Clinical Chemistry Flashcards
List the various forms of carbohydrates
Simple- mono and disaccharides
Short chains- oligosaccharides
Complex CHO’s- polysaccharides
List the isomers of glucose
Galactose- mirror image of glucose
Fructose
What are the 3 disaccharides that can be made using glucose
Maltose= 2x glucose molecules
Lactose= glucose and galactose
Sucrose= fructose and glucose
What is glucose and what is it used for?
C6h12O6
Used to make ATP
Only converted to ATP when needed as ATP cannot be stored
List the 5 metabolic pathways
1.Glycolysis
2. Gluconeogenesis
3. Glycogenolysis
4. Lipogeneis
5. Glycogenesis
Describe glycolysis
Occurs in cell cytoplasm
Conversion of glucose- pyruvate
Converts free energy- ATP
10 enzyme- catalysed reaction= 2 x ATP produced
Describe gluconeogenesis
Release of glucose into the blood
The glucose is made from non-CHO sources such as triglycerides, amino acids and lactate
Describe glycogenolysis
Breaking down of glycogen to glucose
Glycogen comes from liver and muscles
Describe lipogenesis
Making of lipids
Lipids made from excess glucose in the blood
Glucose is made into triglycerides and then adipose tissue
Describe glycogenesis
Making of glycogen from excess glucose in the blood
Glycogen then stored in liver and muscles
What is the main hormone that controls blood glucose?
Insulin
What is insulin?
Peptide hormone
Made of 2 polypeptide chains:
Alpha- 21 amino acids
Beta- 30 amino acids
Describe hormonal control of blood glucose after a meal
Blood sugar is high
So insulin is released from the Beta cells in the pancreas
This stimulates the uptake of glucose by the liver and muscles
What happens when blood glucose concentration is low?
Glucagon is release from alpha cells in the pancreas
Glycogen is converted to glucose
Glucose is released into the blood
Define hyperglycaemia
High blood glucose concentration
Define hypoglycaemia
Low blood glucose concentration
What does glucagon do?
Stimulates glycogenolyis and promotes gluconeogenesis
Reduces glucose consumption by the liver
Promotes lipolysis
Outline the process of hepatic glycogenesis and glycogenolysis
- Glucose enters the liver
- The enzyme glycogen synthase to convert the glucose to glycogen
- The enzyme glycogen phosphorylase converts glycogen back to glucose
What effect does insulin have on hepatic and adipose tissue lipogenesis
Hepatic- Increases the action of acetyl co enzyme A in converting glucose to fatty acids
Adipose- Increases the amount of glucose entering the adipose tissue, which increases the glycerol and fatty acids produced
Prevents the conversion of triacyglycerol back to glycerol and fatty acids
When is insulin released and when its release stopped?
Released when plasma glucose concentration gets above 4.4 mmol/L
When blood glucose concentration decreases insulin is rapidly removed
Describe Type I diabetes and how is it treated?
Tends to be early onset
Autoimmune disease, which causes the destruction of the pancreas
Beta- cels are unable to produce insulin, meaning there’s no/ little insulin present
Therefore insulin needs to e injected
What are some of the chronic complication of Type I diabetes?
Heart attack and stroke
Kidney problems
Nerve damage
Sexual problems
What is diabetic ketoacidosis?
Life threatening emergency where lack of insulin and high blood sugars lads to a build up ketones
Blood becomes highly osmotic so water leaves cells into blood and cells then become dehydrated
What is Type 2 diabetes and how is it treated?
Often late onset and secondary to obesity
Beta-cells become insensitive to insulin combined with the inability of the Beta- cells to produce appropriate quantities of insulin
Treated via lifestyle changes, exercise, hypoglycaemic drugs and blood pressure control
How is the Oral Glucose Tolerance Test carried out?
Performed in the morning, following a 12hr fast
Oral admission of 75g of glucose
In normal patients the blood glucose concentration will return back to normal after 2 hours
In diabetic patients the blood glucose conc remains high after 2 hrs
How do diabetes test strips monitor blood glucose levels?
0.5-1 ul of blood is used
Blood placed on test strip and reacts with glucose oxidase enzyme to make gluconic acid
Blood glucose meter transfers a current to the test strip
Current changes depending on he amount of gluconic acid that as been produced
How does HbA1c work?
Measures average blood glucose for the last 2-3 months because the half life is aprox 180 days
The more glucose in the blood, the more will stick to red blood cells
Non-diabetics will have a 4-5.9% glycated haemoglobin
Diabetics will have a 6.5% glycated haemoglobin
Outline the gross anatomy of the kidneys
2 kidneys
Both surrounded by perinehric fat
Lie outside the abdominal all
Each supplied by a renal artery
Use up 1/5 of cardiac output
Outline renal function
Produce urine:
Filter glomerulus
Reabsorbtion
Secretion
What are the 3 major types kidney functions?
- Homeostasis
- Excretion
- Synthetic
What is GFR?
Glomerular Filtration rate
Amount of filtrate the kidneys produce each minute
What is the average GFR in healthy kidneys?
100-125 ml/min
What 3 things does the kidney synthesise?
- Synthesis of vitamins D
- Synthesis of renin
- Synthesis of erythropoietin