excretion

Question 1

Compare and contrast excretion and secretion

Answer 1

Excretion - harmful substance. (urea,co2,bile pigments)
Secretion - useful product (hormone enzymes)
both require ATP

Question 2

how are excess proteins turned into urea

Answer 2

converted into amino acids
undergo deamination - making ammonia
through the ornithine cycle makes urea

Question 3

what does the PCT reabsorb

Answer 3

All glucose and amino acids
some inorganic ions
water - based on bodies needs

Question 4

how is the PCT adapted for its function

Answer 4

Highly folded microvilli are present to increase surface area

Many co transporters - facilitated diffusion of sodium ions, larger glucose ions

Question 5

at what part of the nephron are the walls impermeable to water

Answer 5

Ascending limb

Question 6

How does the Loop of Henle produce urine

Answer 6

Lowers Ψ in order to make a Ψ gradient.
descending limb: water moves out as its permeable to water. ( ions aren’t permeable.)
ascending limb :active transport of ions out (impermeable to water.)
lower Ψ outside of collecting duct then inside so water moves in - making urine.

Question 7

explain the process of ultrafiltration

Answer 7

Afferent arteriole is wider then the efferent arteriole
high hydrostatic pressure is made
liquid is forced put through the fenestration’s in the endothelium.
Basement membrane stops large substances passing through
podocytes are finger like projections allowing for further filtering

Question 8

what are aquaporins

Answer 8

Aquaporins are channels in the cell surface membrane that allow water molecules to pass through

Question 9

Explain how the stick detects this pregnancy hormone.

Answer 9

hcg can pass into the filtrate int he bowman’s capsule
monoclonal antibodies on the stick are complimentary to the hcg
antibodies are attached to a dye which appear when you are pregnant

Question 10

Suggest why a high intake of protein in the diet will be likely to result in a high concentration of urea in urine.

Answer 10

many amino acids which cant be stored in the body , are converted into urea via deamination - making ammonia - then the orthine cycle produces urea . which is cannot be stored int he body for too long and is then excreted out from the body in the urine.

Question 11

Define excretion

Answer 11

removal of metabolic waste from the body

Question 12

Why do we have to remove waste products from the body

Answer 12

so waste products dont build up and inhibit enzyme activity
to maintain blood concentration substances

Question 13

Name 3 waste products

Answer 13

Co2
Nitrogenous compounds - urea
Bile pigments - broken down haemoglobin

Question 14

What’s the function of the Hepatic artery

Answer 14

oxygenated blood supplied to the hepathocytes

Question 15

What’s the function of the Central Vein

Answer 15

takes deoxygenated blood away from the liver

Question 16

What’s the function of the hepatic portal vein

Answer 16

takes deoxygenated blood from the digestive system

Question 17

What may the hepatic portal vein have

Answer 17

toxic compounds

Question 18

What’s the function of the sinusoid

Answer 18

Where blood from the hepatic artery and hepatic portal vein mix
this increases oxygen concentration

Question 19

What’s the function of the kupffer cells

Answer 19

act as macrophages - injest foreign materials

Question 20

What’s the function of the hepathocytes

Answer 20

secrete bile into the bile caniculi

Question 21

What’s the function of the bile caniculi

Answer 21

where bile is drained into and is transported into the gall bladder

Question 22

Outline 3 functions of the liver

Answer 22

1. store glycogen - when insulin levels rise
2. detoxification - enzymes break down harmful substrates
3. Forming urea

Question 23

How is urea formed in the liver

Answer 23

Amino acids deaminate and form ammonia and a keto acid . Amino group gets removed

Ammonia gets used in the ornithine cycle and gets converted into urea.
Keto acid is used in respiration