The study of the normal function of living organisms and the means by which it is achieved.

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3
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2answers
39 views

Bernoulliโ€™s Principle in the Cardiovascular System

Below are graphs which illustrate the cross-sectional area, velocity, and fluid pressure through each vascular segment of the cardiovascular system. It makes sense that velocity and cross-sectional ...
-1
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0answers
40 views

Can you become trapped inside a giant clam? [closed]

First off, do they close their shells quickly or slowly? Also, with what pressure do they keep their shells closed? Would you become a pearl if you stayed in there?
0
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1answer
36 views

Would a human survive eating only living ants?

After reading an admittedly foolish question about 1 googol ants vs. 1000 humans, I had a question. Could a human survive solely on eating ants (common ants, not the stinging kind, or leafcutters ...
2
votes
2answers
31 views

How do t-lymphocytes become mature if thymus has lost its function?

The development of t-lymphocytes are done by thymus and we also know that the thymus degenerates before puberty and we also know the maximum lifespan of WBC's is 15 days. So, how do t-lymphocytes ...
1
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0answers
20 views

An obscure reference to a “golden vein” [migrated]

In some Yiddish literature there is reference to a 'golden vein' which seems to refer to Hemorrhoids. Is there any reason that hemorrhoids would be described as golden? Edit: In response to the ...
-1
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0answers
60 views

How to eliminate prairie dog colonies from a field? [duplicate]

I have several fields infested by gunnison prairie dogs. These things cause damage to the fields, irrigation system, livestock, and spread disease. For years, I've invited neighbors/friends to come ...
2
votes
0answers
13 views

Peculiarity of chemo senses [closed]

We can easily recall our visual stimulus and auditory stimulus but why can't we recall chemical stimulus like smell and pain? We can recall a song or picture but we can't exactly recall smell and ...
5
votes
1answer
56 views

Where do most mutations come from, mitosis or meiosis?

According to this (old) paper there are 10 times more mutations during meiosis than during mitosis. One reason for that is that recombination often causes replication error and therefore mutations. ...
0
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0answers
42 views

How calorie intake affects weight gain?

There are ton's of textbooks and websites that say that if you want to gain weight you have to increase your calorie intake. My question is how is it possible for a body to take in more calorie than ...
2
votes
1answer
55 views

How does Celiac's Disease cause people to stop growing?

In all of the sites I've looked on, one of the symptoms of Celiac's Disease is the failure to grow in children. Why would an immune attack against gluten cause stunted growth? Celiac.org states: ...
2
votes
1answer
21 views

Physiology of tricuspid and bicuspid(mitral) valves

The tricuspid and bicuspid valves are atrioventricular valves. Both are valves that prevent backflow of blood pumped from the atria to the ventricles. However, the former has 3 "flaps" while the ...
2
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0answers
40 views

Skin extra sensitive to heat after burn

I just got my finger burnt (first degree burn $\Rightarrow$ I didn't even bother to bear the wound). It didn't hurt much, even when I pressed the wound. However, when exposed to heat (hot water, but ...
17
votes
3answers
1k views

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 ...
4
votes
1answer
39 views

What is the relationship between W, X, Y and P, M retinal ganglion cells?

In Guyton and Hall Textbook of Medical Physiology (12e) the retinal ganglion cells are classified into W, X, and Y types. However in Gray's Anatomy (40e) they are classified into Midget and Parasol ...
3
votes
1answer
31 views

How do cold conditions help organ transplants?

Body organs are kept cold in-between explanting them from the donor and implanting them in the new host. How do these cold conditions help organs to stay viable while they haven't fresh blood, energy ...
1
vote
1answer
108 views

How much heat can a human sustain? [closed]

For how long can a human sustain a temperature of 180 degrees Fahrenheit (82oC) without damage in a confined place? For instance, suppose a person is sitting in a steam-filled room, without external ...
4
votes
2answers
110 views

Can carnivores survive on a (processed) vegetarian diet? Why or why not?

There are many differences in for example the digestive system between carnivores, herbivores and omnivores. It seems that in certain kinds of species adaptability with respect to diet is possible. ...
5
votes
2answers
41 views

Why do epithelial cells arrest in response to serum?

Primary epithelial cells, for example human mammary epithelium, fail to proliferate (arrest) in serum-containing medium. Therefore, a common growth medium for epithelium contains pituitary extract ...
4
votes
1answer
60 views

How are smell and taste in fish differentiated?

The senses of taste and smell in different fish classes are described as two distinct senses; smell is mediated by the nasal openings, and taste by epithelial taste buds. They are both forms of ...
22
votes
2answers
2k views

Why does an electrical shock freeze up muscles?

Why is it when someone comes into contact with an electrical supply that their body freezes up and is unable to move away from the electrical source? Can someone explain this through a physiological ...
1
vote
0answers
25 views

classical conditioning paradigm for hippocampal learning

I wanted to know what a suitable classical conditioning experiment would be to analyze learning and memory capabilities in rodent models with respect to hippocampal long-term potentiation. For ...
9
votes
1answer
116 views

What is the convention for log notation in biology?

I'm reading through some oldish (1980s) papers on length-weight relationships in fish and crustaceans. Many report log-log relationships without specifying whether this is natural log, base 10, etc. ...
6
votes
1answer
123 views

Why is the brain dependent on glucose?

The strict dependence of the (human) brain on glucose has always been puzzling to me. While ketones can substitute for a portion of the brain's energy needs, it cannot substitute completely: blood ...
1
vote
1answer
31 views

Are there fish with a double circulatory system?

Our courseware materials say there are such fish, but the internet suggests fish only have a single circulatory system. Thanks!
4
votes
0answers
43 views

What are those visual and auditory reflex controlled by the midbrain? [closed]

The midbrain is a centre for certain visual and auditory reflexes. But what are those reflexes exactly? My study book says that these reflexes are, e.g., responsible for moving the eyes to view ...
3
votes
2answers
54 views

Determining how much energy a plant takes in?

I asked a question on WorldBuilding.SE, "Are diamond berries possible?". This led to asking a question on Chemistry.SE about the amount of energy required to burn a 1 ct. diamond (โˆ’6.527kJ). The ...
2
votes
1answer
26 views

Where does the exudate comes from during inflammation?

During inflammation transudate and exudate is formed by vessels. I would like to make sure if it comes from arterioles, venules, or both, and the reason why.
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vote
0answers
67 views

Why can we control our breath rate but not our heart rate? [closed]

Even though we cannot survive for more than few minutes if we stop breathing or if our heart stops, why is it so that our heart beat is controlled involuntarily while breathing can be voluntarily ...
1
vote
0answers
48 views

How many mitotic divisions do haploid cells undergo before fertilization?

Background This question is about human physiology and gametogenesis. A spermatozoid is not necessarily the direct "offspring" of diploid cell. Stated differently, a spermatozoid cell can be the ...
-5
votes
1answer
94 views

Why do fingers swell during cold winters?

When exercising, tissue in the hands may swell. This may be caused by the muscles generating heat, which leads to blood being pushed to the vessels closest to the surface of your body to dissipate the ...
10
votes
4answers
877 views

How can we differentiate between respiration and breathing?

I am a student of 10th grade, and I eagerly want to learn biology. What is the difference between respiration and breathing?
2
votes
3answers
89 views

Why Doesnโ€™t Hypercalcemia Cause Muscle Spasms?

If you have more calcium in the cell, wouldnโ€™t more attach to troponin and initiate muscle contraction? Why does hypercalcemia cause muscle weakness instead of spasms?
1
vote
1answer
37 views

Does creatine-phosphate (CP) supplementation regenerate NADH?

I have the following facts: It is possible to convert ATP <-> creatine vice-versa. (ref - non scientific) CP supplementation protects against metabolic syndrome. ref1 ref2 Fructose digestion ...
2
votes
1answer
58 views

Does breathing air containing 3% carbon dioxide gives you a headache?

As far as I know, breathing air containing relatively high levels of CO2 may get you a headache. I also know that CO2 level in the fruit bodies of peppers can reach levels as high as 3% at certain ...
2
votes
2answers
210 views

Difference between facilitated diffusion and secondary active transport in cells

Specifically, what is the difference between facilitated diffusion carrier processes (passive transport) and secondary active transport co-transport processes (active transport)? They seem to be the ...
1
vote
1answer
69 views

How is ATP involved in muscle contraction?

The sliding filament mechanism as explained by my text does not elaborate on how ATP is involved in the cross bridge binding and contraction process. How does muscle contraction utilize ATP? In my ...
0
votes
1answer
112 views

Why should or shouldn't we allow the human body to take its natural course? [closed]

For example, when you are sick but don't feel thirsty, this could be due to baroreceptor reflex that is attempting to readjust salt and water balancing. Why shouldn't a patient be left thirsty and ...
4
votes
1answer
99 views

Question about epinephrine

In my class we were told that adrenaline (or epinephrine) causes vasoconstriction. My question was I had always thought that people took this via an EpiPen when they were having an allergic reaction. ...
3
votes
1answer
115 views

Why do people in the scientific community use terminology such as renal, hepatic, cardiac instead of kidney, liver and heart? [closed]

Why is there the need to map these everyday words into another set of words, it seems to complicate matters. Is it done mostly out of tradition or is there some logical basis to it?
0
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0answers
41 views

What is the difference between specific and nonspecific stress response?

My book states that given any stressor, the body will response by providing a specific response to that stressor and a non-specific response that is triggered no matter what the stressor is (fear, ...
2
votes
2answers
137 views

When glucose production is low, the brain turns into keto acid as an energy source, how does this work?

Can someone very generally describe how the brain consumes keto acid when blood sugar has been completely depleted?
1
vote
1answer
25 views

What is the so called “hepatic glucose production”

I came across this term in my readings but I do not understand how this works. Can someone direct me to some reference as to what this "hepatic" glucose production is all about?
1
vote
1answer
64 views

Given an EC50 value, how do I reproduce the sigmoidal curve from which this was calculated?

All-trans retinoic acid (atRA) is a potent ligand for a nuclear receptor called retinoic acid receptor alpha (RARa). The concentration of atRA at which RARa is half maximal is 19nM. The dose-response ...
3
votes
1answer
43 views

Liver - Regeneration in Cirrhosis

Liver is the most resilient of the human organ (on par with or next to skin). A very interesting experiment on liver regeneration is here. Even if two-thirds of the liver is removed, the remaining ...
4
votes
0answers
42 views

Case Study and speculations of Edward Mordake

I am very interested in the case of the man named Edward Mordake who lived in the 19th century. In particular, he had two faces. If you have not heard of this man, please, search this up as there are ...
3
votes
0answers
27 views

Blood as newtonian flow and Poiseuille law [closed]

For a prep exam: A healtly pacient has a carotid with the following characteristics: intern ratio: ๐‘…= 2.8 mm, ๐‘ƒ2 = 89 ๐‘š๐‘š๐ป๐‘”, ๐‘ƒ1 = 90 ๐‘š๐‘š๐ป๐‘”, ๐œ‡blood = 3.5 cp, ๐ฟ=10.0 cm. Using the ...
2
votes
1answer
74 views

How to define drug-resistant or -sensitive cell line when knowing the IC50 values?

I have got the IC50 data for a drug on different cell lines. How to define if the cell line is sensitive or resistant towards this drug? Could anyone tell me how to define this?
2
votes
1answer
23 views

How is circadian rhythm of gastric acid secretion regulated?

Gastric acid secretion shows a circadian rhythm where acid production in the morning is minimal and it reaches a maximum towards the evening. How is this process regulated?
2
votes
3answers
78 views

What is the difference between meristem and bud?

Keep reading both terms quite frequently while studying plant physiology. I did some research trying to establish their differences and I learnt that meristems are undifferentiated cells that can ...
1
vote
2answers
365 views

Why can newborns swim?

I am wondering for someone to discuss the phenomena that newborn babies (humans) are able to submerge underwater up until a few months where that ability is lost again? What is the explanation for ...