Renal Anatomy and Histo Flashcards
Blood flow through kidney
Aorta Renal a. Segmental a. Interlobar a. Arcuate a. Cortical radiate a. Afferent arteriole Glomerulus Efferent arteriole Peritubular capillary Vasa recta Cortical radiate v. Arcuate v. Interlobar v. Segmental v. Renal v. IVC
[afferent arteriole thru vasa recta are nephron-associated]
2 major components of a nephron
Glomerulus
Renal tubule
2 major components of renal corpuscle
Glomerulus Glomerular capsule (Bowman's)
3 layers of glomerular capsule and associated histo
Parietal layer - simple squamous epithelium
Visceral layer - podocytes
Glomerular space - contains primary filtrate
What are the 2 poles of the renal corpuscle?
Vascular pole = associated with afferent and efferent arterioles
Urinary pole = origin of PCT
Renal corpuscles are only found in the _____ of the kidney
Cortex
Bowman’s capsule is continuous with the first portion of the _____
Nephron
______ = single layer of cells having pedicles that interdigitate and make filtration like barrier; filtration slits have ultrathin _______ made of several EC protein molecules critical in regulating filtration
Podocytes; diaphragm
________ cells are phagocytic, and also have the ability to regulate GFR by preventing glomerular distension (contractile properties)
Mesangial
Albuminia is characterized by albumin in the urine. It indicates damage to which of the following:
A. Filtration barrier
B. Glomerular basement membrane
C. Podocytes
D. Nephrons
B. Glomerular basement membrane
What is the most abundant kidney tubule and is found only in the renal cortex
PCT
Describe epithelium of PCT
Simple cuboidal to columnar epithelium with abundant microvilli (brush border)
Basal and lateral cell membranes are highly folded to increase surface area
What differentiates PST from PCT
PST is not as tall as PCT with less well developed brush border. PST is equipped with high affinity sodium glucose transporter
[PCT has abundant mitochondria, most active in resorption and secretion, has Na/K pumps, aquaporins, numerous types of glucose and amino acid transporters]
Describe epithelium of the LOH
Thin limb = thin, permeable simple squamous epithelial wall lacking brush border, some nuclei bulge into lumen
Thick ascending segment = simple cuboidal epithelium with numerous microvillia but no visible brush border
The loop of henle sets up the _______ gradient
Hyperosmotic
The DCT is confined to the ______
Cortex
Describe epithelium of DCT
Lined with simple cuboidal epithlium with sparse microvilli
Luminal surface is smoother than the PCT and fewer in number. Cells are taller than the thick ascending LOH
________ influences Na+ resorption at the DCT
Angiotensin II
Describe epithelium of collecting ducts
Lined with simple cuboidal epithelium but are simple columnar at their ends
What are the 2 individual cell types of the collecting duct epithelium
Light cells = principal cells (target of aldosterone)
Dark cells = intercalated cells (H+ and bicarb transport)
What is the primary target of aldosterone in the kidney
Principal cells (light cells) of the collecting duct
Function of juxtaglomerular granular cells
Mechanosensory, secrete renin if BP is low
Location and Function of macula densa
Distal end of thick ascending LOH; acts as chemoreceptor by monitoring salt levels; signals release of renin from JG granular cells if Na+ is low
Describe epithelium lining of most of the urinary tract, including its 3 layers
Transitional epithelium = urothelium
Layers:
Superficial (stretched and relaxed)
Intermediate (sliding layer)
Basal (stem cells)
Fusiform vesicles (fuse with PM when cell is distended, endocytosed when not distended)
Urothelial plaques (form impermeable barrier)
Describe histology of ureters
Transitional epithelium with 3 indistinct muscularis layers:
Inner longitudinal
Outer circular
Outer longitudinal
Adventitia = typical CT
Describe epithelium of urethra
Changes with location:
Transitional epithelium - possible near origin of urethra at bladder
Majority of urethra is pseudostratified columnar
Distal end is stratified squamous
3 named regions of male urethra
Prostatic urethra - passes through prostate gland
Membranous urethra - through the urogenital diaphragm; homologous to that found in the female
Spongy (penile) urethra - passes through the length of the penis; longest part encased in cylindrical erectile tissue (corpus spongiosum) in the penis to reach external urethral orifice
