Diabetes mellitus
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Transcript of Diabetes mellitus
What you do this lesson
• Copy all notes that appear in blue or green
• Red / White notes are for information and similar notes will be found in your monograph
• Read up on all diabetes information in your monograph for the next lesson
What is Diabetes mellitus?
A failure to control blood glucose levels and an impaired ability to store glucose in the form of liver
and muscle glycogen
Symptoms of diabetes mellitus
Classic symptoms of diabetes are –• Frequent urination, with large volumes of urine (especially at night)• Excessive thirst• Hunger• Weight loss
Other symptoms –• Fatigue• Blurry vision• Gum and urinary tract infections• Slow healing of skin• Genital itching in women
CONTROL OF BLOOD SUGAR LEVELS
• After a meal excess glucose is stored as glycogen in the liver and skeletal muscles)
• As glucose levels fall, the liver releases glucose into the blood stream to prevent hypoglycaemia.
Two hormones control this process -Insulin and Glucagon
Both are secreted in the pancreas by the Islets of Langerhans
Beta (β) cells produce insulin Alpha (a) cells produce glucagon
Insulin and its effects
Insulin is a protein hormone which binds to specific receptors on the cell membrane of target cells and initiates the following
• Insulin binds to receptor
• Activated insulin receptor promotes movement of glucose transporter molecules from intracellular pool to the cell membrane
• Glucose transporters allow glucose to enter the cell
• When insulin levels decrease glucose transporters move from cell membrane to intra-cellular storage pool, where they can be recycled
Insulin• Affects skeletal muscle , liver and fat cells and
stimulates the uptake of glucose by these cells
• Insulin increases the permeability of muscles to glucose as normally they are not very permeable
• Liver cells are very permeable but become more so in the presence of insulin and they are also stimulated to increase glycogen formation
In obese individuals the number of insulin receptors decreases and therefore glucose uptake is decreased.
This reduction in receptors leads to insulin resistance
Glucagon
Low blood glucose
Alpha cells of pancreas release glucagon
Liver breaks down glycogen
Glucose released into blood
Complications associated with diabetes –
• Hypertension
• Stroke
• Kidney disease
• Nerve damage
• Increased risk of atherosclerosis
• Impaired vision due to cataracts or damaged retinas.
Forms of diabetes mellitus
• Type 1 (early onset, insulin dependent diabetes mellitus
IDDM)
• Type 2 (late onset, non-insulin dependent diabetes mellitus
NIDDM)
Type 1 (IDDM)
• Failure of the pancreas to produce adequate amounts of insulin as a result of an autoimmune response
• Accounts for 5-10% of cases
• The sympton weight loss is caused by body breaking down fat to supply energy as cells cannot utilise glucose
• Treatment = regular insulin injections subcutaneously
Type 2 (NIDDM)
• Accounts for 95% of cases• Associated with obesity• Plasma insulin levels normal but cells are
less sensitive to insulin (insulin resistance)• Reduced uptake of insulin into skeletal
muscle and fat cells• Possibly due to a reduced number of insulin
receptors on the cell membrane
In summary insulin is produced but not used
efficiently by the cells
pancreas compensates by producing more insulin
B cells become “worn out” and insulin production decreases
Blood glucose increases and diabetes develops
Treatment for NIDDM
• Diet • Weight control• Adequate exercise• Begin an insulin
increasing agent• Lower blood pressure