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20

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 ...


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 ...


16

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 ...


16

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 ...


15

This is an embryonic stem cell on the tip of a needle photographed on a scanning electron microscope (SEM). The image was taken by Steve Gschmeissner, see here for the original.


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 ...


13

Hemoglobin molecules used to manufacture these products are not contained by a red cell membrane, and when released into the vasculature, these molecules rapidly scavenge nitric oxide.This can result in systemic vasoconstriction, decreased blood flow, increased release of proinflammatory mediators and potent vasoconstrictors, and a loss of ...


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 ...


10

Typically transfusions are indicated for hemoglobin < 7 g/dL (for adults normally: 12-15 grams per deciliter [1]) or < 8-10 g/dL if there is cardiac disease where diminished oxygen carrying capacity cannot be compensated by increased cardiac output. The answer above is theoretical because there is no accurate way to measure blood loss in the clinical ...


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 ...


8

The "purest of all blood" is fresh out of the bone marrow, i.e. in your circulatory system. Menstrual blood is a combination of blood, some mucous, and dead endometrial tissue. The endometrium consists of a single layer of columnar epithelium resting on the stroma, a layer of connective tissue that varies in thickness according to hormonal influences. ...


8

What percent of your blood can you lose before you need a transfusion According to Wikipedia: starting with Class III (more than 30 % of circulating volume loss), hemorrhage requires transfusion. Class I Hemorrhage involves up to 15% of blood volume. There is typically no change in vital signs and fluid resuscitation is not usually necessary. ...


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

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, ...


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 ...


7

It might be better to consider the sampling technology, economic and logistical issues with this question as well as the tech behind the tests. First, some tests still will want a few milliliters of blood - e.g. cell counts for specific cell types. Then there is the need to create and stock many different kinds of sample collection devices and train the ...


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

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 ...


6

Is consumption of blood more "dangerous" compared to meat? Actually yes, a simple high dose of blood is enough to kill. The cause is, though it is most important thing to live when flowing the vessel, it's highly toxic when consumed. There are high chances of getting haemochromatosis or Iron overload. Source and More on this: ...


6

This looks like a macrophage to me, which is a white blood cell. Try Googling "macrophage sem" to see similar images (SEM = scanning electron microscopy/micrograph). The clue is the nature of the cell surface - those ruffles reflect the macrophage's role in engulfing foreign material. Indeed it is possible that some of the particles on the surface are ...


6

In addition to Alan Boyd's answer of a macrophage, it could also be a T cell or B cell. Try doing an image search for lymphocyte SEM and browsing through the different cell types. While the traditional image of T and B cells has been of a smooth round blast cell, they actually have numerous projections, folds, etc. to aid in forming the immunological ...


6

This is a well worded question. There are more reasons than the following but the most apparent is hemoglobin production and its transport. The erythrocyte is a cell whose structure is optimal for its function-the production and transport of hemoglobin. It lacks a nucleus and organelles so that it can devote almost 100% of its energy to hemoglobin ...


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

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 ...



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