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173 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Why do peptide hormones act faster than steroid hormones?
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Because steroid hormones require new protein synthesis
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Explain how an increase/decrease of glucose affects the system.
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When glucose levels go up, for example after a meal, the beta pancreatic islets release insulin and tell the liver to start the uptake of insulin from the blood. On the contrary, when the levels of insulin are low, the alpha islets release glucagon and command the liver to release glucose to the blood.
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only hypoglycemic hormone...
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insulin
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regular blood glucose level...
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between 70 - 100mg/100ml
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define hormone
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chemical released into the bloodstream by a endocrine cell. This chemical will affect a distant target tissue.
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what are the categories of chemical messengers?
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pheromones, hormones, neurohormone, neurotransmitter, parahormone, and autocrine
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define pheromones. Different types and pheromones play an important roles in...
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it is a hormone that is released to the external environment of an organism that affects others of the same and other species. there are two types of hormones: releaser (causes an immediate response) Primer (no immediate response.
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What are some messenger transmitters that do not fall into a specific classification?
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Inorganic Ions, Ca2+, Cyclic Nucleotides and Nitric Oxide
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how is thyroid hormone used to maintain homeostasis...
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thyroid hormone maintains basal metabolic rate
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how is insulin used to maintain homeostasis...
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insulin provides glucose (energy), for cells
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how is aldosterone used to maintain homeostasis...
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maintain proper [Na+] ion in the kidney
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how is acetylcholine used to maintain homeostasis...
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ACh is released to maintain proper contraction of muscle fibers
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What is an exocrine gland?
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When it affects a non-circulating tissue. Exocrine glands are the glands of external secretions. Eg. salivary glands, sweat glands
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Give an example of the endocrine and exocrine function of the pancreas.
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The pancreas (endocrine) releases insulin and glucagon to regulate glucose level in the blood. The exocrine pancreas is involved in the production of bile for the bile duct.
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Give some examples of endocrine tissues...
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ant. pit. gland.
Islets of Langerhans. Thyroid gland. GI track. Adrenal glands. Testes, Ovaries. Kidney |
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Where do endocrine tissues differentiate from?
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from all germ layers.
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What endocrine tissues are form from the mesoderm?
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the mesoderm gives rise to the adrenal cortex, ovaries, testes and kidneys.
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What endocrine tissues form from the endoderm/entoderm?
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The endoderm/ectoderm gives rise to the ant. pit., post pit, islets of langerhans, thyroid, parathyroid, adrenal medulla, and GI track
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Steroid hormones: Derived from.. number of carbons... how do steroid hormone interact with the target cell?
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Steroid hormones are derived from cholesterol. They have 27 carbons, and are lipid soluble. They go right through the cell membrane to affect DNA
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Thyroid hormone is derived from... That makes it a ... hormone
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Thyroid hormone is derived from tyrosine. Tyrosine is an aa, this makes thyroid hormone a peptide hormone which means it is not lipid soluble, but it is soluble in aqueous solutions.
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Epinephrine, norepinephrine and dopamine are all derived from...
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tyrosine
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Serotonin and melatonin are all derived from...
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tryptophan
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How do peptide proteins interact with the target cell?
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They bind to surface receptors on the cell membrane and activate second messenger systems like cAMP
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What is somatostatin? What kind of hormone is it?
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Somatostatin is a growth hormone inhibitor factor. (GHIH). It is a peptide hormone
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give me some examples of peptide proteins.
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glucagon, calcitonin, gastrin, prolactin, FSH and LH
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This type of endocrine cells has an extensive smooth ER
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Steroid producing endocrine. They make lipid droplets that induce biosynthesis
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This type of endocrine cells has an extensive rough ER
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protein hormone endocrine cells. They have less lipid droplets than steroid hormone producing cells and they use the golgi for packing their secretory vessicles w/c are released during Ca++ dependent endocytosis
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What are neurohormones? And how are the releasing cells different from regular neurons?
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Neurohormones are substances that are released into the bloodstream, not the synaptic cleft. The axon terminals of these cells are located where there is a rich blood flow.
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the posterior pit is also called ...
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neurohypophysis
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The cell bodies of the cells that control the function of the post pit are located...
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in the hypothalamus. The axons transect the stalk(infundibulum) and the terminal buttons are in the post pit
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What are neurotransmitters? What are the cells that release them? w/c cells do they affect?
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substances released by neurons. Neurons affect other neurons
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What are parahormones?
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hormones that have a local effect. These can include autocrine neurons
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What is renin?
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Renin is an enzyme that controls the release of angiotensin 2, w/c triggers the release of aldosterone from the adrenal cortex. Aldosterone is a vasoconstrictor
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What kind of glands produce pheromones?
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exocrine glands, which are released into the enviroment.
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What are the two types of pheromones?
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releasers and primers. releasers have create an immediate response from the affected organism. Primers do not.
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What are some of the properties of pheromones?
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pheromones are usually water insoluble, very stable and potent. Pheromones are used for sex attractant (bombykol, silk moth)
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What is the bruce effect?
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If you introduce a strange male mouse to a pregnant female mouse, she will release hormones to lose the pregnancy.
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What is the Whitten effect?
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It is the synchronization of cycles of females when males are introduced to the environment. This happens because of the hormones released by the male.
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What is the Lee Boat effect?
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When female mice are introduced to an environment where there is a pregnant mouse, all the other mice stop their menstrual cycle and experience pseudopregnancy.
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What happens with blood glucose during metabolic regulation?
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If BG is high, then insulin is released from the beta islets of langenhans to signal the liver to start storing glucose away. When BG is low, the alpha islets of langenhans release glucagon to signal the liver to release glucose into the blood and increase the BG.
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During metabolic regulation, how are the plasma Ca++ levels regulated?
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When Ca++ levels are high, calcitonin is released from the thyroid gland, w/c decreases the plasma Ca++ levels. When Ca++ levels are low, the parathyroid hormone is released from the thyroid gland to increase the plasma Ca++ levels. Calcitonin and PTH counteract each other
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During metabolic regulation, how is the osmolarity regulated?
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aldosterone works to increase blood osmolarity by the activation of the renin-angiotensin system. ADH (vasopressin) is released from the post pit to decrease blood osmolarity by increasing water reabsorption at the kidney and creating a more concentrated urine.
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This hormone has a lot to do with body temperature regulation...
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Thyroid hormone
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The neural reflex of mating cause the release of ...
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GnRH (gonadotropin releasing hormone) from the hypothalamus, w/c trigger the release of FHS, LH from the ant pit.
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Neuroendocrine reflex. think mating, birth, child rearing.
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What is the most known function of oxytocin? Think neural reflex
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milk letdown and facilitates child birth by distending the vagina and cervix
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This hormone is released in response to fear (fight or flight) from the adrenal medulla
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epinephrine.
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What is prothoracicotropic hormone (PTTH)?
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prothoracicotropic hormone triggers the release of the molting hormone ecdysome from the prothoracic gland (PTG)
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What triggers the release of ecdysome from the prothoracic gland in insects?
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prothoracicotropic hormone (PTTH)
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What are some examples of humoral regulation?
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Brain hormone (PTTH) in insects, ACTH (adrenocorticotropic hormone) released from the ant pit to increase the production of androgens and cortisol from the adrenal glands. And TSH (thyroid stimulating hormone) released from the ant pit to trigger the release of thyroid hormone form the thyroid gland.
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What is humoral regulation?
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Is the secretion of hormones to regulate a substance that are found in the ECF (extracellular fluid). Changes in the concentration of different substances in the ECF, like glucose or Ca++, trigger the release of insulin/glucagon or PTH/calcitonin respectively. This creates negative (-) and positive (+) feedback systems that regulate the concentrations of these and other substances in the ECF.
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For environmental regulation, which hormone regulates exposure to cold weather?
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Thyroid hormone. TSH is released from the ant pit, w/c triggers the release of thyroid hormone from the thyroid gland, w/c increases metabolic rate and this increases heat production at the cellular level. Increased metabolic rate increases heat production and addresses the cold problem
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What is a photoperiod?
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it is the duration of light in a 24 hr day
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Small hormones are conjugated to larger protein based molecules. This prevents the hormone from getting filtered through the kidneys for example. What are the names of these transporter molecules?
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Globulin and albumin
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What is CBG? Cortisol BG
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It is one of the transporter protein that binds to cortisol. Cortisol has a higher affinity for CBG, but it can also bind to albumin. These binding proteins are used to track hormone levels, like an antibody.
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What is SBG? Sex BG
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It is a sex steroid binding protein. This protein varies for estrogen and angrogens. When Sex steroid hormone is bound to SBG, it is inactive, so it must be released from SBG at the target tissue for it to have an effect. These binding proteins are used to track hormone levels, like an antibody.
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What is TBG? Thyroxin BG
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Thyroxin binding globulin binds to thyroxin so that the hormone doesnt get filtered by the kidneys. The thyroid gland makes two different types of thyroxin, T3 and T4. TBG has a higher affinity for T4. These binding proteins are used to track hormone levels, like an antibody.
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What are catecholamines?
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hormones that are released in a time of stress from the adrenal glands. Eg. epinephrine
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What are neurophysin? And give some examples.
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Vasopressin and oxytocin are released from the post pit. These hormones are bound and stored with a protein called neurophysin. The neurophysin for ADH (vasopressin) is pressophysin and the one for oxytocin is oxytophysin.
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What is the original form of neurophysin before it is associated with the its hormone?
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Neurophysin is first synthesized as pro-neurophysin. Pro-neurophysin is cleaved and converted to neuronphysin before it is associated with its hormone. ex. pressophysin for ADH and Oxytophysin for oxytocin
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Name the different neurophysin proteins that are bound to vasopressin and oxytocin.
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pressophysin is bound to vasopressin and oxytophysin is bound to oxytocin
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What is ELISA?
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Enzyme linked immunosorbent assay. It is used to quantify the amount of a particular protein a sample has by using AB and antigens. It uses a secondary antibody that binds to a primary, w/c is bound to the protein of interest.
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What is the titer?
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titer is a measure of concentration. The titer is a the highest dilution factor that yields a positive reading. A specific example is viral titer. To determine the titer, several dilutions will be prepared, such as 10^-1, 10^-2, 10^-3,...,10^-8. The lowest concentration of virus that still infects cells is the viral titer.
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List 5 of the physiological roles of hormones:
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The physiological roles of hormones are the following:
1- affect cellular synthesis and secretion of other hormones. 2- Metabolic processes, which could be anabolic or catabolic. 3- contraction, relaxation of muscle (skeletal, cardiac, smooth). 4- ..... Process --> gonadal development 5- stimulatory and inhibitory to cell proliferation 6- Excretion - reabsorption of inorganic ions 7- Permissive action on the effects of other hormones. -->it can enhance or inhibit the effect of another hormone 8- Affect animal behavior --> sexual, aggressive, maternal, group |
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How do hormones work?
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they interact with receptors at the target cells by signal transduction mechanisms.
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What are the two major receptor sites on the cell?
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the cell surface and the nucleus
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When hormones bind to the cell surface, they bind to either ______ or ______. What type of hormone binds to the cell surface?
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plasma membrane or trans-membrane peptides. Protein hormones bind to the cell surface. Ex. epinephrine, norepi, ACh
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This type of hormone binds to the cell from within, not the cell membrane.
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Steroid hormones. Ex. thyroid hormone
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What is the hormone receptor complex?
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It is a reactive site that binds to the hormone. It is a ligand binding site, it allows for specificity hormone binding and target cell response.
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What is a radioreceptor assay?
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Its a binding assay in w/c the binder is a receptor rather than an antibody
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What is up/down regulation of receptor?
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means to control the cell response to a particular hormone or neurotransmitter by increasing/decreasing the number of receptors
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What is the mode of action of steroid hormones? In other words, how do they interact with the cell? Think big on this one!!!!
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via an intracellular receptor. Steroid hormones are lipid soluble so they enter the cell through the lipid bylayer. Once inside, the hormone interacts with its receptor. The receptors are hormone specific and species specific. The receptors could be either in the cytoplasm or nucleus. The hormone is then translocated to the nucleus. In the nucleus the hormone will bind to the specific DNA sequence "hormone responsive elements (HREs) and this DNA sequences are upstream of structureal genes that are controlled by the hormone. The hormone-receptor binding allows recruitment of transcription activated factors, w/c control the transcription of sequences from DNA to RNA w/c in turn increases protein synthesis and allows the cell to perform a specific function.
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What are the hormone responsive elements (HREs)?
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they are the specific DNA sequence that the steroid hormone binds to once is translocated to the nucleus
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What are transcription activated factors and how do they play a role in the hormone-cell interaction?
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When steroid hormones are bound to the DNA HREs this allows the recruitment of transcription activated factors. Transcription activated factors increase the initiation of RNA polymerase to increase transcription into RNA w/c then is translated into protein
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What is the receptor activated superfamily?
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receptor activated superfamily are zinc transactivated proteins that mediate steroid hormones. Each superfamily has three domains:
1- Ligand binding Domain 2- DNA binding domain 3- Transcriptional activation domain These differ between different steroid hormones. |
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What are the 3 domains of the nuclear receptor superfamilies?
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Ligand binding domain
DNA binding domain transcriptional activation domain |
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Thyroid hormone has cytoplasm receptors that increase______ and they might bind directly with _____.
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transciption, mitochondria,
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Using Thyroid hormone alternative way to increase the _____ levels.
Hint! What kind of hormone is thyroid hormone? So it needs _____ |
cAMP
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Protein Hormone mode of action:
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quicker than steroid hormones because it doesnt rely on new protein synthesis.
The hormone binds to the surface receptor ad this results in transduction of the cytoplasmic side of the membrane. A cascade of events unfolds individual secondary messenger system. |
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What forms cAMP? And what breaks it down?
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adenyl cyclase forms it and phosphodiesterase breaks it down.
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there is a cell receptor for cAMP that is a protein kinase, what are it's two subunits?
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regulatory subunit
catalitic subunit |
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explain the steps of the cAMP second messenger system:
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The enzyme adenylyl cyclase converts ATP --> cAMP. Enzyme cleavage by phosphodiesterase results in the production of inactive (cAMP). Then cAMP combines with protein kinase (PKA) w/c is composed of two components - regulatory subunit and a catalytic subunit - Interaction of cAMP with the regulatory subunit results in release of the catalitic subunit. The catalitic subunit is therefore free to function as a kinase (phosphorylating enzyme). These kinase phosphorylate proteins that are responsible for activating activation hormones. This works through the G component protein.
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draw a progress map from the moment a steroid hormone comes in contact with the cell:
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steroid --> intracellular receptor--> increase in mRNA synthesis--> increase in protein synthesis
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Draw a progress chart of a protein hormone interaction with its target cell:
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cell surface receptor(G protein)--> 2nd messenger system--> protein receptor--> cell function or phophorylation of existing protein, if phosphorylation of existing protein--> transcriptional activation factor--> the transcriptional activation factor enters the nucleus and promotes mRNA synthesis--> protein synthesis
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What is CREB?
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CREB is cAMP response element binding is a protein that is a transcription factor. CREB binds to CRE cAMP response elements and it increases or decreases the transcription/expression of a particular gene. Once CREB is phosphorylated it recruits the co-activator CBP (creb binding protein w/c increases transcription.
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Some examples of hormones that work through a second messenger system
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Epi, Norepi ha alpha and beta receptors.
AcH has: muscarinic receptors on smooth muscle and are blocked by atropine. and Nicotinic receptors on skeletal muscles that are blocked by curare |
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Acetycholine has muscarinic receptors that are blocked by...
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atropine
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acetylcholine has nicotinic receptors that are blocked by...
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curare
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What are the 4 classes of membrane bound receptors?
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1) Receptors that are enzymes: eg. insulin GF is mediated this way. Tyrosine protein kinase. Gunilate cyclase.
2) Receptors that are channels: ion channels that are activated by neurotransmitters 3) Receotirs that are coupled to the G protein [(GTP binding protein)]: peptide hormone, neurotransmitter and protoglandins. 4)Receptors of unknown transduction mechanisms: receptors linked to intracellular kinases eg. GH and prolactin |
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examples of receptors that are enzymes
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insulin growth factor
tyrosine protein kinase guanilate cyclase |
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examples of receptors that are channels:
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ion channels that are activated by neurotransmitters
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examples of receptors that are coupled to the G protein:
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peptide hormone
neurotransmitter protoglandins |
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examples of receptors that are of unknown transduction mechanisms:
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receptors linked to intracellular kinases
GH and prolactin |
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draw a flow chart of how adenyl cyclase woks in the second messenger system
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G proteins can activate/inhibit--> adenyl cyclase--> cAMP
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What are G proteins?
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G proteins are bound to membrane receptors of the cell that respond to hormonal stimuli(peptide hormones). When the receptors bind to their hormones G proteins activate/inhibit adenyl cyclase w/c activates cAMP as a second messeger system.
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what are phosphoinositides?
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phospholipids present in the plasma membrane
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What are the three types of phosphoinositides?
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arachiodonic acid
-->precursor to prostoglandins inosuto triphosphate (IP3) -->goes into the cytoplasm Diacylglycerol (DAG) --> stays in the membrane |
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What is the calmodulin system?
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it is a Ca++ intracellular receptor. Calmodulin is needed for hormone activation of phoshplipase A2 --> prostogla?? It has a function in processing of enzyme activity. It has a function in endocytosis. It is ubiquitous to all eukaryotic cells. Primary sequence is strongly conserved.
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What happens to Ca++ when it binds to calmodulin?
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it allows it to interact with the substrate.
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There are a number of Ca++ modulated proteins that regulate Ca++ for their activation.
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given
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Whar are some of the roles of the CAM
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it is involved for intracellular Ca++ levels. Enzyme activity. And also in cellular filamentous organelle activity
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What happens during receptor upregulation?
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the # of receptor increases
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What happens during receptor downregulation?
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the # of receptor decreases
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how are some hormones able to regulate the number of receptors in cells?
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when there is chronic exposure to a hormone, the tissue becomes refractory to the hormone and the number of receptors decreases
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The priming response of prolactin happens when...
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the number of PRL(prolactin) receptors increases, so that later exposure to PRL creates a greater response
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the priming response is key to ...
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positive and negative feedback systems
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Give an example of hormones that work in sequence. Think woman!!
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LH and FSH in the ovulation cycle of females. FSH stimulates LH receptors
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Why do we use a hormone-receptor assay?
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in order to see w/c receptors the hormone binds to
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How does the hypothalamus communicate with the pit?
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directly via nerves and indirectly through the circulatory system
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The pituitary has several regions. Name some
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adenalhypophysis, neurohypophysis, median eminence.
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the hypothalamus forms the walls of the _____ ventricle
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third
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the hypothalamus lies _____ to the thalamus
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thalamus
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what are the divisions of the hypothalamus
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anterior region
tuberal region mammillary region dorsal region overly all lateral region |
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the anterior region of the hypothalamus overlies the _____
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optic chiams
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what is the tuber cinereum? where is it?
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the tuber cinereum is part of the hypothalamus and it is situated between the mammillary bodies and the optic chiams. The pituitary gland is attached to the tuber cinereum
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how is the post pit formed during embriogenesis?
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neural tissues evaginate downward from floor of the third ventricle infundibulon of brain to give rise to post pit
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what are chromophobes?
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are cells that show no cytoplasmic stain
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what are chromophils? And what are the two types of chromophils?
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pit cells that have stainable granules. Chromophils are divided into acidophils and basophils.
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What are acidophils?
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these are cells that light up in the presence of an acidic stain like orange G or acetocarmine
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What are basophils?
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cells that light up in the presence of basic dyes. An examples of a basic dye is aldehyde fuchsin. Examples of basophils are gonadotrophs (produce FSH and LH) and thyrotropes (TSH)
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What are some examples of basophils? Give an example of a basic dye
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gonadotrophs (FSH and LH) are basophils and thyrotropes (TSH) are also basophils. An example of a basic dye is aldehyde fuchsin.
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give some examples of acidophils. and give an example of an acidic dye.
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somatotrops (GH) and lactotrops (prolactin) are both examples of acidophils. An example of an acidic dye is orange G
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give an example of a chromophobe.
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corticotrophs are an example of a chromophobe
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as we go up in the evolutionary scale, what happens to the size of the pars distalis and neurohypophysis? And what is the exception?
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the size of the pars distalis and neurphypophysis goes up as you go up in the evolutionary scale. The exception to this rule is the teleost fish
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The teleost fish is the exception when we talk about the increasing size of the neurohypophysis and pars distalis in the evolutionary scale, what proof is there for this exception?
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***teleost
-has no distinct neural lobe -lacks median eminence because median eminence starts with amphibians -it shows great separation of the lobes |
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snake and lizards show very close relativity in this hormone
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gonadothropin
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human and rats showed very close relationship in this hormone
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FSH
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These hormones are produced from pro-opiomelanocortin
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ACTH (adrenalcorticotropin hormone), MSH (melanocyte stimulatin hormone), and LPT (lipotropin), endorphins and enkaphlins
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lipoprotin is a precursor of ...
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endorphins
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what is the function of ACTH
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it triggers the adrenal cortex to produce cortisol
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ACTH in terms of immunofluorescense is a .....
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chromophobe
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What is the hormone MSH?
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in lower vertebrates it controls melanocytes (pigment cells capable of creating melanin)
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What is the hormone LPT?
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lipotropin is a hormone involved in lipid mobilization. Releases free fatty acids.
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What are the endorphins and enkephalins?
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endorphins andenkephalins are natural opiates (morphine like hormones) that bind to morphine like receptors.
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MSH, LPT, ACTH, endorphins and enkephalins are glyco or poly-peptides? Do they show strong homology (similarity in structure)?
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MSH, LPT, ACTH, endorophins and enkephalins are all polypeptide hormones, not glycopeptides. They all show strong homology.
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LPT can be broken down by...
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protein degradation
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One theory has LPT as the ancestor molecule for ____ _____ ____. And ____ and ____ are embbed.
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In this theory LPT is the ancestor molecule for MSH, endorphins and enkephalins. ACTH and MSH are embedded.
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There are 4 diff types of MSH w/in mammalian systems. There is strong conservation of the MSH sequence on the evolutionary scale.
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given
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GH, prolactic, and placental lactogens are protein hormones or glycoproteins hormones
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protein hormones
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what is a prohormone?
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precursor of a hormone
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what is the function of GH?
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growth hormone increases somatic cell growth and metabolic fucntions
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What is the function of prolactin?
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The function of prolactin differs among different systems.
-in mammalian systems it controls lactation. -in lower vertebrates its involved in osmoregulation. -in amphibians its involved in metamorphosis -it has an impact on behavior -it is also considered to be a stress hormone |
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what is a heterologous study?
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an example of a heterologous study is injecting a hormone from a different species to another.
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how can we determine the evolution of a hormone? give the example used with prolactin.
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We use a heterlogous study in which an animal/lower vertebrate is injected with a hormone from another species. In the case of prolactin, lower vertebrates where injected with mammalian prolactin and it was determined that it has many functions. When the same lower vertebrate was injected with prolactin from its own species many more functions were found. This study shows how prolactin has evolved many newer functions while keeping some of its ability for its older functions. This also has to do with receptor evolution
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GH shows high function specificity between non-primates and primates. How was this proven?
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when you inject non-primate GH to a primate you get no function. But when you inject non-primate GH to non-primates you get function. EG. rat GH works in rabbits
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Interestingly, human GH works in fish, but not the other way around. Also, you get more function when you use human GH in fish
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given
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What is placental lactogen and w/c species have it?
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placental lactogen is a hormone whose functions are similar to growth hormone. In pregnant females it modifies the metabolic rate of the mother to provide energy supply for the fetus
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examples of neurohypophyseal hormones...
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oxytocin and vassopresin(ADH)
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what are oxytocin and vassopressin derived from?
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the precursor molecule for both vasopressin and oxytocin is neurophysin. For vasopressin is pressophysin and for oxytocin is oxyphysin
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Where are neurohypophyseal hormones stored and where are they produced?
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neurohypophyseal hormones are produced in the hypothalamus and they are stored in the post. pit
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in mammals the formal name of vassopresin(ADH) is...
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argenine vassopressin (AVP)
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What is the function of ADH and where does it perform this function? Big answer!!! Think of all the effects...
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ADH is the anti-diuretic hormone. It reduces water loss from the kidneys. It acts on the distal tuble and collecting duct to increase water permeability, decrease urine production and increase urine concentration. Because ADH prevents water loss, it increases the ECF. An increase in ECF increases blood pressure and blood volume. More water reabsoption means lower osmolarity because of less concentration of ions. Also, ADH has vasoconstricting effects w/c increase blood pressure.
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What is the function of oxytocin?
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Oxytocin is released for milk let down when the baby is brestfeeding. This is called a neural reflex. Also, oxytocin induces contractions of the uterus and pelvis during child birth.
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give an example of a neural reflex...Which hormone regulates it?
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milk letdown when breast feeding. this is regulated by oxytocin
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Vassopressin is involved in water uptake. Name the gland that releases it
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post pit
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what is oxytocin involved in? name the gland that releases it.
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oxytocin is involved in uterus contractions and milk let down. Oxytocin is released from the post pit
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Name the variant of vassopressin in lower vertebrates and amphibians. how is this function different in fresh water fish.
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Vasotocin. In fresh water fish vasotocin increases glomerular filtration rate by vasoconstricting efferent arteriole and increase urine volume.
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How is argenine vasotocin different from fresh water fish vasotocin?
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argenine vasotocin works by vasoconstricting the EFFERENT arteriole of the glomerulus. This increases glomerular fliltration rate and increases urine output. In lower vertabrates argenine vasopecin vasoconstricts the AFFERENT arteriole and this causes a decrease in GFR, therefore decreasing urine output and increasing water reabsorption.
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What are some of the other options for vassopressin for other species
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Pigs and hippo families use lysine vasopressin
Marsupuals use phenypressin |
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The mammalian neurohypophysis is the source of 3 principal neurohormones...
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Oxytocin. Vasopressin and in some cases Lysine vasopressin
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How does oxytocin interact with ACTH release?
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Oxytocin has inhibitory effect on the corticotropic releasing hormone which triggers ACTH secretion. Therefore, it indirectly inhibits ACTH release
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List the functions of vassopressin (direct and indirect)
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Osmoregulatory function to increase water uptake at the distal tubule and collecting duct of the kidney
This also increases ECF volume, which causes an increase in blood pressure and an increase in blood volume. Therefore vasopressin has an impact on blood pressure. It will stimulate directly ACTH release, via the median eminence. It stimulates thyroid stimulating hormone. Vasoconstricting. It has an effect on social behavior. Impacts SCN (biological clock) This is because hypothalamus neurons use vasopressin that impinge in the SCN. |
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What is the role of somatostatin?
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Somatostatin is a polypeptide hormone that inhibits the secretion of thyroid, somatotropin, glucagon, insulin, thyropin and gastrin hormones
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Which assays detect the presence of pro-homone?
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ELISA and RIA
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These steroid and aa hormones have a larger half-life. What is it about them?
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They have a binding protein attached to them.
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How do you study how a hormone work?
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you screen the target tissue and only tissue that stimulates that tissue.
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How does a bioassay help in the study of a hormone?
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It gives researches a living measurement of a hormone. It studies the physiological response. For example, androgen bioassay used with chicks and the development of the comb in males.
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what are the advantages of bioassays to study hormones? What are the disadvantages?
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It measures the physiological response to a hormone and it measures the active form of the hormone.
The disadvantages are that the bioassay has to be specific for the particular hormone and the sensitivity to detect the physiological levels of the hormone. |
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What factors influence the bioassay?
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how to administer the hormone?
what is the hoormone dissolved in? species or strain of animal used. age, health and season needs to be controlled. |
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RIA is good for determine the hormone _____ and it works by using an ________ against the hormone of interest
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titer, AB
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How is a binding assay developed for insulin?
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-purify insulin
-get antibody(specificity) -generate "hot", radioactive insulin (I125) vs. not radioactive "cold" insulin -I125(hot) is the tracer, hot insulin binds to the AB -if you increase the amount of cold In, this decreases the binding of AB-In. The opposite is true. Everything depends on the amount of cold insulin added. |
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What are the advantages and disadvantages of binding assays?
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ad
-qualitative -it can be very sensitive dis -specificity with AB -assay is only as good as how specific the AB is for the antigen -needs pure hormone to generate AB -you have to deal with radioactivity(hazardous) |
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TRH is present in fish + amphibians, but...
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it does not trigger the release of TSH. The function of TRH in fish and amphibians has not been determined yet
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GnRH controls the release of....
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FSH and LH. It is released in a pulse fashion. The frequencies and pulses dictate w/c of the two will be released. Low freq --> FSH
high freq --> LH |
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