renal system anatomy/histology

Question 1

What are the 3 constrictions of the ureter?

Answer 1

1. uretopelvic junction
2. pelvic inlet (over the iliacs)
3. entrance to bladder

Question 2

What muscle forms the wall of the bladder?

Answer 2

Detrusor muscle

Question 3

What is the trigone of the bladder?

Answer 3

The triangle shaped area between the openings of the two ureters and the urethra

Question 4

What are the changes in the epithelium of the urethra, from bladder to opening?

Answer 4

Transitional epithelium then columnar epithelium then stratified squamous epithelium.

Question 5

What parts of the nephron are found in the renal cortex?

Answer 5

The glomerulus, proximal tubule and distal tubule

Question 6

What parts of the nephron are found in the renal medulla?

Answer 6

The thick and thin limbs of both the ascending and descending Loop of Henle.
Collecting ducts are also found in this layer

Question 7

What is the renal corpuscle?

Answer 7

The blood-filtering component of the nephron - made up of the Glomerulus and Glomerular/Bowman’s capsule

Question 8

What is the juxtaglomerular apparatus?

Answer 8

The point of contact between the distal covoluted tubule and the afferent arteriole, which contains granular cells and the macula densa.

Question 9

What is the function of the JGA?

Answer 9

Maintains appropriate renal blood flow by secreting renin, which results in the production of the vasoconstrictor Ang II - this reduces flow to the glomerulus

Question 10

Where is the macula densa located?

Answer 10

In the terminal portion of the distal covoluted tubule

Question 11

What structures connect the afferent and efferent arterioles?

Answer 11

Glomerular capillaries

Question 12

Why does the afferent arteriole have a greater diameter than the efferent arteriole?

Answer 12

Maintains high pressure in the glomerulus, which creates the hydrostatic pressure required for effective filtration

Question 13

What feature of glomeruluar capillaries allows for effective filtration?

Answer 13

Fenestrated capillary endothelium

Question 14

What feature of Bowman’s Capsule allows for effective filtration?

Answer 14

Has podocytes that wrap around the glomerular capillaries. These podocytes have foot processes with filtration slits which prevent large proteins from being filtered.

Question 15

What are the 3 layers of the glomerular filtration barrier?

Answer 15

1. fenestrated capillary endothelium
2. glomerular basement membrane
3. Podocyte foot processes with filtration slits between

Question 16

What feature of the glomerular basement membrane allows for effective filtration?

Answer 16

Contains type IV collagen that forms a mesh that acts a physical extracellular filter. Also has a negative charge that repels large proteins

Question 17

What is the function of the macula densa?

Answer 17

Senses sodium levels in the distal nephron - if sodium levels are low will trigger juxtaglomerular cells to release renin, which will trigger RAAS activation and increase GFR and sodium reabsorption

Question 18

What type of epithelium lines the ureter?

Answer 18

Transitional epithelium

Question 19

What is transitional epithelium?

Answer 19

Epithelium specialised to the urinary system, that is designed for stretch and to maintain a protective barrier between urine and tissues

Question 20

What are the layers of transitional epithelium?

Answer 20

Layers of cells that are columnar/cuboidal at rest and squamous when stretched. Top layer is umbrella cells

Question 21

What are the parts of the nephron, from proximal to distal?

Answer 21

Afferent/efferent arterioles, glomerulus, proximal convoluted tubule, Loop of Henle (thick descending limb, thin descending limb, thin ascending limb, thick ascending limb),distal convoluted tubule, collecting duct

Question 22

What are the 3 main processes that occur in the nephron?

Answer 22

1. Filtration - creates plasma like filtrate
2. Reabsorption - removes useful solutes from filtrate and returns them to the blood
3. Secretion - adds additional wastes from the blood

Question 23

What is glomerular filtration?

Answer 23

Filtering water and small solutes from the blood, retaining blood cells and large proteins