Blood is a colorless, clear fluid. Blood cells are made of hemoglobin, a protein that allows red blood cells to carry oxygen. Other blood cells, such as white blood cells, platelets and red blood cells, are also produced in the bone marrow.
Blood cells are stored in the spleen. This is a small, bean-shaped organ that lies beneath the left side of the lower ribcage. It’s used to make blood cells.
Functions of the spleen
The spleen is responsible for filtering the blood, which is an essential function in the body. It also helps the body fight infections. The spleen is also involved in regulating blood pressure and storing blood.
The spleen is the body’s primary defense against infections. It has a large number of blood cells that fight infection.
Blood clotting is a natural process when a wound is opened. Blood then flows into the spleen and filters out any damaged blood cells. Clotting then begins to form.
When the blood clotting is complete, it’s removed from the spleen by the spleen’s blood supply. After the blood clotting is complete, the spleen’s job is done. It’s then ready to go back to its regular, non-clotting state.
The spleen is responsible for producing platelets. Platelets are a type of blood cell that help stop bleeding.
Platelets are made in the bone marrow and then travel to the spleen. They can then help platelets to clump together. When the platelets are ready to be released, they’re released from the spleen.
Platelets are also involved in the inflammation response and wound healing process.
White blood cells
The spleen also plays an important role in the immune system. It produces white blood cells, which are immune system cells that fight infections. White blood cells help the body fight infection by:
- Producing antibodies that develop in response to an infectious agent
- Destroying bacteria or viruses
- Phagocytosing or engulfing bacteria or viruses
Structure of the spleen
The spleen is attached to the left side of the lower rib cage. It’s divided into three sections:
- The ventral or anterior section, which contains the red and white pulp
- The central section, which contains the red pulp
- The posterior section, which contains the white pulp
Parts of the spleen
Red pulp is the section of the spleen that’s responsible for blood clotting. There are two regions of red pulp:
- The front section, which is the section of the spleen that contains the major blood vessels. Red pulp is also responsible for releasing the spleen’s white blood cells.
- The posterior section, which contains the spleen’s platelets.
The white pulp of the spleen is located on the spleen’s right side. It’s responsible for removing old blood cells from the blood.
White pulp is also known as the marginal zone. It’s divided into six parts:
- The central area, where white blood cells are stored
- The periarteriolar lymphocyte sheath, which is the region of white pulp that contains lymphocytes
- The paratrabecular lymphoid sheath, which is a region of white pulp that contains T-cells
- The red pulp, which is the section of the spleen that contains red blood cells
- The splenogonadal duct, which is the site where red blood cells leave the spleen
Structure of the white pulp in the spleen
The paratrabecular lymphoid sheath
The paratrabecular lymphoid sheath is a region of white pulp that contains lymphocytes. These are a type of white blood cell that help fight infection.
The splenogonadal duct
The splenogonadal duct is a blood vessel that brings red blood cells out of the spleen.
Parts of the red pulp
The red pulp is the section of the spleen that contains the major blood vessels. It’s also responsible for removing the spleen’s old blood cells.
The ventricular zone is a region of the red pulp that’s surrounded by lymphoid tissue. It’s located within the splenic sinus.
Platelet-rich reticular tissue
The platelet-rich reticular tissue is a region of the spleen that’s characterized by a high concentration of platelets. It’s located behind the red pulp.
Structure of the red pulp
The red pulp is divided into two regions: the ventricular zone, which is on the right side of the spleen, and the central zone, which is on the left side of the spleen.
The central zone of the spleen is divided into two parts: the central artery and the central vein. The central artery is responsible for transporting blood to the red pulp. The central vein is responsible for transporting blood out of the spleen.
The central artery is connected to the central vein. Blood flows from the central artery to the central vein.
The central vein is the large, thin vein that’s responsible for transporting blood out of the spleen. It’s located on the left side of the spleen.
The paracortex is the region of the spleen that contains the white pulp. It’s divided into three parts: the marginal zone, the periarterial lymphoid sheath, and the subcapsular lymphoid sheath.
The marginal zone is the portion of the spleen that’s located on the spleen’s right side. It’s divided into three parts: the red pulp, the subcapsular lymphoid sheath, and the red pulp.
Periarterial lymphoid sheath
The periarterial lymphoid sheath is the region of the spleen that’s located on the spleen’s left side. It’s divided into three parts: the red pulp, the subcapsular lymphoid sheath, and the red pulp.
Subcapsular lymphoid sheath
The subcapsular lymphoid sheath is the region of the spleen that’s located on the spleen’s left side. It’s divided into three parts: the red pulp, the subcapsular lymphoid sheath, and the splenogonadal duct.
The spleen has three main functions: removing old blood cells, removing the spleen’s white matter, and producing white blood cells. It also has a secondary function: storing platelets.
The spleen also has a smaller function: absorbing harmful substances from the blood. This process is called phagocytosis.
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