Histology of Renal Structures Flashcards
Organs of the Urinary system
- Kidneys
- Ureters
- Urinary bladder
- Urethra
Functions of Urinary System
- Regulates fluid balance (fluid volume) of the body
- Excretes organic waste products & conserve nutrients
- Stabilizes pH
- Regulates ion concentrations in the blood
- Endocrine functions: Erythropoietin, Renin, ACE, Vitamin D
The fictional unit of the kidney is…
The nephron
1-4 mi/kidney
Tubular passageways associated with blood vessels
Proximal Convoluted Tubule
Loop Of Henle
Distal Convoluted Tubule
Collecting Duct
Glomerulus is…
A specialized capillary bed attached to arterioles on both sides (maintains high pressure)
Arterioles attached to the glomerulus are:
- Large afferent arteriole
* Narrow efferent arteriole
Afferent arteriole function
Feeds glomerular capillary bed
Efferent arteriole function
Drains glomerular capillary
bed
Arterioles are high resistance vessels. True or false?
True
How do the attached arterioles aid the glomerulus?
- Afferent diameter is greater than efferent diameter, so blood pressure in glomerulus is extremely high
- The high BP forces fluids and solutes out of the blood and into the glomerular capsule that drains into the collecting tubule
Glomerular Filtration Assembly
- Capillary endothelium
- Basement
- Glomerular epithelium
Types of nephrons
2 - Cortical and Juxtamedullary
Cortical nephrons
(85% of all nephrons)
Shorter
Mostly in cortex of kidney, very small portion of LOH enters medulla
Produce “standard” urine.
Juxtamedullary nephrons
- 15%
- Located near corticomedullary junction
- Responsive to ADH
- Produce highly conc urine
Juxtamedullary nephrons can concentrate urine by…
… creating a gradient of hypertonicity in medullary interstitium
Types of cells in Parietal layer of Bowman’s capsule
Simple squamous
Types of epithelial cells in proximal convoluted tubule
Cuboidal or low columnar
The cell apex in PCT has abundant border microvilli. True or false?
True
The loop of Henle is made up of thin and thick ascending and descending limbs. True or false?
True
The think limbs in the loop of Henle are similar to…
…PCT. Cuboidal or low columnar
Types of epithelial cells in thin limbs of loop of Henle
Squamous
PCT or DCT, which is longer?
PCT
DCT & PCT both found in…
…the cortex, lined with simple cuboidal epithelium.
DCT cell features
- No brush border
- No apical canaliculi
- Smaller cells
- Elaborate basal membrane invaginations & associated mitochondria
DCT establishes contact with…
…vascular pole of renal corpuscle of its parent nephron
At what point are the PCT & afferent arteriole modified?
Where the DCT established contact with vascular pole of renal corpuscle of its parent nephron
Extraglomerular mesangial, Goormaghtigh, Lacis cells or Polkissen cells are…
Pericytes found outside the glomerulus, near the vascular pole.
Apart from endothelial cells & podocytes, glomerular
capillaries have…
…mesangial cells adhering to their walls
Which cells have receptors for angiotensin II?
Intraglomerular mesangial cells
Cell type responsible for…
- Production of cytokines & prostaglandins
- Synthesis of extra cellular matrix
Intraglomular mesangial cells have receptors for…
ANF - vasodilator; relaxing blood flow
Juxtaglomerular Apparatus =
Macula densa + Juxtaglomerular cells
Kidneys may sustain 90% loss of nephrons and still not show apparent symptoms. True or false?
True
Nephrolithiasis occurs when…
urine becomes too concentrated and substances crystalize. Stones begin to move down the ureter, causing pain.
There is a progressive decline in urinary function with age. True or false?
True, and the bladder shrinks with aging
Urinary retention is common in females, true or false?
False, males
Length or female urethra
5 cm long
Epithelium of female urethra
Stratified + areas of pseudostratified columnar
Epithelium of prostatic of male urethra
Transitional epithelium
Epithelium of membranous male urethra
Stratified/Pseudostratified columnar
Epithelium of cells and bulbous & pendulous urethra
Mostly pseudostratified columnar + stratified, squamous
Epithelium in the mucosa of the urinary bladder wall
Transitional epithelium: 5-6 cells thick in undistended; 3⁄4 in
stretched epithelium
Muscle fibres in the urinary bladder run…
…in every direction until the bladder neck is approached where 3 layers of smooth muscle are distinct
The walls are thick & folded in an empty bladder. True or false?
True
The walls of the ureters…
…become gradually thicker as the bladder is approached
Peristalsis aids gravity in urine transport. True or false?
True
Calyces, Renal pelvis, Ureter, bladder are lined by…
Transitional epithelium
