Week 9 lec

Question 1

Question: What are the key components of the renal corpuscle?

Answer 1

Answer:
Glomerulus: Capillary loops where filtration occurs.
Bowman’s capsule: Double-layered epithelial cup surrounding the glomerulus.
Urinary space: The true space between the glomerulus and Bowman’s capsule.

Question 2

Question: What are the two layers of Bowman’s capsule, and their characteristics?

Answer 2

Answer:
Parietal layer: Simple squamous epithelium, outer part.
Visceral layer: Contains podocytes, which cover the capillaries and form part of the filtration barrier.

Question 3

Question: What is the role of podocytes in the kidney?

Answer 3

Answer:
Podocytes form the visceral layer of Bowman’s capsule and are part of the glomerular filtration barrier. They have foot processes (pedicels) that wrap around capillaries, forming filtration slits to regulate filtration of blood.

Question 4

Question: What is the function of proximal and distal convoluted tubules in the kidney?

Answer 4

Answer:
Proximal convoluted tubule: Reabsorbs water, ions, and nutrients; secretes wastes.
Distal convoluted tubule: Regulates ion concentration and pH balance.

Question 5

Question: What role do arterioles play in kidney function?

Answer 5

Answer:
Afferent arteriole: Brings blood into the glomerulus for filtration.
Efferent arteriole: Carries filtered blood away from the glomerulus.

Question 6

Question: What are the major components of a nephron?

Answer 6

Answer:
Glomerulus: Filtration of blood.
Bowman’s capsule: Surrounds the glomerulus.
Proximal and distal convoluted tubules: Reabsorption and secretion.
Loop of Henle: Concentrates urine by reabsorbing water and salts.
Collecting duct: Collects urine from multiple nephrons, final water reabsorption.

Question 7

Question: What is the difference between the cortex and medulla of the kidney?

Answer 7

Answer:
Cortex: Contains renal corpuscles and convoluted tubules.
Medulla: Contains loops of Henle and collecting ducts.

Question 8

Question: Why is there very minimal connective tissue in the kidney?

Answer 8

Answer:
The kidney is highly specialized for filtration and reabsorption, leaving minimal space for connective tissue. Fibroblasts, collagen, and myofibroblasts are present but limited.

Question 9

Question: How does the histology of the proximal convoluted tubule (PCT) differ from the distal convoluted tubule (DCT)?

Answer 9

Answer:
PCT: Cuboidal cells with microvilli (brush border), for reabsorption.
DCT: Smaller cells, fewer microvilli, for selective ion transport.

Question 10

Question: What unique structures can be seen in an electron micrograph of a podocyte?

Answer 10

Answer:
Cytoplasmic processes: Wrap around capillaries.
Filtration slits: Spaces between foot processes where filtration occurs.

Question 11

Q: What are the key components visible in a transmission electron micrograph of a podocyte?

Answer 11

A: The components include:
Ur: Urinary space
Pn: Nucleus of podocyte
C: Capillary lumen
Pp: Pedicels (foot processes) of the podocyte
Filtration apparatus: Where filtration occurs between capillaries and the podocytes.

Question 12

Q: What are the two main functions of mesangial cells in the glomerulus?

Answer 12

A:
Contractile: Respond to vasoactive agents and modify glomerular blood flow.
Phagocytic: Remove immune complexes and cell debris, contributing to glomerular health.

Question 13

Q: What are the components of the filtration apparatus in the kidney?

Answer 13

A:
C: Glomerular capillaries (fenestrated endothelium)
BM: Glomerular basement membrane (very thick, ~350nm)
P: Visceral layer of Bowman’s capsule (Podocytes with foot processes, called pedicels)

Question 14

Q: What is the role of podocytes in the kidney?

Answer 14

A: Podocytes form the visceral layer of Bowman’s capsule. Their foot processes, called pedicels, wrap around capillaries and form part of the filtration barrier. They help prevent large molecules, such as proteins, from passing into the urinary space.

Question 15

Q: What structures make up the renal corpuscle?

Answer 15

A: The renal corpuscle consists of:
Glomerulus: Network of capillaries.
Bowman’s Capsule: Double-layered epithelial cup.
Urinary space: The space between Bowman’s capsule and the glomerulus.

Question 16

Q: What is the glomerular basement membrane (GBM) and its function?

Answer 16

A: The GBM is a thick (~350 nm) barrier between the capillaries and podocytes, essential in filtering blood, preventing large molecules from entering the urinary space.

Question 17

Q: What type of epithelium lines the proximal and distal convoluted tubules?

Answer 17

A: Both the proximal and distal convoluted tubules are lined by simple cuboidal epithelium.

Question 18

Q: What structures are found in the medullary ray of the kidney?

Answer 18

A: The medullary ray contains:
Loops of Henle
Collecting ducts Both are lined by simple cuboidal epithelium, with tubules running parallel to each other.

Question 19

Front: What are the key features of the proximal convoluted tubules?

Answer 19

Back:

Major site for reabsorption in the nephron.
Lined with cuboidal epithelial cells.
Microvilli increase surface area for absorption.
Basal striations (mitochondria) provide energy for transport.
Junctional complexes and plicae support lateral transport.

Question 20

Front: How does the distal convoluted tubule differ from the proximal convoluted tubule?

Answer 20

Back:

Shorter in length than proximal tubules.
Contains fewer and shorter microvilli.
Lacks prominent basal striations.
Reabsorption occurs but is more selective, primarily of ions.

Question 21

Front: What is the function of the Juxtaglomerular Apparatus?

Answer 21

Back:

Regulates blood pressure via renin-angiotensin-aldosterone system (RAS).
Macula densa cells sense Na+ concentration.
Juxtaglomerular cells in the afferent arteriole release renin to adjust GFR.

Question 22

Front: What are the two layers of Bowman’s Capsule?

Answer 22

Back:

Parietal Layer: Simple squamous epithelium, forms the outer layer.
Visceral Layer: Composed of podocytes that wrap around the glomerular capillaries.
Podocytes help form the filtration barrier.

Question 23

Front: What is the role of podocytes in the kidney?
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Answer 23

Back:

Part of the visceral layer of Bowman’s capsule.
Have foot processes (pedicels) that form filtration slits.
Filtration occurs through these slits, regulating what enters the urinary space.

Question 24

Front: What are the three components of the glomerular filtration apparatus?

Answer 24

Back:

Fenestrated Endothelium: Allows passage of small molecules.
Basement Membrane: Thick and negatively charged, restricting larger proteins.
Podocytes: Form slits for selective filtration based on size and charge.

Question 24

Front: What are the key features of the transitional epithelium?

Answer 24

Back:

Stratified epithelium that lines the bladder.
Stretches to accommodate bladder filling and relaxes when empty.
Dome-shaped cells at the surface when bladder is relaxed.

Question 25

Front: What is the function of mesangial cells?

Answer 25

Back:

Phagocytic role: Clears immune complexes and debris.
Contractile role: Responds to vasoactive agents and helps regulate blood flow through the glomerulus.