Histo of renal system Flashcards
Kidney Structure (stillborn kidney)
The kidney of a stillborn child consists of distinct regions, including the cortex and medulla.
Papilla and Drainage
The papilla in the kidney projects towards the central pelvicalyceal space and eventually drains into the ureter, which exits the kidney at the hilum.
Cortex
The cortex is darker stained and contains numerous tiny spheroidal structures, which are the developing renal corpuscles.
Medulla
The medulla of the kidney is paler-stained in comparison to the cortex.
Medullary pyramids
The medullary pyramids within the kidney consist of several tubules that converge towards the tip of the renal papillae.
Fibrous Capsule and Renal Sinus
The fibrous capsule of the kidney is continuous with fatty tissue at the hilum, which packs into the renal sinus.
Functional unit of the kidney
The nephron is the fundamental functional unit of the kidneys, responsible for filtering and processing blood to form urine
Components of Nephron
A nephron consists of two main parts: the renal corpuscle, where the initial filtration of blood occurs, and the renal tubule, where the filtered fluid is further processed and carried away.
Renal Corpuscle
The renal corpuscle is the part of the nephron where the initial filtration of blood takes place, separating waste and excess substances from the bloodstream.
Renal tubule
The renal tubule is the portion of the nephron where the filtered fluid from the renal corpuscle is processed, and valuable substances are reabsorbed while additional waste products are secreted.
Components of renal corpuscle
The renal corpuscle consists of two main components: the glomerular capsule (Bowman’s capsule) and the glomerulus.
Explain the glomerular capsule
he glomerular capsule is a single layer of flattened cells resting on the basement membrane, derived from the distal blind end of the renal tubule.
Describe the glomerulus
The glomerulus is a network of anastomosing capillaries located within the renal corpuscle. It plays a crucial role in the filtration of blood.
Capillary loops and podocytes
The capillary loops of the glomerulus are invested in the visceral layer of the glomerular capsule, which contains highly specialized epithelial cells called podocytes.
Visceral and parietal layers of the glomerular capsule
the visceral layer of the glomerular capsule is reflected around the vascular stalk of the glomerulus to become continuous with the parietal layer.
Bowman’s space
A space exists between the two layers of the glomerular capsule, known as Bowman’s space, and it is continuous with the lumen of the renal tubule.
Glomerular filtration barrier
The glomerular filtration barrier is the filtration barrier between the capillary lumen and the space within the glomerular capsule. It consists of the capillary endothelium, the podocyte layer, and the common basement membrane (glomerular basement membrane).
Vascular and urinary poles
The afferent arteriole and efferent arteriole enter and exit the corpuscle at the vascular pole, which is situated opposite to the entrance of the renal tubule (urinary pole).
Renal tubule extends from___________________ and is lined by_______
The renal tubule extends from the glomerular capsule to the junction with the collecting duct and is lined by a single layer of epithelial cells.
Function of the renal tubule
The primary function of the renal tubule is the selective reabsorption of water and inorganic ions from the filtrate.
Zones of the renal tubule (4)
The renal tubule has four distinct zones:
Proximal convoluted tubule - the most convoluted section.
Nephron loop (Loop of Henle) - which dips into the medulla.
Distal convoluted tubule.
Collecting tubule.
Renal cortex is easily identified at low magnification due to__________________________.
It mainly consists of_________________.
The renal cortex is easily identified at low magnification due to the presence of renal corpuscles. It mainly consists of proximal and distal convoluted tubules.
Arcuate arteries and veins demarcate between what?
Arcuate arteries and veins serve as demarcation points between the renal cortex and medulla.
Glomeruli at high magnification
At higher magnification, glomeruli can be identified in the renal cortex, surrounded by the glomerular space. These are important for filtration.
The space between renal corpuscles is filled with…
The space between renal corpuscles is filled by tubules, including the proximal and distal convoluted tubules, involved in reabsorption and processing of filtrate.
Medullary ray
The medullary ray is composed of collecting tubules and is found in the medulla, contributing to the organization of the kidney’s structure.
mesangium and mesangial cells
The spaces between capillary loops in the glomerulus are filled by the mesangium, which contains mesangial cells. These cells play a role in supporting and regulating the capillaries.
Efferent arteriole
The efferent arteriole, which has a smaller diameter than the afferent arteriole, exits the glomerulus. It is important for regulating blood flow within the glomerulus.
Parietal layer of the glomerular capsule is continuous with_____________________
Proximal convoluted tubule
_____________________________ is found at the urinary pole
Proximal convoluted tubule
Transition of epithelial cells between the glomerular capsule and proximal convoluted tubule
The flattened nuclei of parietal epithelial cells line the glomerular capsule. This squamous epithelium is continuous with the epithelium at the entry to the proximal convoluted tubule and transforms into cuboidal epithelium in the subsequent part of the nephron.
Glomerular capillaries microscopically
Glomerular capillaries, which can sometimes contain erythrocytes, are defined by the prominent glomerular basement membrane (GBM). They play a key role in the filtration process within the nephron.
Mesangium and mesengial cells histologically
The mesangium, with a composition similar to the GBM, contains mesangial cells. These cells, which can be recognized by their nuclei. They resemble smooth muscle cells and play a crucial role in regulating capillary flow within the glomerulus.
Podocytes histologically
Podocytes invest the capillary loops exposed to the glomerular space. They have extensive pale-stained cytoplasm and large pale-stained nuclei, contributing to the formation of the filtration barrier in the glomerulus.
Proximal convoluted tubule description
Coiled tube, sections are found within the renal cortex, and they play a significant role in reabsorption and processing of the filtrate.
Tubular epithelium
The tubular epithelium consists of simple cuboidal epithelial cells with a brush border of tall microvilli. This brush border increases the surface area of the plasma membrane, enhancing absorption and reabsorption.
Surfaces of microvilli in PCT epithelium has…
The surfaces of the microvilli are coated with a prominent glycocalyx, which aids in various functions, including cell adhesion and protection.
PCT basement membrane and description of epithelium nuclei
The basement membrane supports the tubular epithelium. The epithelial cells have round nuclei with prominent nucleoli
Peritubular capillaries
A rich network of peritubular capillaries arises from the efferent arteriole of the glomerulus and surrounds the proximal tubules, facilitating the exchange of substances during reabsorption and secretion.
DCT
The DCT is a continuation of the thick ascending limb of the nephron loop after it returns to the cortex. It plays a role in further processing and regulation of the filtrate.
Macula densa
The first part of the DCT forms the macula densa, which is involved in sensing changes in solute concentration and plays a role in regulating renal blood flow and filtration.
The DCT has a brushborder just like the PCT (T/F)
F. Unlike the proximal tubules, the DCT does not have a brush border, which is a feature that increases surface area for reabsorption.
Lumen and nuclei of DCT
The DCT has a larger and more defined lumen, along with more nuclei per cross-section. The cytoplasm of DCT cells is paler in color due to the presence of fewer organelles compared to the proximal tubules.
