Questions tagged [endocrinology]
The area of physiology dealing with the production and effects of hormones.
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Why does the face turn pale in dangerous situations?
I know what the effects are of a dangerous situation on the brain, i.e., an activation of the hypothalamic-pituitary-adrenal (HPA) axis which eventually results in an increased heart rate and elevated ...
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Do any animals other than humans undergo menopause?
Do any animals other than humans undergo menopause?
Also, is there any difference between animals in captivity and animals in the wild as regards menopause? For example, even if menopause has been ...
20
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1answer
568 views
Why are fearful stimuli more powerful at night?
For example, horror movies appear to be scarier when viewed at night than during broad day light.
Does light have any role in this phenomenon?
Are there changes in hormones at night versus during ...
19
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1answer
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What is the female equivalent of the morning erection that some men experience?
There was question about what causes "morning wood." It was answered that the erection in the morning is caused by decline of norepinephrine during REM sleep. Which in part allows to prevent ...
19
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2answers
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Can parts of a human brain be asleep independently of each other, or vary in the times required for them to fall asleep?
I know that some birds and marine animals can continue complicated activity (swimming, flying?) while one hemisphere of their brain is asleep.
I'm interested if human brain has some parts of it that ...
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Do human beings have pheromone receptors?
What is the current consensus on whether or not humans have receptors that detect pheromones?
If there are purported receptors, in what anatomical areas are they located? With what organ systems do ...
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2answers
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Does testosterone increase female sexual behavior?
According to my lecture notes testosterone generally increases sexual behavior.
Given that it's generally thought to be the male hormone I'm not quite sure whether they mean that it also increases ...
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2answers
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Do men have significant hormonal cycles?
I know there's a similar question here. But that discussion dissolved into lunar cycle and a correlation with it. I want to find more towards the original question of is there a periodic hormone ...
11
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1answer
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Is trembling an advantageous response during periods of anxiety?
I originally had planned to ask about whether there was any biological truth in the popular phrase "shivering with fright". However, after doing a fair bit of googling it seems that there is a lot ...
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2answers
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Is it possible for a human to wake up in a wrong way?
There's an old folk saying that goes like "He got out of bed on a wrong foot" - to indicate that the person's day is going poorly because of the way that person woke up.
Is it is possible for a human ...
11
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1answer
249 views
What is basis of multifunctionality of “master glands” in the endocrine system?
I have just started reading about the endocrine system and I am having some difficulty understanding the basis of distribution of glands and associated hormones.
I am using multifuntionality to ...
11
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1answer
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Which brain regions are D1 dopamine receptors expressed, and which brain regions are D2 dopamine receptors expressed?
This is a follow-up question to If D1 receptors stimulate adenylate cyclase (through GPCRs) and D2 receptors inhibit it, then why do mutations in both have similar effects?.
As a further question - I'...
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Can elements of one's environment act directly as hormones?
Can pollution and things in an organism's environment serve as hormones?
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2answers
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What determines testosterone exposure in womb, baby's genetics or mom's body?
I read this article which has the following quote:
The ratio between index and ring finger is believed to be linked to exposure to the male hormone testosterone in the womb.
And I wonder what ...
10
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1answer
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How do female hormones cause blood to clot?
On most female-hormone supplements you get a warning that is something like this:
The use of a combination hormonal contraceptives (CHC), like NuvaRing, is associated with increased risks of ...
9
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2answers
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When glucose production is low, the brain begins using ketoacids as energy… how does that work?
Can someone very generally describe how the brain consumes ketoacids/ketone bodies when blood glucose has been completely depleted?
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Why do men have a higher hematocrit (red blood cell count) than women?
The hematocrit, also known as packed cell volume (PCV) or erythrocyte volume fraction (EVF), is the volume percentage (%) of red blood cells in blood. It is normally 45% for men and 40% for women.
so,...
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2answers
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Do hormone drugs affect whether a person feels sexual attraction to males or females?
I know that ingesting testosterone and other hormonal drugs may stimulate libido and increase sexual desire.
But I wonder, if a man ingests female hormones such as estrogen, will he experience sexual ...
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2answers
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Leptin and fat mass?
I am interested in the relationship between blood leptin concentration and fat mass. It is well known that as fat mass increases, leptin increases.
Have there been studies that look into whether the ...
9
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1answer
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Which human body hormonal systems exhibit 24 hour diurnal cyclical activity?
I'm researching the possible connection between the dream content and the activity of various organ or hormonal systems within the human body. I'm looking for information on biological cycles within ...
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4answers
316 views
What gaseous substances do humans emit?
Other than CO₂ and Methane what other gases do humans produce or emit?
For example, does skin decomposition, or aerobic respiration emit any special gases that people don't normally realize or know ...
8
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1answer
748 views
If so many different hormones/molecules work by activating adenylyl cyclase, how do they have different effects?
It seems that many hormones and molecules work by activating adenylyl cyclase to convert $\text{ATP}$ to $\text{cAMP}$, such as adrenaline and glucagon. Both of these seem to bind to $\text G$ protein ...
8
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1answer
423 views
Neuroendocrinal mechanism of parturition
My book reads,
"The fetus signals that it is mature by secreting certain hormones
that diffuse across the placenta into mother's blood and cause the
secretion of oxytocin from her posterior ...
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2answers
329 views
Is there such thing as a generic “metabolic type”?
A while ago I picked up a book called "Eat right for your metabolic type". The book discussed the effects of the endocrine system on the overall shape and the speed of metabolism.
The book outlined ...
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2answers
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How do chameleons signal cells to change color?
I have read about how they can change color, but is there literature about the chemical signaling process they use to do so? I read that it could be some combination of hormones and neurotransmitters,...
7
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1answer
782 views
Can androgen-insensitive genetic-males get pregnant?
According to the linked report, people with androgen insensitivity syndrome appear as male, but have both feminine and masculine outer genitalia.
However, I was not able to find out whether their ...
asked Jun 11 '15 at 7:11
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3answers
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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 ...
7
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1answer
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Is it purely the nervous system causing vaginal lubrication (arousal)?
My girlfriend was watching some documentary on TLC about a paralyzed woman getting pregnant. I believe that woman still has some feeling, as she spoke about feeling the effects of a bladder ...
7
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1answer
525 views
Counterintuitive action of Vitamin D?
Vitamin D acts in a way which to me is counterintuitive. It functionally supplemets Parathormone. It in the intestinal tract steps up calcium absorption by altering nuclear gene expression and also ...
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1answer
9k views
Single hormone opposite effects
Often, a smooth response to a hormone means that some processes must be sped up and others must be slowed down.
How can a single hormone have opposite effects like this?
7
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3answers
489 views
Biological Pathway of Lipid Hypothesis
I've read a lot on both sides of the debate of low carb vs low fat diets trying to make some sense of what is being proposed. The lipid hypothesis runs roughly along the lines that we have lots of ...
7
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1answer
178 views
What is this small tissue structure found in kidney?
It's covered with white adipose tissue and it is smooth with reddish brown colour. HE dyed with dimensions 3 cm long and 1 cm wide. I'm guessing that this is a rare thing because I already checked ...
7
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1answer
690 views
When did our ancestors switch to a menstrual cycle instead of the estrous cycle?
The Wikipedia page on the Estrous cycle says:
Humans have menstrual cycles instead of estrous cycles. They shed their endometrium instead of reabsorbing it. Unlike animals with estrous cycles, ...
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1answer
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What is meant by “neurotransmitters flooding the brain”?
I frequently hear expressions like "Dopamine flooding the brain" or "X neurotransmitter flooding the brain" used to communicate with general audiences. For example: "Following [orgasm]? oxytocin ...
7
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1answer
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circulating microRNAs are functional?
In plasma and other body fluids, miRNAs can be found. They not only originate from dying cells but also from active secretion and are usually 'packed' into vesicles/lipo-proteic structures (i.e. ...
7
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1answer
291 views
Why are some menstrual cycles irregular?
A friend of mine asked me this today, and I didn't know. I remember studying the menstrual cycle a few years ago, but I can't remember the details (other than it was very hormone-related), and so I ...
7
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1answer
76 views
Would constant light or fading light be registered as more wakefulness promoting by the Supra Chiasmatic Nucleus?
During the fall and winter season, a number of people are experiencing Seasonal Affective Disorder. One of the way it has traditionally been treated is with a dedicated lightbox - a very high ...
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2answers
2k views
Do women have testosterone?
In a documentary on fitness I saw it was stated that women can't get big like men because of their low concentration of testosterone. If it is true that women have testosterone, where is it made? Why ...
6
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1answer
552 views
Genetic engineering for insulin production
In order to put human DNA inside a bacteria in order to have it create Insulin, from what type of cell would you need to take the gene for insulin?
I thought it should be from any somatic cell, since ...
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2answers
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Effect of steroid hormone on specific cells?
As steroid hormones can pass through the plasma membrane by simple diffusion because they are lipid derived hormones, it means that they are capable of passing through every cell of our body, BUT why ...
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2answers
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Renin - enzyme or hormone?
Wikipedia says :
The kidneys secrete a variety of hormones, including erythropoietin,
and the enzyme renin.
Can a substance be both an enzyme and a hormone ? Why is renin both an enzyme and a ...
6
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1answer
8k views
Why would lactate be high in diabetics?
Why are lactate level high in diabetes? For example, type II diabetes are resistant to insulin. If those patients are insulin resistant their gluconeogenesis should be working at a high rate and, ...
6
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2answers
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Why does depolarisation by high intracellular K+ trigger calcium channels opening?
I have learnt that in pancreatic beta cells, glucose being metabolised in the cell causes a high ATP level, which triggers ATP-dependent potassium channels to close. This means that potassium can't ...
6
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1answer
4k views
What causes humans to be sleepy?
Is there a hormone or group of hormones that regulates when we feel sleepy late at night, or in the morning? Or is sleepiness caused by some other non-hormonal mechanism? (e.g. pure psychological, ...
6
votes
1answer
161 views
How can hyperthyroidism induce osteoporosis?
It says in my physiology notes that hyperthyroidism can cause osteoporosis.
I've been trying to figure out how this could be possible for a little more than an hour now. Every article that I look at ...
6
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1answer
2k views
What happens to a human body once a sugary snack is consumed?
I'm looking to understand the effects of sugary snacks and/or drinks on a human body. I'm particularly interested in the timing of the ingestion versus various hormonal levels that may be circadian in ...
6
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1answer
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Enlargement of thyroid gland
Why does thyroid gland enlarge both in hypothyroidism and hyperthyroidism?
Hypothyroid goitre is due to lack of iodine in diet and hyperthyroid goitre (Exopthalmic goitre, Grave's disease) is due to ...
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1answer
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What will happen when humans are injected with plant growth hormones
Will plant growth hormones (PGHs), (let us consider auxins for example) poison our body or not?
I do realise that when you eat a shoot, auxins get digested and are less likely to be poisonous but when ...
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1answer
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Diabetes-diabetes comorbidity
Is it possible to have both type-1 (insulin-dependent) and type-2 (non-insulin-dependent) diabetes mellitus? That is, to have both insulin resistance and zero (or negligible) insulin production? If ...
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1answer
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Is there a relationship between Melatonin, Norepinephrine and depression in humans?
I'm reading a booklet on melatonin published in 1996, titled "Melatonin and the Biological Clock". This particular paragraph caught my attention and I would like to better understand what it means:
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