![]() Question 1: What is a stem cell? Stem cells have the potential to develop into many different cell types in the body during early life and growth. In many tissues they serve as a sort of internal repair system, dividing essentially without limit to replenish other cells as long as the person or animal is still alive. When a stem cell divides, each new cell has the potential either to remain a stem cell or become another type of cell with a more specialized function, such as a muscle cell, a red blood cell, or a brain cell. In the top left corner shows a red blood cells image that comes from stem cells in the top right corner. Stem cells are capable of dividing and renewing themselves for long periods. Unlike muscle cells, blood cells, or nerve cells which do not normally replicate themselves—stem cells may replicate many times. If the resulting cells continue to be unspecialized, like the parent stem cells, the cells are said to be capable of long-term self-renewal. Just above shows a chart of stem cells and how they work. Question 2: Different cells and how they work: 1.Cell Membrane: The thin layer of protein and fat that surrounds the cell. It allows substances to pass into the cell blocking others. 2. Centrosome: A small body located near the nucleus. The centrosomes is where microtubules are made. 3.Cytoplasm: The jelly like material outside the cell nucleus in which the organelles are located. Question 3: What is the red and white blood cells, and how do they work? Red Blood Cells: Also known as erythrocytes. The blood cells that carry oxygen. Red cells contain hemoglobin and it is the hemoglobin which permits them to transport oxygen (and carbon dioxide). Hemoglobin, aside from being a transport molecule, is a pigment. It gives the cells their red color (and their name).They deliver oxygen to the tissues and return carbon dioxide from the tissues to the lungs. They are released from the bone marrow with a life span of 120 days. Unlike most of the other body cells, red cells do not contain a nucleus. The main function of a red blood cell is the transport of oxygen and carbon dioxide. White Blood Cells: These cells circulate throughout the body and tissues providing protection against foreign organisms and matter. White cells can also be known as leukocytes.White blood cells (WBCs), also called leukocytes or leucocytes, are the cells of the immune system that are involved in defending the body against both infectious disease and foreign invaders. White cells must be able to squeeze through the pores in the capillaries and move into the tissues. When an infection occurs in the body, the white cell level of the blood increases. White cells are divided into three groups: Granulocytes, Monocytes and Lymphocytes. Together these cells help the body to fight any infection. The play a vital role in the body’s immune response and can help trigger the body’s rejection of a transplanted organ. Plasma: Plasma is the fluid part of the blood in which the blood cells and the platelets are suspended. Plasma is a sticky fluid that is 95% water. Plasma is the main medium for the transportation of substances throughout the body. It carries nutritive substances to the body structures and removes their waste products. References: http://www.newenglandblood.org/helping/redcells.htm learn.fi.edu en.wikipedia.org: IMAGE http://stemcells.nih.gov/info/basics/pages/basics2.aspx www.csa.com: IMAGE AND CHART |