Endocrinology and Hormones Flashcards
What are the two kinds of endocrine organs. Describe and give examples.
- Primary –> endocrine organs whose primary function is secretion of hormones e.g. pineal gland, hypothalamus, thyroid gland, testes etc.
- Secondary –>endocrine organs which have a non-endocrine primary function. e.g. heart, stomach, liver, kidney, small intestine, skin
What does the pineal gland do?
Produces melatonin and helps to regulate circadian rhythm
What do the hypothalamus and pituitary glands do?
Produce many regulatory hormones which control the function of other endocrine glands
Where is the thyroid gland located and what does it do?
Located in the neck region just below the larynx sitting above and around the trachea.
It Produces hormones T3 and T4 which help to regulate metabolism, it also produces the hormone calcitonin (involved in regulation of calcium)
What does the parathyroid gland do?
- Parathyroid gland produces parathyroid hormone (PTH)
* T3 = tri-iodothyronine and T4 =thyroxine
Where is the thymus?
Lies close to the heart.
Importance of thymus?
- Critical for immune function because T-lymphocytes mature in the thymus
- Produces the peptide hormone thymosin, which stimulates the activity of T cells & antibody production in bone-marrow
Most common thymus disease?
• The most common thymus disease is myasthenia gravis. It arises from the over-production of antibodies directed towards the nAChR at the neuromuscular junction. This causes the muscles to become weak and easily tired.
What is the endocrine function of the pancreas (islets of langerhans)
- Endocrine function is to produce several important hormones: insulin, glucagon, somatostatin, ghrelin (hunger), pancreatic polypeptide
- 99% of pancreas associated with digestion (1% is endocrine)
- Endocrine – linked to blood supply and no ducts.
What are the three broad groups of endocrine disorders?
- Hyposecretion - a gland does not produce enough of its hormones.
- Hypersecretion - a gland produces too much of its hormone, also referred to as
- Tumors develop in the endocrine glands. They may be malignant, or cancerous, but they may also be benign, or non-cancerous.
Examples of hyper secretion:
- Addison’s disease
- Hyperinsulinism
- Cushings disease
- Cogential adrenal hyperplasia
- Graves’ disease
Examples of hyposecretion:
- Type 1 diabetes
- Hypothyroidism
- Type 2 diabetes
Examples of tumour (endocrine disorders)
- Multiple endocrine neoplasia
- Pheochromocytoma
Where are the adrenal glands situated and what is there main responsibilty?
Are situated at the top of the kidneys. Mainly responsible for releasing hormones in response to stress
Adrenal glands have 2 distinct regions:
- Central medulla -> adrenaline & noradrenaline
- Outer cortex -> steroids e.g. cortisol
Cortisol has a negative effect on steroid synthesis
