This report is on the structure and functions of four of the main human cells; Erythrocytes, Monocyte (white blood cell), Nerve cell (neuron) and Stem cell. According to the endosymbiotic theory by Lynn Margulis eukaryotic cells develop from a combination of unnucleated bacteria which previously survived autonomously. Mitochondria and chloroplasts are two of the main organelles of eukaryotic cells which are descendants of bacteria that once existed. Curley,R. (01 December 2006). This report will explain the ultra structural features of each cell and adaption to the function that they perform in the human body.
Erythrocytes are personalized to carry out their function by a red pigment known as haemoglobin. There is no nucleus in Erythrocytes and this makes possible for haemoglobin to be stored, haemoglobin enables the flow of transporting oxygen and carbon dioxide. The walls in Erythrocytes allow the reversible infusion of oxygen and carbon dioxide. Erythrocytes have a biconcave shape and their large surface area helps the cell have more flexibility to fold and bend. The elasticity and flexibility of the disc ensures they can squeeze through the capillaries, whilst the shape of the red blood cell ensures that it strong.
When the membrane is damaged and spherocytes are formed (red circular cells) they become much weaker and will rupture easily. They do not posses mitochondria and in the adult body Erythrocytes are produced in bone marrow. They make up 25% of the body cells and have an average life span of Erythrocytes is 120 days, however bones are continuously re-producing new cells. The human body needs Erythrocytes to stay alive. In comparison white blood cells form part of the immune system that helps fight infections that attack the body. Doohan, J. (11 October 1999)
3.0 Monocyte Cell
A Monocyte is one example of a white blood cell which has a single and defined nucleus. They need a high concentrate of mitochondria in order to fight against fatigue. Monocytes have long tissues which contain a high concentration of mitochondria. There are two types of muscle tissue and these are skeletal and cardiac muscles. Monocytes function is to carry out the process of phagocytosis where molecules found in the blood are injected and broken down. Phagocytosis is there to protect the organism from being attacked by pathogen and to remove dead, dying or damaged cells from the blood. Monocytes replace the injured cells and morph themselves into different cells that are needed. They later merge into the tissues of the body and there they evolve into cells called macrophages which play an important role in killing of some bacteria cells. Monocytes release substances that stimulate other cells of the immune system. The surface of a Monocyte is not smooth because it has specific proteins which allow it to bind the bacteria or virus cells. They are the largest of the white blood cells and have an abundant cytoplasm and a large distinctive U-shaped nucleus. Many granules in the cytoplasm of Monocyte cell near the cell membrane produce digestive enzymes which help them assist in the immune system. Monocytes are produced by the bone marrow from hematopoietic stem cell called monoblasts. Parihar, A, Eubank TD, Doseff AL.(2010).
4.0 Stem Cell
Stem cells are cells that have yet to become a specific cell and their structure allows for them to be formed into any type of cell, this is from blood to bone. Stem cells have the ability to self-renew and develop into different types of mature cells. They acquire the power to repair deoxyribonucleic acid (DNA) damage compared to other cells in the body. Other cells in the body have got one specific role and are limited with their abilities, whereas stem cells have the ability to produce all proteins within the cell. Under experimental or physiologic conditions stem cell can be induced to become tissue or organ specific cells