Hormone Synthesis and Action Flashcards
What are the differences between endocrine and nervous system
Endocrine
- Hormone
- Slow
- Long lasting
- Widespread effect
Nervous System
- Neurotransmitter
- Fast
- Short lived
- Localised effect
How is hormone action regulated
Negative feedback - glands may release hormone or hormone itself signals
Postive feedback - Sense changes and activates mechanism to amplify it
What are the 3 types of hormones
Protein hormones
Steroid hormones
Amine hormones
What are protein hormones
Hydrophilic - transported in blood
Preformed + stored in vesicles
Formed from pre/pro-hormones
Describe the synthesis of steroid hormones
Synthesis in SER as required
Hydrolysis of esters & release of cholesterol
Cholesterol to pregnenolone occurs in mitochondria and is RDS
Processing of pregnenolone in SER
What is unique about steroid hormones
Lipid soluble
How are steroid hormones eliminated
Inactivating metabolic transformations and excretion in urine/bile
What are amine hormones
Thyroid hormones
Tyrosine deriviatives
Small, non-polar, lipophilic
How are steroid and amine hormones transported in blood
Bind onto carrier protein to increase solubility in blood and half life
What is the site of action for peptide hormones
Cell surface receptor
Binding activates cascade
What is the site of action for steroid hormones
Intracellular receptors
Act of genome
What are the types of hormone dysfunction
Overproduction = caused by tumour or exogenous admin of hormone. Treatment = surgical removal
Underproduction = caused usually by auto-immune
Can be primary = primary organ inadequate. Secondary = tropic hormone deficient. Treatment = replacement therapy
Non-functional receptors
