AP 4 lecture 5 Flashcards
What are the main anatomical structures of the kidney?
Renal cortex, renal medulla, renal pelvis, renal pyramids, calyces, and ureter
What is the function of the renal cortex?
The renal cortex contains the glomeruli and parts of the nephron, and it plays a key role in filtration and the formation of urine.
What is the function of the renal medulla?
The renal medulla contains the loops of Henle and collecting ducts, which are involved in concentrating urine.
What is the structure of the nephron?
The nephron consists of the glomerulus, Bowman’s capsule, proximal convoluted tubule (PCT), loop of Henle, distal convoluted tubule (DCT), and the collecting duct.
What are the two types of nephrons in the kidney?
Cortical nephrons and juxtamedullary nephrons
What is the role of cortical nephrons?
Cortical nephrons are involved in basic filtration and are located primarily in the renal cortex.
What is the role of juxtamedullary nephrons?
Juxtamedullary nephrons have longer loops of Henle that extend into the medulla and play a crucial role in concentrating urine.
What is renal physiology?
Renal physiology refers to the study of kidney function, including filtration, reabsorption, secretion, and excretion processes that maintain homeostasis.
What is the glomerular filtration rate (GFR)?
GFR is the amount of filtrate formed by the kidneys per minute, indicating how efficiently the kidneys are filtering blood.
What is the average GFR in a healthy adult?
Approximately 120-125 mL/min
What factors affect GFR?
Blood pressure, blood volume, and the condition of the filtration membrane
What is the filtration membrane in the kidney?
The filtration membrane consists of the endothelial cells of glomerular capillaries, the basement membrane, and podocytes.
What substances pass through the filtration membrane?
Water, electrolytes, glucose, amino acids, and small solutes
What substances are retained by the filtration membrane?
Proteins, blood cells, and large molecules are retained.
What is the flow of blood through the kidney?
Blood flows through the renal artery → segmental arteries → interlobar arteries → arcuate arteries → interlobular arteries → afferent arteriole → glomerulus → efferent arteriole → peritubular capillaries/vasa recta → interlobular veins → arcuate veins → interlobar veins → renal vein
What is the flow of urine through the kidney?
Urine flows from the nephron (collecting ducts) → renal papilla → minor calyx → major calyx → renal pelvis → ureter → bladder
What is the juxtaglomerular apparatus (JGA)?
The JGA is a structure that helps regulate blood pressure and GFR, consisting of juxtaglomerular cells, macula densa, and extraglomerular mesangial cells.
What is the function of the juxtaglomerular cells?
Juxtaglomerular cells secrete renin in response to low blood pressure or low sodium levels, which helps regulate blood pressure.
What is the function of the macula densa?
The macula densa detects sodium concentration in the distal convoluted tubule and signals the juxtaglomerular cells to release renin if sodium levels are low.
What is the renin-angiotensin-aldosterone system (RAAS)?
RAAS is a hormone system that regulates blood pressure and fluid balance, initiated by renin secretion from the juxtaglomerular cells.
How does blood pressure influence GFR?
Increased blood pressure increases GFR, while decreased blood pressure reduces GFR.
How do the kidneys regulate blood volume?
The kidneys regulate blood volume by adjusting the reabsorption of water and sodium, influenced by hormones like aldosterone and ADH.
What is tubular reabsorption?
Tubular reabsorption is the process by which water, ions, and nutrients are reabsorbed from the nephron back into the bloodstream.
What is tubular secretion?
Tubular secretion is the process by which waste products and excess ions are secreted into the nephron for excretion in the urine.
How does the loop of Henle contribute to urine concentration?
The loop of Henle creates a concentration gradient in the renal medulla, allowing water to be reabsorbed and urine to be concentrated.
