AOS 2 unit 16E Malfunctions in homeostasis

type 1 diabetes

an autoimmune disease in which beta cells of the pancreas are destroyed, resulting in an inability to regulate blood glucose levels

What causes type 1 diabetes?

-body’s immune system recognises beta cells in the pancreas as non-self and attacks them using autoantibodies 

leads to

- no insulin

-blood glucose are left un regulated

-alpha cells are also impaired and can no longer function properly.

autoantibodies

proteins created by the immune system that destroy an organism’s own tissues

type 2 diabetes

a disease  in which the body becomes resistant to the effects of insulin and/or doesn’t produce enough insulin to maintain normal blood glucose levels

What can lead to hypoglycaemia and hyperglycaemia

As a result of beta cell attack, people with type 1 diabetes are insulin deficient

hyperglycaemia

the state of having blood glucose levels above the normal range (>7.8 mmol/L)

Why is insulin important for the regulation of blood glucose levels?

 it facilitates the entrance of glucose into cells as well as the production of glycogen. Because glucose can’t be absorbed by people with type 1 diabetes, they are at risk of hyperglycaemia. 

Short term effects of type 1 diabetes

increased urination and excessive thirst

– if levels of glucose in the blood are high, glucose can push through the walls of the glomerulus and end up in the kidney filtrate.

-The presence of glucose in the filtrate increases its osmolality, meaning that the normal osmotic processes that reabsorb water in the nephron don’t function properly.

-As a result, water remains in the filtrate and a larger amount of dilute urine is produced .

-This can cause a person with type 1 diabetes to lose large amounts of water, become dehydrated, and feel thirsty

• excessive hunger and lethargy

- because their cells aren’t receiving the glucose they need to function properly, people with type 1 diabetes often feel tired and lethargic. 

-In an attempt to correct the lack of glucose entering the system, the body stimulates  the sensation of hunger • 

weight loss – the loss of large amounts of water and the inability of cells to grow  and function normally due to a lack of glucose can lead to weight loss in people with type 1 diabetes.

Long term effects of type 1 diabetes

vision loss – the tiny vessels carrying blood to the eye become damaged and leaky, leading to swelling and reduced blood flow

) • heart disease and stroke – the blood vessels supplying the heart and brain can become damaged and blocked, causing cells to be deprived of oxygen and die 

• tingling or numbness in the feet and/or hands – nerves are sensitive to elevated blood glucose levels and can become damaged

 • prolonged wound healing – the damaged blood vessels in people with long term wounds take longer to heal or won’t at all

• kidney damage – the blood vessels that carry blood to the kidney are very small and sensitive, and can easily be damaged by increased blood glucose levels.

hypoglycaemia

the state of having blood glucose levels below the normal range (<4.0 mmol/L)

How can someone become hypoglycaemic

• Too much insulin injected

• Not enough food

• Too much exercise

• ↓ glucagon (alpha cells also impaired)

Effects of hypoglycaemia

• Weakness, dizziness

• Can lead to loss of consciousness or death

Management of Type 1 Diabetes

• Insulin injections (short + long acting)

• Insulin pump (automatic control)

• Regular blood glucose monitoring

Hyperthyroidism

condition where the thyroid gland produces too much T3 and T4, increasing metabolic rate.

triodothyronine

a hormone produced and secreted by the thyroid gland. Also known as T3

-regulating metabolism, growth, body temperature, and heart rate

thyroxine

-a hormone produced and secreted by the thyroid gland. Also known as T4

-essential for regulating metabolism, heart function, muscle control, and brain development.

Graves diseaae (autoimmune)

-The immune system produces an autoantibody called thyroid-stimulating immunoglobulin (TSI)

-antibody recognises and binds to the TSH receptors on the thyroid, stimulating the thyroid to release T3 and T4

Leads to

-elevated levels of thyroid hormones

-constant stimulation to release hormones

The components of the body when thyroid levels are elevated

Treatment

• Medication (reduce hormones)

• Radioactive iodine

• Surgery (remove thyroid)