Search results
Results from the WOW.Com Content Network
The term trophic is from Ancient Greekτροφικός (trophikós) meaning "pertaining to food or nourishment", here used to mean "growth"; this is the same origin as atrophy. This should not be confused with tropic, as in the similar-sounding tropic hormone – the words and concepts are both unrelated.
Tropic hormones are hormones that have other endocrine glands as their target. Most tropic hormones are produced and secreted by the anterior pituitary. [1]: 719 The hypothalamus secretes tropic hormones that target the anterior pituitary, and the thyroid gland secretes thyroxine, which targets the hypothalamus and therefore can be considered a tropic hormone.
The hypothalamus produces the hormones oxytocin and vasopressin in its endocrine cells (left). These are released at nerve endings in the posterior pituitary gland and then secreted into the systemic circulation. The hypothalamus releases tropic hormones into the hypophyseal portal system to the anterior pituitary (right).
The main release-inhibiting hormones or inhibiting hormones are as follows: The hypothalamus uses somatostatin to tell the pituitary to inhibit somatotropin and to tell the gastrointestinal tract to inhibit various gastrointestinal hormones. There are various other inhibiting factors that also have tropic endocrine inhibition activity.
Fig.1: Various tropic cues interact to guide the growth cone; the initial role of these cues was identified as either repulsive (red) or attractive (green). The growth cone is a highly dynamic structure of the developing neuron , changing directionality in response to different secreted and contact-dependent guidance cues; it navigates through ...
Meiosis generates genetic variation in the diploid cell, in part by the exchange of genetic information between the pairs of chromosomes after they align (recombination). Thus, on this view, [28] an advantage of meiosis is that it facilitates the generation of genomic diversity among progeny, allowing adaptation to adverse changes in the ...
This is an accepted version of this page This is the latest accepted revision, reviewed on 19 December 2024. Cell division producing haploid gametes For the figure of speech, see Meiosis (figure of speech). For the process whereby cell nuclei divide to produce two copies of themselves, see Mitosis. For excessive constriction of the pupils, see Miosis. For the parasitic infestation, see Myiasis ...
Since cortisol is what finally reaches other tissues in the body, it is a non-tropic hormone. CRH and ACTH are tropic hormones because they act on the anterior pituitary gland and adrenal glands, respectively, both of which are endocrine glands. [1] Non-tropic hormones are thus often the last piece of a larger process and chain of hormone ...