What would/could happen if there was a problem with one cell in the body? Does the body have a repair system?
There is a 'self-destruct' button in every cell called the lymphocyte. It's a packet of enzymes that is designed to kill the cell in case of a problem, so no, it happens and is normal. The problem you run into in cancer cells is that they don't have these 'self-destruct' buttons and the cells grow out of control.
Martes, Mayo 4, 2010
Hematocrit
Whole blood is composed of plasma (liquid), cells and platelets. If whole blood is placed into a tube and centrifuged, the cells and the plasma will separate. The erythrocytes, which are heavy, will pack into the bottom of the tube, the plasma will be at the top of the tube, and the leukocytes and platelets will form a thin layer (buffy coat) between the erythrocytes and the plasma.
Whole blood is composed of plasma (liquid), cells and platelets. If whole blood is placed into a tube and centrifuged, the cells and the plasma will separate. The erythrocytes, which are heavy, will pack into the bottom of the tube, the plasma will be at the top of the tube, and the leukocytes and platelets will form a thin layer (buffy coat) between the erythrocytes and the plasma.
Erythropoesis
The body must have a way to assess the concentration of erythrocytes in the blood such that erythrocytes are produced at a rate that matches the body's needs. The regulation and production of RBCs is called erythropoesis. The mechanism of erythropoesis occurs in the following way. The kidney monitors the level of oxygen in the blood. If oxygen levels are low then the kidney secretes a hormone called erythropoetin.
The body must have a way to assess the concentration of erythrocytes in the blood such that erythrocytes are produced at a rate that matches the body's needs. The regulation and production of RBCs is called erythropoesis. The mechanism of erythropoesis occurs in the following way. The kidney monitors the level of oxygen in the blood. If oxygen levels are low then the kidney secretes a hormone called erythropoetin.
Blood Cells
Blood cells are formed in the bone marrow. All blood cells arise from the same bone marrow stem cells. Stem cells are immortal, meaning they never die (at least not until you do). Stem cells are also undifferentiated. meaning they have not yet developed into a particular cell type. Furthermore, stem cells are pluripotent, meaning they have the potential to become any type of blood cell.
Blood cells are formed in the bone marrow. All blood cells arise from the same bone marrow stem cells. Stem cells are immortal, meaning they never die (at least not until you do). Stem cells are also undifferentiated. meaning they have not yet developed into a particular cell type. Furthermore, stem cells are pluripotent, meaning they have the potential to become any type of blood cell.
Linggo, Abril 4, 2010
The cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells, that all cells come from preexisting cells, that vital functions of an organism occur within cells, and that all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells. The DNA from those cells may trigger an inflammatory 
reaction as the dead cells combine with other substances.Once the macrophages and other immune system components have essentially digested the body's dead cells, the cells make their way through the bloodstream and eventually into the digestive system for final disposition. There are 3 classes of cells in the human body. Labile cells, stable cells, and permanent cells. Labile cells are dividing all the time--always in the cell cycle. Examples include cells in the digestive tract, skin, respiratory tract, Stable cells are in Gap O most of the time in the cell cycle, but can be stimulated to enter the cell cycle when needed.
# Ribosomes
* composed of rRNA (ribosomal RNA) & protein
* may be dispersed randomly throughout the cytoplasm or attached to surface of rough endoplasmic reticulum
* primary function is to produce proteins
* often linked together in chains called polyribosomes or polysomes
COMPONENTS OF THE CELLULAR ENVIRONMENT
* comprises 60 - 90% of most living organisms (and cells)
* important because it serves as an excellent solvent & enters into many metabolic reactions
When external skin cells die, there are a number of mechanical and chemical methods used to slough them off. Exfoliants and scrub brushes are often employed to remove dead cells and encourage new cell turnover.
reaction as the dead cells combine with other substances.Once the macrophages and other immune system components have essentially digested the body's dead cells, the cells make their way through the bloodstream and eventually into the digestive system for final disposition. There are 3 classes of cells in the human body. Labile cells, stable cells, and permanent cells. Labile cells are dividing all the time--always in the cell cycle. Examples include cells in the digestive tract, skin, respiratory tract, Stable cells are in Gap O most of the time in the cell cycle, but can be stimulated to enter the cell cycle when needed.# Ribosomes
* composed of rRNA (ribosomal RNA) & protein
* may be dispersed randomly throughout the cytoplasm or attached to surface of rough endoplasmic reticulum
* primary function is to produce proteins
* often linked together in chains called polyribosomes or polysomes
COMPONENTS OF THE CELLULAR ENVIRONMENT
* comprises 60 - 90% of most living organisms (and cells)
* important because it serves as an excellent solvent & enters into many metabolic reactions
When external skin cells die, there are a number of mechanical and chemical methods used to slough them off. Exfoliants and scrub brushes are often employed to remove dead cells and encourage new cell turnover.
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