Urinary Histology Flashcards
What is the kidney covered by?
The kidney is covered by a connective tissue capsule.
Are Pyramids located in the medulla or the cortex?
medulla
What is the apex of a pyramid called?
the renal papilla
What is a renal column?
The tissue between adjacent pyramids
What is a renal lobe?
is a medullary pyramid and the overlying cortex plus 1/2 of the renal columns on each side of pyramid
What are Calyces?
extensions of the renal pelvis
What does a minor calyx surround?
one renal papilla
What is a major calyx
A major calyx is the combination of two or more minor calyces
How do the kidneys enable continuous monitoring of the blood and ensure optimal properties of the blood?
- Remove waste from the blood and excrete it as urine
- Regulate electrolyte balance (Na+, H+, K+, and Ca2+)
- Regulate plasma volume & blood pressure
- Produce hormones
What hormones do the kidneys produce?
Erythropoietin, renin, and Converts vitamin D precursor to active form of vitamin D
What does erythropoietin do?
regulation of red-blood cell formation
What does renin do?
involved in control of blood pressure and
volume
What is the structural and functional unit in the kidney
The nephron
What does a nephron consist of?
a renal corpuscle and its tubule
What is a renal corpuscle?
the beginning of a nephron and site for filtering blood
Where does a nephron tubule originate? where does it end?
from renal corpuscles and ends at collecting duct
Collecting ducts are not part of nephron
What does a nephron do?
blood is filtered and urine is produced by the nephron
– Eliminates waste from the body
– regulates H2O concentration
– regulates blood volume and pressure – produce hormones
In humans, a normal kidney contains how many nephrons?
800,000 to 1,000,000 nephrons
What are the segments of a nephron tubule?
1) proximal thick segment
2) thin segment
3) distal thick segment
What are the segments of the proximal thick segment?
first the Prox. convoluted tubule (PCT), and then continuous with the Prox. straight tubule (PST)
Where are the renal corpuscle and the proximal convoluted tubule located in the nephron?
the cortex
Where is the proximal straight tubule located in the nephron?
in the outer stripe of the outer medulla
What segment comes after the proximal straight tubule? Where is it located in the nephron?
the thin segment, which extends from the inner stripe of the outer medulla and down into the inner medulla where it forms a loop back up to the edge of the inner medulla
What comes after the thin limb in the nephron tubule?
the Medullary thick ascending limb (MTAL) of the distal thick segment and then the cortical thick ascending limb (CTAL) that ends approximately at the edge of the medulla
What is the macula densa? Where is it?
an area of closely packed specialized cells lining the wall of the cortical thick ascending limb, at the transition to the distal convoluted tubule.
What does the macula densa do?
The cells of the macula densa are sensitive to the concentration of sodium chloride in the late thick ascending limb. A decrease in sodium chloride concentration initiates a signal from the macula densa that has two effects:
(1) it decreases resistance to blood flow in the afferent arterioles via vasodilation, which increases glomerular capillary hydrostatic pressure and helps return glomerulus filtration rate (GFR) toward normal, and (2) it increases renin release from the juxtaglomerular cells of the afferent and efferent arterioles, which are the major storage sites for renin.[1]
What are the components of the Loop of Henle?
PST, TL, & MTAL
What is next in the nephron tubule after the CTAL?
the distal convoluted tubule (DCT)
Where is the DCT?
in the cortex. The DCT connects to the connecting segment (CS), which connects to the cortical collecting duct
What are the parts of the proximal nephron tubule?
PCT to the macula densa
What are the parts of the distal nephron tubule?
distal to the macula densa. contains the DCT and the connecting segment (CS)
What do collecting ducts do?
conducts urine from nephron tubules to renal papillae
Are Collecting ducts are part of the nephron?
No. Many nephron tubules will contribute to a single collecting duct
What are the components of collecting ducts?
Cortical collecting duct (CCD)- ends at edge of cortex
Medullary collecting duct (MCD)
Where do the collecting ducts dump into the minor calyces?
in the ducts of Bellini in the apex of the renal papilla (in the ‘area cribrosa’)