Renal Corpuscle and Bowman's Capsule Quiz

Renal Corpuscle and Bowman's Capsule Structure and Function

• The glomerulus consists of capillary endothelium and glomerular basement membrane
• The two components of the glomerulus are negatively charged particles and positively charged particles
• The Bowman's capsule has two components: parietal and visceral layers, with podocytes in the visceral layer
• Podocytes have foot processes with interconnecting protein molecules called nephrine
• Nephrine forms a structure called the slit diaphragm, allowing molecules less than 7-9 nanometers to pass through
• The space between podocytes is called the filtration slit, approximately 25-30 nanometers in diameter
• The parietal layer of the Bowman's capsule is continuous with the visceral layer, forming the Bowman's space
• The renal corpuscle allows plasma proteins, electrolytes, glucose, amino acids, lipids, urea, vitamins, and water to pass through
• Plasma proteins such as albumin and fibrinogen, along with negatively charged particles, are important components
• Water makes up approximately 93% of the plasma
• The renal corpuscle also filters waste products like creatinine and ions such as sodium, potassium, chloride, calcium, and magnesium
• The filtration slit and nephrine play a crucial role in controlling the passage of molecules through the renal corpuscle

Structure and Function of the Glomerular Basement Membrane

• The glomerular basement membrane consists of three sub-layers: lamina densa, lamina rara interna, and lamina rara externa.
• The lamina densa layer is made up of type 4 collagen and laminins, creating a dense structure.
• The lamina rara interna, closest to the endothelial cells, is a thinner layer consisting of proteoglycans and heparin sulfate.
• The heparin sulfate in the lamina rara interna is highly negatively charged, creating a barrier for negatively charged particles.
• The lamina rara externa, towards the podocyte lining, also consists of heparin sulfate, contributing to the negative charge.
• The negatively charged glomerular basement membrane repels negatively charged plasma proteins, acting as a filter.
• Positively charged particles, such as electrolytes like sodium and potassium, are attracted to the negative charge and can pass through easily.
• Neutral particles can pass through, but negatively charged particles are repelled and prevented from entering the glomerular capsule.
• The fenestration pores in the endothelial lining, approximately 50 to 100 nanometers in diameter, allow for certain substances to pass through.
• The glomerular basement membrane, with its negatively charged surface, creates a barrier for large molecular weight proteins and other solute molecules.
• The glomerulus is composed of the fenestrated endothelial lining and the glomerular basement membrane, both contributing to the filtration process.
• The negatively charged surface of the glomerular basement membrane repels negatively charged plasma proteins, contributing to its function as a selective filter.