25 votes
Accepted

Why does the face turn pale in dangerous situations?

Red blood cells are not equipped with a motor system to propel them through the blood stream. Instead, they are passively transported through the vasculature by the the pumping action of the heart. ...
  • 51.5k
24 votes
Accepted

What is the female equivalent of the morning erection that some men experience?

Women have erections too! These erections are called clitoral erection. Clitoral erections are usually accompanied with vaginal lubrification. Just like men (see here), the absence of norepinephrine ...
  • 67.7k
13 votes
Accepted

Why is insulin given in type 2 diabetes?

Isn't it illogical to give more of insulin for a deficit amount of receptors? Seems like there is some confusion in the definition of type-2 DM itself. According ...
12 votes
Accepted

Can androgen-insensitive genetic-males get pregnant?

Short answer People with androgen insensitivity syndrome do not have a functional uterus and cannot bear a child. Background Androgen-insensitive genetic males may develop female genitalia and ...
  • 51.5k
11 votes
Accepted

How do chameleons signal cells to change color?

As said by @dblyons, there has not been a lot of research (biochemical) on chameleons. So, the exact part of mechanism that you're looking for is still not understood. However, we have recently caught ...
10 votes
Accepted

Why are fearful stimuli more powerful at night?

Short answer The increased fear responses during the night are believed to be mediated by elevated corticotropin-releasing hormone (CRH) levels in the brain that drive the fear responses in the ...
  • 51.5k
9 votes

Why is insulin given in type 2 diabetes?

This is true for the beginning of the disease. As a reaction to the reduced sensitivity of the cells in the body to insulin (and thus less uptake of glucose from the blood and a resulting ...
  • 49.4k
8 votes

Why do men have a higher hematocrit (red blood cell count) than women?

I found a nice article that has insights to this matter. As posted before me it is true that only adults, but not juvenile individuals show this difference. Direct and indirect effects of sex hormones ...
  • 3,078
8 votes

Effect of steroid hormone on specific cells?

The quick answer is that only certain cell types express the required steroid hormone receptors that are necessary to induce signaling and gene regulation when bound to their target steroid hormones, ...
  • 14.9k
8 votes
Accepted

When glucose production is low, the brain begins using ketoacids as energy... how does that work?

Human body is a glucose driven machine which intake carbohydrates and converts to glucose. Energy is yielded from the glucose and glucose is stored as glycogen. When the carbohydrate intake is somehow ...
  • 1,874
8 votes
Accepted

Could a trans-female person ever become pregnant?

Medical science has reached the point where it is able to consider performing uterine transplants in genetically female (cis-female) patients born without a uterus. In the MedlinePlus report, First ...
  • 4,945
7 votes

How does visual sexual arousal work between the eyes, brain, and genitals/gonads?

Sexual arousal is a very complex response, that includes a whole range of physiological changes, firing of lots of neural pathways, increased muscle tension, elevated heart rate with increased blood ...
  • 2,268
7 votes
Accepted

Do humans have skin cells that trigger oxytocin release in the brain?

Short answer Oxytocin release has been associated with the cutaneous low-threshold (CT) afferent fibers in hairy skin. Background Oxytocin is released from the paraventricular nucleus in the brain ...
  • 51.5k
7 votes

What is the difference between a cytokine, a hormone and a protein hormone?

Parts of the answer are in the text that you provide yourself. But I shall try to add where i can. What do each of these three terms [hormone, cytokine and protein hormone] mean and how are they ...
  • 523
6 votes
Accepted

Question about epinephrine

An allergic reaction requiring an epipen can be caused by swelling in the throat and/or bronchoconstriction (spasms decreasing the diameter of bronchioles). Bronchoconstriction can occur in the ...
6 votes
Accepted

Is it possible for a human to wake up in a wrong way?

I did a quick search and found some research in this area. Sleep inertia is the technical term for feeling groggy for a while after waking up. In a review article by Patricia Tassi, Alain Muzet (...
  • 3,045
6 votes
Accepted

Counterintuitive action of Vitamin D?

There are two pieces to this question: a) How does bone resorption (movement of Ca/Phos out of bone into the blood) result in net improvement in bone structure? Bones are constantly remodeling, ...
  • 3,139
6 votes
Accepted

How do female hormones cause blood to clot?

These combination contraceptives contain two substances: Estrogen and progestin (a synthetic progesterone). Both are used together to overcome the negative effects of single substance drugs as acne or ...
  • 49.4k
6 votes
Accepted

What are the differences between how glucagon and cortisol work to increase blood sugar?

Glucagon and cortisol are VERY different types of hormones, though each of them can affect glucose metabolism and effectively can increase glucose concentrations in the blood (albeit through different ...
6 votes
Accepted

How may the age of a child be estimated when required to do so, in video-graphic evidence?

In short, without direct physical evidence (forensic or medical examination), testimony, or documentation to act as proof, you are left up to the discretion of the court to determine whether evidence ...
  • 4,945
6 votes
Accepted

Are glands in human made up of muscles?

No they are not made of muscles. Glands are modified epithelial tissues. Glands are basically of two types Endocrine and Exocrine glands. Endocrine gland It is a gland that lacks a duct system. ...
  • 8,754
6 votes

Why is insulin given in type 2 diabetes?

Insulin is a "last resort" treatment for people with Type 2 diabetes—partly due to the unpleasantness of injections, but partly due to the fact that high insulin levels can worsen insulin ...
  • 191
6 votes
Accepted

Do all organs of our body secrete hormones?

Good question! The major and most common endocrine glands in the human body include pituitary, thyroid, parathyroid, thymus, adrenal, pancreas, gonads and pineal gland, along with neuroendocrinol ...
6 votes

Steroid hormones: how do they travel through the cytoplasm (not just the blood plasma) if they're hydrophobic?

Firstly not all steroid hormones travel inside the cell and regulate the gene expression. Basically there are two pathways- direct and indirect. Steroid hormones are lipid-soluble, which allows them ...
  • 846
5 votes
Accepted

What is the physiological difference between cortisone and cortisol?

Cortisol is directly given to the patient - it is then called Hydrocortisone. I don't know why this is done but probably to avoid confusion because both names are too similar. The difference between ...
  • 49.4k
5 votes

Do women experience more bonding hormones than men after sex?

Does Oxytocin increase more so for women than for men after sex? Answer: Yes, Oxytocin level shoot up for female after sexual. It is highest at orgasm, which is the main cause women could have ...
5 votes

If a human is stranded with beer but no water, should they drink it?

There is quite a lot of misunderstanding about alcohol (and caffeine) as a diuretic. It's not nearly as cut and dry as you're presenting. There is no answer to your question. Sodium and water are ...
5 votes
Accepted

Artificial Adrenalin

Yes, it is possible to extract adrenaline from the adrenal glands. This was done in 1901, a patent was filed, and it was marketed under the name Adrenalin. It is also known as epinephrine. It is ...
  • 1,152
5 votes
Accepted

How is adrenaline (also known as "epinephrine") a ligand?

The definition of "ligand" in the question, "a molecule or ion which donates a pair of electrons to a central transition metal ion in a complex" is clearly a more technical 'chemistry-type' of ...

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