Foundations of Medicine Flashcards
Three different types or hormones?
Peptide and protein, Steroid and Tyrosine derivatives.
Example of a peptide hormone?
Insulin.
Features of a Peptide Hormone? (5)
3-200 amino acid long.
Synthesised as pre-prohormones
Stored in secretory glands prior to their release.
Sometimes they contain carbohydrates, id they do this will make them a glycoprotein, these carbohydrate groups regulate activity and Half-life.
Work by activating receptors and signalling to send second messengers which include transcription factors.
Example of a steroid hormone?
Vitamin D.
Features of a steroid hormone? (6)
Derived from cholesterol.
Synthesised in the adrenal cortex, gonads and placenta.
Lipid soluble.
Can be acutely regulated (produced quickly) in order to combat stressful stimulations such as blood pressure.
Can be chronically regulated during prolonged starvation to change cellular output.
Act as transcription factors themselves.
Give an example of Tyrosine derivative hormones?
Thyroid hormones.
Features of Tyrosine derived hormones? (3)
Derived from amino acids tyrosine and tryptophan.
Secreted from the adrenal medulla and thyroid.
Rapidly broken down after their release into the blood.
What type of hormone is likely to remain the same for the longest length of time, why?
Steroid hormone, because they are bound to serum globulins in the blood for transport, protecting them from degradation.
What is Facilitated transport?
Movement of particles across a semi-permeable membrane with the aid of a carrier protein, down a concentration gradient.
What is Phagocytosis/pinocytosis, in relation to hormone release?
Uptake of fluid and particles through a membrane enclosed vesicle.
Example of an endocrine, paracrine and autocrine hormone?
Endo - cortisol.
Para - TGF - ß-1
Auto - Insulin like growth factor 1 (IGF-1)
Four different types of receptor? an example of each?
Ionotropic - Nicotinic acetyl-choline receptors.
Metabotropic (G-protein coupled is an example) - Oxytocin receptor.
Kinase-linked - Insulin receptor.
Steroid - Vitamin D receptor.
Features of an ionotropic receptor (channel linked receptor)?
Form a pore through the membrane.
Respond in milliseconds.
Water soluble hormones activate these receptors.
Hormone binding causes a conformational change enabling other particles to enter the cell
Features of a metabotrophic receptor (G-protein coupled receptor)?
Multiple membrane spanning regions.
Responds in seconds.
Hormone binding causes conformational change causing second messengers in the cell to become activated.
Features of a kinase linked receptor (tyrosine kinase receptors)?
Form multi-receptor groups on the cell surface through ligand binding.
The grouping allows auto-activation of the receptors which then allows second messengers to become activated.
Respond in minutes.
