Sunday, April 11, 2010

Updated post about Red Blood Cells

Red Blood Cells

Introduction to Red Blood Cells.

-The name

Red blood cells are also known as RBCs, red blood corpuscles (an archaic term), haematids, erythroid cells or erythrocytes (from Greek erythros for "red" and kytos for "hollow", with cyte translated as "cell" in modern usage). The capitalized term Red Blood Cells is the proper name in the US for erythrocytes in storage solution used in transfusion medicine.

Information on Red Blood Cells.

-Life cycle

Human erythrocytes are produced through a process named erythropoiesis, developing from committed stem cells to mature erythrocytes in about 7 days. When matured, these cells live in blood circulation for about 100 to 120 days. At the end of their lifespan, they become senescent, and are removed from circulation.


-Life cycle (Erythropoiesis)

Erythropoiesis is the development process in which new erythrocytes are produced, through which each cell matures in about 7 days. Through this process erythrocytes are continuously produced in the red bone marrow of large bones, at a rate of about 2 million per second in a healthy adult. (In the embryo, the liver is the main site of red blood cell production.) The production can be stimulated by the hormone erythropoietin (EPO), synthesised by the kidney. Just before and after leaving the bone marrow, the developing cells are known as reticulocytes; these comprise about 1% of circulating red blood cells.


-Functional lifetime

This phase lasts about 100–120 days, during which the erythrocytes are continually moving by the blood flow push (in arteries), pull (in veins) and squeezing through microvessels such as capillaries as they compress against each other in order to move.


Relating to what we have learned- embryonic stem cells

-Artificially grown red blood cells

In 2008 it was reported that human embryonic stem cells had been successfully coaxed into becoming erythrocytes in the lab. The difficult step was to induce the cells to eject their nucleus; this was achieved by growing the cells on stromal cells from the bone marrow. It is hoped that these artificial erythrocytes can eventually be used for blood transfusions.


-How it looks like

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-Red Blood Cell in the human blood

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  • Red Blood Cell in the blood vessel.


The artery that enters any organ divides and thins six to eight times before becoming an arteriole, the capillaries' control valve. Subsequently, the arteriole itself will branch two or three times, reducing its diameter to just 9 microns, and will continue on as a capillary. Some of these capillaries are so small that they cannot let even some large blood cells pass through them. Even red blood cells pass through such capillaries in single file, or else by distorting their shape.

The blood proceeding along the arteries at 1.5 kilometers an hour (0.93 miles per hour) slows down by a thousandth of that rate when it enters the capillaries. Every region of the body has been penetrated by an extraordinarily wide ranging network of capillaries. The capillaries in just one single person could stretch from one end of the USA to the other.109 This incomparable mechanism is brought into being to nourish all the cells in the body. In fact, a cell can be no further than 20 to 30 microns from a capillary—a distance of 0.02 millimeters (0.0007874 inch), which is sufficient to grasp the scale of this magnificent network that visits 100 trillion cells.

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How does waste from the red blood cell goes into the lungs and how does oxygen molecules enters the red blood cell from the alveoli (tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide takes place)

pastedGraphic_4.pdf

-Function of Red Blood Cells

Red blood cells (also referred to as erythrocytes) are the most common type of blood cell and the vertebrate organism's principal means of delivering oxygen (O2) to the body tissues via the blood flow through the circulatory system. They take up oxygen in the lungs or gills and release it while squeezing through the body's capillaries.





-What are the organelles found in the cell?

The organelles found in red blood cells include a plasma membrane and the cells' cytoplasm is rich in hemoglobin, an iron-containing biomolecule that can bind oxygen and is responsible for the blood's red color.

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Hemoglobin

green = heme groups

red & blue = protein subunits


-List the structural features of the cell.

They are biconcave discs, having a depressed center on both sides. These depressed centers allow the cells to have more cell membrane surface which can be exposed to diffusing oxygen while transiting the lungs. This structure also allows them to be more flexible with the ability to twist and bend through the blood vessels.


-What are the functions of these organelles?

Hemoglobin facilitates transportation of oxygen and the plasma membrane keeps the hemoglobin in the cell.


-Why are these functions of the organelles important to the living cell?

Hemoglobin helps in transportation in oxygen so without hemoglobin, the cell will not carry oxygen so it would be useless and die. The person would also die.

Plasma membrane keeps the hemoglobin inside the cell if not it would be all round our blood.


-Diseases involving the red blood cells


  • Anemias (or anaemias) are diseases characterized by low oxygen transport capacity of the blood, because of low red cell count or some abnormality of the red blood cells or the hemoglobin.
  • Iron deficiency anemia is the most common anemia; it occurs when the dietary intake or absorption of iron is insufficient, and hemoglobin, which contains iron, cannot be formed
  • Sickle-cell disease is a genetic disease that results in abnormal hemoglobin molecules. When these release their oxygen load in the tissues, they become insoluble, leading to mis-shaped red blood cells. These sickle shaped red cells are rigid and cause blood vessel blockage, pain, strokes, and other tissue damage.

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Affected by Sickle-cell disease, red blood cells alter shape and threaten to damage internal organs.

  • The malaria parasite spends part of its life-cycle in red blood cells, feeds on their hemoglobin and then breaks them apart, causing fever. Both sickle-cell disease and thalassemia are more common in malaria areas, because these mutations convey some protection against the parasite.
  • Polycythemias (or erythrocytoses) are diseases characterized by a surplus of red blood cells. The increased viscosity of the blood can cause a number of symptoms.


Sources:


Information: http://web.buddyproject.org/web019/web019/blood.html and

http://en.wikipedia.org/wiki/Red_blood_cell


Picture (RBCs):

http://www.sciencequiz.net/jcscience/jcbiology/circulatorysystem/red_blood_cells.jpg

Picture (Blood):

http://images.google.com.sg/imglandingq=red%20blood%20cells&imgurl=

http://www.ich.ucl.ac.uk/gosh_families/

information_sheets/aplastic_anaemia/cells.gif&imgrefurl=

http://www.ich.ucl.ac.uk/gosh_families/information_sheets/

aplastic_anaemia/aplastic_anaemia_families.html&usg=__WzowWDOks0e1tCtfphX

WoSH7Eo0=&h=306&w=424&sz=15&hl=en&sig2=Q81MVRozYH8agpo7nsjzg&itbs

=1&tbnid=V1EOCbZVZLiKtM:&tbnh=91&tbnw=126&prev=/images%3Fq%3Dred%2B

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gbv=2&tbs=isch:1&start=4#tbnid=V1EOCbZVZLiKtM&start=8


Picture (Capillaries):

http://www.harunyahya.com/books/science/blood_heart/blood_heart_12.php


Picture (Capillaries drawn):

http://www.harunyahya.com/books/science/blood_heart/blood_heart_12.php


Definition of alveoli: New Oxford American Dictionary.


109 Biology Today, p. 202. :

http://www.harunyahya.com/books/science/blood_heart/blood_heart_12.php

Hemoglobin diagram: http://en.wikipedia.org/wiki/File:1GZX_Haemoglobin.png

Most information obtained from http://en.wikipedia.org/


Done by:

Christopher, Carisa, Yi Lin, Jaime, Pei Shan, Priyanka

4 comments:

  1. Cannot be seen sorry.

    Red blood cell in the blood vessel.
    The artery that enters any organ divides and thins six to eight times before becoming an arteriole, the capillaries' control valve. Subsequently, the arteriole itself will branch two or three times, reducing its diameter to just 9 microns, and will continue on as a capillary. Some of these capillaries are so small that they cannot let even some large blood cells pass through them. Even red blood cells pass through such capillaries in single file, or else by distorting their shape.

    Tip: Just for next time if you go to a blog which has text the same colour as the background, you can highlight it so that it can be seen. (Just for those who don`t know although most know.)

    : )

    -Christopher Nah

    ReplyDelete
  2. I didn't realise that the red blood cells can alter shape and threaten to damage internal organs!

    ReplyDelete
  3. I did not know that diseases can infect red blood cells and also did not know that the capillaries in just one single person could stretch from one end of the USA to the other. That's really long!

    ReplyDelete
  4. Dear friends,

    Thanks for taking time to read :D

    -Christopher Nah

    ReplyDelete