IPHY 4440 1st EditionExam # 3 Study Guide Lectures: 13-20Lecture 13 (March 10)What are the two nonapeptides and what do they control? And what are their prohormones?1. Oxytocin-like= simulate contraction of smooth muscles. Prohormone: prooxyphysin 2. Vasopressin-like antidiuretic= to inhibit the excretion of water by promoting the retention of water in your body. Prohormone: propressophysin Explain why vasopressin’ role in raising blood pressure is a pharmacological response? - Only when vasopressin in blood concentration becomes really high in the blood but only during unusual circumstances such as getting your arm cut off so need to constrict blood vessels in order to keep that blood pressure going. But physiologically not a normal circumstance because that doesn’t do that under normal circumstances. What are the chemical characteristics of OXY and AVP?- 2 cysteines= Cystine - Amino acid 1) 2) 3) 4) 5) and so on1) and 6) and cysteinescome together to form a cystine and has a tail of 3 amino acids3) and 8) is a neutral aa: makes oxytocin a neutral peptide Amino acid 3) isotocine to have tocin- like activity This is a sequence of oxytocin AVP: basic AA at 8 essential for activity, disulfide bond and tail; 8) Is Arg basic amino acid, in order to have a pressin activity the aa #8 needs tobe a basic acid or Arg; Phe 3) enhances the activity of arg in position number 8; Arg is not the only vasopressin in mammals;If you substitute an amino acid at 8) with lysine instead of Arg it will work because it is a basic aa (pigs and hippos have lysine)Name the main functions of the nonapeptides: -Oxytocin1) Increase reproductive smooth muscle for birth, ejaculation, and orgasm 2) Increase milk letdown by myoepithelial cells of mammary gland (Ducts containing milk, have myoepithelial cells are part muscle/part epithelial, squeeze milk out)-AVP1) Increase water reabsorption= antidiuretic hormone that opens water channels called aquaporins2) AVP action in nephron and collecting duct: Responsible for taking back water in kidney filtrate 2 waysTake some water out of filtrate (top lighter part) and back into the bottomVasopressin binds to receptor first stimulates phosphorylation of aquaporin, then go to membrane to suck up water, insert themselves in membrane to letwater in Vasopressin can stimulate transcription of aquaporin - Alcohol inhibits AVP by decreasing AVP so one cannot contain urine which leads to a big dehydration headache What is the melatonin synthesis pathway? Begins with an amino acid tryptophan 5-hydroxytryptophan serotonin (NAT=enzyme) N-acetylserotonin (HIOMT=enzyme)  melatonin * Melatonin is a biogenic amine so starts with an amino acid  tryptophan Serotonin is a biogenic amine so enzyme converting amino acid into a biogenic amine= decarboxylase (get rid of acid part) in between 5-hydroxy and serotonin Rate-limiting enzyme: NAT because has to go up, increased during dark phaseNOT HIOMT: always enough floating around during synthesis What are the 2 important features of the pineal gland? How is melatonin linked to the pineal gland? 1) Endogenous rhythms (SCN): Master clock that dictates our 24 hours circadiancycle : SCN cant get rid of it because always running/cranking will tell you when it thinks its light/dark, hungry/not hungry2) Mammal pineal lost photoreceptor structure- Melatonin acts in concert with SCN: helps keep our endogenous rhythm on track Describe the pathway when we perceive light and dark?1) light  decrease sympathetic activation  decrease NE  decrease melatonin secretion2) darkness  increase sympathetic activation  increase NE  increase melatonin secretion - Light/dark cycle coming out of sympathetic so the neurotransmitter that comes out of SCG must be norepinephrine travels back to brain to reach pineal gland stimulates it and releases melatonin True/false: Melatonin has a role in facilitating reproductionTrue Name an example of a long day breeder and a short day breeder?Hamster: long day breeders, can produce offspring in spring to fatten up for winterSheep: short day breeders, reproduce when day light getting shorter What are the three advantages to melatonin therapy?1) Aging prevention: Promotes removal of free radicals2) Immune system and cancer: enhances immune surveillance 3) Helps with sleep, reduction of cancer, counteract dysrhythmia Lecture 14 (March 12)Describe the basic anatomy of the thyroid gland?Single, unpaired gland (Honda-shaped in human)Located ventral to tracheaPaired in most non-mammals What are the roles of the follicular epithelium, follicular cells, and C-cells.- Follicular epithelium is a single layer of cells that are filled with colloid containing Tgb- Follicular cell: makes thyroid hormones - C-cells make calcitonin What is the difference between a hypocalcemic and a hypercalcemic hormone?Hypocalcemic hormone: lowers plasma calcium (Blood Ca2+ Bone Ca2+)Hypercalcemic: raises plasma calcium What are the three things that TSH stimulates in T4 synthesis?(+) TPO levels; (+) Tgb synthesis; (+) iodide uptakeWhat are goitrogens?Cause goiters, black iodide uptake, block NIS - Goitrogens that block formation of active iodide decrease TPO)What can occur with an iodide deficiency, reduced T4 plasma levels, and increased TSH secretion?  Hypertrophy (+) cell size Hyperplasia (extreme case) (+) cell number Enlarged thyroid= goiter Lecture 15 (March 17)What are the two schemes involved in deiodinase? Where do they occur in the body?Scheme 1 (in the thyroid gland):a) Outer ring deidodinase= 5’-deiodinase (5’-D). T4 T3b) Inner ring deiodinase= 5-deiodinase (5-D). T3T4 & T3 T2Scheme 2: Type I: Thyroid. Activation & inactivation. Both 5 and 5’  T3, rT3 and T2 Most abundant prevalent way for metabolism and production Type II: in pituitary. Activation. 5 only  T3 Type III: in brain, skin, placenta, gut. Inactivation. 5 only  rT3, T2 The Negative feedback effects of thyroid hormones will be most severely affected if _____ becomes nonfunctional? a) Type I deiodinaseb) Type II deiodinasec) Type III deiodinase ANSWER: BWhat are two methods in measuring the functionality of the thyroid gland?- Measuring the height of the follicular epithelium: Lots of TSH then epithelial cells grow taller - Squamous: Low “activity”  hypothyroid (Low TH)- Cuboidal: Normal “activity”  low cuboidal (Euthyroid= normal TH)- Columnar: high “activity” - Tall cuboidal and columnar