Carbodydrates Flashcards
What are carbohydrates?
Carbs are the major source of energy or ATP to the body.
What form does energy/ATP get into the body?
Glucose
How does the body get glucose?
From carbs in diet or stored glucose.
What is stored glucose?
Glycogen
What is the major source of carbs?
Starch
What are saccharides?
Any series of compounds of C, H and O. Hydrogen to oxygen ratio is 2:1
What are monosaccharides?
4-8 carbon units with one aldehyde unit. These are reducing or simple sugars.
List the three simple sugars or monosaccharides.
Glucose
Fructose
Galactose
What are disaccharides?
These are interactions of two monosaccharides losing a water molecule.
List the three types of disaccharides
Maltose
Lactose
Sucrose
What are polysaccharides?
These are interactions between many units of simple sugars.
Examples of polysaccharides
Starch
Glycogen
Fiber
What enzyme breaks down starch? And where?
Amylase, in saliva and pancreas.
How is starch broken down?
Starch is broken down by amylase in saliva and pancreas into disaccharides and then into monosaccharides and absorbed into intestinal cells.
What happens to monosaccharides in intestinal cells?
Monosaccharides are transported in blood to the liver.
What are the three outcomes of glucose when it reaches the liver?
- Released in the blood
- Stored as glycogen in liver or muscle
- Stored in adipose tissue as fatty acids.
What is glycolysis? What is its outcome?
Glycolysis is the breakdown of glucose to pyruvate and lactate for ATP production stimulated by rise of glucose in cells controlled by insulin, in body’s fed state, which causes a decrease in circulating glucose.
What is glycogenesis? What does it result into?
This is the formation of glycogen from glucose stimulated by insulin in beta cells of the pancreas in the body’s fed state resulting in decreased glucose circulation.
What is glycogenolysis?
This is the breakdown of glycogen with formation of free glucose in hepatocytes and myocytes stimulated by glucagon from alpha cells of the pancreas in the body’s fasting state resulting to increase in glucose circulation.
What is gluconeogenesis?
This is the formation of glucose from amino acids and lipids in the liver stimulated by drop in glucose and glucagon release during fasting state, and increases glucose circulation.
What is insulin? And what are its two functions relating to glucose?
Hormone made in the beta cells of the pancreas that decreases blood glucose by raising cellular intake of glucose and promoting glycogenesis and lipogenesis.
What is glucagon?
Hormone made in the alpha cells of the pancreas that increases blood glucose by stimulating glycogenolysis and gluconeogenesis.
What are other hormones that regulate carbs?
ACTH Epinephrine/adrenaline Growth hormone Thyroid hormones Glucocorticoids
What is hyperglycemia? In what persons is it seen?
This is glucose levels of more than 126 mg/dL seen in DM patients and gestiational diabetes patients
What is hypoglycemia?
These are glucose levels of less than 50 md/dL
When is hypoglycemia seen?
In certain hormone deficiencies
Insulin excess
Some drug reactions, genetic problems, mismanaged DM
What are symptoms of hypoglycemia although it can be asymptomatic?
Nausea Lightheadedness Sweating Shaking Rapid pulse CNS signs like syncope, seizures, coma
What is the main source of energy to the brain?
Glucose
Why are CNS signs symptoms of hypoglycemia?
Glucose is the main source of energy to the brain so very low glucose is detrimental to it.
What glucose level is fatal?
<30 mg/dL
How is neonatal hypoglycemia treated?
It is common and birth but resolves by itself within a few hours.
How is T1 DM related to hypoglycemia?
T1 DM manifests as chronic lack of insulin so there is high spike in glucose. When such patients have an insulin overdose, they are more prone to develop hypoglycemia compared to a normal person.
What is lactic acidosis?
These are high levels of lactate and decreased pH in the blood.
What is lactate?
It is an intermediary in the carb metabolic pathway
What causes lactate acidosis?
Liver dysfunction. Liver normally converts lactate back to pyruvate.
Insufficient oxygen due to shock, sepsis, bleeding excessive exercise.
What is GSD?
It is an inborn error of metabolism in which the body is not able to create or store glycogen. There is an enzyme deficiency in the pathway of glycogen.
What are the tissues most affected by GSD?
Liver and muscle
What are symptoms of GSD?
Hypoglycemia Enlarged liver Weak muscle Cramps Swollen belly Failure to thrive, growth issues