT hormones causes insulin to …?

Answer 29

increase in insulin

Question 30

Increase in plasma AAs causes insulin to …?

Answer 30

increase in insulin

Question 31

waht innervates the islets ?

Answer 31

ANS

Question 32

Steps of insulin secrettion by beta cells?

Answer 32

1. ) glucose enters the body
2. ) after glycolysis, kreb cycle, etc. ATP increases in the body
3. ) depolarisation
4. ) calcium enters cell
5. ) insulin is secreted

Question 33

Main types of glucose transporters?

Answer 33

SGLT - sodium-glucose linked transporters

GLUT - facilitated diffusion glucose transporters

Question 34

Glut 1 ?

Answer 34

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.

Question 35

Glut 2 ?

Answer 35

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.

Question 36

Glut 3 ?

Answer 36

In the brain and main substrate is glucose. It is involved in neuronal glucose absorption.

Question 37

Glut 4 ?

Answer 37

In insulin sensitive tissue, makes up 80 % of GLUTS. Involved in insulin mediated glucose uptake and may be related to type 2 diabetes.

Question 38

Glut 5 ?

Answer 38

In the small intestine and sperm. Main substrate is fructose and is involved in intestinal fructose absorption.

Question 39

What is so special about glut 10?

Answer 39

It provides a constant low level of glucose to cardiac muscle.