The Urinary System Flashcards
What is the organization of the urinary system?
Two kidneys
Two ureters
One urinary bladder
One urethra
What do the kidneys do?
make urine and carry out other vital functions
What do the ureters do?
carry urine to the urinary bladder
What does the urinary bladder do?
collects, stores, and releases urine
What does the urethra do?
empties urine from the body
What are the six functions of the urinary system?
- Eliminating organic waste products, such as urea, uric acid, creatine, and ammonia
- Regulating blood volume and pressure by: adjusting the volume of water lost and releasing erythropoietin and renin
- regulating plasma concentrations of ions;
- helping stabilize blood pH: by controlling loss of hydrogen ions and bicarbonate ions in urine
- conserving nutrients
- assisting the liver in detoxifying poisons
What does the renal lobe of the kidny consist of?
- renal pyramid
- overlying area of renal cortex
- adjacent tissues of renal columns
What is the order that urine production goes in?
urine from renal papilla -> minor calyx -> major calyx -> renal pelvis -> ureter
Compare the anatomy of kidneys between domestic animals
- cattle do not have a distinct renal pelvis
- human, cattle, and pig have multipyramidal or multilobar kidneys
- cat, dog, and horse have unipyramidal or unilobar kidneys
How much cardiac output do kidneys receive?
20-25%
How many ml of blood flow per minute do kidneys receive in humans?
1200 ml
What are the nephrons of the kidney?
the collecting system and functional unit
What do nephrons consist of?
- renal corpuscle
- renal tubule
What are the parts of the renal tubule?
- proximal convoluted tubule (PCT)
- the Loop of Henle
- distal convoluted tubule (DCT)
Describe the renal corpuscle
spherical structure consisting of:
- Bowman’s capsule: forms the outer wall of the renal corpuscle and encapsulates the glomerular capillaries
- glomerulus: capillary network
Describe the parts of the Bowman’s capsule
- Parietal epithelium: a simple squamous epithelium, forms the outer wall. Continuous with visceral epithelium
- Visceral epithelium: covers glomerular capillaries
- Capsular space: separates the parietal and visceral epithelia
Describe the parts of the visceral epithelium
- consists of large cells (podocytes) with complex processes or “feet” (pedicels) that wrap around specialized lamina densa of glomerular capillaries
- Filtration slits: narrow gaps between adjacent pedicels
Describe the glomerulus
- consists of 50 intertwining capillaries
- are fenestrated capillaries
- blood delivered via afferent arteriole
- blood leaves in efferent arteriole: flows into peritubular capillaries which drain into small venules
Describe the proximal convoluted tubule (PCT) of the renal tubule
- first part nearest to Bowman’s capsule
- Loop of Henle which consists of:
a descending limb
a sharp turn
an ascending limb
each limb contains a thick segments and a thin segment
Describe the distal convoluted tubule (DCT) of the renal tubule
convoluted tubule beyond the Loop of Henle
Describe collecting ducts
recieve fluid from many nephrons
each collecting duct:
- begins in cortex
- descends into medulla
- carries fluid to papillary duct that drains into a minor calyx
What are cortical nephrons?
- 85% of all nephrons
- located mostly within cortex
- Loop of Henle is short
- peritubular capillaries surround entire renal tubule