4 Endocrine Flashcards
What are the two major systems controlling body functions?
1) nervous system
- –rapid, discrete, confined control
2) endocrine system
- –slower and general control
Do the nervous and endocrine system influence each other?
Yes.
- hypothalamus (brain) controls adrenal medulla (endocrine tissue) and pituitary
- hormones can affect nervous system with behavior
what type of glands are ductless?
endocrine (secrete hormones directly into blood)
is the pancreas endo or exocrine?
BOTH
hormones travel through____ to target cells
circulation
what are the 3 general/classic hormone structures?
1) amines =phenal + amine
2) paptides =chains of AA
3) steroids =basci 4-ring structure
amine hormones are derived from?
tyrosine
Name the amine thyroid hormones and amine catecholamines?
Thyroid --triiodothyronine (T3) --tetraiodothyronine (T4 or Thyroxine) Catecholamines --epinephrine --norepinephrine --dopamine
why is it T3 and T4?
T4= 4 atoms of iodine attached T3= only 3 atoms of iodine attached
majority of hormones are?
protein hormones (short or long chains of AA)
what forms sulfide bonds in protein hormones?
cysteine
describe peptidehormones?
- a few to 200 AA long
- MOST hormones are proteins
structure of steroid hormones?
4-ring structure
steroid hormone synthesized from?
cholesterol
what are the steroid hormone?
- adrenal cortical homrones
- gonadal hormones (sex hormones)
- vitamin D
- all synthesized from cholesterol
why is vitamin D considered a hormone?
bc it is synthesized in the body in liver
how many layers of adrenal cortex are there?
3
what type of hormone is:
1) growth
2) testosterone
3) thyroid hormones
1) protein
2) steriod
3) amines
how do hormones bind?
to specific receptors in a LOCK AND KEY fashion.
*but they can overlap in function due to similar structure
Can hormones overlap in function?
Yes. they can overlap in function due to similar structure but they typically have a specific ‘lock and key’ receptor
Good example of overlapping hormone function? (common affect of ppl on high doses of anabolic steroids)
aldosterone =Na+ retention estrogen and testosterone > H2O retention (bc structures are similar to aldosterone)
*high water retention (puffy, bloated on period)
what are the 3 main functions of hormones?
1) tissue growth and metabolism (GH)
2) fluid balance (aldosterone/antidiretics)
3) reproduction (sex steroids/gonadotrophs)
what types of hormones are water soluble and transported freely?
catacholamines (amine) and peptides
what types of hormones are water INsoluble and require a carrier protein?
thyroid (amine) and steroid hormones
most insoluble hormones are transported by?
TBG aka thyriod binding globulin
What are the common carrier protein for insoluble hormones?
1) TBG 75%
2) TTR 10%
3) albumen 12%
4) lipoprotein 3%
what is TTR? formerly known as?
TTR aka transthyretin
*formerly TBPA aka thyroxine-binding prealbumen
what is the most prevalent PLASMA protein?
albumen
a hormones mechanisms of action is dependent on?
structure
peptides and catecholamines bind to ______ receptors?
plasma protein receptors
peptides and catecholamines bind directly to plasma membrane receptors and act through?
secondary messenger
G protein purpose?
intermediate between receptor and effector protein
*usually causes phosphorylation to turn ON something in the cell
binding to receptors results in?
1) activation of cyclizing enzymes and preoduction of a 2nd messenger and then;
2) protein phosphorylation which starts MANY things
4 common mechanisms of action after phosphorylation?
1) activation of enzymes
2) increased or decreased cell permeability
3) contraction/relaxation
4) synthesis/secretion of something
goal of a hormone binding?
acitvation of enzyme or kinase to phosphorylate and activate a process within the cell
steroid/thyroid hormones or catecholamines/peptides FASTER acting?
atecholamines/peptides are faster! takes minutes to hours whereas steroid take hours to days
steroid/thyroid hormones bind to _____ receptors and directly alter?
intracellular receptors and directly alter GENE TRANSCIPTION
steroid/thyroid hormones or catecholamines/peptides requir carrier protein?
steroid/thyroid hormones
steps in steroid/thyroid hormones cell interaction?
1) hormone moves through fatty membrane
2) bind to receptors intracellulary in the cytoplasm or nucleoplasm
3) moved as complex to DNA chromatin
4) activates certain genes
5) alteration of transcription
6) trasnlation
7) proteins
