This summary Human Biology includes books, slides and lecture notes. Titles are clearly marked in color, and expressed figures are all included. The text is written in English. Good luck, it worked for me ;-)!
The endocrine system produces hormones
Endocrine glands = ductless organs that secrete into interstitial fluid, lymph and blood => INTERNALLY (not in ducts !)
Differences with nervous system as a communication tool :
Reach nearly every living cell as they circulate in the blood (exception : blood-brain barrier) => No need for direct
connections as nervous system
Each hormone acts only on its “target cells” (have the appropriate receptor)
Endocrine control slower : Nerve impuls can travel in fraction of sec. From secreting hormone to affect = at least
20 sec. => Highly effective for LT-controls (eg regulating blood pressure,etc.)
The endocrine and nervous often interact : eg release of some hormones depend on input from sensory neurons.
Hormones are classified as steroid or nonsteroid
Steriod hormones : related to cholesterol (a lipid) => Lipid soluble : Enters cell, bind to extracellular receptor =>
Activate genes that produce new proteins.
Nonsteroid hormones : related to proteins => Lipid unsoluble (cannot cross cell membrane) => Bind to receptors on
cells surface => initiates series of events but hormones never entered the cell.
STEROID HORMONES enter target cells
As cell membrane is composed of bilayer of phospholipids, SH can easily diffuse across => inside, SH bind to specific
hormone receptors => form “hormone-receptor” complex with NUCLEUS => Inside nucleus, hormone-receptor
complex attaches to DNA => activating specfic genes => causes formation of messenger RNA, which leaves nucleus
and directs synthesis of certain proteins => Proteins then carry out the cellular response to the hormone.
Slower than NSH because entire protein production process begins only after arrival of hormone in cell : mins- hours.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller IsoldeLas. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $3.18. You're not tied to anything after your purchase.