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What is the main function of the kidney?
What is the main function of the kidney?
What is the structural and functional unit of the kidney?
What is the structural and functional unit of the kidney?
What is formed by the expansion of the proximal end of each nephron?
What is formed by the expansion of the proximal end of each nephron?
What is the function of the podocytes?
What is the function of the podocytes?
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What is the name of the space between the capillary lobules?
What is the name of the space between the capillary lobules?
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What is the term for the narrow spaces or filtration slits between the pedicles of adjacent podocytes?
What is the term for the narrow spaces or filtration slits between the pedicles of adjacent podocytes?
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What is the function of the renal corpuscle?
What is the function of the renal corpuscle?
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What is the first component of the barrier?
What is the first component of the barrier?
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What is the characteristic of the cytoplasm in the proximal convoluted tubules?
What is the characteristic of the cytoplasm in the proximal convoluted tubules?
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What is the name of the double-walled cup that surrounds the glomerulus?
What is the name of the double-walled cup that surrounds the glomerulus?
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What is the characteristic of the cells in the distal convoluted tubules?
What is the characteristic of the cells in the distal convoluted tubules?
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What is the function of the juxtaglomerular apparatus?
What is the function of the juxtaglomerular apparatus?
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What type of cells are found in the afferent arteriole?
What type of cells are found in the afferent arteriole?
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What is the characteristic of the macula densa cells?
What is the characteristic of the macula densa cells?
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What is the function of the extra glomerular mesangial cells?
What is the function of the extra glomerular mesangial cells?
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What is the characteristic of the basement membrane in the distal convoluted tubules?
What is the characteristic of the basement membrane in the distal convoluted tubules?
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Study Notes
Kidney Functions
- The kidney has four main functions: regulation of total body water, maintenance of extracellular fluid, excretion of waste products of metabolism, and regulation of blood pressure.
Kidney Structure
- The kidney consists of an outer dark-stained cortex and an inner pale medulla.
- The structural and functional unit of the kidney is the nephron.
Nephron Structure
- Each nephron consists of:
- Bowman's capsule
- Proximal convoluted tubule
- Loop of Henle (with descending and ascending segments)
- Distal convoluted tubule
Renal Corpuscles
- The proximal end of each nephron is expanded to form Bowman's capsule, which is indented by a globular tuft of capillaries called the glomerulus.
- Each renal corpuscle has two poles: a vascular pole and a urinary pole.
Bowman's Capsule
- Bowman's capsule is a double-walled cup formed of parietal and visceral layers, separated by Bowman's space.
- The parietal layer is lined by a single layer of squamous epithelium.
- The visceral layer dips inward between capillary lobules and is lined by podocytes.
Podocytes
- Podocytes are stellate in shape and give many primary and secondary processes (foot processes or pedicles).
- The pedicles make intimate contact with the basement membrane of blood capillaries, with narrow spaces or filtration slits (25 nm) between them.
Filtration Barrier
- The filtration barrier consists of:
- Fenestrated endothelium
- Basement membrane
- Filtration slit membrane
- This barrier is present between the blood circulating in capillaries and the filtrate in the capsular spaces.
Proximal Convoluted Tubules (PCT) vs. Distal Convoluted Tubules (DCT)
- PCT:
- Lined with simple cuboidal epithelium
- Has brush borders
- Cytoplasm is granular and deeply acidophilic
- Basal part of cytoplasm shows vertical acidophilic striations
- Cell borders are ill-defined
- Only 3-5 nuclei appear in a cross-section
- DCT:
- Lined with shorter cuboidal cells
- No brush border
- Less granular and less acidophilic cytoplasm
- Less basal striations
- Cell borders are more distinguishable
- 5-8 nuclei appear in a cross-section
Juxtaglomerular Apparatus
- Modifications in the wall of the afferent arteriole and in the portion of the distal convoluted tubule that lies in contact with the renal corpuscle.
- Components:
- Epitheloid cells (Juxtaglomerular cells) in the afferent arteriole
- Macula densa cells in the distal convoluted tubule
- Extra-glomerular mesangial cells
- Function: controls blood pressure
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Description
This quiz covers the functions of the kidney, including regulation of total body water, maintenance of extracellular fluid, and excretion of waste products. It also explores the structure of the kidney, including the cortex and medulla.
