Urinary System Flashcards
(44 cards)
What type of organ are kidneys considered?
A major excretory organ, maintaining the body’s internal environment
What are the functions of the kidneys?
- Regulate total water volume and total solute concentration in water
- Ensure long term acid-base balance
- Excrete metabolic wastes, toxins, and drugs
- Produce erythropoietin to regulate RBC production and renin to regulate blood pressure
- Activate vitamin D
What is the function of ureters?
Transport urine from kidneys to urinary bladder
What is the function or urinary bladder?
Temporary storage reservoir for urine
What is the function of urethra?
Transports urine out of body
What is the order of urine flow?
Renal pyramid -> minor calyx -> major calyx -> renal pelvis -> ureter
What are nephrons?
The structural and functional units that form urine
What are the main two parts of nephrons?
- Renal corpuscle
- Renal tubule
What are the two main parts of renal corpuscle?
- Glomerulus:
- Tufts of capillaries composed of fenestrated endothelium; highly porous
- Filtrate: plasma derived fluid that renal tubules process to form urine - Glomerular capsule
- Aka Bowman’s capsule; cup shaped, hollow structure surrounding glomerulus
- Consists of two layers
What are the two layers of glomerular capsule?
- Parietal layer: simple squamous epithelium
- Visceral layer: clings to glomerular capillaries; branching epithelial podocyes; filtration slits b/w foot processes allow filtrate to passes into capsular space
What are the three major parts of the renal tubule?
- Proximal convoluted tubule
- Nephron loop
- Distal convoluted tubule
What does distal convoluted tubule drains into?
Collecting duct
What are the characteristic of the proximal convoluted tubule?
- Cuboidal cells with dense microvilli that form brush border
- Reabsorption and secretion
- Confined to cortex
What are the characteristics of the nephron loop?
- Aka loop of Henle
- U shaped structure consisting of two limbs; descending and ascending limb
What are the characteristics of the distal convoluted tubule?
- Cuboidal cells with very few microvilli
- More secretion than reabsorption
- Confined to cortex
What are the characteristics of the collecting duct?
Contains two cell types:
- Principal cells; maintain water and calcium balance
- Intercalated cells; maintain acid-base balance of blood
What are the two major groups of nephrons?
- Cortical nephrons: Make up 85% of nephrons; almost entirely in cortex
- Juxtamedullary nephrons: important in production of concentrated urine; long nephron loops deeply in medulla; peritubular capillaries “vasa recta”
What is the role of juxtaglomerular complex?
- Regulate the rate of filtrate formation (GFR) and blood pressure
- Production of concentrated urine
What is a macula densa and what does it do?
Tall, closely packed cells of ascending limb which contains chemoreceptors that sense NaCl content of filtrate
What are granular cells and what does it do?
Enlarged, smooth muscle cells of arteriole; act as mechanoreceptors to sense blood pressure in afferent arteriole; contain renin
What are extraglomerular mesangial cells?
Located between arteriole and distal tubule cells
How many times do kidneys filter body’s entire plasma volume?
60
Urine is produced from _____?
Less than 1% of original filtrate; contains metabolic wastes and unneeded substances
What does porous membrane b/w blood and interior of glomerular capsule do?
Allows water and solutes smaller than plasma proteins to pass