Type 2 Diabetes Mellitus (intro) Flashcards
Type 2 DM accounts for what % of all diabetes cases?
90-95%
What is type 2 DM?
Progressive metabolic disease characterized by insulin resistance & beta cell exhaustion in the pancreas
Define carbohydrate metabolism
The process of breaking down carbs into glucose for energy (ATP production)
Normal glucose regulation:
In presence of O2 breaks down to form ____ & ____
CO2 & water
Normal glucose regulation:
What is the source of energy for cells?
Glucose
Normal glucose regulation:
Where is glucose absorbed in the body?
Into the bloodstream at the intestines
Normal glucose regulation:
We require a continuous supply of glucose for normal _____ function
Normal cerebral function
Normal glucose regulation:
How does the body response to increase in blood sugar levels?
By stimulating the pancreas to release insulin which binds to cell surface membranes, making them more permeable to glucose
Normal glucose regulation:
What happens to glucose after absorption?
Glucose is either used for energy, stored as glycogen in the liver, or converted to fat
Fasting glucose regulation
Even during periods of fasting (i.e. sleep), a small amount of glucose is constantly secreted to maintain body functions (basal glucose production)
Carbohydrate metabolism:
What happens when the body needs more energy?
The glycogen & fat can be converted back into glucose
Carbohydrate metabolism:
Where can excess glucose be excreted?
In the urine (esp. after a high carb meal)
Carbohydrate metabolism:
What happens in between meals?
In between meals the liver releases glucose into the bloodstream & the pancreas releases a small (basal) amount of insulin
What is the most dense form of fuel storage?
Fats
Fat Metabolism of triglycerides breaks down into what?
Glycerol molecules & 3 fatty acids
Fat metabolism:
Glycerol molecule
Can enter glycolytic pathway & be used with glucose for energy
Fat metabolism:
Fatty acids
Stored in tissue & can be used for energy (during starvation)
What can happen if we are using fatty acids as an energy source?
Can lead to ketoacidosis (undesirable accumulation of ketones in blood)
What are considered the building blocks of proteins?
Amino acids
How are amino acids stored in the body?
Excessive AA can only be stored in limited amounts in the body
What may be broken down for energy in the absence of carbs & fats
Proteins (NOT preferred source)
What is glycolysis? & how does it work?
Glucose breakdown
Glycolysis pathway breaks down glucose into ATP & is vital for cellular function
Explain how glucose molecule breaks down
Glucose breaks down into pyruvate, NADH, & ATP
Is excess glucose in the bloodstream effective for energy use?
NO
What is glycogenesis?
Process of glycogen formation when glucose supply exceeds need for ATP synthesis
How long is glucose stored in the cells?
Stored in cells to saturation point for ~ 12-24 hrs
The amount of glycogen formed is dependent on ____ ____
Energy demand (i.e. sitting vs. exercising)
Where is glycogen mainly stored in the body?
Liver & muscles (i.e. skeletal)
What is the reverse process of glycogenesis?
Glycolysis
What is glycogenolysis?
Breakdown of stored glycogen to make glucose
When does glycogenolysis occur?
When glucose levels become too low (i.e. prolonged starvation)
Where does the process of glycogenolysis occur in the body? What is it in response to?
Occurs in the liver & muscle tissue in response to hormonal & neural signals:
1) epinephrine
2) glucagon
3) insulin
What does glycogenolysis inhibit?
Glucogenesis
What is gluconeogenesis?
Synthesis of glucose by the liver from non-carbohydrate sources
Where does gluconeogenesis occur in the body?
Primarily the liver
Gluconeogenesis:
What happens in cases of starvation/ prolonged fasting?
AA and fats are converted to glucose
1) from stored fat to fatty acids &/or glycerol
2) AA to lactic acid
Gluconeogenesis can lead to development of ____
ketones → which can lead to ketoacidosis
Gluconeogenesis plays a role in…
acid-base balance
What kind of functions does the pancreas have?
has BOTH endocrine (hormone-producing) & exocrine (digestive enzyme-producing) functions
Exocrine acini → digestive juices → duct → duodenum
Islets of Langerhans in the pancreas contains:
1) Beta cells → insulin; amylin
2) Alpha cells → glucagon
3) Delta cells → Somatostatin
4) F/PP cells → pancreatic polypeptide
List 5 actions of insulin
1) Glucose uptake in muscle & adipose tissue
2) glycolysis
3) glycogen synthesis
4) protein synthesis
5) uptake of ions (esp. K+ and PO4)
List 5 things insulin stops
1) Gluconeogenesis
2) glucogenolysis
3) lipolysis
4) ketogenesis
5) proteolysis
What is insulin?
Hormone released by beta cells in Islets of Langerhans in the pancreas
Insulin also play a role in producing ___ ___
Nitric oxide → helps maintain healthy endothelial tissue & support beta cell health
Insulin is required by body cells to initiate what?
active transport of glucose into the cell
1) skeletal cells → store glucose as glycogen
2) adipose tissue → stops release of fatty acids
3) Liver → stops gluconeogenesis, starts producing glycogen & fat
Insulin stimulates the ____, ____, & ____ of glucose
uptake, use & storage of glucose
List 3 types of glucose regulating hormones
1) Amylin
2) Somatostatin
3) Counter-regulatory hormones
- Epinephrine
- Cortisol
- Growth hormone
How does amylin work?
Slows glucose absorption in the SI; suppresses glucagon secretion (manages postprandial blood sugar)
How does somatostatin work?
Decreases GI activity; suppresses glucagon & insulin secretion. Secreted with heavy fat/ high carb meal
How do counter-regulatory hormones work?
They counteract insulin & raise blood glucose levels when needed
List 1 examples of an incretin. List 5 examples r/t incretins
1) Glucagon-like peptides (GLP-1)
2) growth hormone (GLP-1 can influence GH secretion)
3) cortisol (excess can impair GLP-1 signaling)
4) epinephrine (opposing effects on glucagon)
5) progesterone (r/t glucose homeostasis; can stimulate incretins)
6) estrogen (not fully understood)
How do GLP-1’s work? Hint: 5
1) Released after meals
2) stimulate insulin secretion
3) suppresses glucagon
4) delays gastric emptying
5) increases satiety
How does estrogen work?
Increases beta cell activity, which may help explain the cardioprotective effects seen in premenopausal women
After menopause, women are at increased risk of?
CV disease & type 2 DM, esp. with unhealthy lifestyle habits
What secretes glucagon?
alpha cells in the pancreas
Glucagon causes the liver to..
breakdown stored glycogen to produce glucose (glycogenolysis)
List 2 things activated by glucagon
1) activation of gluconeogenesis in liver
2) activates lipase, to break down adipose tissue into fatty acids
Question 1:
When blood sugar level is high will insulin or glucagon be released?
Insulin
Question 2:
When are insulin levels their highest?
occur ~ one hour after meals
Question 3:
When are insulin levels their lowest?
Occur during fasting (i.e. overnight)
Question 4:
When do you have your highest glucagon levels?
Occur during fasting to help raise blood glucose levels
What is normal glucose levels
70-100 mg/dL
Pre-diabetic fasting glucose levels
101-125 mg/dL
Diabetic fasting glucose levels
> 126 mg/dL
Classifications of diabetes Hint: 5
Type 1
1) Type 1A → autoimmune destruction of pancreatic beta cells
2) type 1B → idiopathic diabetes
Type 2
Pre-diabetes
Gestational
Drug induced
