8. Endocrine system Flashcards
Role of endocrine system
= helps maintain homeostasis in the body
- BGLs, sexual characteristics, reproduction, growth and development, stress response, overall maintenance of the body’s internal environment
What may cause homeostatic imbalance
- May result from elevated or depressed hormones
-May be due to
o Faulty feedback loop
o Dysfunction of the gland
o Altered metabolism of hormones (too fast or too slow)
o Non-endocrine production of hormones cancerous growths
homeostatic imbalances and diseases in the pituitary
- Syndrome of inappropriate antidiuretic hormone
o Sodium is diluted leading to hyponatremia and hypoosmolality
o Results from a brain injury or from a cancer secreting ADH - Diabetes insipidus (low ADH production)
o Either results from a neurogenic cause i.e. insufficient ADH produced or a nephrogenic cause i.e lack of response by target cells in the kidney - Acromegaly
o Abnormal production of growth hormone after the skeleton and other organs finish growing - Gigantism
o Characterised by excessive growth and height significantly above average
o Caused by excessive GH production in childhood
o Patients may grow over 7 foot tall - Dwarfism - Is mainly caused by two disorders
o Achondroplasia - autosomal dominant disorder
o Growth hormone deficiency (also known as pituitary dwarfism)
homeostatic imbalances and diseases in the Thyrroid
Too much or too little production of thyroid hormones may be caused by
- Hypothyroidism major cause is iodine deficiency = decreased production of thyroxine and triiodothyronine
- Hashimoto’s thyroiditis Autoimmune disease where the thyroid gland is attacked by a variety of cell and antibody mediated immune processes
- Hyper thyroiditis (overactive thyroid) thyroid gland produces and secretes excessive amounts of thyroid hormones
o Graves disease
homeostatic imbalances and diseases in the parathyroid
- Major problem is over activity known as hyperparathyroidism.
- Increased PTH causes a calcium imbalance where calcium is taken from the bones and increases in the blood.
- Patients may develop kidney stones, osteoporosis and hypocalcaemia.
- Patients may also have fatigue and depression.
- Hypoparathyroidism is decreased function of the parathyroid glands.
- Blood test reveal low levels of calcium, which can lead to cramps, twitching muscles and eventually tetany
homeostatic imbalances and diseases in the pancreatic
= diabetes mellitus
o Collection of disorders characterise by glucose intolerance, chromic hyperglycaemia (high BGLs) and alterations in protein, fat and carbohydrate metabolism
TYPE 1: autoimmune (destruction of the pancreatic beta cells). As a result they produce insufficient amounts of insulin. Polyuria and polydipsia are common
o Gestational diabetes - glucose intolerance during pregnancy
TYPE 2: is related to diet and life style.
Insulin is produced but either not in sufficient quantities or the insulin receptors on the cells surface become “blind” to insulin
homeostatic imbalances and diseases in the adrenal glands
- Disorders of the adrenal cortex are mostly related to excessive production of hormones
- Hyperaldosteronism may be caused by a primary adrenal cortex problem or a secondary production of aldosterone
o Symptoms include hypertension (due to hypervolemia) Hypokalaemia leading to muscle weakness and alkalosis
o Treatment includes: surgery for an adrenal adenoma or an aldosterone antagonist such as spironolactone - Hypercortisolism is usually the result of Cushing’s syndrome.
- Most common cause of Cushing’s syndrome is exogenous administration of glucocorticoids for asthma, immunosuppression etc.
Pathophysiology of graves disease
Thyroid and parathyroid disorder - Hyperthyroidism
- Autoimmune disease where thyroid stimulating immunoglobulins bind to thee thyroid cells and stimulates the production of too much thyroid hormone
Signs and symptoms of graves disease
- Anxiety and irritability
- Tremor of hands or fingers
- Heat sensitivity
- Increase in perspiration or warm, moist skin
- Weight loss
Tests to diagnose graves disease
Blood tests
- T3 and T4 tests for thyroid function
- Other elevated hormone levels
Radioactive iodine test
Diagnostic imaging of the endocrine organ e.g. MRI, CT
Pathophysiology of hashimoto’s thyroiditis
Thyroid and parathyroid disorder
- Inflammation damages thee gland leading to decreased thyroid hormone production
- Phase of both hyperthyroidism = excess thyroid and hypothyroidism = decrease thyroid hormone production
- Caused by a lack of insufficient insulin or insulin resistance
Signs and symptoms of hashimoto’s thyroiditis
- Goiter – enlarged thyroid gland
- Constipation, fatigue, increased sensitivity to cold, pale and dry skin, hair loss
- Increased thirst (polydipsia) increased hunger, (polychasia) increased urination (polyuria)
tests to diagnose hashimoto’s thyroiditis
Anti-thyroid antibodies tests
Anti-thyroid
Antibodies Tests
Pathophysiology of diabetes mellitus
-Caused by a lack of insufficient insulin or insulin resistance
signs and symptoms of diabetes
-Increased thirst (polydipsia) increased hunger, (polychasia) increased urination (polyuria)
tests to diagnose diabetes
= blood test - glucose testing
Pathophysiology of cushing syndrome
- Too much cortisol
- Pituitary gland produces too much ATCH hormone = too much cortisol
Signs and symptoms of cushing syndrome
- Rapid weight gain, buffalo hump, moon face, hirsutism, baldness, depression and anxiety
Tests to diagnose Cushing syndrome
midnight plasma cortisol or late-night salivary cortisol,
24-hour urinary free cortisol test, and the dexamethasone suppression screening test.
Pathophysiology of Addison’s disease
- Too little cortisol
- Adrenal insufficiency
Signs and symptoms of
Addisons disease
- Chronic fatigue, muscle weakness, weightless, loss of appetite, N and V and Low BP
Tests to diagnose addison’s disease
Blood levels of sodium, potassium and cortisol and ATCH
Pathophysiology of Diabetes insipidus
- Caused by lack of the hormone Vasopressin (ADH)
Signs and symptoms of Diabetes insipidus
Extreme thirst and heavy urination, fatigue, dehydration
Tests to diagnose Diabetes insipidus
Blood testes - glucose testing
What are the cardiovascular effects of increased insulin secretion
- Essentially, increased insulin (hyperinsulemia) is a precursor to insulin resistance which is a failure of your body to control blood glucose levels. In turn, high blood glucose can damage the nerves that control your heart and surrounding blood vessels
- Increased insulin secretion includes thickening of the blood vessels leading to thickening and hardening this increases BP
Microvascular changes that may occur as a result of diabetes
- Damage to the eyes (retinopathy) leading to blindness
- Damage to kidneys (nephropathy) leading to renal failure
- Damage to nerves (neuropathy) leading to impotence
- Diabetic food disorders (which include severe infections leading to amputation)
What changes may impact wound healing in patients with diabetes?
- People with poorly managed diabetes have poor circulation
- Blood supply to the wound is critical for wound healing
- As a results of narrowed blood vessels (poor circulation) diabetic wound healing is impaired because less oxygen can reach the wound and the tissues do not heal properly
what is diabetic ketoacidosis and why does it occur in patient with poorly controlled type 1 diabetes
- A serious complication characterised by extreme hyperglycaemia and usually occurs following a stress such as infection or omission of insulin
The body produces excess blood acids (ketones)
- This condition occurs when there isn’t enough insulin in the body
- Occurs because the body has no insulin before it is diagnosed or poorly controlled type 1 diabetes
Function of tropic hormones?
= is to stimulate other glands for the production of some other hormones, most tropic hormones are secreted by anterior pituitary
Glands and hormones involved in tropic hormones
- TSH which stimulate thyroid gland for thyroxine secretion
- ACTH that stimulate adrenal gland to secrete glucocorticoids
- LH that stimulate release of steroid hormones
- FSH that stimulate production of hormones which help in sperm and ovum maturation
- pituitary gland produces a hormone MSH which stimulate the melanin production which control pigmentation.
