Endocrine systems Flashcards
Function of endocrine systems
Regulation of homeostasis by slow, long-lasting chemical signalling. Hormones secreted from glands act on target organs via circulatory system and often requires activation by the nervous system
What are the 2 mechanisms for glands?
Endocrine (internal) or exocrine (external)
What is the hypothalamus?
Brain area with various physiological functions important for maintaining homeostasis by linking nervous and endocrine systems
Function of hypothalamus
Completes homeostasis
Gland
Produces hormones
Hormones
Have effects on different targets and can be secreted at different rates
A target
Acted upon by different hormones
Chemical
Acts as a hormone or neurotransmitter
Tropic vs Non-tropic hormone
Tropic: regulates production/secretion of another hormone in a gland
Non-tropic: has a direct effect on target organ
Name 3 different hormones
Peptides, amines and steroids
Peptides
Preprohormone precursor is translated and packaged into vesicles to be stored in cytosol. These vesicles fuse with plasma membrane and release the hormone into the blood
Amines
Synthesized from amino acid tyrosine by enzymes, packaged into secretory vesicles and stored until release where vesicles fuse with plasma membrane and released into blood
Steroids
Synthesized from lipid cholesterol by enzymes, diffuse across the plasma membrane into blood when synthesizes and can be converted into different hormones once in blood
Water-soluble vs Lipid soluble hormones
Water-soluble: free in blood or bind to plasma proteins and include peptides and some amines
Lipid-soluble: bound to plasma proteins and include steroids and some amines.
What are the 2 hormone receptors?
Membrane and internal