Review of hormonal mechanisms E1 Flashcards
What are the 4 types of intercellular messengers in the body?
Endocrine
Autocrine and paracrine
Neuroendocrine
Neurotransmitters
What are the 3 types of hormones and give examples of them?
Peptide - from hypothalamus, ant & post pituitary, pancreas and GiT
Steroid- cortisol, aldosterone and sex hormones
Derived from tyrosine - thyroid hormones and catecholamines
How is peptide hormones synthesised?
Gene transcription to mRNA in nucleus then mRNA translated to protein in membrane. Then prehormone made at RER then prohormone made from cleaving AA from pre. Mature hormone packaged and stored into secretory granules. Then exocytosis.
How are steroid hormones synthesised?
Cholesterol undergoes various enzymatic activity creating hormones which diffuses out of the cell and bonds to plasma proteins for transportation.
Are peptide hormones lipophilic, do they have a long half life and are they free hormones?
Hydrophilic
Free hormone
Short half life
Why do steroid hormones have a long half life?
Bound to plasma proteins which delay metabolism and provides and circulating reservoir of hormones
Which receptors do peptide hormones bind to on a target cell?
G proteins
Tyrosine kinase
Do steroids need receptors?
No already lipophilic can diffuse in but need intracellular receptors which act as hormone regulated transcription factors
Where are most hormones metabolised?
By enzymes in liver, kidney and or blood
Where are hormones secreted from?
Endocrine glands
What is negative and positive feed back?
Negative - Consequence negatively controls process
Positive - consequence enhances or amplifies process further
Apart from feedback regulation what are the other two ways hormone release is regulated?
Neuroendocrine reflexes
Diurnal (day to night) and circadian Rhythm (around a day)
What are the 3 mechanisms of which endocrine disorders can occur?
Hormone excess - hyper secretion like tumour or immunological factor
Hypo secretion of hormone due to genetics, immunological attack, destruction by disease, surgical removal
Decreased target - cell responsiveness
At level of receptor or downstream enzyme
Which is primary and secondary from endocrine gland or pituitary?
Endocrine primary
Pituitary secondary
What 3 tests can be done to check endocrine functionality?
Signs and symptoms
Endocrine investigations
Imagining
