Chapter 11 - Disruptions to Homeostasis Flashcards Preview

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Flashcards in Chapter 11 - Disruptions to Homeostasis Deck (72):

What is a good example of a hormonal problem that can cause serious disruption to homeostasis?

Diabetes (Diabetes Mellitus)


How does Diabetes affect a person?

-A person with diabetes has an abnormally high blood glucose level, a condition called hyperglycaemia.

-A diabetic either does not produce enough insulin or their cells have an abnormal resistance to the effects of insulin.


What is the main role of Insulin?

-To stimulate cells to take in glucose from the blood.

-It also stimulates conversion of glucose into glycogen by liver and muscle cells.


What happens when a person produces insufficient insulin or if their cells are resistant to the effects of insulin?

The amount of glucose in the blood remains high and they excrete large quantities in the urine.


What are the two forms of Diabetes ?

1. Type 1 Diabetes
2. Type 2 Diabetes


What is Type 1 Diabetes?

Sometimes called Insulin Dependent Diabetes, usually begins in childhood and therefore used to be called juvenile diabetes.


How many percent of Australians suffer from Type 1 Diabetes?

10-15% of Diabetes patients suffer from Type 1.


Why does Type 1 Diabetes occur?

-It occurs because a fault in the patient's immune system causes the destruction of beta cells in the islets of Langerhans of the pancreas.

- Since beta cells produce insulin, a person with type 1 Diabetes does not produce insulin.

-In most cases the patient's cells respond to insulin in the normal way, so the disease can be managed by giving the patient insulin.


What is the treatment for Type 1 Diabetes ?

-Insulin cannot be taken in tablet form because it is digested in the alimentary canal.

-The only treatment is regular injections of insulin or use of a programmable pump that provides a continuous supply of insulin under the skin.


Is there a cure for Type 1 Diabetes?

- Insulin injections do not cure type 1 diabetes.

-The patient must have regular injections to stay alive, but even with injected insulin the long-term effects are likely to be kidney failure, heart attack, stroke, amputations, blindness or nerve damage.


What is Type 2 Diabetes?

-AKA Non-insulin dependent or Adult Onset Diabetes

-It usually develops in people over the age of about 45 years, although increasing numbers of younger people are now being diagnosed.

-Type 2 patients are able to produce insulin but their cells do not respond to it.

-It is a lifestyle disease; it is more common in people who are not physically active and are overweight or obese.


Why is the incidence of Type 2 diabetes in Australia, and other affluent countries, increasing rapidly?

It is due to the larger number of people who do not adopt a healthy lifestyle.


What are some lifestyle factors that increase the risk of developing type 2 diabetes?

- Lack of physical activity.
- Being overweight or obese.
- A diet that is regularly high in fat, sugar and salt, and low in fibre.
- High blood pressure.
- High blood cholesterol.
- Smoking.


What are the symptoms of Type 2 Diabetes?

-Type 2 Diabetes develop gradually and often there are no symptoms or they are not noticed.

-It is estimated that about half of Australians who have type 2 diabetes have not yet been diagnosed.

-Because the cells do not respond to insulin, they do not take up glucose from the blood.


Is there a cure of Type 2 Diabetes?

-There is no cure for type 2 diabetes, but the earlier a diagnosis is made the better the chances of successful management of the condition.


What happens if Type 2 Diabetes is remained undiagnosed or untreated?

- There is an increasing risk of complications such as heart disease, stroke, kidney disease, eye problems, nerve damage and skin and foot problems.


What are some of the treatments possible to reduce Type 2 Diabetes?

- Careful diet
- Regular physical activity
- Maintaining a healthy weight
- Monitoring blood glucose
- Medication if blood glucose cannot be controlled by other meausres.


What 2 hormones does the Thyroid Gland secrete?

1. Thyroxine (T4)
2. Tri-iodothyronine (T3)


What is the role of Thyroxine?

1. Thyroxine affects nearly every tissue in the body by stimulating carbohydrate, protein and fat metabolism.

=Regulates basal metabolic rate.

2. Some of the energy released from the chemical reactions stimulated by the thyroxine is in the form of heat that is important in maintaining body temperature.

=Important in the long-term homeostasis of body temperature, such as in the gradual change in metabolic rate that occurs from summer to winter.


What controls the secretion of Thyroxine?

Thyroid Stimulating Hormone (TSH)

-TSH is secreted by the anterior lobe of the pituitary but its release is controlled by the hypothalamus in the brain.


What happens when there is an excess of or a deficiency in thyroxine?

-It can both cause disorders.

-In some cases the imbalance of thyroxine can be due to an imbalance in TSH.


What is Hyperthyroidism?

Too much thyroxine.


When does Hyperthyroidism occur?

Occurs when the thyroid gland produces too much hormone.


What is Grave's disease?

- Most common type of Hyperthyroidism.

-It is an enlargement of the thyroid caused by an immune system reaction.

-Although not inherited, there does seem to be a genetic predisposition for the condition.


What are the symptoms of Grave's disease?

When the cells are overstimulated, the symptoms of hyperthyroidism are:

-Rapid heart beat
-Weight Loss
-Increased appetite
-Protruding eyeballs (aka Exophthalmia)


How can Hyperthyroidism be treated?

1. It can be treated with drugs that block the thyroid gland's use of iodine

2. By surgery to remove some or all of the gland.

3. Give the patient a drink containing radioactive iodine.


What does radioactive iodine molecules do?

-They are taken up by the thyroid cells, which are then killed by the radioactivity.

-Cells elsewhere in the body do not absorb iodine and are unaffected.

-The radioactive iodine is eventually excreted in the urine.


What is the Hypothyroidism?

-Too little thyroxine.

-Much more common than hyperthyroidism.

-About 6-10% of Australian women may be affected and aa smaller proportion of men.

-Occurs either through problems with the thyroid gland or due to problems with the pituitary gland or hypothalamus.


Explain the structure of a Thyroxine and tri-iodothyronine molecule.

-A thyroxine molecule contains four iodine atoms (hence T4)

-A tri-iodothyronine molecule contains three atoms of iodine (hence T3)


How does the thyroid gland become enlarged?

-When there is a deficiency of iodine in the diet which can prevent the thyroid gland from making enough hormones.

-The thyroid gland may then become enlarged in an effort to increase hormone production.

-Enlargement of the thyroid is known as Goitre.


Is iodine deficiency always visible in a person suffering from it?

No, many people suffer from Iodine deficiency without it being severe enough to produce visible swelling of the neck.


How many Australians suffer from Iodine deficiency?

About 46% of people are affected, so iodine deficiency is now a public health problem.


What did the government do to ensure that people get sufficient Iodine?

The federal government introduced compulsory addition of iodine into most breads in September 2009.


Why is adequate iodine very important during pregnancy?

-Deficiency of iodine in the mother's diet affects development of the baby's brain and also retards physical development.

-In serious cases, the baby may be born with severely retarded mental and physical growth and impaired movement or hearing, a condition known as cretinism.


What are some causes of Hypothyroidism?

-Hashimoto's disease; A common cause, which is an attack on the thyroid gland by the patient's immune system.

-Surgery for cancer of the thyroid that involves removal of all, or a large part, of the gland.


List 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


List the treatments of Hypothyroidism?

- Tablets containing thyroid hormone are prescribed.

- No cure and the hormone tablets must be taken for the rest of the person's life.

-The dose of thyroid hormone must be carefully monitored because too little will not relieve the symptoms of hypothyroidism but too much will result in hyperthyroidism.


List the behavioural causes of disruption.

-Excessive Activity
-Eating habits


What type of drugs can cause disruption?

-Many medicinal drugs help the body to maintain homeostasis.

-Non-medicinal drugs may disrupt homeostasis.


How do non-medicinal drugs cause disruption?

-Many of them do this by binding to receptor proteins on neurons and other cells.

-The drug molecule may be similar to a particular neurotransmitter, and by binding to the receptor site it can speed up or slow down the transmission of nerve impulses.


Describe Caffeine.

-Most widely used drug in the world.

-Stimulates metabolism and the central nervous system so that people use it to make them feel more alert and energetic.


Describe Caffeine in relation to Homeostasis.

- Caffeine binds to receptors on the surface of heart muscle fibres and mimics the effect of adrenaline.

-In this way it seems to increase HR, although there is conflicting evidence on this, Caffeine increases blood flow through the lungs and relaxes involuntary muscles in the bronchioles increasing air movement in and out of the lungs.

-Caffeine is sometimes used to treat breathing problems in premature babies.


Describe Alcohol.

-Another drug that is widely used in most societies.

- It depresses the central nervous system, producing feelings of relaxation.


Describe Alcohol in relation to Homeostasis.

Lots of side effects:

-stimulation of insulin production which, in turn, speeds up glucose metabolism resulting in a lowering of blood sugar levels.

-it inhibits production of antidiuretic hormone, which reduces water reabsorption in the kidney leading to increased urine output and dehydration.


What is Amphetamine and methamphetamine?

-Used medicinally, but they are also used as recreational drugs.

-They enter the brain and cause the release of noradrenaline, dopamine and serotonin.


What is the role of Noradrenaline and dopamine?

-They are both neurotransmitters and hormones.

-Serotonin is a neurotransmitter.

-Amphetamines may improve alertness and motivation and may help a person to think more clearly, but they also influence homeostasis by affecting things such as appetite and weight control.


Describe MDMA/ecstasy.

-It is a synthetic amphetamine.

-It causes the release of noradrenaline and dopamine, and the accumulation of serotonin.

-Ecstasy initiates the body's fight-or-flight response so that the user feels more energetic.


Describe MDMA in relation to Homeostasis.

-Increases heart rate and blood pressure
-Increases breathing rate
-Causes sweating and dehydration
-Decreases appetite
-High doses may cause a rapid rise in body temperature and blood pressure, heart palpitations and vomiting.


What does Cocaine do?

It blocks the removal of the neurotransmitters dopamine, noradrenaline and serotonin from the synapse between nerve cells.


Describe Cocaine in relation to Homeostasis.

-It stimulates the central nervous system

-Increases in heart rate, blood pressure, body temperature, breathing rate, dilated pupils and loss of appetite.


Describe Heroin.

-Can be used medicinally as a powerful painkiller but is more often used as a recreational drug.

-When injected, the drug rapidly enters the brain and binds to receptors resulting in intense, euphoria, decrease in perception of pain and relief in intense euphoria, decrease in perception of pain and relief from anxiety.


Describe Heroin in relation to Homeostasis.

-Heroin has profound effects on homeostasis especially the control of breathing.

-Breathing rate slows down (and may even stop), blood pressure and body temperature drop, and heartbeat may become irregular.

-Due to these effects on homeostasis, a large dose of heroin may cause unconsciousness, coma of death.


Can exercise be bad for you?

Yes, excessive activity can cause physical damage to structures such as tendons, muscles, ligaments, cartilage, bones and joints.


How can excessive activity disrupt homeostasis?

•If nutrition is inadequate, excessive exercise can cause the protein in muscle to be broken down for energy.

•Instead of building muscle, muscle mass may be reduced.

•There is a strong link between eating disorders, such as anorexia and bulimia, and excessive exercise.

•Can cause great stress on the heart and can lead to cardiovascular problems.

•Affects calcium metabolism.


How does excessive activity affect calcium metabolism?

While regular exercise can increase deposition of calcium in bones, making them stronger, over-exercise can lead to a loss of calcium from bone.

-Osteoporosis (reduced bone density)


What is Amenorrhoea?

•Occurs in women who engage I a lot of physical exercise (such as top athletes) whom may cease menstruation.

•This occurs when their energy intake is inadequate for the level of physical activity.

•It seems that in order to conserve energy, menstruation stops.

•Amenorrhoea greatly increases the risk of osteoporosis.


What are some deficiency diseases caused by eating habits?

•Pernicious Anaemia


Why do our body need iron?

Without iron the body cannot make hemoglobin, the pigment in red blood cells that carries oxygen.


What is Anaemia?

It it the deficiency of hemoglobin, or of red blood cells.


What happens when there is an insufficient amount of haemoglobin?

•The blood cannot carry enough oxygen to the cells.

•This slows the rate of cellular respiration and thus the release of energy.

•An anemic person may feel weak, fatigued and breathless and have a high heart rate.


What is Pernicious Anaemia?

It is another cause of Anaemia which is a deficiency of vitamin B12 in the diet.


List the properties of Vitamin K.

- Vitamin K is essential for blood clotting.

- Bacteria in the large intestine make most of our vitamin K with a little coming from food.


Why is it that in Australian hospitals parents of newborn infants are routinely offered a vitamin K injection for their baby?

-To guard against the chance of excessive bleeding.

-This is because babies are born without any gut bacteria, and there is little vitamin K in breast milk, so young babies can have severe bleeding.


What is a Menopause?

It is the when a woman's ovaries stop releasing eggs and cease secretion of oestrogen and progesterone so that menstruation stops.


Facts about Menopause.

1. In most women it occurs between the ages of 48 and 55.

2. Prior to menopause, there is a period of 2 to 6 years during which hormone secretions gradually decline and ovulation and menstruation becomes irregular.

3. 20% of women experience no symptoms leading up to menopause; for 60% the symptoms are mild. but the remaining 20% symptoms are severe.


What is the correct meaning of the term 'menopause'?

It is cessation of menstruation, but in everyday use it refers to the whole period of gradual decline in oestrogen and progesterone secretion and the accompanying changes.


What are the symptoms that accompany this period of change?

- hot flushes and night sweats
- crawling, prickling or itching sensations under the skin
- headaches
- thinning and dryness of the walls of the vagina
- aches and pains
- frequent urination
- reduced sex drive
- tiredness and irritability
- disturbances in mood, loss of self esteem and depression
- sleeping difficulties


What are the treatment available for Menopause?

Menopause is not an illness; it is a natural event and therefore does not necessarily require medical treatment.

1. MILD - regular exercise and healthy eating habits usually enable them to cope with the changes occurring in their bodies.

2. MODERATE - there are herbal and other natural remedies that can help.

3. SEVERE - hormone replacement therapy (HRT).


What is Hormone Replacement Therapy (HRT)?

It is when the woman is given oestrogen and progesterone to make up for her body's loss and to try to smooth out irregularities in their natural secretion.


How does HRT take place?

The hormones are given in the form of pills, patches, gels, implants or a nasal spray.


What are the risks involved with HRT?

-Women are usually advised to take the lowest effective dose of hormones for the shortest possible time.

-Hormone therapy must be carefully managed to suit the individual's needs.


What are some side effects of HRT?

-Breast Tenderness

- Risk of developing breast cancer
- Cardiovascular disease
- Thrombosis (clots in the blood vessels)