(Hormone Signal Distribution)
Tell what type of signal each would be -
1. insulin secreted by beta islet cells and acts on skeletal muscle to increase glucose uptake (distant non-self)
2. insulin acts on nearby alpha islet cells to suppress secretion of glucagon (near non-self)
3. insulin acts on beta islet cells to inhibit release of insulin (acts on self)
I'll give you the biosynthetic pathway - give me the class
1. synthesized from AA
2. derived from tyrosine and tryptophan
3. derived from cholesterol
4. Where do steroids come from?
1. peptides (<50 aa) and proteins (>50 aa)
2. amino (NH2) acid derivatives
4. adrenal cortex, gonads, corpus luteum, placenta, Vit D
(Peptide and Protein Hormone Synthesis)
Put these in order
(a) conversion from prepro to prohormone in ER
(b) mRNA transferred to cytoplasm and translated on ribosomes to preprohormone
(c) stored in vesicles until endo cell is stimulated
(d) single gene is transcribed into a mRNA and directs primary structure
(e) prohormone packaged in GA fro secretion. Enzymes break prohormone into hormone
d, b, a, e, c
(Examples of protein hormones)
1. proinsulin is broken down into what and what by what enzyme?
2. do all of the proteolytic cleavages occur in all species?
3. some only occur where?
1. into insulin and free C peptide by B cell peptidases
3. intermediate lobe of pituitary
1-2. What are the two main classes of amines (one with three subs)?
3. How do half lifves of thyroid hormones and catecholamines compare?
4. tryptophan is a precursor to what two things?
1. catecholamines (NE, E, and dopamine)
2. thryoid hormones
3. thryoid hormones have half life of a few days, (inactivated by deiodinases) - catecholamines have half life of a few minutes
4. serotonin and melatonin
1. lipid derivatives of what?
2. give me a couple kinds of steroids
3. How quickly are hormones secreted from cells? how much storage?
4. increased secretion = ?
5. all steroids bind to what?
2. sex steroids, adrenal steroids
3. very quickly; very little storage
4. accelerated synthesis
5. plasma proteins produced by the liver
She wants us to understand that we can drive to certain things via enzymes
1. Eicosanoids are a large group of molecules derived from what?
2. The principal groups of lipid-derived paracrine signal molecules (bind to receptors) are what 4 things?
3. What is the primary precursor? where is it stored? relased through what?
4. How quickly metabolized?
1. polyunsaturated fatty acids
2. prostaglandins, prostacyclins, leukotrines, and thromboxanes
3. arachadonic acid; membrane lipids; lipases
4. rapidly (t1/2 = seconds)
What is the major center for hormonal control?
tina clarkson will cover this more
(Feedback: Basic Physiology Principal)
(How are hormones regulated?)
1. System of control based on what?
2. What is the net result?
3. Knowledge of this system is used to our advantage for what?
1. stimulation and inhibition of secretory cells
2. balanced delivery that can shift as needed
3. diagnostic testing
(Hormone Regulation - negative feedback)
1. the ____ of the pathway inhibits ____ to the pathway
2. comprable to what?
3. system described as what?
4. is this the primary regulatory system?
learn this diagram bitch
1. output, inputs
3. homeostatic (designed to keep the system at or near a setpoint)
(Hormonal control - negative feedback)
1. Can the setpoint be changed?
2. learn this graph (i don't really think it is an example of the above thing though)
1. yes - there are systems to do this
1. more or less common than negative?
2. Does hormone action cause more or less secretion?
3. Does it reinforce the stimulus?
4. Is it homeostatic?
read this (the LH surge)
1. less common
2. more (elevates concentration)
3. yes (self-augmenting)
4. no (sends variable being regulated even father from normal value)
(Positive feedback during childbirth)
1. cervix stretching stimulates receptors in the brain that stimulate production of what? what type of hormone? has a profound effect on what?
2. so what does ultimate build up of oxytocin result in?
1. oxytocin; posterior pituitary hormone; muscle tissue
note the difference between long loop and short loop
(Negative Feedback example)
1. Hypothalamic neruons secrete what? which stimulate what to do what?
2. What does TSH bind to? stimulating what? which affect what?
3. When blood concentrations of thyroid hormones increase above a threshold what happens?
4. What are characteristics of a hypothyroid dog?
1. thyroid releasing hormone (TRH); cells in the anterior pituitary to secrete thyroid-stimulating hormone (TSH)
2. receptors on epithelial cells in the thyroid gland; synthesis and secretion of thyroid hormones; probably all cells of the body
3. TRH-secreting neurons in the hypothalamus are inhibited and stop secreting TRH
4. overweight, hair falls out, lethargic, don't like cold
(More Feedback: glucose regulation)
1. Eat chocolate
2. Glucose is absorbed in the intestine and the level of glucose in the blood rises
3. Elevation of blood glucose concentration stimulates what in the pancreas to release what?
4. What does insulin facilitate? What happens as a result?
5. When the level of blood glucose falls sufficiently, what happens to the stimulus for insulin release?
3. endocrine cells (beta); insulin
4. entry of glucose into many cells of body; blood glucose levels fall
5. it disappears and insulin is no longer secreted
(Regulation of hormone secretion)
The concentration of hormone as seen by target cells is determined by 3 factors:
1. rate of production
2. rate of delivery
3. rate of degradation and elimination
(Regulation of hormone secretion)
(rate of production)
1. are synthesis and secretion the most highly regulated aspect of hormone control? What is control mediated by?
(rate of delivery)
2. example of slow delivery? fast delivery?
(rate of degradation and elimination)
3. do they have characteristic rates of decay? are they metabolized and excreted through several routes?
4. shutting off secretion of a horome with short half life causes what?
5. what if half-life is long?
1. yes; + and - feedback loops
2. low blood flow; high blood flow
3. yes; yes
4. circulating hormone concentration to plummet
5. effective concentrations persist for some time after secretion ceases
(Regulation of Hormone Secretion: receptors and target cells)
1. more than one hormone type target cell?
and so on
2. can different proteins be expressed on the plasma membrane at different times and in different bumbers to affect transmission?