Excretion

Question 1

structure of liver

Answer 1

• hepatocytes are arranged in lobules

- central vein exit point of blood

Question 2

What blood vessels supply the liver with blood?

Answer 2

hepatic artery and hepatic portal vein

Question 3

How is bile drained from the liver?

Answer 3

canaliculus

Question 4

What happens at the sinusoid

Answer 4

Blood form hepatic artery and portal vein mix, hepatocytes use this mixture and carry out function

Question 5

What are the function of liver?

Answer 5

Control blood-glucose level
Bile, Cholesterol and plasma protein synthesis
Detoxification of Alcohol
Breakdown hormone
Destroy Red Blood Cells
Store vitamins, A D B12 Iron and glycogen

Question 6

What is detoxification?

Answer 6

Process of reactions that render toxins harmless

Question 7

Describe the detoxification of alcohol

Answer 7

ETHANOL —ethanol dehydrogenase—> ETHANAL —Ethanal dehydrogenase—> ethanoic acid —> acetyl coenzyme A

Question 8

What coenzyme is used in detoxification of alcohol

Answer 8

NAD is reduced (gain 2 hydrogen each step)

Question 9

What is the use of NAD

Answer 9

Break and oxidise fatty acids (excess alcohol intake means less NAD therefore fatty acids build up)
Accepts hydrogen from reaction as a coenzyme.

Question 10

What are the stages of Urea formation?

Answer 10

Deamination

Ornithine cycle

Question 11

What is formed during deamination?

Answer 11

keto acid

NH3 ammonia

Question 12

Describe the ornithine cycle, including the reactants and products.

Answer 12

NH3 + CO2 + O —> C + H2O
C + NH3 —> A + H2O
A+ H2O —> Urea + O

Question 13

How is kidney failure assessed?

Answer 13

Using Glomerular Filtration Rate
90-120 normal
<60 chronic kidney disease
<15 is kidney failure

Question 14

What are the causes of kidney failure?

Answer 14

Diabetes mellitus
Heart disease
Hypertension
Infection

Question 15

How is kidney failure treated?

Answer 15

Renal Dialysis

Kidney Transplant

Question 16

Explain how renal dialysis is used to treat kidney failure

Answer 16

• Blood passes through partially permeable dialysis membrane tube
• Tube goes into Dialyser
• Dialysis Fluid contains the right concentrations of substances for exchange

Question 17

How is kidney transplant used for kidney failure treatment

Answer 17

• New kidney attached to blood supply and bladder to replace the other
• using immunosuppressant drugs to prevent body attacking kidney

Question 18

Advantages of kidney transplant

Answer 18

No need for dialysis

improved quality of life ( better self image and better physically)

Question 19

What can urine be tested for?

Answer 19

Glucose
Alcohol
Drugs
Anabolic steroids
hCG

Question 20

How is a pregnancy test carried out?

Answer 20

• blue beads attached to antibodies
• human chroinic gonadotrophin (hCG) bind to antibody if present
• Antibodies move along a strip
• Antibodies with hCG will go to an area with fixed antibodies where it will bind to form a blue line
• Antibodies without will bind to a different line to show test worked

Question 21

How is test for anabolic steroids in urine done?

Answer 21

Using Gas Chromatography

Question 22

What is osmoregulation?

Answer 22

Control of water and salt levels in the body

Question 23

How does Antidiuretic Hormone work?

Answer 23

• ADH bind to receptor on cell
• controlled reactions occur to form vesicles with aquaporins (channel protein for water)
• vesicle merge with cell membrane next to collecting duct
• cell more permeable to water

Question 24

What are the three layers that make up the kidney?

Answer 24

Cortex
Medulla
Pelvis

Question 25

What is ultrafiltration?

Answer 25

Filtration of the blood at a molecular level.

Question 26

What substances is filtered out of blood by kidneys

Answer 26

``` Water Amino Acids Glucose Urea inorganic Ions ```

Question 27

What's left in capillaries after ultrafiltration?

Answer 27

Blood cells | Large Proteins

Question 28

What creates pressure in glomerulus?

Answer 28

Difference in lumen size between larger Afferent arteole compared to smaller lumen of Efferent arteole

Question 29

Direction of substances movement in the kidney system

Answer 29

Afferent - Glomerulus - Bowman's Capsule - Efferent - Proximal Convoluted Tubule - Loop if Henle - Distal Convoluted Tubule - Collecting Duct

Question 30

Difference between proximal and distal convoluted tubules

Answer 30

Proximal inner walls have cell with microvilli

Question 31

Kidney adaptations for Ultrafiltration

Answer 31

- Narrow gaps between cells in capillary endothelium - Basement membrane prevent large molecules from getting through - Podocytes with Major processes holds cells away from endothelium of capillary to maintain space between for fluids to go through.

Question 32

function of proximal convoluted tubule

Answer 32

Reabsorbs Glucose and Amino Acids

Question 33

What is the mechanism for reabsorbtion in PCT

Answer 33

- Na+ actively pumped to blood vessel - Na+ conc decrease - Na+ with Glucose and amino acids from PCT diffuse into cell via Cotransport proteins - Water potential decrease - Water move in - glucose and amino acid diffuse into blood

Question 34

Adaptations for cells lining PCT

Answer 34

- highly folded cell membranes (next to lumen and blood vessel) - contransport proteins - lots of mitochondria

Question 35

Mechanism in the loop of henle

Answer 35

- Na+ and Cl- ions actively pumped out of ascending limb - WP of medulla decreases - water move out of descending limb - Na+ and Cl- move into descending limb - bottom of loop of henle is permeable to ions - ions move out WP decrease - water move out of collecting duct

Question 36

What is the water potential in the medulla and why

Answer 36

- Low - ions are actively pumped out of ascending limb - ions diffuse into meddula at the bottom of ascending limb

Question 37

How is the water potential in renal medulla decreased?

Answer 37

The bottom of the ascending limb is permeable to Ions, so moves out into medulla. Na+ and Cl- pumped out of ascending limb

Question 38

Why does the medulla need a low water potential?

Answer 38

To reabsorb more water.

Question 39

What happens to the loop of Henle when a species of animal have low water accessibility? And why?

Answer 39

``` Longer loop of Henle. - longer loop = longer ascending limb = more ions pumped out =medulla water potential is much lower =more water reabsorbed ```

Question 40

What is haemodiialysis?

Answer 40

Blood passed through machine with dialysis fluid via a tube using countercurrent flow. Wastes move out of blood to dialysis fluid.

Question 41

Disadvantages of haemodialysis

Answer 41

Have regular visits to hospital | May take a while

Question 42

What is Peritoneal dialysis?

Answer 42

Tube implanted into abdomen Dialysis fluid fills the Peritoneum cavity ( the space outside of the organs in the stomach inside the peritoneum) Exchange occur between dialysis fluid.

Question 43

Disadvantages of Peritoneal dialysis

Answer 43

Equilibrium can be reached so need to be replaced often But can be done at work or at home so more portable, less regular visits.

Question 44

What hormone is detected for pregnancy tests?

Answer 44

hCG, human chorionic gonadotropin