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19

Unlike erythrocytes that have a very rigid shape and almost cannot change their size (hence the size distribution is indicative and can be used for diagnostic purposes in medicine), lymphocytes can change their size in a wider range, this is why you see the numbers 6-9 and 10-15 μm. And they indeed cluster into several different groups: so-called "large ...


19

Red blood cells are initially produced in the bone marrow with a nucleus. They then undergo a process known as enucleation in which their nucleus is removed. Enucleation occurs roughly when the cell has reached maturity. According to one research (Ji, et al., 2008), the way this occurs in mice is that a ring of actin filaments surrounds the cell, and then ...


15

I've been doing a little more digging myself and have found a couple of other advantages: Risk of Venous-thromboembolism (deep vein thrombosis/pulmonary embolism (1)). Blood group O individuals are at lower risk of the above conditions due to reduced levels of von Willebrand factor(2) and factor VIII clotting factors. Cholera Infection Susceptibility ...


14

The less antigens a woman (or in fact a female of any species close enough to humans for this phenomenon) has, the higher are the risks of triggering an immune reaction during her pregnancy, if the child has those antigens. The Rhesus incompatibility is probably the most common case of this problem. One could thus assume that in populations that are ...


14

The red colour of blood isn't actually to do with food at all. The primary purpose of the blood is to carry oxygen to all the cells that require it to release energy. Red Blood Cells are filled with an iron containing pigment called haemoglobin. When it has oxygen bonded to it, haemoglobin has a bright red colour - it is this that gives blood its red ...


13

summary: O2 could form a linear complex with the Fe atom, but then it would start to look more like a mineral Fe=O...O bond - a linear bond would be like a transition state to an iron oxide (rust). An Fe-O-O bent bond preserves more of the electronic character of the O2 molecule and promotes strong but reversible binding to Hemoglobin. The oxygen ...


13

According to the Wikipedia entry for the ABO blood group system: Anti-A antibodies are hypothesized to originate from immune response towards influenza virus, whose epitopes are similar enough to the α-D-N-galactosamine on the A glycoprotein to be able to elicit a cross-reaction. Anti-B antibodies are hypothesized to originate from antibodies produced ...


10

Most likely they were measuring the hemoglobin concentration, in units of g/dL (i.e. 101 kg/m3). Assuming by your username you are male, the reference range for [Hb] is approximately 13.8 to 18.0 g/dL (sources vary somewhat), which roughly matches the "19" you were told was the upper bound. Wikipedia also notes that [Hb] "is typically tested before or after ...


9

The blood of the fetus does not mix with the blood of the mother. Instead, the placenta provides a system where the two separate blood streams flow past each other with thin separation allowing nutrients to flow between the two streams but the not the blood cells and other large components.


8

I want to know can +ve and -ve blood group of a couple could be a cause of miscarriage in pregnancy? Yes. In extreme cases, it can. You are talking about Rh Incompatibility, and can become a big issue when the mother has Rh(-) blood and the father has Rh(+) blood (such as the case with your cousin and his wife). What could have happened (but definitely ...


8

Your question has many questions in it. As for the evolution of Rh factor, Blancher and Apoil (2000) attribute the high level of sequence similarity (92%) of the two RH locus genes, RHD and RHCE to a gene duplication event in the common ancestor of human, chimps, and gorillas. Their analysis of the cDNA from these genes revealed "complex recombination ...


7

First of all we should distinguish between the physiological clotting factors that are parts of the normal clotting pathways, and those that might affect clotting pathways but are not observed under healthy conditions. TPA (tissue plasminogen activation), PAI-1 (plasminogen activator inhibitor) and prothrombin are normal clotting factors that are essential ...


7

There are many different variants of O (all loss-of-function) indicating that this mutation has arisen many times in the human population. The prevalence of O is indeed taken as evidence of balancing selection. Various pathogens use the A or B antigens as receptors. The cited paper presents evidence about the phylogeny of the ABO gene in human populations ...


6

This could be a very long answer, but I'll try to keep it brief. The first thing to understand is what causes the anaemia. I'm going to refer to defective haemoglobin found in a sickle cell patient as HbS and normal haemoglobin as HbA. Under certain circumstances (low O2 concentrations) the HbS protein is prone to aggregating into long filaments. Here is ...


6

We each inherit either A, B, AB or no antigens from our parents. The current thought is that when you're between 0-6 months old you are exposed to bacteria/viruses that contain very similar antigens (A or B). These antigens are similar enough to the A and B antigens found on red blood cells that any antibody created against these bacterial antigens would ...


6

Substances such as blood trigger the Cough reflex, so if for any reason blood accumulates in the airways, it will be ejected this way. If you have a look at chest anatomy, you can see how this could be caused (look at Trachea down to the lungs, aorta and the carotid arteries above the heart). A shot through the chest can peforate many large blood vessels, ...


6

Mammalian tongues are red because of haemoglobin. Blue/black colouration is due to the additional presence of melanin. At the boundary between the epidermis and dermis are melanophores, cells that contain melanin. This brown pigment absorbs ultraviolet radiation from the sun that might otherwise damage the underlying dermal tissue. Melanin in the dark ...


5

The oxygen saturation (in lungs) and desaturation (in target organs) takes place via diffusion along the concentration gradient (i.e. partial pressure for gases). Therefore as long as RBCs from two different sources and having different partial pressure of oxygen mix up, the oxygen level starts to equilibrate between these cells. But diffusion as a passive ...


5

Antibodies and other immune responses do indeed occur against the donor's white blood cells. However, white blood cells are present in relatively tiny quantities (3-10 million WBCs per ml of blood vs 4-6 billion cells per ml). Because the number of WBCs is so low, the immune reaction to them is also proportionally lower, with fever being a typical (and ...


5

The oxygen-carrying capacity of the blood is: amount of haemoglobin * % saturation The average blood donation is approximately 10% of total blood volume. . Since the donation will have no effect on the % saturation, the oxygen-carrying capacity at each altitude will go down by 10%. By inspection of the graph in the question, the % saturation goes down ...


5

Nope, nope, and nope. A cursory glance over any page on hematopoesis will reveal that blood cells are replenished from HSC, hematopoetic stem cells, which are self-renewing stem cells. Telomerase is activated in stem cells.


5

Not really no. Most blood transfusions we think about are red blood cells or platelets, which don't have the immune function you're asking for. That's a good thing. Usually, if there are white blood cells in the transfused blood, the host's immune system will recognize them as foreign and destroy them. Remember, your cells all look like foreign invaders ...


5

A very good question, and it is most likely because of the last option. It had a nucleus for part of its life. After the RBC jettisons its nucleus, it still remains very metabolically active for approximately 3 months. It maintains its cell membrane integrity, it metabolizes glucose, it interacts constantly with its environment, numerous cellular functions ...


4

The key feature of type O blood as "universal donor" is that the incoming red blood cells have neither A nor B antigens and so the resident antibodies (anti-A , anti-B) will not react with them. Since transfusions are carried out with packed red blood cells the plasma antibodies of the donor don't matter - they will not be introduced into the recipient.


4

The molecular basis of copper-transport diseases in Trends in Molecular Medicine, Volume 7, Issue 2, 1 February 2001, Pages 64–69, has a link to a 1973 paper by JM Gillespie entitled "Keratin Structure and Changes with Copper Deficiency," stating Menkes patients are often diagnosed from their unusual hair structure – termed pili torti – also known as ...


4

No, because gelatin is a mixture of collagen-derived peptides. When you eat them, they are first hydrolyzed by stomach acids into constituent amino acids. These amino acids are then absorbed from the small intestines as nutrients.


4

As far as I am aware it is the RhD and ABO blood groups that matter with blood donation - though you may wish to contact a blood donation organisation for more specific information on how they handle & categorise the blood. But using just RhD and ABO gives 8 combinations, positive and negative of A, B, AB, and O. You can find out more about the blood ...


3

It's pretty straightforward. White blood cells have all the usual organelles while mature red blood cells are missing most of them. WBC can have specialized lysosomes depending on their function, as well as granules if they are granulocytes. This goes into the different WBC types in some detail.


3

I've actually wondered this myself from time to time, without ever bothering to look it up. Well, it's actually happening. That WSJ article says the following, which just blows my mind: Researchers at the Rogosin Institute are taking tumor cells from mice, encapsulating them in beads made from a seaweed-derived sugar called agarose, and implanting them ...



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