Chapter 18 (part 1) Flashcards
endocrine system part 1
what is the endocrine system?
all the endocrine cells and tissues of the body that produce hormones or paracrine factors
what are the functions of the endocrine system?
- regulates long-term processes (growth, development, and reproduction)
- uses chemical messengers to relay information and instructions between cells
- works with the nervous system to maintain homeostasis
what is the difference exocrine and endocrine cells?
exocrine secrete products into epithelial surfaces via ducts and the endocrine cells are ductless and release directly into the blood
what are the four common responses of the target cell?
- produce a new hormone
- make a new enzyme (protein)
- increases or decreases the rate at which an enzyme or protein is manufactured in cell
- open or close a gate or channel in the membrane
what is direct intercellular communication?
ions and molecules transferred between 2 adjacent cells of the same type
what is paracrine intercellular communication?
THE MOST COMMON TYPE OF INTERCELLULAR
cell to cell information transfer in a single tissue
what is endocrine intercellular communication?
endocrine cells release chemical (hormones into blood stream)
what is synaptic communication?
occurs across synaptic clefts
what is a hormone?
glands containing specialized cells that release chemical messengers
what are the three groups of hormones?
- amino acid derivatives
- lipid derivatives
- peptide hormones
amino acids derivatives are made from..
tyrosine and tryptophan
peptide hormones are..
all hormones of the hypothalamus, chains of amino acids. start as prohormones and then converted to active peptide hormones
lipid derivatives are..
eicosanoids and steroid hormones, last longer because they are bound to specific transport “taxi” proteins in blood
tyrosine makes
A.A.
D.E.N.T
- dopamine- happy and deals with movement
- epinephrine
- norepinephrine }catecholamines
- thyroid hormones
tryptophan makes (A.A.)
melatonin: pineal gland
serotonin: brain and gut
glycoproteins
P.T.
long chains of 200+ amino acids linked together
short polypeptides and small proteins
P.T
all hormones cerated by hypothalamus, heart, digestive system, pancreas, thymus and posterior lobe of pituitary
prostaglandins
(L.D.)
*eicosanoids
INFLAMMATION/ PAIN
vasodilation- is when blood vessels increase in size. prostaglandins can be converted to thromboxane causing vasoconstriction
leukotrienes
(L.D.)
*eicosanoids
can trigger contractions in smooth muscles of bronchioles. overproduction is the major cause of inflammation in asthma and allergic rhinitis
cortex of adrenal gland
(L.D.)
*steroids
salt, sugar, sex
mineralocorticoids, glucocorticoids, gonadocorticoids
kidneys
L.D.
calcitriol
reproductive organs
L.D
estrogens and progesterone- the ovaries
testosterone- the testes
what are free hormones?
remain functional for less than an hour and diffuse out of bloodstream and bind to receptors on target cells. broken down and absorbed by the cells of the liver and kidneys and down by enzymes in plasma or interstitial fluids
what are bound hormones?
remain much longer because they are bound to special transport proteins (albumins)
down regulation
cells decrease the number of membrane receptors, responds as if there is a low hormone concentration. signal is strong
up regulation
increase of number of receptors due to the absence of a hormone. when there is a low level of a hormone, cells make a lot of receptors to detect the tiniest amount of that hormone. signal is weak
lipid soluble steroids hormones
are the only messengers in their pathways and use direct gene activation.
*eicosanoids, prsotglandandins, and leukotrienes
receptors are intercellular (inside the membrane)
water soluble non-steroid hormones
the first messengers and they use a second messenger system to get their message inside the cell
* peptide hormonesa and D.E.N
receptors are extracellular (outside the membrane)
what is amplification?
chain reaction in the target cell exponentially increases hormone effect
