Lecture #14 - Urinary System Flashcards
The Kidney
Describe the kidney (color, location)
What is located on the kidneys convex surface where vessels, ureters, and nerves enter/exit?
- red/brown color
- located retroperitoneally (behind peritoneum), lateral to T12-L3 vertebrae
- hilum
The Kidney
What are the functions of the kidney?
MFS
- maintain chemical consistency of blood
- filters fluid from blood
- sends toxins, metabolic wastes, and excess water out of body
-> main waste produces: urea, uric acid (+ammonia), creatine
External Anatomy of Kidneys
What are the different types of capsules located external to the kidney?
Describe these capsules that are located external to the kidney.
- fibrous capsule: dense CT surrounding the kidney; inhibits spread of infection
- perirenal fat capsule: external to renal capsule
- renal fascia: external to perirenal fat capsule; contains pararenal fat
Internal Anatomy of Kidneys
Name the major internal sections of the kidney.
Describe these internal sections of the kidney
- renal cortex: superficial region; granular appearance
- renal medulla: consists of cone-shaped renal pyramids
- renal pelvis: contains major and minor calyx
What is the functional unit of the kidney and each kidney contains more than 1 million of these.
nephron
Mechanisms of Urine Production
Name the different mechanisms of urine production.
Define the different mechanisms of urine production.
FRS
- filtration: filtrate of blood leaves kidney capillaries
- resorption: most nutrients, water, and essential ions reclaimed
- secretion: active process of removing undesirable molecules
Nephron - Structure
What is the nephron mainly composed of?
Which nephron structure is the first part of the nephron?
- renal tubule
- renal corpuscle - first part of nephron
Nephron - Structure - Renal Corpuscle
What structures are found in the renal corpuscle?
Describe these structures.
- glomerulus: cluster of capillaries; are fenestrated (have openings that make it permeable)
- glomerular capsule: parietal layer: simple squamous epithelium; visceral layer: consists of podocytes (help filter out blood)
Nephron - Filtration membrane - Renal Corpuscle
What is the filtration membrane?
What are the three layers of the filtration membrane?
What are the functions of the filtration membrane?
- filter that lies between blood in glomerulus and capsular space
- fenestrated endothelium of capillary
- filtration slits (between food process of podocytes)
- basement membrane
- holds back most proteins
- allow passage of water, ions, glucose, amino acids, urea
Nephron - Renal Tubule
Name the order in while filtrate processes to renal tubules from the glomerulus.
What does the collecting duct do?
- proximal convoluted tubule -> nephron loop (descending, ascending limb) -> distal convoluted tubule -> collecting duct
- collecting duct:
-> receives urine from several nephrons
-> conserves body fluid
-> (secretes antidiuretic hormone (ADH) which increases permeability of collecting ducts and distal convoluted tubule)
Classes of Nephron
What are the different classes of nephrons?
Describe the different classes of nephrons.
- cortical nephrons: 85% of nephrons; make dilute urine; contains peritubular capillaries
- juxtamedullary nephrons: 15% of nephrons; concentrate urine; contain vasa recta
Blood Vessels Associated with Nephrons
What are the different types of blood vessels associated with nephrons?
Describe these blood vessels associated with the nephron.
- glomeruli: produce filtrate that becomes urine; fed and drained by arterioles (afferent+efferent); generate 1 liter of fluid every 8 minutes
- peritubular capillaries: low pressure, porous; adapted for absorption; secretes molecules into urine
- vasa recta: thin-walled looping vessels (descend into medulla); part of kidneys urine concentrating mechanism
Juxtaglomerular Complex
What is the function of the juxtaglomerular complex?
What things make up the juxtaglomerular complex? Describe them
- regulates blood pressure
- macula densa: tall, closely paced epithelial cells located at the end of nephron loop; monitor sodium concentration in the filtrate; signal granular cells to secrete renin
- granular cells: modified smooth muscle cells with secretor granules; contain hormone renin
-> renin is secreted in response to falling blood pressure in afferent arteriole; leads to increased water absorption and increased blood pressure
Ureter
What is the function of the ureter?
Describe the histology of ureter
- carries urine from kidneys to urinary bladder
- oblique entry into bladder prevents backflow of urine
- mucosa: transitional epithelium
Urinary Bladder
Describe the urinary bladder.
What is the function of the urinary bladder?
Describe the difference of the urinary bladder when it is full vs. empty
- collapsible, muscular sac
- stores and expels urine
- full bladder: spherical; expands into abdominal cavity
- empty bladder: lies entirely in pelvis