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

learn more… | top users | synonyms

1
vote
3answers
95 views

Are all healthy animals more likely to defecate near the end of a rest-cycle?

Just what the title states. It stems from observation & personal experience that a person/dog/cat/monkey is more likely to relieve oneself immediately after it wakes up from the peak-sleep cycle ...
1
vote
2answers
372 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 ...
1
vote
1answer
61 views

How does ANF increase GFR?

ANF as we know reduce the Na+ uptake and K+ removal in the distal tubules and it also functions as a Vasodialator (?) But again it says that ANF increases the Glomerular filtrate ? But if it is acting ...
1
vote
1answer
37 views

Is the sense for salt depending on the electrolyte level in our body?

I often noticed, after (heavy) physical activity like cycling, running, swimming or working an isotonic drink (to recover the electrolyte level) tastes less "salty" compared to when drinking it before ...
1
vote
1answer
35 views

How are cyclic hormones characterized?

I have a question regarding the description of a subset of peptide hormones, called cyclic hormones. Two examples of cyclic hormones would be somatostatin and melanin-concentrating hormones. I know ...
1
vote
1answer
75 views

Could light/occasional smoking strengthen the lungs?

Here's my thought process, correct me where I'm wrong. It seems the human body has thresholds. Examples: You lift too much weight, and the muscles and tendons risk serious injury, but otherwise ...
1
vote
1answer
261 views

Advantage of cup-like shape of blood cells, spores?

Mold spores sometimes have the same shape as platelets in blood. If I were designing a spore it would probably be spherical. Is there any advantage to this cup-like shape? Maybe there is some ...
1
vote
1answer
81 views

Why are new vessels more permeable in microvasculature?

I know for microvasculature New microvasculature (arterioles, venules) are always more permeable as they lack pericytes. and then I have this sentence about new blood vessels (not specific) ...
1
vote
1answer
91 views

Death because of no radio waves [closed]

I read somewhere that a man dies if he is isolated from natural electromagnetic fields and waves. (I imply fields of radio frequencies and below.) Is it true?
1
vote
1answer
2k views

Are there more/less favourable phases of menstrual cycle to donate blood?

I was wondering whether it makes a difference when during the menstrual cycle a female is donating blood in terms of: Blood quality (iron or hormones levels) Her health/safety I am aware that ...
1
vote
3answers
117 views

Does the necessary Carbon Dioxide need to be in the atmosphere for mammals?

In the answers to this question, we've learnt that carbon dioxide is necessary for mammalian life, but is it necessary in the atmosphere/to breathe it in? Or does the act of respiration give a ...
1
vote
1answer
48 views

Double use of ATP in relaxing myosin & active transportation of calcium?

Is the ATP molecule which is bound to the myosin head for relaxation of the muscle (i.e., to break the cross bridge) also utilized for active transport of calcium to the sarcoplasmic reticulum during ...
1
vote
1answer
77 views

What specific sensory nerves act as receptors for “pins and needles” (neuropathy)?

According to this excellent answer, the difference between "pain" and "pins and needles" (neuropathy) is that different receptors (sensory nerves) trigger in reaction to different stimuli. Different ...
1
vote
1answer
134 views

Duplicity Vs. Singularity of Mammals Organs [closed]

Are there known evolutionary reasons why mammals contain 2 of some organs (such as lungs and kidneys) and only 1 of some (such as liver)?
1
vote
1answer
94 views

How Ants know about Earthquake?

How does an ant know about Earthquake is it because of an organ or due to other factors?
1
vote
1answer
61 views

Can tubular secretion regarded as local hormone?

Tubular secretion is : The process in which ions and other waste products are transported into the distal tubules of the nephron. can it be regarded as local hormone??
1
vote
1answer
43 views

How does a blunt force stimulate histamine to develop early stages of inflammation?

I know that viruses and sharp forces can stimulate mast cells by cut or by a virus infecting them and then release histamine. How can blunt force do this and cause inflammation? It doesn't have the ...
1
vote
2answers
90 views

Is Sinus node conduction necessary for heart beating?

Assume a patient with previous cardial infaction which SA node not possible to activate action potential anymore. However, SA trying to beat unsuccessfully repeatedly waisting energy. Therefore, I ...
1
vote
1answer
48 views

Sitting much, thrombosis and hypoxia

I am thinking the more reasons why sitting much lead to thrombosis i.e. clotting of blood in blood vessels and then hypoxia in the deep tissues eventually. What are the physiological mechanisms for ...
1
vote
1answer
26 views

To understand synthesis of e-NOS and n-NOS with respect to Ca and calmodulin

I found this sentence in my notes interesting E-NOS and n-NOS are Ca-calmodulin dependent ferments. They are synthesized in small concentration as a response to physiological signals which ...
1
vote
1answer
1k views

Can food swallowed when a person is upside down reach the stomach?

If a person positions himself upside down and swallows food, will it reach the stomach against gravity? If so how?
1
vote
1answer
16 views

does phagocytosis dependent on opsonization?

does phagocytotic activity of macrophages and neutrophils depends on opsonization by IGg (antibody) and C3 complex,if it does, so then why macrophages and neutrophils are categorized in Innate immune ...
1
vote
1answer
35 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!
1
vote
1answer
40 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 ...
1
vote
1answer
117 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 ...
1
vote
1answer
69 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 ...
1
vote
1answer
38 views

Is Norepinephrine beta2 adrenomimetic?

I know that it has alpha1, alpha2 and beta1 effects. It has beta2 receptor where epinephrine can effect. However, to say that it is beta adrenomimetic, I am not sure. That is ligand binding beta2 ...
1
vote
1answer
74 views

Does pupil size affect image focus in persons with no lens?

If an individual has no lens like Claude Monet (who had them removed). They should be able to still focus the images they see in a well light area if they shrink their pupils to a very small size ...
1
vote
1answer
102 views

Why is LH level much higher than FSH level at ovulation?

My teacher showed us an elaborate collection of graphs with one of them showing FSH and LH plasma levels during the menstrual cycle. LH level was almost 3 times higher than FSH level. Why? Does this ...
1
vote
1answer
51 views

All or nothing phenomena

We know that an action potential is produced by an active cell membrane when the stimulus reaches a certain threshold. When it does, an action potential fires, and when it doesn't, nothing happens. ...
1
vote
1answer
154 views

brain activity responsible for imagination

Which part of brain is responsible for advance or unseen imagination For example:ones brain can make a situation in mind which is impossible to happen ...which part of brain is hyper active?
1
vote
1answer
33 views

What triggers the release of gonadotrophin-releasing hormone with the onset of puberty?

I am interested to know the process of development of puberty. During puberty, when boys/girls reache 12-14 (puberty) years of their age, their hypothalamus releases gonadotropin releasing hormone ...
1
vote
1answer
123 views

Why the scent of mouth gets dirty after not eating for a long time?

After a long time of hard workout,not eating and nervousness makes your taste and scent of mouth very uncomfortable and bad why this happens and is there any way to prevent it?
1
vote
1answer
109 views

Simultaneously using both hands - How does that work?

Is some part in one hemisphere the decision maker and "calling the shots" - controlling the opposite side's hand "directly" and controlling its own side's hand through the corpus callosum. Or: is ...
1
vote
1answer
70 views

difference between ischemia and oxygen-glucose deprived medium

Ischemia is roughly defined as insufficient blood flow to a specific region of the body and in the literature it is generally considered as causing oxygen and glucose deprivation in the tissue and ...
1
vote
1answer
252 views

Earwax versus Mucus

Something I have wondered for a while is why have two different primary defense mediums, ie earwax and mucus, that perform the same function? As far as I know, mucus and earwax are both part of the ...
1
vote
1answer
59 views

Nervous system: Pain and Pleasure?

If you have a constant pain in your body, why does a greater pain or pleasure make you not feel the original pain?
1
vote
1answer
74 views

Missing 4$H_2O$s (per glucose) in Cellular Respiration… Where can they be?

I having trouble understanding the equation of the cellular respiration. The thing that bothers me is the number of $H_2O$ molecules. Generally, cellular respiration is written thus : $C_6H_{12}O_6 + ...
1
vote
1answer
35 views

Are there any forms of heart failure where cell size decreases?

I think hypertrophy happens in most of the cases. However, I am not sure if hypertrophy always happens. I started to think about wet lungs (pulmonary reason for the left-sided heart failure). Can the ...
1
vote
2answers
260 views

Hypovolemia and orthostatic hypertension

What is the physiological mechanism behind the occurrence of orthostatic hypertension in the presence of hypovolemia?
1
vote
1answer
35 views

What are the movement mechanisms of thrombus?

I am thinking how thrombus (veins, arteries and heart) can move. Secondary mechanisms come to my mind only: some enzyme which lyses it, probably adhesion mechanism. Blood circulation (flow rate) ...
1
vote
1answer
94 views

Voltage-gated Potassium channels in the action potential of cardiomyocyte?

There is one type of potassium voltage-gated channels open in Phase 1 too. Some call them early repolarization channels. I am not convinced that the channels are different in different phases: 0, 2, ...
1
vote
1answer
82 views

Physiology of skin and leather: why do salt borders occur?

I discussed a leather store about the white border aka salt border on leather shoes. They said that it is due to inner features of leather and you could try to add some fat/cream to push it back ...
1
vote
1answer
89 views

(Web)app to search metabolic/signalling pathways

I'm looking for an application where you can find pathways by selecting a chemical occurring in it. So, for example, selecting 6-phosphogluconolactone brings up the pentose phosphate pathway or any ...
1
vote
1answer
31 views

Amphibian blood circulation

In an amphibian blood entering the right atrium shows higher levels of oxygenation than that in left atrium when : A.It is hyperactivated B.it is hibernating C.it is submerged D.it is in the ...
1
vote
1answer
1k views

What is the physiological difference between snorting/swallowing cocaine

I know that mucosa inside the nose absorbs cocaine molecules when snorting cocaine, but what difference is there compared to swallowing? Also more cocaine administration equals more cocaine molecules ...
1
vote
1answer
87 views

What stops the coagulation process?

Whenever there are minor/major injury to blood vessels, the platelets, fibrin, thrombin, etc. are recruited. They then seal the wound and block bleeding. What tells them that their job is done?
1
vote
2answers
185 views

What use a pair of lips?

Pardon my ignorance ... A lip is apparently a very sensitive tactile device - as it at-least serves to warn it's owner they may just be about to consume something that could cause injury. Primates ...
1
vote
1answer
115 views

Is stereo olfactory ability restricted to humans?

Most animals I see around seem to have two nostrils - humans, snakes, birds, fish .. and so on. From reading online I see that 2 nostrils provide a stereo olfactory effect. This stereo effect is ...
1
vote
1answer
42 views

Possible calculations with temperature, humidity, images and VIS spectrum of a plant in an Integrating sphere

I am currently working on a project which involves growing some plants in a integrating sphere made of foam. I have added temperature, humidity and soil moisture sensors as well as a Spectrometer (350 ...