chapter 74 Flashcards
What does endocrine mean?
Internally secreting. It is an information signaling system.
The edocrine system uses what to do what?
Uses ductless glands that secrete hormones into bloodstream that effect changes downstream.
What are the 2 systems of control in the body?
Endocrine and Nervous system.
What is the classic endocrine signaling?
Hormones travel to distant organs to regulate the target organs function. They can be very specific to certain organs or they can act systemically.
What is neuroendocrine?
Another type of signaling that is not classical endocrine that is released by neurons.
What is paracrine?
A type of signaling that is not a classical endocrine but it affects function of neighboring cells.
What is Autocrine?
A type of signaling that is not a classical endocrine but it affects function of the same cell.
What is cytokines?
endocrine hormones.
How far will endocrine actions travel?
To distant target cells.
How far will paracrine actions travel?
Target cells in the neighborhood.
How far will autocrine actions travel?
Acts on the same cell that produced it.
What will lead to hormone secretion?
A change in internal and/or external environment.
What is it called when the hormone travels through our vascular system to target cell where it elicits an action at the cellular level to restore and maintain the normal dynamics?
Homeodynamics.
What is the opposite of homeostasis?
Static because homeostasis is very dynamic.
Name 4 major body functions that are regulated by endocrine signaling?
metabolism, growth, reproduction, water & electrolyte balance.
Name the 3 general chemical structures released by endocrine systems?
- Proteins and polypeptides. 2. Steroids. 3. Amine derivatives.
Steroids are synthesized via what?
Cholesterol.
Amine derivatives are what?
They are like proteins but derived from Amino Acids.
What hormones are proteins (aka peptides) or polypeptides?
Pituitary, parathyroid and pancreatic.
Where are steroids produced at?
Adrenals, ovaries, testes, and placenta.
Where are amine derivatives secreted from?
From thyroid and adrenal medullae.
What are the sizes of peptide/protein hormones?
3-100’s of Amino Acids in size.
What part of cells will peptide/protein hormones be made at?
Rough endoplasmic reticulum.
How are the peptide/protein hormones made?
active.
Hormones are encoded by genes that transcribes the hormones blueprint to what?
mRNA
The mRNA does what?
Translates the blueprints into protein precursors called preprohormone.
The preprohormone is sent to the Rough ER where it does what?
It is cleaved to make the prohormone.
The prohormone is then sent where? What happens here?
hormone.
Are peptide hormone water soulable?
Yes.
Will peptide hormones need help crossing the cell membrane?
Yes.
Most hormones are what?
Peptides or polypeptides.
When peptide hormones are needed how will they get out of cells?
Secretory vesicles fuse to the cells membrane, and with the appropriate signal exocytosis occurs.
Can a prohormone be secreted?
Yes and then it is converted into its active form by enzymes.
Where will enzymes that activate prohormones be made at?
Kidney and lungs.
Where will steroid hormones come from?
All are synthesized from cholesterol.
How are steroid hormones stored?
They are not usually stored.
Are steroid hormones water or lipid soluble?
Lipid soluable.
Will steroid hormones need help passing through the cell membrane?
No.
Since steriod hormones are not stored how are the precursors stored?
Steroid secreting hormone cells have large stores of cholesterol in cytoplasmic vacuoles.
What causes the cholesterol to be synthesized into the requred steroid?
A stimulus.
Where will most of the Cholesterol come from that is used to make steroid hormones?
From plasma and not from dietary intake.
What type of cholesterol can steroid producing cells make?
De novo cholesterol.
Where will de novo cholesterol synthesis happen at?
cytosol of steroid producing cells.
The de novo cholesterol making process is similar to what?
The keogenic pathway.
What is needed to make de novo cholesterol?
NADPH and ATP.
How regulated is the making of de novo cholesterol?
Highly because of all the players involved.
Name 5 types of steroid hormones?
glucocoricoids, mineralcorticoids, androgens, estrogens, progestins.
Vitamin D is not really a vitamin why?
it is derived from cholesterol, but it can be synthesized by de novo cholesterol.
What will Vitamin D act as?
A true hormone.
Steroid hormones are synthesized for release.
Immediate.
When are steroid hormones synthesized?
On an as-needed basis.
Where are enzymes that produce steroid hormones from cholesterol found at?
In mitochondria and endoplasmic reticulum.
How will steroid hormones move through the blood?
They are not water soluable so they need to be bound to globulins (proteins).
Name the sex hormone binding golbulins?
Testosterone & estradiol.
Name the coricosteroid binding golbulin?
Cortisol.
What is the rate limiting step in steroid hormone synthesis?
Transport of free cholesterol from cytoplasm into the mitochondria.
What are the 2 groups of Hormones derived from amino acid tyrosine?
thryoid and catecholamines.
What is a thyroid hormone?
A double tyrosine with 3 or 4 iodine atoms.
What are the 2 thyroid hormones?
T3- has 3 iodine aka triiodothyronine, and T4 has 4 iodine aka thyroxine.
Where are thyroid hormones made at?
By thyroid gland.
Are thyroid hormones water or lipid soluable?
Lipid soluable.
Thyroid hormones can pass through cell membranes but how will they pass through plasma?
They bind to thyroxin binding globulin.