Feedback Control Glucose - Lecture 5 Flashcards
What source of the energy does the brain use?
Glucose
Can the brain metabolise fatty acids?
No
-Blood-brain barrier makes brain inaccessible to plasma fatty acids.
What is Hypoglycaemia
Blood sugar is <2.5 mmol/l
What is the recommended blood glucose levels?
4mmol/l
What can Hypoglycaemia lead to?
Confusion
Coma
Damage of Blood Vessels
What is the Fed State?
This is the state immediately after a meal, were there is a lot of nutrients
What the state between meals?
The Post Absorptive State
What hormones control glucose concentration in the absorptive and post-absorptive states?
Insulin
Glucagon
- Both produced by the pancreas
What hormones control glucose concentration in emergencies?
Adrenaline
-Produced from the adrenal gland
What hormones control glucose concentrations during starvation?
Cortisol
Growth Hormone
Where is Cortisol produced?
Adrenal Gland
Where is Growth Hormone produced?
Pituitary gland
What are the areas of the pancreas that produces insulin?
The Islets of Langerhans
What are the cells in the Islets of Langerhans called?
Beta Cells - these produce insulin
What cells of the pancreas produce glucagon?
Alpha Cells
What produces Somatostatins?
Sigma Cells
What happens in the absorptive state of glucose digestion/assimilation?
Increase in Glucose
Increase in Insulin
Decrease in Glucagon
What happens to the concentration of Insulin and Glucagon in the blood after eating a rich carbohydrate meal?
Large increase in Insulin secretion
Glucagon levels reduce
What is the function of Insulin?
Stimulates conversion of glucose into glycogen, fatty acids into triglycerides and amino acids into protein.
Favours anabolism
What is the function of Glucagon?
Stimulates conversion of glycogen into glucose and triglycerides into fatty acids.
What is the hormone of the fed state?
Insulin
What is the hormone of the hungry state?
Glucagon
What are the effects of Insulin?
Insulin lowers the Glucose level
How does Insulin reduce the blood glucose?
Stimulating the uptake of glucose from the blood into muscle and fat cells.
Activating the enzymes in liver and muscle which convert glucose into glycogen.
(Insulin also promotes the incorporation of amino acids into protein in muscle and promotes lipogenesis in adipose tissue)
How does insulin promote glucose uptake into muscle and fat?
Insulin causes glucose transporter proteins (GLUT4) to be inserted into the plasma membrane
What factors cause Insulin to be released?
Increase Glucose levels Increase in Amino Acids Increase in Parasympathetic activity Increase in Glucagon Release of GIP
What factors cause Insulin Insulin release inhibition?
Decrease in Glucose levels
Increase in Sympathetic Activity
What is GIP?
Glucose-dependent insulinotropic polypeptide
What causes Diabetes Mellitus?
Lack of Insulin production
Impaired Cellular response to Insulin
How is Diabetes Mellitus detected?
Oral Glucose Tolerance Test
What is glycosuria?
Glucose found in the urine
What are the effects of severe Diabetes?
Very High Glucose concentration after meal
Glycosuria
Extra metabolism of fatty acids - Produces extra Acetyl Co A
-Ketone Bodies formed
Ketone Bodies lower the blood pH
What are the signs of Type 1 Diabetes Mellitus? (6)
- Childhood onset
- Little/no insulin secretion
- Defect in Beta-cell function
- Ketosis develops
- Insulin injections for treatment
- Symptoms develop rapidly
What are the signs of Type 2 Diabetes Mellitus? (6)
- Adult onset (until recently)
- Insulin secretion may be normal (or exceed normal)
- Defect in insulin sensitivity
- Ketosis rare
- Diet/exercise and oral drugs for treatment
- Symptoms develop slowly
What stimulates the release of Glucagon? (3)
- Decreased blood glucose
- Amino acids (raises [glucose]p after protein meal)
- Sympathetic nerve activity
What causes inhibition of Glucagon release? (2)
- Raised blood glucose
- Insulin
How does Glucagon raise Glucose Concentration? (4)
- Increasing liver glycogenolysis.
- Inhibiting liver glycogen synthesis.
- Promoting liver gluconeogenesis.
- Promotes lipolysis in liver and adipose tissue.
What occurs if we go without food for long periods of time?
- Fats are metabolised.
- Protein is catabolised.
What does Protein Catabolism lead to?
Muscle wastage
During Starvation what is broken down first?
Protein and fat. However Protein metabolism increases and fat metabolism decreases as weeks of starvation increases
Where is adrenaline secreted?
Medulla of the Adrenal gland
What are the parts of the adrenal gland?
Cortex (Outer part)
Medulla (Inner)
Where is Corisol secreted from?
The Zona Fasiculata of the Adrenal Gland
What pattern does Cortisol secretion display?
Diurnal rhythm
Concentrations decrease during the day.
Concentrations increase during the night
What is a diurnal rhythm?
Concentrations decrease during the day.
Concentrations increase during the night
What are the effects of Adrenaline release in response to stress? (4)
- Raises Glucose concentration
- Stimulates Glycogenolysis
- Stimulates Gluconeogenesis
- Released during short-termed emergencies
What are the effects of Cortisol release in response to stress? (5)
- Raises Glucose concentration
- Stimulates Proteins catabolism
- Stimulates Gluconeogensis
- Lipolysis stimulation
What two hormones are used in stressful situation to increase glucose concentration?
Cortisol
Adrenaline
Where is Growth Hormone secreted from?
Anterior Lobe of Pituitary Gland
What is the effect of Growth Hormone in response to starvation? (3)
- Decreases glucose uptake by muscle – “glucose sparing” action
- Mobilises glucose from liver
- Promotes lipolysis in fat cells
What hormones maintain glucose concentration in starvation?
Cortisol
Growth Hormone
What is the symbol given for glucose concentration?
[Glucose]p
What hormones maintain [Glucose]p in absorptive and post-absorptive states?
Insulin
Glucagon
What are the 5 hormones that influence [Glucose]p?
Adrenaline Insulin Cortisol Glucagon Growth Hormone
