The renal corpuscle begins the process of forming urine by filtering plasma from the blood. Its specialized filtration barrier controls which substances enter the nephron, while the nearby juxtaglomerular apparatus (JGA) helps regulate filtration and blood pressure.
The renal corpuscle consists of the glomerulus, a tuft of capillaries, and Bowman’s (glomerular) capsule, which surrounds the glomerulus and collects filtrate. Blood enters the glomerulus through an afferent arteriole and leaves through an efferent arteriole. The pressure in this capillary bed supports filtration.
All flashcards
What is the renal corpuscle?
The glomerulus, a tuft of capillaries, together with the surrounding Bowman’s capsule, which collects filtrate.
What are podocytes and pedicels?
Podocytes are specialized cells of the visceral layer of Bowman’s capsule. Their finger-like projections, called pedicels, interdigitate to form filtration slits.
What are the components of the filtration membrane?
Fenestrated glomerular capillary endothelium, the shared basement membrane, and the filtration slits between podocyte pedicels.
What does the macula densa monitor?
It monitors tubular-fluid composition, including sodium concentration, and senses fluid movement. Its signals influence nearby juxtaglomerular cells.
How does the renin pathway affect blood pressure?
Renin acts on angiotensinogen to produce angiotensin I, which ACE converts to angiotensin II. Angiotensin II constricts blood vessels and stimulates aldosterone release; aldosterone promotes renal sodium reabsorption and associated water retention.
Quiz questions
What is the main transport advantage of the PCT brush border?Answer: It increases the membrane surface area available for transport.
What type of epithelium lines the thin portions of the loop of Henle?Answer: Simple squamous epithelium.
How does ADH increase water recovery in collecting ducts?Answer: It stimulates insertion of aquaporin channels into cell membranes.
Why do negatively charged substances tend to cross the filtration barrier less readily than positively charged substances?Answer: Negatively charged proteins associated with the barrier repel negatively charged substances.
How can aldosterone increase blood pressure through its effect on the kidney?Answer: It increases sodium reabsorption, and water follows sodium, promoting fluid retention.
Based on Anatomy and Physiology 2e by J. Gordon Betts, Kelly A. Young, James A. Wise, Eddie Johnson, Brandon Poe, Dean H. Kruse, Oksana Korol, Jody E. Johnson, Mark Womble, Peter DeSaix (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.