Disruptions to homeostasis

Question 1

Overstimulation or understimulation of messenger systems (Nervous and/or hormonal) can cause?

Answer 1

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

Question 2

Example of disruption to homeostasis:

Answer 2

an undersecretion of insulin could lead to diabetes

Question 3

What causes the disruption to homeostasis to occur ?

Answer 3

• 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

Question 4

Insulin deficiency will cause ?

Answer 4

Diabetes mellitus

Question 5

Explain diabetes mellitus

Answer 5

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

Question 6

Explain type 1 diabetes

Answer 6

• 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

Question 7

How do type 1 diabetes patient gets insulin ?

Answer 7

• 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

Question 8

Explain type 2 diabetes

Answer 8

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

Question 9

Explain how insulin works in normal physiology

Answer 9

Insulin binds to insulin receptors and triggers the opening of glucose transporters in fat and muscle cells, allowing glucose removal from the blood stream

Question 10

Explain how insulin works in type 1 diabetes

Answer 10

Insulin is not produced by beta cells in the pancreas and hence glucose is not removed from the bloodstream, causing diabetes

Question 11

Explain how insulin works in type 2 diabetes

Answer 11

Prolonged overproduction of insulin leads to desensitization of the insulin receptors and hence glucose is not removed from the blood stream , causing diabetes

Question 12

Why blood glucose concentrations however never remain constant?

Answer 12

• 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

Question 13

What is hyperthyroidism?

Answer 13

Graves’ disease
thyroid gland produces too much hormone
enlargement of the thyroid caused due to immune system reaction

Question 14

What are the symptoms of hyperthyroidism?

Answer 14

rapid heartbeat, weight loss, increased appetite, fatigue, sweating, anxiety and, protruding eyeballs

Question 15

What are the treatments of hyperthyroidism?

Answer 15

drugs that block the thyroid gland’s use of iodine, surgery to remove some or all of the gland, drink containing radioactive iodine

Question 16

What is hypothyroidism?

Answer 16

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)

Question 17

What are the symptoms of hypothyroidism?

Answer 17

slow heart rate, unexplained weight gain, fatigue or a feeling of lack of energy, intolerance to cold, swelling of the face and goitre

Question 18

What are the treatments of hypothyroidism?

Answer 18

adequate iodine in the diet, tablets containing thyroid hormone

Question 19

treatment for diabetes using hormone synthetic

Answer 19

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®

Question 20

Advantage of using recombinant DNA technology to produce insulin

Answer 20

• 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

Question 21

treatment for thyroid deficiency using hormone synthetic

Answer 21

tablets made from the dried and powdered thyroid glands of animals, mainly pigs
Levothyroxine = synthetic form of T4

Question 22

Human growth hormone using hormone synthetic

Answer 22

extracted from the pituitary glands of deceased people
made by genetically engineered E. coli bacteria
enhance athletic performance and in anti-ageing treatments

Question 23

explain Behavioral causes of disruptionwith drugs

Answer 23

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

Question 24

Excessive activity can cause

Answer 24

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

Question 25

Unhealthy eating habits

Answer 25

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

Question 26

Hypertension (High blood pressure) are caused by?

Answer 26

Cause by:

• genetic factors,
• excessive salt intake,
• overweight or obesity,
• lack of exercise,
• high alcohol consumption
• kidney disease

Question 27

Smoking can causes

Answer 27

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.