Endocrinology Flashcards
(147 cards)
What does the endocrine system consist of?
Organs or tissues that synthesize and secrete hormones
Hormones
Carrier proteins
Organs or tissues that are affected by hormones
List some organs or tissues in the endocrine system
Pituitary Hypothalamus Adrenal gland Heart Pancreas Thymus
What is a hormone?
A hormone is a chemical substance made by an organ or tissue and secreted into the blood to have a specific effect on a tissue or structure
Where is a hormone secreted into after being synthesized by an organ or tissue?
Into the blood
What are endocrine hormones?
Hormones that affect or act on distant tissue, cells or organs
What are paracrine hormones?
Paracrine hormones are hormones that act locally, that is, tissues, cells or organs close by
What are autocrine hormones?
These hormones affect the cells that synthesize them by interacting with sepecific membrane receptors on its surface to induce effects
Give an example of an endocrine hormone
Insulin
Thyroxine
Cortisol
Give an example of a paracrine hormone
Neurotransmitter
Give an example of an autocrine
Bombesin
How are hormones classified?
By their tissue of origin and by their structures
Give the four classes of hormones
Polypeptides/protein
Steroids
Amino acid derivatives
Fatty acid derivatives
Majority of hormones fall under what class?
Polypeptides/proteins
What class of hormone is soluble on water only ?
Polypeptides/proteins
Polypeptide hormones are water soluble. What does this imply?
They circulate freely. That is, unbound without transporters
What is the half-life of a polypeptide hormone?
Short half life of 10-30 minutes
What is the half-life of a steroid?
Long half life of 30-90 mins
Polypeptides/proteins are water soluble, so move freely, unbound then bind to a membrane receptor. What does this imply about their effect?
They need a second messenger to actually carry their action in the cell
Give some examples of polypeptides
Insulin
Parathyroid hormone PTH
ACTH
What hormone class is insoluble in water?
Steroids
Steroid are water insoluble. What does this imply for their movement?
They require transporters/carrier proteins
How do steroids effect their function in terms of receptors?
Since they have transporters, they do not bind to membrane but diffuse into the cell and bind to cytoplasmic receptor
Give examples of steroids
Estrogen
Cortisol
What hormone type is soluble both in water lipids?
Amino acid derivatives