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16 Cards in this Set
- Front
- Back
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List the 5 mechanisms of hormonal communication in the body
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autocrine
paracrine endocrine neurotransmission neuroendocrine |
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How do water soluble hormones (peptides) exert their effects?
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bind to cell membrane receptor
trigger cascade within the cell to cause effect |
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How do steroid hormones exert their effects?
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steroid diffuses into the cell
binds receptor in cytosol enters nucleus triggers gene expression mRNA is made, proteins are synthesized |
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What percent of hormones are peptides? What are their characteristics?
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~70%
bind plasma membranes, are water soluble, short half life |
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What percent of hormones are steroids? What are their characteristics?
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~15%
act in nucleus, lipid soluble, longer half life (hours), bound in the plasma |
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What are the two smallest classes of hormones?
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catecholamines
Iodothyronines |
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What is the function of the hypothalamus?
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production of hormones that are stored in the neurohypophysis
production of inhibiting and releasing factors to regulate the adenohypophysis control of visceral regulatory activities |
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What is the structure of releasing hormones?
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small peptides synthesized in neurons
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List the hormones that come from the hypothalamus
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CRH
GnRH TRH somatostatin PIF ADH oxytocin |
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What is the importance of the diaphragma sellae in the dog and horse?
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it is incomplete
allows infection to get to pituitary from guttural pouch, allows tumors of the pituitary to get to the brain |
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What is secreted by the adenohypophysis?
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TSH, ACTH, GH, FSH, LH, prolactin, MSH
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How do signals go from the hypothalamus to the pituitary?
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unmyelinated neurons
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What is the purpose of the complex vasculature of the pituitary?
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portal system delivers high conc of factors from hypothalamus
transfers pituitary secretions to main circulation *things can lodge (bacteria, tumor emboli) and cause problems |
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What are the three types of cells in the adenohypophysis?
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eosinophils
basophils chromophobic |
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What is special about the cells of the adenohypophysis?
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pluripotent, can switch types if necessary to produce appropriate products
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What are the components of the vascular system of the pituitary?
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posterior hypophyseal artery
anterior hypophyseal artery hypophyseal portal circulation |
