Somatic cells

Somatic cells are any cell of the body that are not gametes (sperm or egg cells), germ cells (cells that develop into gametes) or stem cells. Essentially, all the cells that make up the body of a organism and are not used to directly form a new organism during reproduction are somatic cells. The word somatic comes from the Greek word σὠμα (soma), meaning body. In the human body, there are about 220 cell types somatic.

Examples of somatic cells

There are many different types of somatic cells in the human body because almost all cells found inside and on the surface of the human body, with the exception of the cells that develop into sperm and eggs, are somatic cells. In addition, mammals have many organ systems that specialise in specific functions, so there are many different specialised cells. The following is an overview of some of the main types of cells in the human body.

Bone cells

Old bone cells are constantly being replaced by new bone cells. The two broad categories of bone cells are called osteoblasts and osteoclasts. Osteoblasts form bone and help maintain it. They are cube- or square-shaped and produce bone-forming proteins. They also communicate with each other and produce certain molecules, such as growth factors, that promote bone growth. Osteoclasts, on the other hand, resorb or dissolve old bone. They are large cells that have multiple nuclei. When the work of an osteoblast or osteoclast is done, it undergoes programmed cell death known as apoptosis.

Muscle cells

Muscle cells are also known as myocytes. They are long, tube-shaped cells. There are three types of muscle, each of which is made up of specialised myocytes: muscle smooth muscle, cardiac muscle and skeletal muscle. Smooth muscle lines the walls of internal organs such as the bladder, bladder muscle, and skeletal muscle. uterus and the digestive tract. The cardiac is only found in the heart and allows the heart to pump blood. Skeletal muscle is attached to bone and helps move the body.

The various parts of myocytes have special terminology because myocytes are very different from other cell types. The cell membrane is called sarcolemmathe mitochondria are called sarcosomes, and the cytoplasm is called sarcoplasm. The sarcomere is the part of the cell that contracts and allows muscle movement, forming long chains called myofibrils that run through each muscle fibre. Muscle cells cannot divide to form new cells. This means that, although muscles may enlarge with exercise, babies actually have more myocytes than adults.

Nerve cells

Nerve cells are called neurons. Neurons are found throughout the body, but there is a particularly high density of them in the brain and the spinal cord, which control the body’s movements. They send and receive information to and from other neurons and organs through chemical and electrical signals. Neurons maintain a certain voltage, and when this voltage changes, it creates an electrochemical signal called an action potential. When an action potential occurs in a neuron, the neuron will release neurotransmitters, which are chemicals that affect target cells. Examples of neurotransmitters include dopamine, serotonin, epinephrine (adrenaline) and histamine.

Neurons have a unique structure as shown in the diagram above. The main parts of a neuron are the soma, the axon and the axons. dendrites. The soma is the body of the cell and contains the nucleus. The axon is a long protrusion that transmits electrical impulses. The dendrites fan out from the soma and receive impulses from other neurons. The end of the axon branches at the axon terminals, where neurotransmitters are released.

Blood cells

Blood cells are called haematopoietic cells or haemocytes. There are three general types of blood cells: red blood cells, known as erythrocytes, white blood cells or leukocytes, and platelets, also known as thrombocytes or yellow blood cells. These cells, along with plasma, comprise the contents of the blood.

Erythrocytes carry oxygen to the cells through the molecule molecule of haemoglobin, and they pick up the carbon dioxide waste products of the cells. They make up 40 to 45 percent of the blood volume. Approximately one quarter of the cells in the human body are erythrocytes. They live for about 100 to 120 days and have no nucleus when mature. Leukocytes defend the body against foreign substances and infectious disease agents, such as viruses and bacteria. They have a very short shelf life of only three to four days. Platelets are small cell fragments that help blood to clot after injury. They also have a short lifespan, living for five to nine days.

Differences between somatic cells and gametes

Somatic cells are produced through the process of cell division of the mitosis. They contain two copies of each chromosomeone from an organism’s mother and one from its father. Cells with two copies of each chromosome are called diploid. Sperm and egg cells, called gametes, are formed through the meiosiswhich is a slightly different process of cell division that results in cells having only one copy of each chromosome. These cells are called haploid. Gametes are haploid because a sperm and an egg fuse together during the fertilisation to create a new organism with diploid cells.
Mutations in somatic cells can affect an individual organism, but do not affect offspring as they are not transmitted during reproduction. However, mutations that occur in gametes can affect offspring as gametes are passed on. When the gametes fuse, they become the first somatic cell of the offspring, which subsequently divides to form all other somatic cells. Therefore, while mutations in the somatic cells will not affect the next generation, mutations in the gamete cells will, and can sometimes have drastic effects. For example, if a mutation occurs and there is an extra chromosome in the fertilised egg, all somatic cells will also have that extra chromosome when it divides. An extra chromosome 21 results in Down’s syndrome.

• Cell: basic biological unit of living things.
• Gametes: permatozoon or egg cell.
• Apoptosis: programmed cell death in which a cell destroys itself.
• Diploid: a cell with two copies of each chromosome; somatic cells are diploid.