Hormone chemistry Flashcards
Exocrine glands
release enzymes to the external environment through ducts . exocrine glands include sweat, mucous and digestive glands
Endocrine glands
release hormones directly into body fluids
What is the pancreas?
its both exocrine and endocrine ! : it will release digestive enzymes through the pancreatic duct and its an endocrine gland bc it releases insulin and glucagon directly into the blood.
effects of endocrine vs the nervous system
endocrine system effects are slower, less direct and longer lasting compared to those of the nervous system .
how do all hormones act?
they bind to proteins called receptors- each receptor is highly specific for its hormone
in general what are the effects of the endocrine system?
alter metabolic activités, regulate growth and development and guide reproduction.
the endocrine system works in conjunction with the nervous system, there are neurons which stimulate the endocrine glands to secrete their hormones
Hormones exist in which 3 basic chemistry types?
1) peptide hormones
2) steroid hormones
3) tyrosine hormones
what are peptide hormones?
derived from peptides. all of these are made from the ROUGH ER, which is then transported to Golgi (where pro hormone is cleaved and modified with carbs to its final form). Golgi will package it to vesicles, and upon stimulation by another hormone or nervous signal, cell releases the vesicles via exocytosis
are peptide hormones water soluble or insoluble?
WATER SOLUBLE ! : move freely thru the blood but have a hard time diffusing thru the cell membrane ! so they attach to a membrane bound receptor , the receptor can act in diff ways ( one of them being … activate an intracellular second messenger like cAMP or cGMP or calmodulin).
what is a second messenger?
cAMP, cGMP, calmodulin. these are called second messengers bc its the hormone that is the first messenger. the second messenger will activate/deactivate enzymes or ion channels and often creates a cascade of chemical reactions that amplifies the effect of the hormone.
what is the significance of the cascade effect?
its one way that a small concentration of hormone can have a significant effect
What are the peptide hormones that YOU HAVE TO KNOW FOR THE MCAT?
Anterior pituitary hormones: FSH, LH, ACTH, hGH, TSH, Prolactin
posterior pituitary hormones: ADH and oxytocin
parathyroid hormone or PTH
pancreatic hormones: glucagon and insulin
what are steroid hormones?
derived from or are chemically similar to cholesterol , formed in SER and the mitochondria. since they are lipids they need a protein transporter to go into the blood. they can diffuse thru the cell membrane . once inside the cell they can combine with receptor in the cytosol. this receptor can transport the steroid into the nucleus , and the steroid can act at the transcriptional level.
What are the steroid hormones that you need to know for the MCAT?
adrenal cortex releasing : cortisol and aldosterone
the gonadal hormones: estrogen, progesterone and testosterone!
what are tyrosine derivatives?
thyroid derivatives are the thyroid hormones T3 and T4 and the catecholamines formed in the adrenal medulla ( epinephrine and norepinephrine)
