The maintenance of a constant internal environment - for example temperature, carbon dioxide concentration or water concentration, etc. within an organism.

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272 views

Why do you die if you cannot breathe?

I was wondering what the actual reason for death by suffocation is. Obviously it is related to oxygen deprivation. But what is the underlying cause of death? Is it due to insufficient oxygen for ...
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4answers
4k views

If body temperature is 37°C (98.6°F), why are most people more comfortable at around 21°C (70°F)?

It may be different for other people, but for me, anything above 32°C (90°F) is very uncomfortable, and my body is inclined to seek cooler temperatures. But I would think that at 32°C, the body would ...
11
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1answer
250 views

What biological functions does crying serve?

Tears suddenly start flowing out of our eyes when we find our long lost friend or when someone unexpectedly decides to break up with us. Do tears really save us from harm? Or are they just the reflex ...
9
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106 views

Last-ditch efforts to maintain thermal homeostasis

I was in the gym's steam-room today and a thought occurred to me: have I truly thwarted all possible mechanisms for maintaining thermal homeostasis? There's sweating, which is thwarted because the ...
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20k views

Glomerular Filtration Rate

In practice, when you have vasoconstriction of the glomerular capillaries and subsequently an increase in blood pressure, glomerular filtration rate increases. However, this seems counterintuitive to ...
9
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2answers
612 views

How does the body measure dehydration?

What, physically, does the body do to measure it? I assume it's measured by how how turgid or plasmolysed certain 'sample cells' are, or water concentration in the blood, What is the way they use to ...
7
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1answer
146 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 ...
6
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2answers
374 views

Why do people feel extreme cold at different temperatures compared to other people of same body structure?

I have seen some people shivering in the room temperature of 18°C while others of similar body structure do not feel that much amount of cold. Of course the clothing of both people is similar if ...
6
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1answer
63 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
774 views

How does the brain cool itself?

Thoughout life everyone tells you that brain is essentially a computer but just like computers your brain would create immense amounts of heat by being in use, so if that's the case how does it cool ...
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4answers
3k views

Is lemon water an alkalizing agent in the body?

I was recently having a discussion with someone about whether lemon water actually increases the pH of your body (by which I assume they mean the blood); their claim was that once Citric acid was ...
3
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1answer
60 views

Euthyrodism and goitre

I read in Tortora and Derrickson that goitre is associated with euthyrodism. How is that possible?
3
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1answer
48 views

Do river sharks (genus Glyphis) have reduced rectal glands for salt removal?

Do river sharks of the genus Glyphis have reduced or absent rectal glands for salt removal?   The rectal gland of marine sharks removes excess salts to maintain osmotic balance (Oguri 1964).  In ...
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52 views

Can tardigrades survive being eaten?

Compared to a tardigrade, the cockroach seems fragile. But can tardigrades survive the acidic environment of being eaten by most animals?
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52 views

Human leukocytes (re)circulation/migration in homeostatic state

One can easily find information on the topic of leukocytes trafficking between vessels and peripheral tissues during inflammation. But what happens during normal states when there is no pathology? ...
2
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1answer
196 views

Osmolarity vs. Tonicity

We're learning about osmoregulation in AP Biology and the terms Tonicity and Osmolarity are really confusing me. I watched this video on Khanacademy to try to understand what the difference is, and ...
2
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1answer
63 views

Blood pH at Higher Altitudes

My Campbell's Biology Textbook says the following: "For example, when an elk or other mammal moves up into the mountains from sea level, physiological changes that occur over several days ...
2
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1answer
116 views

Hibernation in ectotherm and endotherm

Both snake and weasel hibernate. Which of the following is correct? A. They will die when temperature decreases below the critical temperature. B. Weasel will die when temperature ...
1
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1answer
93 views

What is enantiostasis?

I have searched around and read my textbook but I am failing to understand how enantiostasis is different to homeostasis. For reference, Wikipedia definition is as follows: Enantiostasis is the ...
1
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1answer
82 views

Why do we get sleeply after we eat?

After we have eaten, we feel cold and sleepy. I think it's because the maximum blood supply is transferred towards the digestive system so that digestion is done, and therefore the brain to does not ...
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1answer
28 views

Giving diuretics to insipidus patient

I read in Tortora and Derrickson that giving diuretics to diabetes insipidus patients may in fact alleviate the symptoms of the disease. How is this possible?
1
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1answer
66 views

How does the brain regulate its temperature?

I recently ran into a bio-physical paradox while trying to solve an engineering problem, using nature's way as a guide; namely the brain. I'm working on designing a totally new system of liquid/gas ...
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1answer
34 views

Regarding cancer cells and radio-frequency ablation

Are cancer cells destabilized if near a strong electromagnetic field over a long period of time? I read this technique of using radio-frequency ablation and heat shock to kill cancer cells. I don't ...
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11 views
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51 views

What's the feedback regulation of Thyroid diseases and body temperature?

While going through the feedback regulation, the control of blood glucose level by insulin and glucagon is quite discussed in multiple materials including the textbook. I also understand the basic ...
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40 views

Is there a homeostatic setpoint for number of hours of sleep required by a human?

I've heard this TED.com talk about dieting and it mentions that there's a very definitive setpoint within the human brain about how much a human should weight. The speaker mentions that after as much ...
0
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2answers
2k views

Why do endotherms need more food than ectotherms?

I have a rough idea: its as endotherms need more food to keep their temperature stable whilst ectotherms use less of their food in respiration, but that's just me parroting the textbook I don't really ...
0
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1answer
135 views

Hypothalamic breakdown and effect of temperature on membrane lipids

I'm in my last year of high school and doing a research assignment on thermoregulation. In the excellence level exemplar for the standard, a student made the statement: Once the body's internal ...
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39 views

Contraction of scrotum in heat?

The mean temperature in desert regions is 50°C. Can human scrotum ascend testes to the pelvic cavity to cool them down?