Renal I

Question 1

What are the 4 functions of the kidneys?

Answer 1

1. Regulation of water, inorganic ion balance, and acid-base balance
2. Removal of metabolic waste products from the blood and their excretion in the urine
3. Removal of foreign chemicals from the blood and their excretion in urine
4. Production of hormones/enzymes

Question 2

What is the function of erythropoietin?

Answer 2

It is the hormone that controls erythrocyte production

Question 3

What is the function of renin?

Answer 3

It is the enzyme that controls the formation of angiotension and enfluences blood pressure and sodium balance

Question 4

What are the 3 main hormones/enzymes produced by the kidneys?

Answer 4

Erythropoeitin, renin, and 1,25-dihydroxyvitamin D

Question 5

Where are the kidneys located?

Answer 5

Behind the peritoneum of the abdominal cavity on either side of the vertebral column against the posterior abdominal wall.

Question 6

The kidneys are connected to the […] by the […]

Answer 6

The kidneys are connected to the bladder by the ureter

Question 7

Urine leaves the bladder via the […]

Answer 7

Urine leaves the bladder via the urethra

Question 8

How does the length of the urethra compare between males and female

Answer 8

Males have a longer urethra than females.

Question 9

Name the sequence of structures that blood passes through beginning when it arrives via the renal artery all the way to the glomerulus

Answer 9

Renal artery -> interlobar artery -> arcuate artery -> interlobular artery -> afferent arteriole -> glomerulus

Question 10

What is the functional unit of the kidney? How many are there in each kidney?

Answer 10

The nephron. There are about 1 million per kidney.

Question 11

Each nephron consists of what two components?

Answer 11

Renal corpuscle (glomerulus + Bowman’s capsule)
Tubule

Question 12

At what structure in the nephron does urine formation begin?

Answer 12

The glomerulus.

Question 13

What is the function of the collecting duct? What are the two parts of it

Answer 13

Its function is to merge the urine of that nephron with that of other surrounding nephrons. Its two sections are the cortical collecting duct and the medullary collecting duct.

Question 14

What are the three sections of Bowman’s capsule? Describe where they are located.

Answer 14

Paterial layer: outside layer
Bowman’s space: space between patietal layer and visceral layer
Viscerial layer/podocytes: inside layer that touches the glomerulus

Question 15

Where is the juxtaglomerular apparatus located and what is its function

Answer 15

It surrounds the afferent arteriole of the glomerulus. Its function is to secrete renin.

Question 16

Foot processes are found on what renal structure?

Answer 16

The glomerular capillary wall

Question 17

Describe the structure from bottom to top of the glomerular capillary wall.

Answer 17

Endothelial cells with fenestra
GBM
Visceral glomerular epithelial cells (podocytes)

Question 18

Describe the process by which substances get filtered at the glomerular capillary wall.

Answer 18

The filtrate first passes through the fenestrae (windows) of the endothelial cells, then the basement membrane, then through the filtration slides between the foot processes.

Question 19

The glomerulus structure is comprised of […]

Answer 19

The glomerulus structure is comprised of entangled capillary loops surrounded by Bowman’s capsule

Question 20

Beginning in the glomerulus, name the consecutive structures through which urine passes as it gets processed. For each structure, include whether it is situated in the renal cortex or medulla.

Answer 20

Glomerulus: cortex
Bowman’s capsule: cortex
Proximal convoluted tubule: cortex
Proximal straight tubule: cortex and medulla
Descending thin limb of Henle’s loop: medulla
Ascending thin limb of Henle’s loop: medulla
Ascending thick limb of Henle’s loop (macula densa at the end): medulla and cortex
Distal convoluted tubule: cortex
Cortical collecting duct: cortex
Medullary collecting duct: medulla

Question 21

The blood vessel surrounding the nephron tubule is called the […]

Answer 21

peritubular capillaries

Question 22

What part of the peributubular capillary is oxygenated vs deoxygenated?

Answer 22

It is oxygenated when it enters and leaves the glomerulus all the way until it reaches the descending limb of Henle’s loop in the medulla. The descending limb of the loop of Henle is surrounded by deoxygenated blood.

Question 23

What are the three processes of urine formation?

Answer 23

1. Glomerular filtration
2. Tubular secretion
3. Tubular reabsorption

Question 24

Describe the composition of glomerular filtrate, including what is and is not in it compared to the plasma.

Answer 24

Glomerular filtrate is cell-free and except for proteins, contains all the substances in plasma in virtually the same concentrations as in plasma.

Question 25

What is the difference between reabsorption and secretion?

Answer 25

Tubules -> peritubular capillaries = reabsorption
Peritubular capillaries -> tubules = secretion

Question 26

What is the formula for the amount of urine excreted?

Answer 26

Amount excreted = amount filtered + amount secreted - amount reabsorbed

Question 27

Give an example of a substance that gets completely eliminated in the urine.

Answer 27

Para-amino-hippurate (PAH)

Question 28

Explain how para-amino hippurate undergoes the 3 processes of urine formation.

Answer 28

1. Filtration: a small amount will filter into Bowman’s space but most will not.
2. Reabsorption: none
3. Secretion: everything in the capillary will be secreted into the tubule
   End result: 100% elimination

Question 29

Describe how water undergoes the 3 processes of urine formation.

Answer 29

1. Filtration: most does not get filtered into the tubule but a small amount does.
2. Reabsorption: most gets reabsorbed into the capillaries
3. Secretion: none is secreted
   End result: near 100% elimination

Question 30

Describe how sodium undergoes the 3 processes of urine formation.

Answer 30

1. Filtration: most does not get filtered into the tubule but a small amount does.
2. Reabsorption: most gets reabsorbed into the capillaries
3. Secretion: none is secreted
   End result: near 100% elimination

Question 31

Describe how glucose undergoes the 3 processes of urine formation.

Answer 31

1. Filtration: most does not get filtered into the tubule but a small amount does
2. Reabsorption: everything that was filtered gets reabsorbed
3. Secretion: none
   End result: 0% elimination (none ends up in urine)

Question 32

Where are the macula densal located?

Answer 32

At the end of the thick ascending limb of the loop of Henle, in the cortex.

Question 33

Urine leaves the tubule via the […]

Answer 33

Renal pelvis