CHAPTER 41 Flashcards
define Hormones
chemical signals that is secreted from the endocrine cells.
define endocrine cells
cells that secrete the chemical signals.
define Target cells
receptors for the chemical signals
where does the circulating cells diffuse into?
the circulating cells diffuse into the blood where they can activate the target cells far from the site of release.
compare and contrast paracrine and autocrine.
Paracrine= signal affects the target cells that are near the site of release.
autocrine: signal affects the cells that released the signals.
how do some of the endocrine cells exit ?
some of the endocrine cells can exit as single cells such as in the digestive tract.
compare and contrast endocrine and exocrine glands.
endocrine glands: secretory organs composed of endocrine cells which secrete signals into the extracellular fluid.
endocrine glands: have ducts that carry their signals to the outside of the body or a body cavity.
how do neurons communicate with one another?
through neurotransmitter
what are the neurotransmitters called that diffused to the blood?
neurohormones
what are pheromones?
chemical signals that are secreted in the environment.
what action is taken by our body in response to the chemical signals>
signals are widespread in the sense that they can diffuse throughout the body, so in response the tissues in our body evolves sensitivity to the hormones to coordinate their activities with the secreting organ.
give an example of how the body reacts to the signals.
an example of the signals being widespread and the tissues evolving is = testosterone. testosterone is released when the sperms are made by testes but it is also active on tissues such as the brain, vas deferens, penis, liver and muscles . each of these tissues as a result has evolved ability to respond to the single signal.
another example
epinephrine
what is the other name for epinephrine?
epinephrine is also called adrenaline whic his released by the adrenal glands.
what is the function of epinephrine>
fight and flight response
released by fear provoking stimulus.
what are the four main things that results from epinephrine release
1) speeds heart rate and the strength of contractions.
2) constricts the blood vessels to the gut , muscles get blood supply.
3) stimulates breakdown of glycogen for quick enrgy
4) stimulates breakdown of fat as a source of energy.
how many responses can result from one hormone?
one hormone can trigger responses in different types of cells.
what is an example of a hormone acting on different types of cells?
ex: epinephrine
fight or lfight response which acts on different parts of the body such as the brian, liver, penis , vas deferens.
what does epinephrine bind to?
epinephrine binds to the receptors in theh eart, blood vessels , liver and fat cells.
what determines where the hormones acts>
where hormones act depends on the receptors.
what determines the action of it( function) ?
what is does depends on the type of cell that it binds to in terms of the downstream cascade initiated by receptor in that cell type.
what else can the chemical signals be used for>
chemical signals were pivotal for communication between orgnanisms.
what is the function of prolactin in mammals>
in female mammals , prolactin is responsible for mammary tissue stimulation for the production of milk
function of prolactin in pigeons and doves
causes production of “crop milk” . when the birds are feeding their new borns the sloghed off lining of crop is regurgitated to feed young.
prolactin in amphibians
- prepare for reproduction by seeking for water sites.