Skip to main content
23 votes
Accepted

How did the largest/longest dinosaurs hold their head and necks up?

There are lots of papers on this. A good summary article is Why sauropods had long necks; and why giraffes have short necks, by Taylor​ and Wedel. They list a number of anatomical features that ...
iayork's user avatar
  • 14.2k
14 votes
Accepted

Do eye's muscle share the same nerve?

Each eye is controlled separately. Three cranial nerves emerge at the brain for each eye to control the so called extraocular muscles. That we usually move both eyes in one direction is due to that ...
adjan's user avatar
  • 2,106
11 votes
Accepted

Bending your little finger without bending ring finger

This does not have to be the case always, For example if you are a pianist you need all your finger to work independently. OK, So coming to the main question. In simple words, They are all ...
Tensor_Product's user avatar
11 votes
Accepted

Can acetylcholine leak away from the synapse and cause spasms?

The enzyme responsible for the breakdown of acetylcholine (Ach), i.e., acetylcholinesterase, rapidly degrades, and inactivates Ach in the synaptic cleft after release. This process is particularly ...
AliceD's user avatar
  • 52.5k
8 votes

Why does it hurt the next day after doing significant exercise?

It should be noted that in some people (somewhere between 1% and 3% of the population, depending on who's counting) there is another mechanism for delayed muscle pain. Myoadenylate Deaminase ...
Hot Licks's user avatar
  • 200
8 votes
Accepted

Biological Neural Network Training for Babies

Biological neurons function in a very different way, as compared to the simplistic artificial neural networks of machine learning. For example, see how real neurons work and how they connect with each ...
Julia's user avatar
  • 284
7 votes

What causes spontaneous muscle twitches?

Short answer Spontaneous muscle twitches are thought to be caused by spontaneous activation of motoneurons controlling the muscles. Background Spontaneous muscle activity (twitching) is referred to ...
AliceD's user avatar
  • 52.5k
7 votes
Accepted

Are there genetic causes underlying the difference in circumference of the upper arm and foream?

The first answer explains that proximal limb segments do more "work" * using quotes to be careful w.r.t. technical definitions of work. Genetically, this is correct--it's the ancestral condition for ...
Kara's user avatar
  • 587
7 votes

Do eye's muscle share the same nerve?

There are basically four different types of eye movements: smooth pursuit (think about following a moving target with both your eyes, note how smooth the movement is) saccades (think about moving ...
Deepak's user avatar
  • 173
7 votes

Biological Neural Network Training for Babies

Some babies start walking by 12-15 months, so it's not exactly years before they can do it. They can also grasp things with their hands from birth. When first born they still don't have full ocular ...
MattDMo's user avatar
  • 15.3k
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. ...
Tyto alba's user avatar
  • 8,782
6 votes

Are there genetic causes underlying the difference in circumference of the upper arm and foream?

Yes, there are genetic reasons for this. But your observation is either incorrect or abnormal. The shoulder (and hip) muscles do the heavier work, thus have larger (and bulkier) muscles. The more ...
anongoodnurse's user avatar
6 votes

Why doesn't muscle strength depend on its length?

It's simply that the fibers are arranged end-to-end. If you simplify this down and imagine a single muscle fiber you have actin and myosin like this: ...
bob1's user avatar
  • 12.4k
5 votes

8 abdominal muscles but 10 pack

The only "way" someone can have a 8-pack or 10-pack is due to genetics. Across the rectus abdominis muscle you have either 3 or 4 tendinous bands going over it, consequently resulting in either a 8 or ...
Ebbinghaus's user avatar
  • 2,603
5 votes
Accepted

Mechanism of Myosin Head Bending in Cross Bridge Cycle Power Stroke Phase

Introduction: This is going to be quite a long answer. To have an introduction to the topic, you can have a look at articles from Wikipedia and RCSB Protein Data Bank. The exact mechanism of physical ...
another 'Homo sapien''s user avatar
5 votes

Why is there smooth muscle in our bronchioles?

Our airways close up to make them more efficient. The respiratory tree from the mouth to the terminal bronchioles can't absorb oxygen, so each time you breath all the air moved into and out of the ...
Bob bobbington's user avatar
5 votes

What is the actual storage form of energy in muscles? ATP or Glycogen?

If you are only given glycogen and ATP as choices, then glycogen is the correct answer. The reason for this is, that muscle cells need ATP also for other very important processes (such as keeping the ...
Thawn's user avatar
  • 1,239
5 votes
Accepted

What is the actual storage form of energy in muscles? ATP or Glycogen?

This is a typical MCQ which in order to answer you have to have been at somebody’s lectures or be able to read his mind. The antithesis of education! Cells don’t store energy like car batteries. ...
David's user avatar
  • 25.9k
5 votes
Accepted

What are the max angles of human eyeball rotation?

There shall be slight differences due to physiology. Nevertheless, the average vertical ascending angle is 25 degrees and descending angle, 30 degrees. Within the x-y plane of which we assume to be ...
Epistemonaut's user avatar
5 votes
Accepted

Apart from nerve cells and muscle cells, what types of cells do not undergo mitosis in adult man?

To answer the numbered questions: In general, neurons never divide by mitosis. However, I believe you may have unintentionally misphrased your question; there are functional neural stem cells in the ...
VVayfarer's user avatar
  • 258
4 votes
Accepted

Which of the response is faster? voice or hand action?

Assuming that we are talking about a situation at the physical limit of the brain: Speaking a word will always be slower than pushing a button. A whole word requires a contraction of the diaphragm to ...
nico's user avatar
  • 240
4 votes
Accepted

Why are successful human rock climbers so dissimilar to Hominidae primates who spend extended time periods climbing?

As a rock-climber myself I’ll attempt to answer: The selection criteria for competitive rock-climbing is exclusively based on sustain non-resting, extremely challenging moves up a rock-face. The two ...
RunzWitScissors's user avatar
4 votes
Accepted

brain and fingers movement theorie

The body indeed uses lateral inhibition / surround inhibition. When using a muscle, neighbouring muscles are sometimes activated to. So active muscles are excited while nearby muscles are (partially) ...
Dwarz's user avatar
  • 179
4 votes
Accepted

Is the ACh receptor more permeable to sodium ions?

Short answer No. There are differences in Na+ versus K+ permeability, but you have it backward: potassium is actually slightly more permeable; however, these differences are not the only factors ...
Bryan Krause's user avatar
  • 45.9k
4 votes

Why is there a mass limit on biological powered flight?

One of the physical limits to biological flight is muscle physiology. Muscle force output is proportional to muscle physiological cross sectional area (PCSA) multiplied by its specific tension (Gans, ...
kmm's user avatar
  • 12.3k
3 votes
Accepted

Location of t tubule in muscle

Interesting question. Indeed it is related to the working of cardiac muscles. First of all, lets have a look at the structure of a sarcomere of a cardiac muscle from here: Here, what we can see is ...
another 'Homo sapien''s user avatar
3 votes
Accepted

How correlated are the lengths of tendons in different part of a human body?

I couldn't find studies analysing clearly enough tendons size, but a couple of sources show that they are probably correlated: One study found correlation between dimensions of Achilles'tendon and ...
Pere's user avatar
  • 586
3 votes

What causes humans to be physically weak compared to animals like gorillas?

Evolutionary tools that are not needed for increased survival rate of offspring of a certain lineage deteriorate with time. The deterioration might have a form of gene expression changes or mutation ...
nya's user avatar
  • 191

Only top scored, non community-wiki answers of a minimum length are eligible