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19 Cards in this Set
- Front
- Back
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What are cytokines?
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They are chemicals that cells release and which influence nearby cells.
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What is an autocrine response?
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When the chemical feeds back to influence the same cell that released the chemical.
When the influence involves diffusion to nearby target cells this is a paracrine function. |
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Some hormones are proteins or polypeptides. TRUE/FALSE
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TRUE. Oxytocin, TSH, and insulin. Some are derivatives of amino acids, thyroxin, and epinephrine.
Others (steroids) are cholesterol derivatives. |
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Hormones act by affecting the permeability of cell membranes to molecules that affect cell function. TRUE/FALSE
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TRUE.
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How do polypeptide hormones interact with receptors?
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Polypeptide hormones(epinephrine) interact with receptors on the cell surface.
Once having reacted with a specific cell surface receptor, this, via intermediary molecules called G proteins, stimulates a second messenger within the cell activity. The 2nd cell messenger is often cyclic AMP. |
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What are some other secondary messengers?
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Cyclic GMP
Inositol triphosphate Diglyceride and Calcium. |
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Where do steroid hormones act?
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They act on cytoplasmic receptors and the resulting complex moves to the nucleus to influence DNA transcription of proteins.
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Where does thyroid hormone act?
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It directly enters the nucleus where it alters DNA causing production of certain enzymes.
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Do some substances have more than one receptor type?
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Yes. Epinephrine, acts on alpha receptors, to produce vasoconstriction, and on beta receptors to produce vasodilation.
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What do Gastrin, Secretin and Cholecyctokinin have in common?
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They are hormones that do not have their own glands. They are secreted by the digestive tract.
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What is GH?
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Somatotropin
origen-ant. pituitary and is a polypeptide. It is regulated by GH releasing hormone(GNRH) and inhibiting hormone(somatostatin). It promotes growth of bone and cartilage/increases protein synthesis/promotes lipid breakdown to fatty acids. |
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What effect does GH have on the liver?
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It induces the liver to produce somatomedins, protein growth factors.
It is stimulated(GH) when blood amino acis and glucose levels are reduced. |
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What are somatomammotropins?
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They are produced by the placenta and resembles somatotropin in structure and function.
It increases blood levels of glucose and fatty acids(maternal) and increases the availability of nutrients for the fetus. |
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What is prolactin?It is from the acidophil cells of the ant. pituitary. TRUE/FALSE
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True. It is regulated by prolactin releasing and inhibiting hormone(PIF) from hypothalamus.
It functions to stimulate milk secretion in pregnancy. |
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What is the difference between estrogen and progesterone regarding breast involvement.
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Estrogen stimulates development of the breast duct system, breast fat deposition and stroma. progesterone stimulates the development of breast glandular tissue and alveoli.
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What is the difference between prolactin and oxytocin?
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prolactin stimulates milk secretion into the alveoli during pregnancy and nursing. Oxytocin stimulates breast myoepithelial cells to contract, thereby ejecting the milk.
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Can prolactin be produced in excess?
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Yes. It may occur in prolactin producing tumors or with excess thyroid releasing hormone(TRH) production, which stimulates prolactin secretion in addition to TSH secretion.
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What is Galactorrhea?
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It is excess milk secretion, which results from excess prolactin, as well as amenorrhea and anovulation secondary to disturbances of the menstrual cycle.
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Does excess prolactin production occur in males?
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Yes. It results in decreased sperm production, testosterone deficiency and impotence.
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