 |
| The different types of cells in the human body and their functions |
Different types of cells in the human body and their functions:
![Bone cells: The bone cells include osteocytes, osteoblasts, osteoclasts, osteogenic cells (stem cells), and lining cells. Osteoclasts are very large multinucleate cells that are responsible for the breakdown of bones. The breakdown of bone is very important in bone health because it allows for bone remodeling. Osteoclasts are formed by the conjoining of many different cells created from the bone marrow that travel in the circulatory system. Osteoclasts are usually found grouped in the small pits on bone surfaces called Howship's lacunae.[5] The pits are sites of bone resorption. After latching on to the site of the bone where it is supposed to resorb it, the osteoclast releases a number of enzymes which break down the bone tissue. The final product of the resorption of the bone is calcium and phosphorus ions. This reabsorption process can sometimes take up to weeks for the osteoclast to complete. The breakdown of bones is controlled by hormones in the bloodstream which instruct the osteoclasts when and where to break down bone tissue. Osteoblasts are bone cells that are responsible for the formation of new bone. Osteoblasts deposit a collagen matrix and release minerals that combine to make the bone mineral. Unlike the much larger osteoclasts, osteoblasts are much smaller; they only have one nucleus. Osteoblasts also group to form new bone. Osteoblasts are important because they allow the bones to be made, remodeled, and repaired. The osteoblasts come from the differentiation of osteogenic cells in the tissue that covers the outside of the bone, or the periosteum and the bone marrow.[6] The osteoblast creates and repairs new bone by actually building around itself. First, the osteoblast puts up collagen fibers. These collagen fibers are used as a framework for the osteoblasts' work. The osteoblast then deposits calcium phosphate which is hardened by hydroxide and bicarbonate ions. The brand new bone created by the osteoblast is called osteoid.[7] Once the osteoblast is finished working it is actually trapped inside of the bone once it hardens. When the osteoblast becomes trapped, it becomes known as an osteocyte.[8] Other osteoblasts remain on the top of the new bone and are used to protect the underlying bone, these become known as lining cells. Osteocytes are osteoblasts which have become trapped inside of the bone matrix. Once an osteoblast creates the new bone around itself, it is trapped and can no longer move or form bone; this is how an osteocyte is created. When the osteoblast is transformed into an osteocyte, the transformation causes the osteocyte to lose a majority of its organelles. What replaces these organelles are large quantities of microfilaments. Osteocytes develop long branches which allow them to contact each other and also contact the bone lining cells. The osteocyte lies within a small chamber called a lacuna, which is within the bone matrix.[9] Osteocytes remain in contact with other cells in the bone through gap junctions—coupled cell processes—which pass through small channels in the bone matrix called the canaliculi.[10] The osteocyte is still a mysterious cell—biologists still have not figured out the true function of the osteocyte. Even though the function of the osteocyte is still under investigation, there are some ideas on what they might do. One function of the osteocyte might be the remodeling of the bone through growths of new arms on the cell. It is also known that osteocytes can secrete growth factors which activate lining cells or stimulate osteoblasts. Finally, it is believed that the osteocyte might compensate for the strain on the bone due to their many arms which extend out to other osteocytes.[11] Lining cells come from osteoblasts which have become flattened. Bone lining cells have flat organelles so they can easily cover the bone without interfering with other cells functions. Bone lining cells are mainly in adults, some however are in the bones of children. Bone lining cells are connected to other bone lining cells through gap junctions and are able to send cell processes through canaliculi. The lining cells are relatively inactive forms of osteoblasts that cover all available surfaces of the bone. Bone lining cells are responsible for the immediate release of [calcium] in the bone if calcium in the blood is too low. Bone lining cells are also responsible for the protection of the bone from harmful chemicals which would eat away the bone. It is also thought that bone lining cells are important in the maintenance of the bone fluids.[10][11] Bone cells create molecules made from proteins which are used to communicate with other bone cells. These molecules are called growth factors and cytokines. These factors control cell division, differentiation, and survival of the cells.](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi05rmhvde0lWyNSvpykLb7OP3bRtgc0Kab9tA5ye9yTOSNoYG7u_tnfZCR-ZeaF0Xr1J9yUaqMVnzZd8XGsh0bgOLAsvYB_H1SSeWmzJXynZH1oWEtG2GLj6MK3fsmQqYxfyEkLMuc8WU/s1600/bone+cell.GIF "Bone cells: The bone cells include osteocytes, osteoblasts, osteoclasts, osteogenic cells (stem cells), and lining cells. Osteoclasts are very large multinucleate cells that are responsible for the breakdown of bones. The breakdown of bone is very important in bone health because it allows for bone remodeling. Osteoclasts are formed by the conjoining of many different cells created from the bone marrow that travel in the circulatory system. Osteoclasts are usually found grouped in the small pits on bone surfaces called Howship's lacunae.[5] The pits are sites of bone resorption. After latching on to the site of the bone where it is supposed to resorb it, the osteoclast releases a number of enzymes which break down the bone tissue. The final product of the resorption of the bone is calcium and phosphorus ions. This reabsorption process can sometimes take up to weeks for the osteoclast to complete. The breakdown of bones is controlled by hormones in the bloodstream which instruct the osteoclasts when and where to break down bone tissue. Osteoblasts are bone cells that are responsible for the formation of new bone. Osteoblasts deposit a collagen matrix and release minerals that combine to make the bone mineral. Unlike the much larger osteoclasts, osteoblasts are much smaller; they only have one nucleus. Osteoblasts also group to form new bone. Osteoblasts are important because they allow the bones to be made, remodeled, and repaired. The osteoblasts come from the differentiation of osteogenic cells in the tissue that covers the outside of the bone, or the periosteum and the bone marrow.[6] The osteoblast creates and repairs new bone by actually building around itself. First, the osteoblast puts up collagen fibers. These collagen fibers are used as a framework for the osteoblasts' work. The osteoblast then deposits calcium phosphate which is hardened by hydroxide and bicarbonate ions. The brand new bone created by the osteoblast is called osteoid.[7] Once the osteoblast is finished working it is actually trapped inside of the bone once it hardens. When the osteoblast becomes trapped, it becomes known as an osteocyte.[8] Other osteoblasts remain on the top of the new bone and are used to protect the underlying bone, these become known as lining cells. Osteocytes are osteoblasts which have become trapped inside of the bone matrix. Once an osteoblast creates the new bone around itself, it is trapped and can no longer move or form bone; this is how an osteocyte is created. When the osteoblast is transformed into an osteocyte, the transformation causes the osteocyte to lose a majority of its organelles. What replaces these organelles are large quantities of microfilaments. Osteocytes develop long branches which allow them to contact each other and also contact the bone lining cells. The osteocyte lies within a small chamber called a lacuna, which is within the bone matrix.[9] Osteocytes remain in contact with other cells in the bone through gap junctions—coupled cell processes—which pass through small channels in the bone matrix called the canaliculi.[10] The osteocyte is still a mysterious cell—biologists still have not figured out the true function of the osteocyte. Even though the function of the osteocyte is still under investigation, there are some ideas on what they might do. One function of the osteocyte might be the remodeling of the bone through growths of new arms on the cell. It is also known that osteocytes can secrete growth factors which activate lining cells or stimulate osteoblasts. Finally, it is believed that the osteocyte might compensate for the strain on the bone due to their many arms which extend out to other osteocytes.[11] Lining cells come from osteoblasts which have become flattened. Bone lining cells have flat organelles so they can easily cover the bone without interfering with other cells functions. Bone lining cells are mainly in adults, some however are in the bones of children. Bone lining cells are connected to other bone lining cells through gap junctions and are able to send cell processes through canaliculi. The lining cells are relatively inactive forms of osteoblasts that cover all available surfaces of the bone. Bone lining cells are responsible for the immediate release of [calcium] in the bone if calcium in the blood is too low. Bone lining cells are also responsible for the protection of the bone from harmful chemicals which would eat away the bone. It is also thought that bone lining cells are important in the maintenance of the bone fluids.[10][11] Bone cells create molecules made from proteins which are used to communicate with other bone cells. These molecules are called growth factors and cytokines. These factors control cell division, differentiation, and survival of the cells.") |
| The 5 bone cells are osteocytes, osteoblasts, osteoclasts, osteogenic cells (stem cells), and lining cells. |
Bone cells: The bone cells include osteocytes, osteoblasts, osteoclasts, osteogenic cells (stem cells), and lining cells.
Osteoclasts are very large multinucleate cells that are responsible for the breakdown of bones. The breakdown of bone is very important in bone health because it allows for bone remodeling. Osteoclasts are formed by the conjoining of many different cells created from the bone marrow that travel in the circulatory system. Osteoclasts are usually found grouped in the small pits on bone surfaces called Howship's lacunae. The pits are sites of bone resorption. After latching on to the site of the bone where it is supposed to resorb it, the osteoclast releases a number of enzymes which break down the bone tissue. The final product of the resorption of the bone is calcium and phosphorus ions. This reabsorption process can sometimes take up to weeks for the osteoclast to complete. The breakdown of bones is controlled by hormones in the bloodstream which instruct the osteoclasts when and where to break down bone tissue.
Osteogenic cells are the only bone cells that divide. Osteogenic cells differentiate and develop into osteoblasts which, in turn, are responsible for forming new bones. Osteoblasts synthesize and secrete a collagen matrix and calcium salts.
Osteoblasts are bone cells that are responsible for the formation of new bone. Osteoblasts deposit a collagen matrix and release minerals that combine to make the bone mineral. Unlike the much larger osteoclasts, osteoblasts are much smaller; they only have one nucleus. Osteoblasts also group to form new bone. Osteoblasts are important because they allow the bones to be made, remodeled, and repaired. The osteoblasts come from the differentiation of osteogenic cells in the tissue that covers the outside of the bone, or the periosteum and the bone marrow. The osteoblast creates and repairs new bone by actually building around itself. First, the osteoblast puts up collagen fibers. These collagen fibers are used as a framework for the osteoblasts' work. The osteoblast then deposits calcium phosphate which is hardened by hydroxide and bicarbonate ions. The brand new bone created by the osteoblast is called osteoid. Once the osteoblast is finished working it is actually trapped inside of the bone once it hardens. When the osteoblast becomes trapped, it becomes known as an osteocyte. Other osteoblasts remain on the top of the new bone and are used to protect the underlying bone, these become known as lining cells.
Osteocytes are osteoblasts which have become trapped inside of the bone matrix. Once an osteoblast creates the new bone around itself, it is trapped and can no longer move or form bone; this is how an osteocyte is created. When the osteoblast is transformed into an osteocyte, the transformation causes the osteocyte to lose a majority of its organelles. What replaces these organelles are large quantities of microfilaments. Osteocytes develop long branches which allow them to contact each other and also contact the bone lining cells. The osteocyte lies within a small chamber called a lacuna, which is within the bone matrix. Osteocytes remain in contact with other cells in the bone through gap junctions—coupled cell processes—which pass through small channels in the bone matrix called the canaliculi. The osteocyte is still a mysterious cell—biologists still have not figured out the true function of the osteocyte. Even though the function of the osteocyte is still under investigation, there are some ideas on what they might do. One function of the osteocyte might be the remodeling of the bone through growths of new arms on the cell. It is also known that osteocytes can secrete growth factors which activate lining cells or stimulate osteoblasts. Finally, it is believed that the osteocyte might compensate for the strain on the bone due to their many arms which extend out to other osteocytes.
Lining cells come from osteoblasts which have become flattened. Bone lining cells have flat organelles so they can easily cover the bone without interfering with other cells functions. Bone lining cells are mainly in adults, some however are in the bones of children. Bone lining cells are connected to other bone lining cells through gap junctions and are able to send cell processes through canaliculi. The lining cells are relatively inactive forms of osteoblasts that cover all available surfaces of the bone. Bone lining cells are responsible for the immediate release of [calcium] in the bone if calcium in the blood is too low. Bone lining cells are also responsible for the protection of the bone from harmful chemicals which would eat away the bone. It is also thought that bone lining cells are important in the maintenance of the bone fluids.
Bone cells create molecules made from proteins which are used to communicate with other bone cells. These molecules are called growth factors and cytokines. These factors control cell division, differentiation, and survival of the cells.
Osteoclasts are very large multinucleate cells that are responsible for the breakdown of bones. The breakdown of bone is very important in bone health because it allows for bone remodeling. Osteoclasts are formed by the conjoining of many different cells created from the bone marrow that travel in the circulatory system. Osteoclasts are usually found grouped in the small pits on bone surfaces called Howship's lacunae. The pits are sites of bone resorption. After latching on to the site of the bone where it is supposed to resorb it, the osteoclast releases a number of enzymes which break down the bone tissue. The final product of the resorption of the bone is calcium and phosphorus ions. This reabsorption process can sometimes take up to weeks for the osteoclast to complete. The breakdown of bones is controlled by hormones in the bloodstream which instruct the osteoclasts when and where to break down bone tissue.
Osteogenic cells are the only bone cells that divide. Osteogenic cells differentiate and develop into osteoblasts which, in turn, are responsible for forming new bones. Osteoblasts synthesize and secrete a collagen matrix and calcium salts.
Osteocytes are osteoblasts which have become trapped inside of the bone matrix. Once an osteoblast creates the new bone around itself, it is trapped and can no longer move or form bone; this is how an osteocyte is created. When the osteoblast is transformed into an osteocyte, the transformation causes the osteocyte to lose a majority of its organelles. What replaces these organelles are large quantities of microfilaments. Osteocytes develop long branches which allow them to contact each other and also contact the bone lining cells. The osteocyte lies within a small chamber called a lacuna, which is within the bone matrix. Osteocytes remain in contact with other cells in the bone through gap junctions—coupled cell processes—which pass through small channels in the bone matrix called the canaliculi. The osteocyte is still a mysterious cell—biologists still have not figured out the true function of the osteocyte. Even though the function of the osteocyte is still under investigation, there are some ideas on what they might do. One function of the osteocyte might be the remodeling of the bone through growths of new arms on the cell. It is also known that osteocytes can secrete growth factors which activate lining cells or stimulate osteoblasts. Finally, it is believed that the osteocyte might compensate for the strain on the bone due to their many arms which extend out to other osteocytes.
Lining cells come from osteoblasts which have become flattened. Bone lining cells have flat organelles so they can easily cover the bone without interfering with other cells functions. Bone lining cells are mainly in adults, some however are in the bones of children. Bone lining cells are connected to other bone lining cells through gap junctions and are able to send cell processes through canaliculi. The lining cells are relatively inactive forms of osteoblasts that cover all available surfaces of the bone. Bone lining cells are responsible for the immediate release of [calcium] in the bone if calcium in the blood is too low. Bone lining cells are also responsible for the protection of the bone from harmful chemicals which would eat away the bone. It is also thought that bone lining cells are important in the maintenance of the bone fluids.
Bone cells create molecules made from proteins which are used to communicate with other bone cells. These molecules are called growth factors and cytokines. These factors control cell division, differentiation, and survival of the cells.
 |
| Chondrocyte cells |
 |
| Nerve cells |
 |
| The Nerve cell |
 |
| Epithelial cells |
 |
| The Epithelial cell |
 |
| Real epithelial-cells |
Epithelial cell: Epithelial cells come in different shapes depending on where in the body they're found. These shapes are called squamous, cuboidal, columnar and ciliated columnar.
Epithelial cells help to protect or enclose organs. Most produce mucus or other secretions.
An example of this would be your skin, which is made up of many stratified layers of epithelial cells. As the top layer wears down, cells from the bottom layers constantly grow up to replace them.
Squamous epithelial cells are flat and are usually found lining surfaces that require a smooth flow of fluid such as your blood vessels, or lining areas that require a very thin surface for molecules to pass through, such as the air sacs in your lungs.
Cuboidal epithelial cells, as their name suggest, are shaped like cubes. These are typically found in tissues that secrete or absorb substances, such as in the kidneys and glands.
Columnar epithelial cells are long and thin, like columns. These are usually found in places that secrete mucus such as the stomach. They can also specialize to receive sensory information in places like taste buds on your tongue and inside of your nose.
Cilliated columnar cells have their apical (or outside facing) surface covered with many tiny little hairs called cilia. These are used to push mucus and other particles along, making it flow in a specific direction.
In addition to these shapes, epithelial cells can be described as being either simple or stratified.
These terms refer to how many layers are present.
Simple tissue has only one layer of epithelial cells, while stratified tissue has many layers stacked on top of each other
(Stratified cells are found in places that need to withstand a lot of wear and tear from their environment).
 |
| Muscle cells |
 |
| Three type of muscle cells |
Muscle cells: A myocyte (also known as a muscle cell) is the type of cell found in muscle tissue. Myocytes are long, tubular cells that develop from myoblasts to form
muscles in a process known as myogenesis. There are three specialized forms of myocytes: cardiac, skeletal, and smooth muscle cells, with various properties.
Skeletal muscles cells are attached to long bones and assist in their movement (by muscle contraction).
Cardiac muscles cells are present only in heart muscle and responsible for heart beats.
types of cells in the body
Smooth muscle cells are flexible yet, can contract and relax and are present in stomach, intestine, blood vessel walls (vascular tissue) etc. helping in the movement of food through the gut.
smooth muscle-1
Secretory cell: Many human cell types have the ability to be secretory cells. They have a well-developed endoplasmic reticulum and Golgi apparatus to fulfill their function. Tissues in humans that produce secretions include the gastrointestinal tract which secretes digestive enzymes and gastric acid, the lung which secretes surfactants, and sebaceous glands which secrete sebum to lubricate the skin and hair. Meibomian glands in the eyelid secrete sebum to lubricate and protect the eye.
7. Adipose cells: These are fat cells and are storage in nature to store fat. Especially seen in the soles, palms, bums etc. They reduce friction to the body.
8. Blood cells: These cells include RBC’s, WBC, Thormbocytes etc. They are always motile and never stay in one place. They have limited life span and they never multiply to form new cells. Instead new cells are formed from other cells.
TYPES OF CELLS IN HUMAN BODY (BASED ON THEIR FUNCTION)
Different cells and their functions help the body carry out many physiological functions. These cells include
Conductive cells: Nerve cells, muscle cells come under this category. They have internal ability to conduct an electric impulse from region to other distant region in the body.
Connective cells: Bone cells, blood cells come under this category. They help connect other cells and tissues.
Glandular cells: These cells secretory cells. They form glands like pancreas,salivary glands etc and help in the production of enzymes, hormones etc.
Storage cells: Adipose cells, some liver cells etc act to store materials like fat for later use. This fat is consumed in times of starvation and also in excess cold temperatures.
Supportive cells: These are the cells which are present as support to adjacent cells. Ex: Glial cells in the brain and spinal cord help provide nourishment to the nerve cells and also protect them from shocks and trauma.
Special type of cells: These are specialized cells with important functions in the body. They are
a) Sperms: These cells unlike others have haploid DNA (i.e. have only one set of chromosome). They are present only in the males after puberty. These cells have a tail which enables them to swim and move in the female uterus. They have an enzyme hayaluronidase which helps them penetrate through uterine tissue and reach into oocytes.
sperm cells-
CLICK TO ENLARGE
b) Oocytes: Cells are haploid and present in adult female genital system. They are also haploid like sperms. They start to form after puberty and continue so till the stage of menopause. They accept sperm cells to form zygote (fertilized egg). This further grows in the uterus to form a baby.
c) Stem cells: These are basic cells or parent cells which can differentiate into any cell based on the requirement. These stem cells in human body are given so importance due to their promising role in treatment of disorders in future. See the article on stem cell types.
d) Rods & cones: These cells are in eye and have capacity to capture image color and light.
e) Ciliated cells: These cells are present as lining of respiratory tract, esophagus etc. and have a pointed thread like cilia which move in one particular direction to pass material.
Human tissue types are again dependent on the types of cells involved in their formation.
f) Blood cells: These are quite interesting cells and they are never attached to one another. Blood cells freely flow in the liquid blood. Some of them are not alive (RBC‘s) while others are alive and have varied shapes like WBC, platelets (spindle shape). Further these WBC’s are of different types. Of them macrophages have ability to eat (gulp) any foreign particle like bacteria in the body. Hence they are body defense cells.
Besides, there are cells which form covering tissue. These can be of different shapes, will ability to constrict, dilate, secrete and even absorb. Such cells are seen in the lining of intestine, stomach, lungs, nephrons etc. The examples include goblet cells, paneth cells etc.
