9. Disruptions to homeostasis Flashcards
What is diabetes mellitus?
A conditon that occurs in people when they have abnormally high blood glucose levels
How does a diabetic person react to insulin?
Either their body doesn’t produce it
Or their cells have an abnormal resistance to insulin and the effects of it
What is the main role of insulin?
Stimulate cells to take in glucose from the blood
Also stimulates the conversion of glucose into glycogen by liver and muscle cells
What happens if a person doesn’t produce or respond to insulin?
The amount of glucose in their blood remains high and they excrete large amounts in their urine
When does Insulin-dependant diabetes begin?
It usually begins in childhood
In Australia, how many people who suffer diabetes, have type 1 diabetes?
10-15%
Why does type 1 diabetes occur?
Because a fault in the patients immune causes the destruction of beta cells in the Islets of Langerhans in the pancreas
Do type 1 diabetes patients respond normally to insulin?
Yes, despite their body not producing it, normally they react to it like anybody else would
Why cant a treatment of type 1 diabetes be tablets?
Because the tablets would go to a persons alimentary canal while insulin needs to enter the bloodstream
What are the treatments for type 1 diabetes?
Regular injections of insulin or a programmable pump that provides a continuous supply of insulin under the skin
Is type 1 diabetes curable?
No, the patient has to receive injections for the rest of their life
What are the risks of type 1 diabetes even if you have regular injections?
Kidney failure Heart attack Stroke Amputation Blindness Nerve damage
When does adult-onset diabetes develop?
Usually in people over 45yo but there has been an increasing amount of people under 45 developing it
What is different about type 2 diabetes patients than type 1?
Type 2, patients are able to produce insulin but their cells don’t respond to it
What are lifestyle factors that increase the risk of type 2 diabetes?
Lack of physical activity Being overweight or obese A diet that's regularly high in fat, sugar and salt, and low in fibre High blood pressure High blood cholesterol Smoking
How many Australians are estimated to know they have type 2 diabetes?
1/2 the people who have type 2 diabetes know they have it
Is there a cure for type 2 diabetes?
No but the sooner a diagnosis is made, the better chance for a successful management plan of the condition
What happens is type 2 diabetes remains uncured?
Increasing risk of heart disease stroke kidney disease eye problems nerve damage skin and foot problems
What are the treatments for type 2 diabetes?
A management program that aims to keep blood glucose levels within normal range careful diet regular physical activity maintaining healthy weight monitoring blood glucose levels Medication if nothing else works
Where is the thyroid gland located and what does it secrete?
Located in the neck and secretes thyroxine (t4) and tri-iodothyronine (T3)
What des thyroxine affect?
Nearly every tissue by stimulating carbohydrate, protein and fat metabolism
Meaning the secretion of T4 regulates basal metabolic rate
How does T4 maintain body temperature?
Some of the energy released from the chemical reactions stimulated by it produced heat
How is T4 important in the long term homeostasis of body temperature?
it gradually changes the body temperature from summer to winter
What is the secretion of T4 controlled by?
Thyroid-stimulating hormone (TSH)
Where is TSH secreted from?
The AL of PG but the release is controlled by the hypothalamus
When does hyperthyroidism occur?
When the thyroid gland produces too much hormone
What is the most common type of hyperthyroidism?
Graves disease
What is hyperthyroidism?
An enlargement of the thyroid caused by an immune reaction, it’s not inherited but seems to have a genetic predisposition
Symptoms of hyperthyroidism:
Rapid heart beat Weight loss Increased appetite Fatigue Sweating Anxiety
How is hyperthyroidism treated?
Treated with drugs that block the thyroid glands use of iodine
Surgery to remove some or all of the gland
Drink radioactive iodine
Iodine molecules are taken in by the thyroid cells which are killed due to radioactivity
Cells elsewhere don’t absorb the iodine
Eventually excreted through urine
What is hypothyroidism?
When there is too little thyroxine and is much more common than hyperthyroidism
When does hypothyroidism occur?
Wither through problems with the thyroid gland or due to problems with the pituitary gland of the hypothalamus
Symptoms of hypothyroidism:
Slow heart rate Unexplained weight gain Fatigue Lack of energy Intolerance to cole Swelling of face and goitre (thyroid)
Explain the thyroid gland problem that is due to lack of iodine
Deficiency of iodine in the diet can prevent the thyroid from making enough hormones
Why is it important to have enough iodine while pregnant?
If you don’t, it affects the babys brain and physical retard development
Baby may be born with cretinism- severly retarded mental and physical growth and impaired movement and hearing
What does cancer of the thyroid mean in terms of producing T4?
Due to cancer, part or all of the gland may be removed making it impossible to produce enough hormones
Treatments for hypothyroidism:
Tablets containing thyroid hormone must be taken for the rest of the patients life.
Needs to be closely monitored as too little prescribed, wont relieve symptoms
Too much prescribed, results in hyperthyroidism
How did diabetes used to be created?
By using insulin from the pancreas of cows and pigs
What was the problems with using animals for diabetes treatments?
Supplies were expensive and limited
Extracts had to be purified and even then patients suffered allergic reaction
What is now used to make insulin for diabetes patients?
Recombinant DNA that was cultured and yeast
How did hypothyroid patients used to be treated?
With tablets made from dried and powdered thyroid glands of animals
What is the most common prescribed drug for thyroid hormone replacement?
Levothyroxine
How is hGH made?
It is synthesised by cells in the APG and is essential for normal growth and metabolism
What does it mean if you have a hGH deficiency?
Results in retardation, dwarfism and can result from either inherited or acquired disease
How did hGH used to be treated?
Previously had to be extracted from PG of deceased people but a single years supply required up to 50 PG, creating significant shortages
How is hGH made now?
Made by genetically engineered E.Coli bacteria which has created a virtually unlimited supply
What else can hGH be used for?
Treat growth problems
Enhance athletes performance
Anti-ageing treatments
How do non-medicinal drugs disrupt homeostasis?
By binding to receptor proteins on neurons and other cells
It can now speed up or slow down the transmission of nerve impulses
How can excessive activity disrupt homeostasis?
Can cause physical damage to structures like tendons, ligaments, muscles, cartilage, bones and joints
Also due to the fact nutrition may not be adequate, might cause muscle mass to be reduced as it is being used for energy
How can eating habits disrupt homeostasis?
Inadequate levels of certain vitamins and minerals in the diet can lead to deficiency diseases
Hypothalamus is main regulator of appetite
How can Emphysema disrupt homeostasis?
Reduces the surface area for gas exchange so there is difficulty taking in oxygen
What is emphysema?
A lung disease in which the walls of alveoli break down, resulting in abnormally large air sac
Most common cause is smoking
How can fevers disrupt homeostasis?
For infectious diseases, a higher body temp helps the immune system overcome infection
It disrupts homeostasis as many of the reactions occurring in the body are heat sensitive
How can hypertension disrupt homeostasis?
High blood pressure occurring when homeostatic responses are unable to keep the blood pressure at normal level
How can injuries disrupt homeostasis?
Excessive blood loss would limit the supply of oxygen and glucose to the cells, and removal of CO2 and other wastes
Punctured or collapsed lung would impair the exchange of gas
