Biology

Ok I know that atria and ventricles contract independently and it makes sense heart would beat slower but what is the exact reason. The accesssory pacemaker that activates ventricles, is is lot slower than AV node is that the reason? Thanks

Hello everyone, I don't understand the importance of this. Now I don't exactly understand what is the importance of filtration fraction. If normal GFR is 125 ml, in aortic stenosis filtration fraction increases, what does this mean? Does it mean that kidney has to now work harder to maintain 125 ml GFR? But in aortic stenosis both GFR and renal flow decreases. I don't understand the significance of filtration fraction? Also why does catecholamines constrict the efferent arteriole more than the efferent, I can understand how this would increase pressure up stream and increase GFR, is that the reason? Thanks

Hello everyone, Wiki: The atrioventricular septum is a septum of the heart between the right atrium (RA) and the left ventricle (LV). I can't identify this in pics. I have not heard of a connection between right atrium ad left ventricle. Is this some embryological structure or can you see it in normal heart. Are tricupsid and mitral regions also called atrioventriclar regions? Can anyone provide me a clear pic. Thanks

In aortic stenosis there is ventricular hypertrophy and this could lead to reduced cardiac ooutput. My question is why is the ventricular hypertrophy in aortic stenosis, inferior to ventricular hypertrophy you get in exercise. Why is their better ventricular hypertrophy that increases cardiac output occurs, in exercise. Thanks

Hello everyone, Vasomotor centre for example, increases heart rate and increases blood vessel constriction and raises total peripheral resistance. The end result is increase in stroke volume. My question is if blood pressure is raised too much by constricting blood vessels, wouldn't that make it hard for the ventricles to pump blood and decrease stroke volume. Thanks

i am a bit confused about the shape/ positioning of transverse myelitis inflammation. 'Transverse implies that the inflammation is across the thickness of the spinal cord'. i don't quite understand what this means, could someone explain in more detail, describing what area the inflammation covers and it's shape/ positioning? thankyou

I want to measure the pH of sweat in order to estimate the anaerobic threshold by detection of lactic acid. Many references point out that it's lactate, not lactic acid, that is found in sweat. However, according to this article: http://www.bentham.org/open/tocorrj/articles/V003/38TOCORRJ.pdf Artificial sweat is synthesized with lactic acid as per standard ISO 3160-2, (20g/l NaCl, 17.5 g/l NH 4 Cl, 5g/l acetic acid and 15 g/l d,l lactic acid with the pH adjusted to 4.7 by NaOH). Also, I want to measure the pH by the potential sensed by copper-zinc electrodes in series etched on a PCB. Would that work? Thanks.

Hello everyone, First of all I don't understand the pic. Why is the endolymph moving in opposite direction to the movement of head, shouldn't it move the same way. How is inertia involved in this and what is the paragraph saying. Thanks

Hello everyone, I'm totally confused with this. If there is a lesion in A, why can't you see the left visual field. According to the arrows, if there is a lesion at A, you would not be able to see white areas in pic C. Are they talking about a particular eye or what you see, please either way I don't understand this. What I'm thinking is if there is a lesion at A, when you look at an object you see an object with some areas missing, I'm assuming this is wrong and you can see a whole image in lesion A, but I don't understand. Your help would greatly appreciated. Thanks

It started sometime before December. I came down with some mild cold symptoms. Then, as soon as I thought I was getting over it, I got the stomach flew for the first week of December. The first night I was puking all night. The next day I was okay (i.e. I could function). Then, on the third day, I started getting stomach cramps and extremely frequent diarhea. The stomach cramps peeked in the middle of the day (they got pretty bad) and then over the next 24 hours or so I slowly started to feel better. For about a week, things started to look better for me until I started coming down with more cold symptoms. They still haven't left. Just yesterday, I started getting mild sy…

Recently i've faced a man who believe there was giant human about 15 to 30 ft tall. human become shorter from them with time. So i'm interested to know whether scale law limit animal growth? or it is not applicable on human see this pictures http://www.genesispark.com/genpark/giant/giant.htm http://www.stevequayle.com/Giants/pics/giant.femur.html

could anyone please give me an easy way to do the hardyweingburgh equation and how to put it to exam questions, im a mature student who has never covered anything like this before. please any help would be appreciated.

Hello everyone, I don't understand how depolarisation jumps when axons are myelinated. Ok myelin is an insulator so in that section no current passes through. But how does that make the current jump, when current reached myelin wouldn't it be inhibited, why does it still travel. Also what do they mean by developing current sinks at nodes of ranvier. Thanks

Hello everyone, Ok I know this goes away from stoma, so why do myelinated nerves use only this type but not antidromic.Thanks

Hello everyone, I have a quick question, let's say there is a L1 dermatome, which is a large area. Now my question is does L1 nerve divide into many branches to supply this area, also do these branches carry only sensory nerves? Thanks

Biotechnology and Microbiology students Portal is seeking a Moderators for given below forum categories,It is a volunteeropportunity with a commitment of 1-2 hours per day. Categories are: Molecular Parasitology Antimicrobials and Vaccines Mycology Bacterial Genetics and Signaling Identifying and Culturing Bacteria Pathogenic Bacteria / Host-Pathogen Interactions Environmental Microbiology Cell Culture and Tissue Culture Cell Signaling/Transduction Clinical Research Recombinant Gene Expression Immunology Stem Cell Biology Virology RNA Proteomics Protein Detection (Western blots, gels, IP) Pharmacology and Drug Discovery Matrix Biology Lab Automation Glycobiology For …

Hello everyone, I have a very poor understanding in this area. 1. In gel electrophoresis, let's say I used many DNA fragments.Then I used a filter paper, and used a probe to detect a specific DNA fragment. Then the pictures you see of electrophoresis, is it this filter paper you see, I mean you can not see the position of fragments in the machine right. Also does this filter paper, exactly mimic the positions of fragments in electrophoresis. Please excuse the stupidity. 2. Gel electrophoresis can be used to measure the length of the DNA accurately. Ok if have standard pieces of known size you can do this, but I still don't get how this works. I mean how can …

What is it exactly? Why is it so impotent? Can someone write me a short essay to try to explain this? Thanks allot much appreciated.

Hello everyone, Ok I read the definitions but I'm confused. What I'm thinking is genome, is the amount of DNA in one diploid cell. So when they say we have 20 000 genes in our body, are they referring amount of DNA in one diploid cell. Also what do they mean when they say human genome is extremely heterogenous. Thank you

Ok I can see the 5 end is negative, is the 3 end positive due to OH. So in other strand this goes other way round. Is this what they mean when they say there is reverse polarity in a DNA molecule. Thanks!!

I have a question for those who are way more knowledgeable about biological/chemical responses . What effects could living with only the opposite sex have on a persons hormonal/biological chemistry ? For example a woman who lives with 4 males and has nearly no interaction with other females , Would or could this throw off the persons biological/chemical clock or rhythm ? or even affect the person natural female traits ? Now hopefully i worded this all correctly.

Let's say I wanted to start up a laboratory where I constantly did research with fish, in particular goldfish. And I would probably be killing a lot of goldfish each week, maybe 20. Furthermore, I wanted to have a lab full of assistants who were also doing research (inside and outside of the lab). What kind of ethical constraints am I going to run into? Are there many problems that I will come into because I'm using fish?

http://socyberty.com/disabled/prosthetic-hand-made-by-kids/ Yeah, you can't beat kids when it comes to prosthetics. I really wish I had a picture of the hand, but I don't and I'm sorry to dissapoint you. Another simple share.

I am trying to discover more about human interaction, and whether it can be scientifically related. Right now I have something that I have been working on, but would like to know if it makes sense. My formula is: sensory and mental input ---> chemical reactions ----> neurological responses ----> emotion. What I am wanting to know is 1) is energy transferred in the process, when we are receiving input? 2) if so, what form is it in? 3) when we have resulting emotion, is it permanant or does it eventually go away after the neurons are fired.. ? Thanks for any input!

Is there a transfer of Energy when emotions are created from chemical reactions in the brain?