control of blood glucose qp

Question 1

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describe how ultrafiltration works in the glomerulus

Answer 1

afferent atriole is much larger than efferent atriole meaning hydrostatic pressure is created pushing smaller substances such as minerals and water out of periable glomerilus capplieries into bowmans capsual

Question 2

-Scientists investigated the relationship between the thickness of the kidney
medulla of different species of mammals and the concentration of their
urine.
The graph shows their results.

Explain the pattern shown by the results in the graph above.

Answer 2

thicker medula means longer loop of henle
longer loop means increase in sodium ion conc
water potential gradient is maintained for longer meaning more water is reabsorbed

Question 3

Furosemide inhibits the absorption of sodium and chloride ions from the
filtrate produced in the nephrons.
Explain how furosemide causes an increase in the volume of urine
produced.

Answer 3

as sodium and chloride ions are not absorbed the watere potential of filtrate decreases as less water moves in via osmosis into the collecting duct

Question 4

Give the location of osmoreceptors in the body of a mammal.

Answer 4

thalamus in the brain

Question 5

When a person is dehydrated, the cell volume of an osmoreceptor
decreases.
Explain why.

Answer 5

becuase water moves out via osmosis and into the blood stream to signal to the brain that it is thirsty

Question 6

Stimulation of osmoreceptors can lead to secretion of the hormone ADH.
Describe and explain how the secretion of ADH affects urine produced by
the kidneys.

Answer 6

adh causes more water to be reabsorbed via osmosis backinto the blood stream from the collecting duct meaning that volume of urine is smaller and more concentrated.
also increases permiability of memebrane to allow faster rate of osmosis

Question 7

some people with diabetes do not secrete insulin.
explain how a lack of insulin affects reabsorbtion

Answer 7

• high conc of glucose in blood
• high conc of glucose in filtrate
• reabsorbed via active transport
• full saturation of carrier protiens
• glucose not fully absorbed

Question 8

describe how having a thicker medulla affects reabosrbtion

Answer 8

• longer loop of henele
• more sodium ions move out
• more water reabsorbed form descending loop via osmosis

Question 9

describe how urea is removed from the blood

Answer 9

• hydrostatic pressure generated
• forces urea out of blood into bowmans capsule

Question 10

explain how urea is concentrated in the filtrate

Answer 10

• reabsorbtion of water via osmosis
• due to active transport and faccilitated diffusion generationg water conc gradient
• occours at PCT

Question 11

explain why the urine of a non-diabetic person does not contain glucose

Answer 11

• leaves the blood at kindney
• is absorbed at PCT

Question 12

a high blood glucose conc could cause glucose to be present in the urine of a diabetic person suggest how

Answer 12

high conc of glucose in filtrate
too high saturation of glucose carriers

Question 13

expalin why individual with high glucose conc, produces larger volume of urine

Answer 13

• lowers WP
• lower WP gradient
• less osmosis