hormones Flashcards
what are the 2 classes of hormones
lipid soluble and water soluble
are lipid soluble hormones hydrophobic or hydrophillic
hydrophobic
are water soluble hormones hydrophobic or hydrophilic
hydrophilic
examples of lipid soluble hormones
steroids - testosterone, estrogen
thyroid hormones
nitric oxide
examples of water soluble hormones
amines - epinephrine and norepinephrine
peptides - oxytocin
proteins - insulin, growth hormone
eicosanoids - prostaglandins and leukotrienes
what do prostaglandins and leukotrienes do
act locally as hormones in most tissues of body (so little found in blood)
released by virtually all cells (excludes RBC)
what do prostaglandins do and where do they act
smooth muscle, blood flow, promote fever, intensifys pain
what do leukotrienes do
stimulate WBC movement and mediate inflammation
what do nonsteroidal anti-inflammatory drugs do
inhibit prostaglandin synthesis but do not effect leukotriene synthesis
how do lipid soluble hormones act (step by step)
1 hormone detaches from carrier in blood stream
2 diffuses through interstitial fluid and cell membrane into cell
3 binds and activates receptor
4 receptor-hormone complex alters gene expression
how do water soluble hormones act (step by step)
1 diffuses from blood and binds to receptor in plasma membrane
2 starts reaction inside cell, forming second messenger
3 second messenger causes activation of several proteins
4 activated proteins produce physiological responses
5 second messenger is inactivated
explain the control of hormone secretions
release in short bursts
controlled by negative feedback
what are hormones regulated by
-signals from nervous system
-chemical changes in blood
-other hormones
what is acromegaly
excessive growth hormone in adults
what is pituitary dwarfism
low levels of GH in children
