Intro to endocrine Flashcards
Name all the endocrine organs
Hypothalamus, Pituitary gland, Adrenal gland, Pancreas, Thyroid gland, Parathyroid glands
What is a hormone?
A hormone is a chemical which is release in to the blood and travels around the body until it binds to a specific receptor on its target tissue. This will then cause a change within the cell.
What is the difference between a hormone and a neurotransmitter?
They can sometimes be the same chemical but a hormone, is release from a gland in to blood to travel to its target tissue where as a neurotransmitter is released from a neurone and crosses a synapse.
Where as neuroendocrine hormones are released from nerves and enter into bloodstream, when acting on a target tissue.
What is a tropic hormone?
It is a hormone which stimulates the release/production of another hormone.
What is a trophic hormone?
These hormones affect growth/ the level of growth hormone.
Describe peptide hormones
These hormones are made from chains of amino acids. They are hydrophilic and lipophobic. They are synthesised into a preprohormone and then cleaved into a prohormone. They are then stored in vesicles until their release is stimulated.
They travel through the blood freely before binding to surface receptors on their target cells.
These hormones are fast acting (seconds or minutes).
Describe how steroid hormones work.
These hormones are all derived from cholesterol. Due to being lipophilic, these hormones can only be synthesised when required as there is no way to store them.
Once synthesised they freely pass through cell membrane, they they bind to a transporter (such as albumin) to travel in the blood.
When they reach their target tissue, these hormones pass through the cell membrane and bind to intracellular receptors. These receptors then cause change in gene activation within the dna, this will change the proteins produced and cause the desired outcome.
These are slow acting hormones (hours or days)
What type of receptors do peptide hormones bind to?
GPCR (g- protein coupled receptors) or tyrosine kinase linked receptors.
GPCR’s cause modification of existing proteins and tyrosine kinase linked receptors alters gene expressed so acts more slowly.
What are amine hormones?
These hormones are produced from tyrosine or tryptophan (only melatonin is produced from tryptophan) and they are all presysnthesised and stored.
They are subdivided in to two categories, catecholamines- which act like peptide hormones (e.g. dopamine, norepinephrine, epinephrine) and thyroid hormones- which act like steroid hormones.
