Ch 25: Urinary System Part 1 Flashcards
What are the functions of the kidneys?
- Regulating total water volume and solute concentration in water
- Regulate ECF ion concentration
- Ensures long-term aic-base concentrations
- Removal of waste
- Activation of vitamin D
- Gluconeogenesis
What are the endocrine functions of the kidneys?
- Renin: regulate BP
- EPO: regulate RBC production
What are the organs of the urinary system?
- Kidneys
- Ureters
- Bladder
- Urethra
What are the kidneys?
Major excretory organs
Where is the kidney located?
Retroperitoneal T12-L5
Right kidney is lower than left
What sits atop the kidneys?
Adrenal gland
What enters the kidneys add exits at hilum?
- Ureters
- Renal blood vessels
- Lymphatics
- Nerves
What are the supportive tissues of the kidneys?
- Renal fascia
- Perirenal fat capsule
- Fibrous capsule
What is the renal fascia?
Anchors outer layer of kidney
What is the perirenal fat capsule?
Fatty cushion of the kidney
What is the fibrous capsule?
Prevents spread of infection to kidney
What is the renal cortex?
Granular-appearing superficial region
What is the renal medulla?
Composed of cone-shaped medullary (renal) pyramids
What is the minor calces?
Drain pyramids
What is the major calyces?
Collect urine from minor calyces emptying urine into renal pelvis
What is the renal pelvis?
Funnel-shaped tube continuous with ureter
What is the route of urine flow through the kidneys?
Renal pyramid → minor calyx → major calyx → renal pelvis → ureter
What is pyelitis?
Infection of renal pelvis and calyces
What is pyelonephritis?
Infection/inflammation of entire kidney
How is pyelitis and pyelonephritis treated?
Antibiotics
What does kidneys do to blood?
Cleanses blood adjusting its composition allowing a rich blood supply
How much is the CO to kidneys?
1200mL per kidneys/minute
What flows out of the kidneys through a similar path?
Arterial and venous
What is the nerve supply of the kidneys?
Renal plexus
What are the ureters?
Transport urine from kidneys to urinary bladder
What is the urinary bladder?
Temporary storage reservoir for urine
What is the urethra?
Transports urine out of body
Describe the path of blood through the renal blood vessels
Aorta → Renal artery → Afferent arteriole → Glomerus (capillaries) → Efferent arterioles → Peritubular capillaries (vasa recta) → Renal vein → Inferior vena cava
What are nephrons?
Structural and functional units that form urine
How many nephrons are in a kidney?
Over 1 million
What are the 2 parts of the nephrons?
- Renal corpuscle
- Renal tubule
What are the components of the renal corpuscle?
- Glomerus
- Bowman’s capsule
What is the glomerulus?
Highly porous that allows filtrate formation
- What is the Glomerular capsule (Bowman’s)?
Cup-shaped, hollow structure surrounding glomerulus
What are the components of the renal tubule?
- PCT
- Loop of Henle
- DCT
What is the purpose of the PCT?
Closest to the renal corpuscle that functions in reabsorption and secretion confined to the cortex
What is the loop of Henle (Nephron loop)?
- Proximal descending limb is continuous with proximal tubule
- Distal descending limb that is thin
- Thick ascending limb
What is the purpose of the DCT?
Farthest from the renal corpuscle that assists with more secretion than reabsorption confined to the cortex
What is the collecting ducts?
- Receive filtrate from many nephrons
- Fuse together to deliver urine through papillae into minor calyces
What are the cells associated with the collecting ducts?
- Principal cells
- Intercalated cells
What is the purpose of the principal cells?
Maintains water and Na+ balance
What is the purpose of the intercalated cells?
Maintains acid-base balance of blood
Where does urine delivery enter after the collecting ducts?
Minor calyces
What are the 2 classes of nephrons?
- Cortical nephrons
- Juxtamedullary nephrons
How much of nephrons are corticol?
85%
What is the importance of juxtamedullary nephrons?
Production of concentrated urine
What is the structure of cortical nephrons?
Almost the entire cortex
Describe the structure of juxtamedullary nephrons
- Long nephron loops deeply invade medulla
- Ascending limbs have thick and thin segments
What are the capillaries associated with the renal tubules?
- Glomerus
- Peritubular capillaries
What is the glomerulus?
Specialized for filtration, fed and drained by arteriole
Why is blood pressure high is the glomerus?
- Afferent arterioles larger in diameter than efferent arterioles
- Arterioles are high-resistance vessels
What are the peritubular capillaries?
Low-pressure, porous capillaries adapted for absorption of water and solutes
What is the capillary associated with juxtamedullary nephrons?
Vasa recta
What is the vasa recta’s function?
Formation of concentrated urine
What is the function of the juxtaglomerular complex?
Regulation of rate of filtrate formation and blood pressure
What are cells associated with JGC?
- Macula densa
- Granular cells
- Extraglomerular mesangial cells
What is the macula densa?
- Chemoreceptors that sense NaCl content of filtrate
- Located in thick ascending limb of nephron loop
What are the granular cells?
- Secretory granules that contain enzyme renin
- Mechanoreceptors; sense blood pressure in afferent arteriole
What are the extraglomerular mesangial cells?
- Interconnected with gap junctions
- May pass signals between macula densa and granular cells