Introduction to Endocrine System Key Concepts Flashcards
What coordinates cell, tissue and organ activities
Hormones
Hormones compared to the nervous system
Hormones are slower acting, longer lasting and indirect, when compared with the nervous system
Where do hormones circulate
Circulate in blood and extracellular fluid and bind to specific receptors
how do hormones generally exert their effect on target cells?
- altering membrane permeability
- activating or inactivating key enzymes
- changing genetic activity
how many classes of hormones are there?
3
amino acid derivatives and peptide hormones are water soluble which means:
cannot cross the plasma membrane, bind to extracellular receptors, use secondary messengers e.g. cAMP
Lipid derivatives are lipid soluble which means:
can diffuse across the plasma + bind to intracellular receptors
how is hormone secretion regulated?
it is regulated by the NS, blood and other hormones
the pineal gland…
is found in the brain, secretes melatonin (hormone) + melatonin helps set circadian rhythms
Heart’s endocrine function
natriuretic peptide (increased sodium secretion by kidney)
Thymus’ endocrine function
thymosins (stimulate T cell production)
Adipose tissue’s endocrine function
releases leptin (satiety signal)
digestive system’s endocrine function
examples: gastrin, CCk, GIP, secretin
Kidneys endocrine function
EPO (RBC production), renin (blood pressure) and calcitriol (vitamin D)
Gonads endocrine function
male = testes
female = ovaries
