The kidney

Question 1

How is urine produced?

Answer 1

Filtration of plasma which is then reabsorbed

Question 2

What are nephrons?

Answer 2

Basic functional unit of a kidney

Question 3

What do nephrons include?

Answer 3

Afferent and efferent arterioles

Question 4

What are afferent arterioles made from?

Answer 4

Small vessels

Question 5

What is the function of afferent arterioles?

Answer 5

One supplies each nephron to deliver blood to glomerular capillaries

Question 6

What are efferent arterioles made from?

Answer 6

Glomerular capillaries

Question 7

What is the function of efferent arterioles?

Answer 7

Carry unfiltered blood to tubules and supply renal tissue with blood

Question 8

What are tubular components?

Answer 8

Hollow tubes formed by epithelial cells

Question 9

What are Bowman’s capsule, loop of Henle and distal and proximal tubules?

Answer 9

Tubular components

Question 10

Function of Bowman’s capsule

Answer 10

Collects fluid around glomerulus

Question 11

Function of proximal tubule

Answer 11

Reabsorbs sugar, amino acids, water, urea and chlorine

Question 12

Function of loop of Henle

Answer 12

Establishes osmotic gradient for urine and reabsorbs chlorine

Question 13

Function of distal tubule

Answer 13

Empties into collecting duct under hormonal control

Question 14

What are glomerular filtration, tubular reabsorption and tubular secretion?

Answer 14

Renal processes

Question 15

What is glomerular filtration?

Answer 15

Removal of 15-25% of water and solutes from the blood

Question 16

What does glomerular filtration rate depend on?

Answer 16

Hydrostatic and osmotic pressure of blood plasma and permeability of membranes

Question 17

What is the function of the glomerular membrane?

Answer 17

Retains blood cells and plasma proteins but permits water and small molecules

Question 18

What is renal clearance?

Answer 18

Various substances are removed from plasma and excreted in urine

Question 19

If plasma clearance < glomerular filtration rate what has occurred?

Answer 19

Substance has been reabsorbed

Question 20

What is the clearance rate of glucose and urea?

Answer 20

0ml and 62.5ml

Question 21

If plasma clearance = glomerular filtration rate…

Answer 21

Substance is not reabsorbed

Question 22

What is the clearance rate of inulin?

Answer 22

125ml/min

Question 23

If a substance is secreted and not reabsorbed then…

Answer 23

Clearance rate > glomerular filtration rate

Question 24

How do you measure renal plasma flow?

Answer 24

PAH (acid)

Question 25

What is glomerular filtration rate driven by?

Answer 25

Arterial blood pressure

Question 26

What mechanisms cause auto regulation?

Answer 26

Myogenic, tubuloglomercular feedback and neural mechanisms

Question 27

What is tubular reabsorption?

Answer 27

Recovery of useful products filtered out during glomerular filtration

Question 28

What must occur to a substance before epithelial transport?

Answer 28

Cross the luminal membrane of tubule cell Pass through cytosol and cross basolateral membrane to interstitial fluid Diffuse through interstitial fluid and penetrate capillary wall to blood plasma

Question 29

What is the only tubular component not involved in sodium reabsorption?

Answer 29

Bowman's capsule

Question 30

When is glucose reabsorbed?

Answer 30

When it has been filtered by the glomerulus

Question 31

Do the kidneys regulate blood plasma?

Answer 31

No, unless diabetic

Question 32

Where does phosphate reabsorption occur?

Answer 32

Tubules

Question 33

Where is excess phosphate excreted?

Answer 33

Urine

Question 34

What does the proximal convoluted tubule remove?

Answer 34

75% sodium and water to the loop of Henle

Question 35

What is the loop of Henle made up of?

Answer 35

Descending, thin ascending and thick ascending limb

Question 36

What is the descending limb's permeability?

Answer 36

Highly permeable to water but impermeable to salts

Question 37

What is the permeability of the thin ascending limb?

Answer 37

Permeable to sodium and chlorine ions but low permeability to water

Question 38

What is the permeability of the thick ascending limb?

Answer 38

Low permeability of water but active transport of sodium and chlorine

Question 39

What is the role of the distal convoluted tubule?

Answer 39

Transport of potassium, hydrogen and NH3 into lumen but sodium chlorine and HCO3 out of lumen

Question 40

What is the role of the collecting duct?

Answer 40

Reabsorbs NaCl by active transport

Question 41

What is the permeability of the collecting duct?

Answer 41

Permeable to water and urea

Question 42

How does urea contribute to urine?

Answer 42

Urea is impermeable in early collecting tubule but becomes more concentrated as it passes to medulla