Overview
This lecture explains the structure and function of the Malpighian body (renal corpuscle), focusing on its components, filtration process, and the specialized cells involved.
Structure of the Malpighian Body
- The Malpighian body consists of the Bowman's capsule and glomerulus.
- The afferent arteriole brings blood into the Bowman's capsule, forming the glomerulus network.
- The efferent arteriole carries filtered blood away from the Bowman's capsule.
- The afferent arteriole has a larger diameter compared to the efferent arteriole.
Layers of the Bowman's Capsule
- The inner visceral layer is made of specialized cells called podocytes.
- The outer parietal layer is composed of squamous epithelium.
- The cavity enclosed by these layers collects the filtrate from the blood.
Podocytes and Filtration
- Podocytes have projections called pedicels that wrap around the capillaries of the glomerulus.
- Glomerular capillaries have fenestrations (pores) allowing filtration.
- The filtering membrane consists of three layers: capillary endothelium, basement membrane, and podocyte layer.
- Filtration occurs as blood components pass through the filtering membrane into the Bowman's capsule cavity.
Key Terms & Definitions
- Malpighian body — Structure in the kidney made up of Bowman's capsule and glomerulus.
- Bowman's capsule — Cup-like structure encasing the glomerulus and involved in filtration.
- Glomerulus — Network of capillaries within the Bowman's capsule.
- Afferent arteriole — Blood vessel bringing blood into the glomerulus.
- Efferent arteriole — Blood vessel taking filtered blood away from the glomerulus.
- Podocyte — Specialized cell in the Bowman's capsule visceral layer, involved in filtration.
- Pedicel — Projections from podocytes that wrap around capillaries.
- Fenestration — Pore in capillary walls that allows passage of substances.
- Basement membrane — Thin layer between capillary endothelium and podocytes, part of the filtering membrane.
Action Items / Next Steps
- Practice drawing the Malpighian body and label its main components.
- Review the roles of podocytes and the filtering membrane in renal filtration.