Endocrinology and endocrine disorders Flashcards
The endocrine system and nervous system are required for…
Cell to cell communication
Homeostasis
Regulation of growth, development, reproduction, senescence
Response and adaptation to external environment
What is a hormone?
A chemical messenger produced and secreted by a specialised endocrine gland that is transported in the bloodstream to a distant target organ/cell where it ellicit a physiological response
What are the three classes of hormone?
1) protein/peptide (hydrophilic)
e. g growth hormone
2) Cholesterol derivatives
steroids hydrophobic
vitamin D hydrophobic
3) Modified amino acids
adrenaline hydrophilic
thyroid hormone hydrophobic
Circulating hormone level is influenced by
1) Rate of secretion
- by endocrine gland
2) Rate of metabolism
- by target tissue, blood, liver, kidney
3) Serum binding proteins?
- transport in blood - solubility issue etc..
Responsive tissues must have specific receptors for that hormone……
either: on
cell membrane (water soluble hormone) E.g peptides
Inside cell (lipid-soluble hormones) e.g steroids
regulation of hormone secretion occurs by…
By physiological changes or by feedback mechanism
What are the main types of endocrine dysfunction?
Hyposecretion
hypersecretion
ectopic hormone secretion
end organ insensitivity/resistance
Hyposecretion can be caused by…
Genetics Diet Imunological disease cancer/TB iatrogenic idiopathic
hyposecretion treatment involves…
Hormone replacement
steroids or thyroid hormone straightforward
absorbed in GI tract
high success
Protein hormones
difficult
must be injected
species specific
Hypersecretion can be caused by…
Functional tumour
Ectopic hormone secreting tumour
immunological diseases
also consider
substance abuse
Hypersecretion treatment
Surgical removal of gland (but then need hormone replacement therapy)
Irradiation of gland to reduce function
(replacement therapy)
Antagonists of the hypersecreted hormone
