Questions tagged [physiology]
The study of the normal function of living organisms and their anatomical parts and the means by which their normal functioning is achieved.
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How many cells are there in the apical meristematic tissue?
How many cells are there in the apical meristematic tissue?
Looking at this picture...
, I would tend to think that there are few hundreds cells in the meristem tissue. But I guess this is a picture ...
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Na+ / K+ ATPase: How does it restore resting membrane potential? [duplicate]
Could not find any sources talking about this (in a clear manner). If the Na+ / K+ ATPase pumps 3 Na+ out for every 2 K+ it pumps in, thus making the cell more negative, why is the Na+ / K+ ATPase ...
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Can severe vasoconstriction increase systolic blood pressure?
I know that, vasoconstriction results in increased total peripheral resistance which is responsible for the rise in diastolic blood pressure. Also, cardiac output is responsible for the systolic blood ...
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is ventricular depolarisation same as depolarisation during nerve impulse conduction? [closed]
Does the change in membrane charge accumulation occur in a similar way in heart and nerves cells?
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How does lactulose cause the removal of ammonia from the colon?
Lactulose is also used to reduce the amount of ammonia in the blood of patients with liver disease. It works by drawing ammonia from the blood into the colon where it is removed from the body.
[Source]...
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At small axon diameters (<1 µm), why does myelination not increase neuronal conduction velocity?
As per the diagram below (and other graphs available online), why do unmyelinated fibres have a higher conduction velocity than myelinated fibres when the axon diameter is less than around 1 µm?
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Asexual Reproduction Of sponges through endogenous or exogenous budding?
I was studying asexual reproduction in sponges and came across two website
Wikipedia of Gemmule and there is a line....
Only Endogenous Types of Buds develop into New Sponges.
Then as I was reading ...
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Does posture matter while drinking water?
I have heard a lot of people (where I am from, India) say that one must drink water sitting, not standing. Recently, I also came across a video that said the same thing (link). The reason given is ...
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Taking cold shower / drinking cold water after / during training
(I am a new-comer in biology SE so sorry if violated any rules)
Effect of cold showers after intense training
I have read the answer to this question, but it seems there are discussions on the ...
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Why largest cats so much larger than canids?
It is striking to me that there is no dog-like creature larger than a wolf while there are at least two species, tigers and lions, many (at least twice and probably 3 or 4) times the size of the ...
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What is the pH of cytosol? And plastids?
My teacher ask this question, and I answered 7 to 7.4, but she said it's wrong.
I read a lot and found the same answer (wikipedia)
I'm here asking for confirmation of this and the pH inside & ...
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Why does higher venous volume increase atrial pressure?
If the cardiac output stays the same (hypothetically, although obviously it doesn't stay the same), then why does higher venous volume increase right atrial pressure? Shouldn't the flow rate be ...
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What are some good books on oncology?
I'm looking for some book suggestions on oncology, preferably I want them to be fairly recent. I am not worried if they are fairly technical, as long as they have good accurate content and layout.
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What happens to intrinsic factor exactly at the terminal ileum, where B12 is absorbed?
IF is very important for IF-dependent B12 absorption in the terminal ileum, the mechanism by which most of dietary B12 is absorbed. The B12-IF complex bind to IF receptors on enterocytes, but does the ...
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Why is there a mass limit on biological powered flight?
So, this is a thing I never fully understood. There are a lot of reasons for a flying creature to be limited in mass (though I'm unsure if I'm familiar with all of them), from energy consumption to ...
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Do animals with their eyes ~180 degrees apart have depth perception?
Lots of animals have their eyes more on the side of their head, like an octopus or a parrot. Are animals with eyes more on the side able to tell the depth of objects at different distances? It seems ...
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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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Are there neuron mediated reactions faster than reflexes?
I'm interested in how fast the human body can respond to a stimulus. I know the fastest reflex, the blink reflex, operates around 100ms from stimulus to reaction. I also know that the blink reflex ...
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Is breathing a reflex action or is it an intrinsic process?
The process of breathing is controlled by respiratory centers in the brain stem. Do these centers have an innate activity, i.e., just send out signals to breathing muscles intrinsically, and have the ...
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Electrical transmission vs Chemical transmission
"The advantage of electrical transmission, apart from speed, is it can favour synchrony in firing. For example, in the brain stem a nucleus called the inferior olive can generate oscillations due to ...
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How does the microbial environment in your gut initiate?
Clearly, a zygote does not harbor any microbes. As it develops, and the alimentary canal tissue is differentiated, I logically assume that there is still no microbial activity in the fetus's gut. I'm ...
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Why is defibrillation in asystole ("flat line") useless?
In most popular medical dramas, when a patient has a cardiac arrest and "flatlines" the doctors many times use a defibrillator to "shock the heart back into rhythm'. I know that actually, the proper ...
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Is there any case in which excitability increases with lowering the RMP?
My professor says , at a more negative RMP, less sodium ion channels are inactivated, so if you take 2 of the exact same neuron with the same threshold potentials, and try to excite them starting from ...
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What was the evolutionary benefit of enclosing hemoglobin in cells?
The ancestral solution to oxygen transport is with hemoglobin (or, similar proteins) dissolved in blood (or, "hemolymph", but, basically, dissolved in water. ) What was the advantage of enclosing the ...
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Are ligand gated channels saturable?
A major difference between simple diffusion and facilitated diffusion is that facilitated diffusion has a maximum transport and velocity; the rate of diffusion is limited, whereas in simple diffusion, ...
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Why does water stress lead to alkalinity of xylem sap in plants?
I was reading this book: Plant Physiology and Development, Sixth Edition by Lincoln Taiz, Eduardo Zeiger, Ian M. Møller, and Angus Murphy when this doubt came to my mind. Abscisic acid, the stress ...
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Why does the affinity of haemoglobin for oxygen decrease at high altitudes?
My class 12 NCERT book says, Pg 226
The body compensates low oxygen availability by increasing red blood cell production, decreasing the binding affinity of haemoglobin and by increasing breathing ...
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Why do earthworms surface after a rain?
Googling, I find two different explanations for why earthworms tend to surface after a rain.
This page from UCSB, for example, gives both answers, contradicting itself:
The first explanation is ...
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Do endocrine cells always lie adjacent to capillaries?
The circulatory system transports plasma contents to the body via the interstitial circulatory system, reabsorbed with the lymphatic system. Cell metabolism "waste products" are transported into the ...
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Why do patients with type 2 diabetes not show the body wasting seen in type 1 diabetics?
Type 1 diabetes results from the destruction of the cells in the pancreas that produce insulin, while type 2 diabetes is characterized by so-called "insulin resistance", presumably a reduced ...
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Are there any animals that are unable to hear the human voice?
Humans and animals have different hearing ranges. The frequency range of a human, for example, is stated with 20 Hz to 20 kHz, whereas the fundamental voice frequency is stated with 125 Hz for men, ...
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Should we induce fever to assist healing?
I am currently reading "The Fundamentals of Anatomy Physiology" 10th edition, and have found it an incredibly interesting book. I have just been reading about the lymphatic system, and the various ...
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Why would it be beneficial for cortisol and corticosterone to exhibit pronounced anti-inflammatory activity?
These questions are always a little silly (as we will never truly know), but it always struck me as odd that corticosterone and cortisol exhibit pronounced anti-inflammatory activity.
Because these ...
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Why is arterial pO2 normal in carbon monoxide poisoning?
Arterial blood gas measurements often show that pO2 is 'normal' even though haemoglobin is bound to carbon monoxide with high affinity.
Is this because there is still oxygen bound to some subunits of ...
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Do tall people have more cells?
Within a single species, how does the relative number of cells in the body relate to the relative size of the organism?
Let's say we take two humans, one of them is 6 feet tall and the other one is 5 ...
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Can food swallowed when a person is upside down reach the stomach?
If a person positions him/herself upside down and swallows food, will it reach the stomach against gravity? If so how?
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How can an animal live without a head / brain?
The human body is unable to do anything if it loses its head - as the brain is separated from the body, the body immediately dies.
But why does the same not happen to other species or animals? (As ...
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How long can an octopus survive out of the water?
I saw videos of octopuses crawling on the ground and I was wondering how long an octopus can survive when out of the water? Does it depend on either its size (i.e., does a big octopus from deep sea ...
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Is mucus significantly affected by the presence of ions?
In mucus, there is besides water and the mucins (Proteins for mucus), there are Ions like $Ca^{2+},Na^{+}$, etc. I have read that These Ions can Control the mucus swelling, i.e. the volume that the ...
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What is the human energy consumption by organ?
The human brain uses about 25% of the human body's metabolic energy. How are the other 75% spent, in terms of portioning to its various systems?
I thought this could be answered by a simple search, ...
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How long can an infant human hold his/her breath as part of the "dive reflex"?
Various other questions on the site have talked about the Diving Reflex, which is also known as the Mammalian Diving Reflex. This reflex is observed in mammals of various species, but also in human ...
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Mithradates - Developing immunity to poison?
According to legend, Mithridates studiously researched and examined all known toxins and experimented with potential remedies by using prisoners as his guinea pigs. Supposedly, Mithridates’ toils paid ...
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How does an electrical impulse spread in a muscle fiber spread from the motor end plate?
Does this impulse in skeletal muscle spread much in the same way it does in neurons, with an initial potential change that spreads to its immediate surroundings and is then re-amplified or is it the ...
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Does increasing contractility increase LV ESP?
I see many PV diagrams showing a negligible difference in the ESP when contractility increases. I'm wondering why this is the case, because if more blood is being pumped out into the aorta, the MAP ...
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Can all animals breathe manually?
Originally I was pondering about why we have the ability to breathe manually. I couldn't think of any tangible advantage, given that the body can develop mechanisms to regulate the rate of breathing ...
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How is Calcium regulated in myocardic AP and plateau phase?
The plateau phase is maintained by influx of calcium and outflux of potassium in the second stage:
My conjecture is that calcium transforms between two phases
ionated phase (free calcium from i/c SR ...
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How does the descending branch of the loop of Henle equilibrate concentration?
I'm learning physiology and I have a hard time figuring out how the cortico-papillary gradient is created.
Most explanations go as follow:
1) Sodium is pumped out the ascending branch into the ...
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Can Chilopoda "vocalize" or produce sound for the express purpose of communication, as opposed to sound as a byproduct of other movements?
Is there any species of Chilopoda that can "vocalize" or or otherwise produce sound for the express purpose of communication, as opposed to sounds it might create as a byproduct of other movements ...
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Which types of blood vessels can regenerate in humans/mammals?
Which types of blood vessels can regenerate in humans/mammals?
From what I understand, arteries and arterioles can be created later in life, while this is not necessarily the case with veins. However ...
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What is the function of the Hyoepiglottic ligament?
The hyoepiglottic ligament (ligamentum hyoepiglotticum) is an elastic band that connects the epiglottis to the hyoid bone.
Although I can find information about the clinical significance of this ...
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