Disruptions to homeostasis Flashcards
Overstimulation or understimulation of messenger systems (Nervous and/or hormonal) can cause?
Disruptions to nervous transmission could be due to excessive action potentials transmitted or too few action potentials transmitted
Disruptions to homeostasis occur when there is an oversecretion or an undersecretion of hormones that regulate homeostasis
Example of disruption to homeostasis:
an undersecretion of insulin could lead to diabetes
What causes the disruption to homeostasis to occur ?
- Naturally occurring conditions/ diseases/ changes to biological systems/ genetics
- Behaviour: adopting lifestyle choices such as smoking or taking certain drugs that mimic neurotransmitters or certain hormones
Insulin deficiency will cause ?
Diabetes mellitus
Explain diabetes mellitus
Hyperglycemia: abnormally high blood glucose level
Diabetic person:
-does not produce enough insulin
-cells have an abnormal resistance to the effects of insulin
-Resulting in glucose accumulating in blood and thus cannot be used by cells
Explain type 1 diabetes
- begins in childhood (juvenile diabetes)
- fault in the patient’s immune system = destruction of beta cells
- Unable to produce insulin or produce very little insulin
How do type 1 diabetes patient gets insulin ?
- need to take insulin several times a day via injection
- use of a programmable pump provide a continuous supply of insulin under the skin
- constant monitoring of blood sugar levels and carbohydrate intake is part of life with type 1 diabetes
Explain type 2 diabetes
non-insulin-dependent or adult-onset diabetes
affects people over the age of about 45 years
able to produce insulin but their cells do not respond to it
lifestyle disease
develops gradually and often there are no symptoms
management program to keep blood glucose levels within the normal range
Explain how insulin works in normal physiology
Insulin binds to insulin receptors and triggers the opening of glucose transporters in fat and muscle cells, allowing glucose removal from the blood stream
Explain how insulin works in type 1 diabetes
Insulin is not produced by beta cells in the pancreas and hence glucose is not removed from the bloodstream, causing diabetes
Explain how insulin works in type 2 diabetes
Prolonged overproduction of insulin leads to desensitization of the insulin receptors and hence glucose is not removed from the blood stream , causing diabetes
Why blood glucose concentrations however never remain constant?
- Reason : inevitable time delay between the change in the blood glucose concentration and the onset of actions to correct it
- results in oscillation / fluctuations in glucose levels
What is hyperthyroidism?
Graves’ disease
thyroid gland produces too much hormone
enlargement of the thyroid caused due to immune system reaction
What are the symptoms of hyperthyroidism?
rapid heartbeat, weight loss, increased appetite, fatigue, sweating, anxiety and, protruding eyeballs
What are the treatments of hyperthyroidism?
drugs that block the thyroid gland’s use of iodine, surgery to remove some or all of the gland, drink containing radioactive iodine
What is hypothyroidism?
Hashimoto’s disease
problems with the thyroid gland, problems with the pituitary gland or hypothalamus, surgery for cancer of the thyroid, iodine deficiency (pregnancy = cretinism in babies)
What are the symptoms of hypothyroidism?
slow heart rate, unexplained weight gain, fatigue or a feeling of lack of energy, intolerance to cold, swelling of the face and goitre
What are the treatments of hypothyroidism?
adequate iodine in the diet, tablets containing thyroid hormone
treatment for diabetes using hormone synthetic
injections of insulin
obtained from the pancreas of cows and pigs
allergic reactions or infections
1980s, genetically engineered human insulin was produced
recombinant DNA - Humulin®
Advantage of using recombinant DNA technology to produce insulin
- constant/reliable supply all year round/unlimited supply;
- less risk of contamination/infection;
- identical to insulin produced in the body so less risk of allergic reactions/ immunologic reactions;
- can be produced without the killing of animals;
- cheaper/easier to extract and purify;
- more available/large amount;
- more rapid response;
- overcomes problems related to dev. of tolerance to pig/cattle insulin
- No religious objections
treatment for thyroid deficiency using hormone synthetic
tablets made from the dried and powdered thyroid glands of animals, mainly pigs
Levothyroxine = synthetic form of T4
Human growth hormone using hormone synthetic
extracted from the pituitary glands of deceased people
made by genetically engineered E. coli bacteria
enhance athletic performance and in anti-ageing treatments
explain Behavioral causes of disruptionwith drugs
non-medicinal drugs: alcohol or ecstasy
may disrupt homeostasis
drug molecule may be similar to a particular neurotransmitter
binds to the binding-site of receptor/ complementary to the binding-site
speed up or slow down the transmission of nerve impulses
Excessive activity can cause
can cause physical damage to structures such as tendons, muscles, ligaments, cartilage, bones and joints
can cause the protein in muscle to be broken down for energy due to inadequate nutrition
muscle mass may be reduced
Unhealthy eating habits
Inadequate levels of certain vitamins and minerals in the diet = deficiency diseases
deficiency of iron in the diet = deficiency of haemoglobin = anaemia
blood carry less oxygen = rate of cellular respiration is low = low energy levels
weak, fatigued and breathless, high heart rate
deficiency of vitamin B12 in the diet = pernicious anaemia
Hypertension (High blood pressure) are caused by?
Cause by:
- genetic factors,
- excessive salt intake,
- overweight or obesity,
- lack of exercise,
- high alcohol consumption
- kidney disease
Smoking can causes
Walls of the alveoli (air sacs) break down, resulting in abnormally large air spaces.
Results in a chronic condition called emphysema
reduces the surface area available for gas exchange = difficulty taking in enough oxygen.
