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Terms in this set (117)
what are the two major communication systems in the body?
nervous system and endocrine system
Whats one advantage and disadvantage of the endocrine system compared to the nervous system?
endocrine has longer delays but effects last for greater lengths of time
can a single endocrine gland secrete more than one hormone?
can single cell types secrete more than one hormone?
no -- the presence of multi hormone secretion reflects the presence of different types of endocrine cells in the same gland
Where is insulin, glucagon and somatostatin from?
what does insulin do
lower blood glucose level
what does glucagon do
increase blood glucose levels
what does somatostatin do
inhibit secretion of pancreatic hormones
what type of cells secrete insulin
what type of cells secrete glucaon
what type of cells secrete somatostatin
where do endocrine cells secrete stuff
into interstitial fluid that diffuses into blood supply
where do exocrine cells secrete stuff
has duct that sends stuff to intestinal lumen or has stuff exit the body
where are norephinephrine and epinephrine produced
what are the three major chemical classes of endocrine hormones
amine hormones, peptides/proteins, and steroids
the amine hormones are all made from what
where are the amine hormones produced
thyroid, adrenal medulla, and hypothalamus
name the amine hormones
tyrosine, DOPA, dopamine, norepinephrine, epinephrine, T4, T3,
what type of endocrine hormones contain iodine
where are thyroid hormones made
what are the thyroid hormones
tetraiodothryonine (T4) and triiodothyronine (T3)
what is an enlarged thyroid gland that results from iodine deficieny
how much iodine is required per year
where are epinephrine and norepinephrine produced
the adrenal medulla
where is dopamine produced
name the catecholamines
epinephrine, norepinephrine, dopamine
what is the biggest class of hormones
peptides and proteins
true or false: peptide and protein hormones are produced in all tissues all over the body
what type of endocrine hormone are insulin and glucagon
inactive preproinsulin becomes what before it becomes cleaved into insulin and c peptide?
what is proinsulin cleaved into
insulin and c peptide
when we detect in diabetics if they have the right amount of insulin, what do we measure
c peptide level
describe the ways in which the body responds to high vs low glucose levels
1. High blood glucose levels
2. Beta cells release insulin into blood (pancreas)
3. Insulin secreted into interstitial fluid
4. Muscle and other cells use glucose as an energy source OR liver converts glucose to glycogen, fats and proteins
5. Blood glucose levels fall—? less insulin produced
1. Low blood glucose level
2. alpha cells release glucagon into bloodstream (Pancreas)
3. Liver converts glycogen to glucose
4. Blood glucose levels rise: less glucagon produced
peptide hormone processing and synthesis pathway
1. The preprohormone contains a signal sequence of amino acids that directs the protein into the lumen of the rough ER
The reason its pre pro is cus it needs to contain the signal sequence in order to get into the lumen
2. Signal sequence is cleaved by enzymes in the ER, now at the inactive prohormone stage
3. Goes to the Golgi complex
4. Secretory vesicles containing enzymes and pro hormone bud off the Golgi. The enzymes chop the pro hormone into one or more active peptides plus additional peptide fragment
Secretory vesicles containing peptides are stored in the cytoplasm until the cell receives a signal for secretion
5. When a cell receives a signal, the secretory vesicle releases its contents by Ca+ dependent exocytosis into the extracellular space/interstitial fluid
6. The hormone moves into the circulation for transport to its target in the blood plasma
Protein hormones, like insulin, are water soluble and dissolve easily in the extracellular fluid for transport rhoguhout the body
The half life for peptide hormones is usually quite short (only several minutes) so the hormone must be continually secreted for a response to be sustained
where are steroids made
gonads, adrenal cortex, placenta during pregnancy
are peptide hormones water soluable?
what class of hormones can enter through the plasma membrane?
what hormone must be continually secreted due to its short half life?
all steroid hormones are derived from what
where is cortisol from
whats another name for cortisol
What is the role of aldosterone?
stimulates Na+ and H2O reabsorption and K+ and H+ secretion in the kidney
Where does aldosterone act?
Aldosterone is aka
name all of the steroids
cortisol, aldosterone, testoterone, and estradiol
What type of hormone is only produced when required and why?
steroids because they are hydrophobic and cant be stored in secretory vesicles
What does this description describe the production of: When a stimulus activates endocrine cells, precursors in the cytoplasm are rapidly converted to active hormone, the hormone concentration in the cytoplasm rises and diffuses out of the cell via simple diffusion?
steps in steroid hormone synthesis
1. Cells in both the gonads and the adrenal cortex are stimulated to synthesize steroid hormones by binding of an anterior pituitary gland hormone to its cell surface receptor
In endocrine cells
2. Activation of these G protein coupled receptors leads to adenyl cyclase activation, cAMP production, and PKA activation
3. Inside the cell, cholesterol is stored in a large, non-membrane bound form. PKA phosphorylates numerous target proteins including the enzyme cholesterol esterase, an enzyme that releases free cholesterol that is transported into the mitochondrion
4. Cholesterol is modified in a step wise manner by a series of enzymes located in the mitochondria and smooth ER in order to produce specific steroid hormones
What determines what hormone Is produced is dependent on the hormones
Know that all of the hormones involve multiple steps in order to result in the fully functional hormones
Occurs in the smooth ER and mitochondria depending which steroid (shuffled between the two
5. Steroid hormones are hydrophobic and fdiffuse easily across membranes, both out of their parent cells and into their target cells
This also means that steroid secreting cells cant store hormones in secretory vesicles
So only produce when REQUIRED
When a stimulus activates endocrine cells, precursors in the cytoplasm are rapidly converted to active hormone, the hormone concentration in the cytoplasm rises and diffuses out of the cell via simple diffusion
What type of hormones are usually bound to carrier protein because theyre not very soluble in plasma or other fluids
steroids and thyroid hormone
are steroids and thyroid hormones soluble in plasma?
what is a generic protein carrier molecule
binds cortisol/steroid hormones
do steroid hormones exist in plasma?
yes, but most are bound to large proteins. Its only the free hormone however that can actually diffuse out and enter target cells
Where are the adrenal glands located?
on top of the kidneys
what portion of the adrenal mass does the adrenal medulla occupy?
what portion of the adrenal mass does the adrenal cortex occupy?
does the adreneal medulla secrete more epinephrine or norephinephrine
4 times more ephinephrine
What part of the adrenal gland secretes catecholamines?
What part of the adrenal gland secretes sex hormones?
What part of the adrenal gland secretes glucocorticoids?
What part of the adrenal gland secretes aldosterone?
The cells of each layer of which part of the adrenal gland possess distinct enzymes to produce specific hormones?
what does a hormone's plasma concentration depend on?
1. rate of secretion by endocrine gland
2. rate of removal by organs, endocyotsis by cells, enzymes break down
what types of hormones remain free in the plasma
peptides and catecholamiones
what types of hormones are protein bound in the plasma
steroids and thyroid hormone
what type of hormones are water soluble
catecholamines and peptide proteins
what types of hormones act intracellularly
steroids and thyroid hormones
what type of hormones bind extracellular receptors
peptides and catecholamines
peptides and catecholamines rate of excretion/metabolism
steroids and thyroid hormones rate of excretion/metabolism
slow (hours to days)
epinephrine and thyroid hormone have what kind of effect
glucagon, cortisol, and epinephrine have what type of effect on blood glucose levels?
what are the three types of input that control hromone secretion
changes in the plasma concentration of mineral ions or organic nutrients, neurotransmitters released from neurons to the endocrine cell, another hormone acting on the endocrine cell
insulin secretion pathway
insulin secretion pathway
type 2 diabetes results in an issue in reponsiveness of secretion?
hyporesponsiveness! cellular responsiveness to insulin is reduced
type 1 diabetes results in an issue in reponsiveness of secretion?
syposection. it results from a reduction in active pancreatic beta cells
what ist he most important control area for homeostatic regulation of the internal envionrmnet
What's the master gland?
what typeps of behavoirs does the hypothalamus control
Behaviors having to do with the preservation of the self (eating and drinking) and preservation of the species (reproduction)
hypothalamus brain image
connects hypothalamus to pituitary gland
pituitary gland sphenoid bone
what is actuatlly two glands with different embryoogical orgins that fuse together during development
whats the pocket of bone that the bituitary sits in
Whats a true endocrine gland: anterior pituitary gland or posterior pituitary gland
the anterior pituitary gland
why isnt the posterior pituitary a real endocrine gland?
its just an extension of the neural components of the hypothalamus
What synthesizes vasopressin
what synthesizes oxytocin
What are the two posterior pituitary hormones?
oxytocin and vasopressin
regulates water levels and blood pressure
what two processes is oxytocin involved in in women
1. nipple sucking activates paraventricular to release oxytocin and ejaculate milk
2. during labor, stretch receptors in the cervix spend signals to the brain and hypothalamus which releases oxytocin --> contraction
how are posterior pituitary hormones stored and released?
1. Neurohormone Is made and packaged in the cell body of neuron which is in the the hypothalamus
2. Vesicles are transported down axons
3. Vesicles containing neurohormone are stored in the axon terminal where they wait for a AP
4. When an AP passes down the neuron, the neurohormone is released into blood
what are the hypothalamic hormones that regulate anterior pituitary gland function called?
hypophysiotropic hormones or hypothalamic inhibiting/releasing hormones
can non hypothalamic hormones also influence the anterior pituitary gland?
YES; so its not as bad for the anterior pituitary if the hypothalamus is damaged
what are the gonadtrophins in the anterior pituitary?
FSH and LH
Name the anterior pituitary hormones
Midline feature on the base of the brain marking the point at which the pituitary stalk exits the hypothalamus to connect to the pituitary. Contains elements of the hypophyseal portal system.
what does prolactin do versus oxytocin in milk production
prolactin controls fat cells in breast to actually make the milk vs. oxytocin secretes
Neurohormones from the hypothalamus reach the anterior pituitary through a specialized circulatory region called what?
the hypophyseal portal system
how does othe hypophyseal portal system work
1. Neurons syntehszinig trophic hormones release them into capillaries of portal system
2. Portal vessels carry the trophic hormones directly to the anterior pituitary
3. Endocrine cells release their hormones into the second set of capillaries for distribution to the rest of the body
describe the 3 hormone sequece for hypophysiotrophic hormones
2.(hypothalamus) increase in hormone 1 secretion
2. (in hypothalamus pituitary portal vessels) Increase in hormone 1 plasma concentration
3.( Anterior pituitary ) increase in hormone 2 secretion
4. Increase in hormone 2 plasma concentration
5. (Third endocrine gland) increase in hormone 3 secretion
6. Target issues that are responsive to that third hormone
7. Biological effect
True or false: the milk ejection reflex involves both the anterior AND posterior gland
What is the name of the precursor hormone for adrenocorticotrophic hormone (ATCH)?
Whats another bioactivate peptide yielded by the cleavage of pro-opiomelanocortin?
whats the funciton of beta endorphin
endogenous opioid that blocks pain receptors
chart of hypophysiotrophic hormones in the anterior pituitary and what they control
short loop feedback definition
pituitary hormones feedback to decrease hormone secretion by the hypothalamus
long loop feedback definition
In long loop feedback, the last hormone in a pathway feeds back to suppress secretion of hormones by the hypothalamus AND anterior pituitary
molecular cortisol pathway
1. confromational change when cortisol binds receptor protein
2. activated receptor cortisol complex moves into nucles
3. activated recpeptor cortisol complex binds to regulatory region of target gene and activates transcription
what is the control pathway for cortisol secretion called
hypothalamic pituitary adrenal (HPA) pathway
what two stimuli act on the HPA pathway?
circadian rythym and stress
where is CRH released from
corticotrophin releasing hormone is released f rom the hypothalamus
where is the anrenocorticotropic hormone released from
where is cortisol released from
what are the three functions of cortisol
protect against hypoglycemia, regulate blood pressure, suppress immune system
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