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Biology Module 5 > Excretion 5.2 > Flashcards

Excretion 5.2 Flashcards

1
Q

why is excretion important?

A

important in maintaining metabolism

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2
Q

what is excretion?

A

process by which excess toxic waste products of metabolism are removed from the body

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3
Q

give examples of excretory organs

A

lungs,kidney,liver and skin

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4
Q

what is metabolic waste made of?

A

carbon dioxide

nitrogenous waste

urea

water

salts

ammonia

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5
Q

mammals produce urea, fish and birds/insects produce..?

A

fish- ammonia

birds and insects- uric acid

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6
Q

what is bile pigments?

A

breakdown of haemoglobin from old red blood cells in the liver

they colour the faeces

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7
Q

what is urea made of?

A

undigested food and fibre

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8
Q

how does the skin act as an excretory organ?

A

sweat contains salts, urea, water, uric acid and ammonia

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9
Q

what happens if products of metabolism build up in the body?

A

build up of CO2 and NH3 is toxic

this can interfere by altering the pH or act as inhibitors and reduce the activity of enzymes

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10
Q

what is the role of the liver

A

breakdown of unwanted or toxic substances and the production of excretory waste,

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11
Q

what are hepatocytes?

A

liver cells

contains a nuclei, golgi apparatus, folded membrane and mitochondria

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12
Q

what is the difference between the hepatic artery and hepatic vein

A

hepatic a - receives oxygenated blood from the heart ( smaller than v bcs carries only 30% blood)

hepatic v - brings deoxygenated blood back to heart (bigger bcs carries 70%)

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13
Q

describe the internal structure of the liver

A

. hepatocytes
. lobes -> lobules (connective tissue)
. sinusoids ( wide capillaries)
. branch of hepatic vein ( drains blood away from lobule)
. kupffer cells
. bile caniculli

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14
Q

function of the bile caniculli?

A

where bile is produced and secreted

drains it into the bile duct which then brings it to the gall bladder to be stored

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15
Q

why might blood in the hepatic portal vein contain toxins

A

after digestion of alcohol, blood from the intestine contains toxins

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16
Q

what are the functions of liver

A

storage of glycogen

detoxification

formation of urea

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17
Q

explain the role of the liver in storing glycogen

A

hepatocytes are involved in converting glucose into glycogen

glycogen can be broken down to release glucose into the blood

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18
Q

explain how detoxification works on hydrogen peroxide (substance in the liver)

A

catalase breaks down hydrogen peroxide into oxygen and water (by-product)

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19
Q

what happens when too much alcohol is taken

A

cirrhosis

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20
Q

explain how detoxification works on alcohol

A

ethanol, broken down by hepatocytes into ethanal then to acetic acid which is less harmful

21
Q

what does NAD do

A

breakdown fatty acids used in respiration

22
Q

what happens if NAD is used up

A

breakdown of fatty acids is no longer possible

FA converted back to lipids

builds up in liver and can cause hepatitis or cirrhosis

23
Q

describe AA in the liver

A

excess amino acids cant be stored in the body as their amino group make them toxic

they cant also be excreted as a whole because theyre full of lots of energy

so, excreted via deamination

24
Q

what is deamination

A

removal of an amino group from the amino acid leaving ammonia

25
Q

describe ammonia in the liver

A

very toxic and insoluble , quickly converted in to urea which is less soluble and less toxic

26
Q

what are the products of deamination?

A

ammonia and keto acid

27
Q

function of kupffer cells

A

attached to the walls of the sinusoids, remove bacteria and break down old RBC​

28
Q

what is the function of the hepatic portal vein

A

brings products of digestion from small intestine to liver so that any harmful substances can be filtered out and destroyed before digestion

29
Q

what are the kidney tubules called

A

nephron

30
Q

what does the nephron consist of

A
  • bowman’s capsule
  • glomerulus
  • proximal and distal convoluted tubule
    -loop of henle
  • collecting duct
31
Q

what does the filter barrier consist of

A

endothelial and epithelial cells
basement membrane

32
Q

function of bowman’s capsule

A

contains the glomerulus and where ultrafiltration takes place

33
Q

function of glomerulus

A

knot of capillaries where pressure forces all the solutes in the blood plasma to the Bowman’s capsule

34
Q

function of endothelium cells of filter barrier

A

gaps, allow dissolved substances/ blood plasma to pass capillary

35
Q

function of basement membrane of filter barrier

A

prevents large molecules and proteins from entering

36
Q

function of epithelial cells of filter barrier

A

podocytes, gaps between cells to let blood pass through lumen of Bowman’s capsule

37
Q

what is ADH?

A

hormone

constricts blood vessles

helps the kidneys control the amount of water and salt in the body

38
Q

what is ultrafiltration

A

the process of filtration of blood from the glomerulus into the Bowman’s capsule because of increased glomerular blood pressure

39
Q

describe the process of ultrafiltration (6 marks)

A
  1. Blood flows into glomerulus through the afferent arteriole, that carries the blood away​
  2. The afferent arteriole is wider than the efferent arteriole ​
  3. The difference in diameter ensure that blood in the capillaries of glomerulus maintains a pressure higher than the Bowman’s capsule​
  4. This pressure difference pushes fluid from the blood into the Bowman’s capsule​
40
Q

what is filtered out of the blood
?

A

Water​

Amino acids​

Glucose ​

Urea​

Ions

41
Q

describe the process of selective reabsorption (6 marks)

A
  1. Na+ ions are pumped out of the cells actively
  2. conc. of Na+ ions in cytoplasm decreases creating a concentration gradient
  3. Na+ ions diffuse into cell through a cotransport protein - carrying glucose or an AA at the same time
  4. Water moves into cell by osmosis
  5. Glucose/AA diffuse into blood
42
Q

how are the cells needed in reabsorption specialised? (4 marks)

A

microvilli – increases surface area for reabsorption

Cytoplasm, lots of mitochondria to release ATP ​

43
Q

What is osmoregulation

A

the control of water potential in the blood​

44
Q

how does ADH change the water content of the blood when it is too low or high?

A

: Blood ADH levels rises when dehydrated​

water potential​drops

Detected by osmoreceptors in the hypothalamus ​

The posterior pituitary gland is stimulated to release ADH into the blood​

DCT walls and collecting duct walls are more permeable, so more water is reabsorbed into the blood by osmosis​

highly concentrated urine produced so less water lost​

: When blood ADH levels fall when hydrated, vice versa occurs​

45
Q

state 2 things that lead to kidney failure
(4 marks)

A

infections

high blood pressure

46
Q

describe what could happen to the body due to kidney failure
3 things

A

.Waste products to build up - weight loss and vomiting​

. Anemia

. Imbalance of electrolytes - brittle bones​

47
Q

what is renal dialysis?

A

when the patient’s blood is filtered

48
Q

what is a kidney transplant? ( 4 marks )

A

new kidney to replace damaged kidney.​

New kidney must have same blood and tissue type​

Y: cheaper than dialysis​

N: organ rejection

49
Q

what are steroids and what are the negatives?

A

Anabolic steroids are drugs that builds up muscle tissue​

Athletes are banned from taking these, as it is unfair and has dangerous side effects like liver damage

Biology Module 5 (7 decks)

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