Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key

image

Play button

image

Play button

image

Progress

1/39

Click to flip

39 Cards in this Set

  • Front
  • Back
Hormones falls into three chemical classes:
1) Amines

2) Peptides and Proteins

3) Steroids
The amine hormones are all derivatives of the animo acid __________:
Tyrosine
Amine hormones include:
- the tyroid hormones

- catecholamines
- epinephrine
- norepinephrine
- dopamine
Norepinephrine is produced by the:
adrenal medulla
Dopamine is produced by the:
hypothalamus
There are _____ adrenal glands, one on top of each ______
- two

- kidneys
Each adrenal gland is comprises two distinct endocrine glands _______ & _______.
- an inner adrenal medulla

- a surrounding adrenal cortex
The adrenal medulla secretes:
amine hormones
the adrenal cortex secretes:
steroid hormones
THe adrenal medulla is really a modified:
sympathetic ganglion whose cell bodies do not have axons, but instead release their secretions into the blood, thereby fulfilling a criterion for an endocrine gland
The adrenal medulla secretes mainly two amine hormones: ____________ & ____________
- Epinephrine

- Norepinephrine
In humans, the adrenal medulla secretes appx _____ epinephrine than norepinephrine
- 4 times more
Why does the adrenal gland secrete more epinephrine than norepinephrine?
Because the adrenal medulla expresses high amounts of an enzyme called phenyl-N- methyltransferase which catalyzes the step that converts noepinephrine to epinephrine.
Epinephrine and norepinephrine exert actions similar to those of the _______, which, because they do not express PNMT, make only ....
sympathetic nerve

norepinephrine
Most hormones are either
peptides or proteins
Peptides are initally synthesized on the
ribosomes of the endocrine cells as larger proteins known as preprohormones, which are than cleaved to prohormones by proteolytic enzymes in the rough endoplasmic reticulum
After preprohormones are cleaved to prohormones by proteolytic enzymes in the rough endoplasmic reticulu, what happens?
the prohormone is than packaged into secretory vesicles by the golgi apparatus
the prohormone is than packaged into secretory vesicles by the golgi apparatus. What happens during this process
The prohormone is cleaved to yield the active hormone and other peptide chains found in the prohormone
When the cell is stimulated to release the contents of the secretory vesicles by exocytosis, the other peptides are..
secreted along with the hormone
when exocytosis happens, instead of just one peptide hormone, the cell may ....
be secreting multiple peptides hormones that differ in ther effects on target cells
Many peptides serve as both _________ & as ____________
- neurotransmitter (or neuromodulators)

- hormones
some hormones secreted by the endocrine glands in the GI tract (like cck) are also produced by:
neurons in the brain, where they may function as neuromodulators
Steroid hormones are primarily produced by the:
adrenal corex and the gonads (testes and ovaries) as well as by the placenta during pregnancy
The step 1 of the general process of steroid hormone synthesis
- In both the gonads and the adrenal cortex, the cells must be stimulated by binding their respective tropic hormone from the pituitary to plasma membrane receptors
The step 2 of the general process of steroid hormone synthesis
2. These receptors are linked to G-proteins, which activate adenylyl cyclase and thus cAMP production
The step 3 of the general process of steroid hormone synthesis
3. The subsequent activation of protein kinase A results in Phosphorylation of numerous cytosolic and membrane
The step 4 of the general process of steroid hormone synthesis
4. When the cell is stimulated by a tropic hormone (e.g ACTH or LH), free cholestrol is released from the lipid droplet by the action of the enzyme cholestrol esterase, which is activated by protein kinase A
The step 5 of the general process of steroid hormone synthesis
5. A carrier protein called the steroidogenic acute regulatory (StAR) protein then transports the free cholestrol to the mitochondria
The step 6 of the general process of steroid hormone synthesis
6. Peripheral - type benzodiazepine receptor step
The step 7 of the general process of steroid hormone synthesis
7. Once at the inner membrane, cholesterolis acted upon by enzymes called cytochrome P450s
The step 8 of the general process of steroid hormone synthesis
8. After P450 modifications occur in both the mitochondria and in the smooth E.R , thus the intermediates are shuttled back and forth between the two organelles by an unclear mechanism
The step 9 of the general process of steroid hormone synthesis
9. Once formed, the lipophillic steroid hormones are not stored in the cytosol, but instead diffuse out through the lipid bilayer of the plasma membrane into the interstitial fluid and from there into the circulation
What important step of the general process of steroid hormone synthesis facilitates the subsequent steps in the process
Step 3 - The subsequent activation of protein kinase A results in the phosphorylation of numberous cytosolic and membrane proteins
Cells producing steroid hormones synthesize some of their own cholestrol for this purpose from.....
molecules of acetate, but typically most of the cholestrol enters the cells in the form of low density lipoproteins (LDLs)
Receptors on the cell surface bind to circulating LDL; when this occurs, the LDL/receptor complex is
internalized into the cell cytosol by endocytosis
When the LDL/receptor complex is internalized into the cell cytosol by endocytosis, what happens?
The cholesterol is stored in anesterfied form in large, non-membrane-bound lipid droplets
The cytochrome P450s are
A family of related proteins that can attach hydroxyl groups to carbon atoms and that participate in cleaving carbon - carbon bonds
As the P450 enzymes modify cholesterol, intermediates form, which must be futher modified before...
the final steroid hormone is produced
The final product of steroid synthesis depends upon
the cell type and amounts of the enzymes it expresses