Spleen Anatomy and Physiology

Summary

This educational video script delves into the intricate anatomy and physiology of the spleen, detailing its location beneath the diaphragm on the left side, nestled between ribs 9 and 11. It explains the spleen's blood supply from the splenic branch of the celiac trunk and its drainage into the portal vein. The script further explores the spleen's histology, highlighting the roles of white pulp in immune response and red pulp in filtering old or abnormal red blood cells. It also touches on the spleen's crucial function in platelet sequestration, offering a comprehensive understanding of this vital organ.

Takeaways

• 📍 The spleen is located below the diaphragm on the left side, between ribs 9 and 11.
• 🔍 It is an intraperitoneum organ, not retroperitoneal, and is in the left upper quadrant.
• 🌿 The spleen's blood supply comes from the splenic branch of the celiac trunk, a branch of the descending aorta.
• 🔄 The splenic vein drains the spleen, also draining part of the pancreas, and joins the inferior mesenteric vein before forming the portal vein.
• 📏 The spleen measures approximately 5 inches in height, 3 inches in width, and 1 inch in thickness, weighing about 7 ounces.
• 🔢 The spleen is often referred to as the 'organ of odd numbers' due to its dimensions and weight in inches and ounces.
• 🧬 The spleen's white pulp, containing immune cells, plays a crucial role in mounting an immune response and producing antibodies.
• 🔴 The red pulp, making up 75% of the spleen, is responsible for filtering and destroying old or abnormal red blood cells.
• 💊 The spleen also has a role in sequestering platelets, maintaining their levels in circulation, which is vital for coagulation.
• 🔎 The spleen's structure includes the peri-arterial lymphatic sheath, marginal zone, and follicles, which are key in immune response activation.

Q & A

What is the location of the spleen in the human body?

The spleen is located below the diaphragm on the left side of the body, specifically under the ribs between ribs 9 and 11.

Is the spleen an intraperitoneum or a retroperitoneal organ?

The spleen is an intraperitoneum organ, meaning it is within the peritoneal cavity.

Which artery supplies blood to the spleen?

The spleen is supplied by the splenic artery, which is a branch of the celiac trunk from the descending aorta.

How does the blood drain from the spleen?

Blood drains from the spleen through the splenic vein, which also drains part of the pancreas, and then joins the inferior mesenteric vein before merging with the superior mesenteric vein to form the portal vein.

What are the approximate dimensions and weight of the spleen?

The spleen is about 5 inches high (12-13 cm), 3 inches in width (7-8 cm), and about 1 inch thick (2.5 cm). It weighs approximately 7 ounces (200 grams).

What is the function of the white pulp in the spleen?

The white pulp, which makes up about 25% of the splenic tissue, contains immune cells like T cells and B cells. It is crucial for mounting an immune response, producing antibodies, and fighting infections.

What is the primary function of the red pulp in the spleen?

The red pulp, which constitutes about 75% of the spleen, is responsible for filtering and destroying old or abnormal red blood cells, as well as clearing pathogens from the circulation.

How does the spleen filter red blood cells?

The spleen filters red blood cells through the venous sinus, where slits between endothelial cells allow only healthy cells to pass. Abnormal or old red blood cells are too large or misshapen to pass through and are phagocytized by surrounding macrophages.

What is the role of the spleen in platelet sequestration?

The spleen sequesters about one-third of the body's platelets, which are important for coagulation and clot formation. This helps maintain appropriate levels of platelets in circulation.

What happens to a person's immune system if the spleen is removed?

If the spleen is removed, a person's immune system is compromised, resulting in lower amounts of antibodies in the blood and an increased risk of infections.