General Principles Flashcards
compare endocrine and nervous systems
endocrine: slow acting, long duration, maintains homeostasis
nervous: fast acting
definition of hormones
substances released by endocrine glands and transported throughout the blood stream to target tissues where they regulate specific functions
difference between primary and secondary endocrine glands
some organs have secondary endocrine functions because they can secrete hormones but it is not their primary function
examples of hormones released by the hypothalamus
releasing and inhibiting hormones
examples of hormones released by the pituitary anterior lobe
luteinizing hormone
follicle stimulating hormone
prolactin
growth hormone
adrenocorticotropin
thyroid stimulating hormone
examples of hormones released by the pituitary posterior lobe
antidiuretic hormone/vassopressin
oxytocin
examples of hormones released by the thyroid
T4/T3
calcitonin
examples of hormones released by the parathyroid
parathyroid hormone
examples of hormones released by the testis
testosterone
estradiol
MIH
inhibin
examples of hormones released by the ovary
estradiol, progesterone, inhibin
examples of hormones released by the pineal
melatonin
examples of hormones released by the placenta
hCG
progesterone
estrogen
what are the three categories of hormones
amino acid derivatives
peptide hormones
lipid derivatives
which amino acid is used to create thyroid hormone
tyrosine
which chemical structure are lipid derived hormones based on
cholesterol
which types hormones are hydrophobic
steroids and some amines
what do cell membrane hormone receptors activate
what is their timescale
intracellular second messengers
elicited within seconds to minutes
what do intracellular receptor systems alter
what is their timescale
alter transcription rates
effects take hours - act genetically
what does signal amplification lead to
how does it come about
a long term response
secondary messengers
what can hormones alter
either the structure of proteins or protein synthesis
key determinants of effective [hormone] in plasma
rate of activation or conversion
extent of binding to plasma proteins
rate of removal from the blood by metabolic inactivation and excretion
rate of secretion into the blood by the endocrine gland (most important)
what hormones are bound to carriers in the blood
steroids and amines
why can peptides not be taken orally
they would be broken down
how can target cells control hormone concentration in the blood
they can internalize and degrade the hormone
