Questions tagged [endocrinology]

The area of physiology dealing with the production and effects of hormones.

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Is Pars intermedia functional in humans?

My textbook says, "Pars intermedia secretes only one hormone called melanocyte stimulating hormone (MSH)." My teacher says that in humans MSH is secreted by the anterior lobe because the ...
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Question on steroid hormones [duplicate]

I have learnt that there are 2 types of hormones: peptide hormones (hydrophilic, mostly bind to receptors on cell membrane) steroid hormones (hydrophobic, can pass through cell membrane and bind to ...
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Do circadian hormones fluctuations follow sleeping patterns or the time of day?

It is said that testosterone and cortisol are at their highest early in the morning, at 8 am, and lowest at night. What happens, though, if someone regularly goes to sleep at 8 am and wakes up in the ...
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Hormonal effects of Luteinizing hormone on endometrium

What is the effect of luteinizing hormone on the endometrium? A general answer to this query is that it only thickens it. The same could also be said for the effect of Follicle stimulating hormone (...
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Apparent paradox in Glucagon action

Glucagon stimulates glycogenolysis and gluconeogenesis, thus increasing the plasma glucose concentration — so that tissues get enough glucose in the fasting state. However glucagon also inhibits ...
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Why do beta-1 and beta-2 adrenergic receptors result in two completely different effects (though both use Gs pathway)?

$\beta_2$ adrenergic Receptors are $G_s$-coupled 7-TM proteins. Considering that $G_s$ , by activation increases $[\text{cAMP}]_\text{cytosol}$ which inhibits MLCK of smooth muscles (and causes ...
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When assessing a threat, does the amygdala compare the stimulus to memories of the amygdala or the hippocampus?

Two excerpts from the one article. My understanding of this excerpt is that the amygdala is using its own memories: The amygdala learns how to respond to various stimuli based on it’s reference to ...
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Why severely increased Ligand (eg Hormones) concentration downregulates the Receptor?

As an example continuous high blood level of GnRH in humans causes a suppression of LH and FSH. This is due to the fact that increased GnRH downregulates GnRH-Receptors . My question is how this is ...
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Glycogenolysis & Gluconeogenesis

Is glycogenolysis and Gluconeogenesis is the same in the terms of product formed? This doubt arrived when I was attempting true & false and the question was Glucocorticoids stimulate ...
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Steroid hormones: how do they travel through the cytoplasm (not just the blood plasma) if they're hydrophobic?

I get that steroid hormones need hydrophilic plasma protein carriers (eg albumin, TBG) to travel in the plasma because they're not soluble in the plasma. However, I don't see any sources talking about ...
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1answer
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Why isn't there T2 thyroid hormone?

The follicles in the thyroid, intake iodine and bind them onto the tyrosine rings (attached to the thyroglobulin). This produces either MIT or DIT (tyrosine rings with 1 or 2 iodines attached ...
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Silly question about two human mechanisms: induced “REM dreams” by masturbation?

First of all, I'm a layman concerning Biological discussion. Well, my question is simple: is there any relationship between the hormones liberated by masturbation and REM phase of sleep? I'm ...
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Which hormones, metabolites, or other molecules build up as the day progresses, other than melatonin and adenosine?

Melatonin and adenosine reach peak levels around midnight/bedtime. I was wondering what other molecules also buildup as the day progresses. Particularly molecules that affect the CNS and/or immune ...
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How does exercising/starved muscle import glucose (released by liver)?

Adrenaline releases glucose from the liver during sport or if starved. This glucose goes to the blood through GLUT2 transporter. But how does it get transported into the muscle cells? GLUT4 is the ...
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Endocrine system in frogs, interstitial pressure gradient prevents absorption into blood?

Frogs have an elastic interstitial space and the pressure gradient to capillaries prevents reabsorption (Hendrick, 2013). Does this mean that diffusion of hormones into capillaries becomes a problem, ...
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Why is the thyroid gland in the neck?

The neck seems like an odd place for it. All other neck anatomy must interface between the head and abdomen (trachea, esophagus, circulation, spine etc). Surprisingly I have not been able to find ...
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What is the function of dreaming? Does a particular hormone secretion interfere with dreaming? Why do some people dream more?

I'm really interested to know when we are sleeping how a series of stories come to our mind that we called this process dreaming. If you know a useful article on this topic, please tell me thanks.
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Why do patients with type 2 diabetes not show the body wasting seen in type 1 diabetics?

Type 1 diabetes results from the destruction of the cells in the pancreas that produce insulin, while type 2 diabetes is characterized by so-called "insulin resistance", presumably a reduced ...
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Why would it be beneficial for cortisol and corticosterone to exhibit pronounced anti-inflammatory activity?

These questions are always a little silly (as we will never truly know), but it always struck me as odd that corticosterone and cortisol exhibit pronounced anti-inflammatory activity. Because these ...
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Why is angiotensin converting enzyme localized in the lungs

I understand that it's also found elsewhere, such as in renal capillaries, but I can't see logic behind it being located in the lungs. Isn't ACE's function, through making more angiotensin II, causing ...
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Are hormones antigenic?

I have been asked whether hormones are antigenic. I would have to think that the answer is no because they are used as various drugs such as FSH in infertility treatments without the need of ...
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327 views

Differences between neurotransmitters and neuromodulators

According to the Wikipedia article on neuromodulation a neuromodulator can be conceptualized as a neurotransmitter that is not reabsorbed by the pre-synaptic neuron or broken down into a ...
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Effect of angle of light on flowering of plants

I understand that the angle of light changes the direction of growth in plants (phototropism), but would the angle of light have any effect as such on the flowering of plants? Thank you!
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What are cells not affected by hormones called?

Cells that are affected by hormones are called target cells which have their own receptors that listen to signals. I'm unsure of the actual name of cells that are not affected by hormones, I tried ...
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How does the body make sure that Vasoactive Intestinal Protein reaches only the target tissue?

Vasoactive Intestinal Protein (VIP) is a 28 amino acid neuropeptide that has several effects in several systems. These include the cardiovascular system, respiratory systerm, urinary system, immune ...
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Why males are more prone to cardiovascular diseases such as heart attacks than females?

I often see more people of males undergoing treatment for heart disease. It is often said that female reproductive hormone (oestrogen) has some cardio-protective action by preventing constriction of ...
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Are neurotransmitters part of the endocrine system?

I was speaking with a substitute teacher of mine, and we were discussing whether neurotransmitters are part of the endocrine system or not. My class just spent an entire semester on the topic of the ...
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Are all endocrine glands associated with common human feelings?

I was looking at endocrine glands and found it interesting that a few of them have some very understandable feelings/mentalities associated with them. In particular: Gonads: arousal/romance ...
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Can stress and arousal be independent?

I'm trying to figure out if it's possible to have a stress response without being initially, or simultaneously aroused. I'm defining stress to be physiological stress (ie. release of cortisol) and ...
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Prolactin and Dopamine throughout orgasm?

Dopamine is also known as a prolactin-inhibiting hormone, which keeps prolactin levels in the body in check. However, during orgasm, dopamine is released to make the experience pleasurable. I know ...
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What happens to eyelids when we feel sleepy?

Why is that whenever we feel sleepy, our eyelids start to feel heavier. It is not like we can any time close our eyes and will immediately fall asleep. But, when we feel sleepy our eyelids ...
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How are testosterone levels distributed among men and women?

Wikipedia tells me that men have 7 to 8 time higher levels of testosterone than women, on average. Since the hormone is linked with performance in certain athletic events, my hypothesis, which I ...
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Could certain drugs enable one to consistently eat above TDEE or BMR without fat gains?

I heard anabolic steroids and stuff like DNP and ephedrine and etc. can somewhat enable one to eat more and get away with it without much or any fat gain, despite eating more than the body would ...
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What's the difference between releasing hormones and tropic hormones?

I've been reading my textbook and two terms have appeared that, after a bit of looking, I still can't seem to be able to distinguish. Here's what the textbook says (McGraw Hill Bio 12, 2011): After ...
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Is there any way bicondylar/bigonial, bizygomatic or bitemporal breadth can change in adults?

Without cosmetic surgery or etc., are there any cases/example wherein a human adult has had a change in significance regarding these regions of the face? I have seen many anecdotes where people have ...
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What's the difference between the neuroendocrine system vs endocrine system?

This is what I have understood so far: Neuroendocrine system involved neuroendocrine cells (also known as neurosecretory cells) that receive nerve impulses by a sensory neuron to release ...
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Hormones - biotic or abiotic

Are hormones biotic or abiotic? I have tried reading different articles, and I've found that it is both, but can that be true?
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Why is erythropoietin produced in the kidney?

Erythropoietin is a hormone produced in the kidney to stimulate the generation of more red blood cell. It is triggered by low oxygen via HIF transcription factors. Makes sense. Oops, oxygen is low, ...
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What is the difference between a cytokine, a hormone and a protein hormone?

I'm trying to figure out the difference between hormone, cytokine and protein hormone. It's clear to me that all three are biological messengers, but there seems to some ambiguity and overlap between ...
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Delay of sleeping on cortisol cycle

I was told that cortisol has to be measured at 9am or 4pm, because those where its peak level. But I wonder if changes on sleep patters affect the cortisol cycle. I mean, if I usually go to sleep ...
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Why are the hormones dopamine, adrenaline, noradrenaline and serotonin so ubiquitous across the animal kingdom?

As far as I know there is no reason for the makeup of a given hormone to be universal as it merely serves as a carrier from one part of the brain to another. So why are the above hormones seen across ...
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Is vitamin D a vitamin or a hormone?

Some people like to say that vitamin D is a hormone. A simple set of differences between hormones and vitamins is described here. Vitamin D is not (for the most part) absorbed through food but ...
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Can men also become only bald on their legs?

Often hair loss that primarily affects the top and front of the scalp will happen to men (and female) during aging. Male pattern hair loss is believed to be due to a combination of genetics and the ...
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Does estrogen increase muscular growth in females?

Regarding humans it is said that most psychological effects caused in men by testosterone are caused in women by estrogens. There are many studies on that, particularly regarding temporary shifts of ...
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Hormonal terms Somatotrophin or somatotropin?

Are Somatotropin and Somatotrophin hormones the same? It's confusing because when you type in Somatotrophin in google, it says, "a growth hormone secreted by the anterior pituitary gland.", but there'...
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How is the urea cycle regulated with respect to protein deficit?

Proteins cannot be stored in the body. Excess proteins from the diet are deaminated in the urea cycle that takes place in the liver. The liver is the first contact since these amino acids are ...
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What allows the hypothalamus to detect a lack of thyroid hormones?

On the website www.yourhormones.com it is written: "If there is insufficient thyroid hormone available for the brain, this will be detected by the hypothalamus and thyrotropin-releasing hormone ...
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Are releasing-hormones and release-inhibiting hormones from the hypothalamus ever present in the blood?

Our teacher said that these two hormones are normally never present in the blood stream, and to be carfeul of it if it comes as a question. I'm not conviced to be honest, is this true?
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Do ovaries produce estrogen before menarche?

It is traditionally taught that estrogen is produced by the granulosa cells of the follicle. But before menarche, where does the estrogen come from? Is it from the thin layer of granulosa cells lining ...
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difference between neurotransmitters and hormones

I have been reading a lot about neurotransmitters and hormones but what's the difference between them both or are they the same? It's been confusing for a while now. Also, why do some ...

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