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Biology > Excretion - Module 5 > Flashcards

Excretion - Module 5 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

what is excretion

A

The removal of metabolic waste from the body.
e.g: carbon dioxide and urea

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2
Q

how is urea formed

A

Formed from the breakdown of amino acids

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3
Q

what is deamination

A

The amino group (-NH2) of an amino acid is removed, together with an extra hydrogen atom. These combine to form ammonia (NH3)
+organic acid

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4
Q

formula for dissociation of carbonic acid

A

H2CO3 -> H+ + HCO 3-

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5
Q

where is urea produced

A

the liver

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6
Q

ornithine cycle (simple)

A

Ammonia + Co2 -> urea + water

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7
Q

why is urea removed from body

A

Nitrogen in amino acids can’t be stored
nitrogen forms ammonia
ammonia is highly toxic
urea is less toxic

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8
Q

what are the 3 main kidney functions

A

-osmoregulation- maintaining water balance of the blood
-Excretion - removing waste products such as urea from the blood
-Maintaining correct balance of ions in t he blood

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9
Q

where does Ultra filtration take place

A

-between glomerulus and bowmans capsule

*first stage of making urine
remove small molecule from blood which enter nephron

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10
Q

what happens in the renal cortex

A

where blood is filtered
has dense capillary networks that carry blood/ connect renal artery to nephrons

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11
Q

what happens in renal pelvis

A

collects urine

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12
Q

renal medulla

A

contains tubules of nephrons which remove salt, urea, water from the blood

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13
Q

renal artery

A

takes “dirty” blood cotaining urea to kidney

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14
Q

renal vein

A

“clean” blood away from kidney

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15
Q

Ureter

A

take urine from kidney to bladder

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16
Q

What s the order of the nephron. From blood to ureter

A

1) Afferent arteriole
2) Glomerulus
3)Efferent arteriole
4) Bowman’s capsule
5) PCT (Proximal convoluted tube)
7)Loop of Henle
8) DCT ( Distal convoluted tubule)
9) Collecting duct
10) pelvis/ureter?

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17
Q

Afferent arteriole

A

arteriole that takes blood into the glomerulus

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18
Q

efferent arteriole

A

arteriole that takes the filtered blood away from the glomerulus

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19
Q

Glomerulus

A

tangle of capillaries surrounded by the Bowman’s capsule

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20
Q

DCT

A

Distal convoliuted tubule.
A second twisted tubule located in the cortex

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21
Q

PCT

A

Proximal convoluted tubule
the first, coiled region of the tubule after the bowmans capsule, found in the cortex

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22
Q

Collecting duct

A

urine passes down the collecting duct through the medulla to the pelvis

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23
Q

Loop of Henle

A

A long loop of tubule that runs down from the cortex through the medulla to a bend at the bottom of the loop. The ascending limb travels back up through the medulla to the cortex

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24
Q

describe and explain how the first barrier of ultrafiltration works

A

-Blood in the glomerulus is under high pressure because the afferent arteriole is wider than the efferent arteriole
-This forces liquid and small molecules in the blood out through the capillary wall.
- The fluid passes through the capillary Endothelium which has narrow gaps and acts like a sieve

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25
Q

describe and explain how the 2nd barrier of ultrafiltration works

A

-It then passes through the basement membrane which is made up of collagen fibres and other proteins and acts as a second sieve
-Proteins and blood cells cannot pass through the basement membrane so remain in the blood

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26
Q

describe and explain how the 3rd barrier of ultrafiltration works

A

-The fluid finally passes through the podocyte cells in the epithelium of the Bowman’s capsule

-The podocyte cells act as an additional filter to ensure that any large plasma proteins, platelets etc do not enter the tubule

-The filtrate that enters the bowmans capsule contains amino acids, water, glucose and urea

(small molecules pass the slit in epithelium between podocytes)

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27
Q

The filtrate that enters the bowmans capsule contains…

A

amino acids, water, glucose and urea

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28
Q

Endothelium

A

inside wall of blood vessels

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29
Q

epidermis

A

outside wall

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30
Q

what is the main function of the nephron

A

To return the useful filtered substances to the blood

31
Q

Facilitated diffusion

A

Diffusion of particles through carrier proteins or channel proteins in the plasma membrane. Does not require ATP
specific

32
Q

Process of selective reabsorption in the PCT

A

1) Na+ ion pumped out of cell walls of PCT.
Na+ ions move into blood plasma
2) Na+ ions from filtrate now diffuse by facilitated diffusion into cell wall of PCT
Proteins are Co-transported. Glucose + amino acids diffuse with Na+
3) Water potential of filtrate increases so water moves by osmosis into cells of the wall of the PCT
-some urea also diffuses back through the walls
4) All glucose, amino acids, and some urea are absorbed back into the blood

33
Q

Hepatic artery

A

Supplies liver with oxygenated blood

34
Q

Hepatic portal vein

A

Blood from small intestine

35
Q

5 roles or the liver

A

-controlling glucose levels
-secrete bile
-synthesise plasma proteins such as fibrinogen. Globulin, albumin…
-Transamination
-detoxification of substances such as hydrogen peroxin

36
Q

What happens in sinusoids

A

Blood from hepatic artery and portal vein mix in sinosoid

37
Q

Bile duct

A

Takes bile to gall bladder to be stored

38
Q

Why Hepatocytes arranged in thin blocks

A

Have good blood supply to get enough O2 and break down any harmful materials in the blood quickly

39
Q

Hepatocytes close contact to ___ which aids ____

A

Bile canaliculi

Diffusion

40
Q

Kupffer cells attach to walls of ____ to ____

A

Sinusoids

Remove bacteria and break down old RBCs

41
Q

Hepatic vein

A

Takes deoxygenated blood away from live

42
Q

Selective reabsorption in the PCT

A

1)Na+ ions pumped out of PCT.
Na+ ions move into blood plasma

2) Na+ ions from filtrate now diffuse by facilitated diffusion into cell.
Proteins are co-transport so glucose + amino diffuse with Na+

3) water potential of filtrate increases so water moves by osmosis into cells of the wall of the PCT . (from filtrate)
some urea also diffuses back through the walls

4)All glucose, amino acids and some urea are reabsorbed into the blood

42
Q

Selective reabsorption in the PCT Process

A

1)Na+ ions pumped out of PCT.
Na+ ions move into blood plasma

2) Na+ ions from filtrate now diffuse by facilitated diffusion into cell.
Proteins are co-transport so glucose + amino diffuse with Na+

3) water potential of filtrate increases so water moves by osmosis into cells of the wall of the PCT . (from filtrate)
some urea also diffuses back through the walls

4)All glucose, amino acids and some urea are reabsorbed into the blood

43
Q

selective reabsorption of water

where does it take place

describe concentration of tissue fluid coming into loop of henle

A

-take place in loop of Henle = section of tubule enabling mammals to produce urine more concentrated than own blood
-Filtrate reaching the top of the loop of Henle from the PCT is isotonic with tissue fluid surrounding tubule

44
Q

what is the mechanism behind the loop of henle called

A

the Countercurrent multiplier mechanism

45
Q

how does the the Countercurrent multiplier mechanism work?

A

1)Near top of ascending limb, Na+ and Cl- ions are actively transported into the medulla.
The ascending limb is impermeable to water, so water stays inside tubule. This creates a low WP inside medulla due to high conc. of ions

2) Because there’s a low water potential in the medulla than in the descending limb, water moves out of the descending limb into the medulla by osmosis. This makes the filtrate more concentrated (the ions can’t diffuse out- descending limb isn’t permeable to them). The water in the medulla is reabsorbed into the blood through the capillary network.
3) Near the bottom of the ascending limb, Na+ and Cl- ions diffuse out into the medulla, further lowering the water potential in the medulla
4) The first three stages massively increase the ion concentration in the medulla, which lowers the water potential. This causes water to move out of the collecting duct by osmosis. As before, the water in the medulla is reabsorbed into the blood via the capillary network.

(The volume of water reabsorbed from the collecting duct into the capillaries is controlled by changing the permeability of the collecting duct ADH)

46
Q

what is osmoregulation

A

The control of the water potential of the blood

47
Q

what happens to water potential of urine when you exercise

A

WP lowers

48
Q

ADH =

A

Anti Diuretic Hormone

49
Q

Process of ADH release

A

WP of blood is monitored by cells called osmoreceptors in the hypothalamus. When osmoreceptors are stimulated by a low water potential in the blood, the hypothalamus sends nerve impulses to the posterior pituitary gland to release a hormone called ADH into the blood

50
Q

Process of ADH effects

A

ADH molecules bind to receptors on the plasma membranes of cells of the DCT and collecting duct. Protein channels called aquaporins are inserted into the plasma membrane. These channels allow water to pass through via osmosis, making the walls of the DCT and Collecting Duct more permeable to water.
More water is reabsorbed from these tubules into the medulla and into the blood by osmosis.
A small amount of concentrated urine is produced, which means less water is lost from the body.

51
Q

what happens when a increase in water potential is detected by osmoreceptors in the hypothalamus?

A

Hypothalamus sends nerve impulses to the pituitary gland. Pituitary gland releases less ADH, walls of collecting duct become less permeable to water. Less water reabsorbed, larger volume of urine produced

52
Q

What can you expect to find in the urine of a diabetic ?

A

glucose

53
Q

What can you expect to find in the urine of someone with high blood pressure

A

abnormal protein

54
Q

is glucose found in a healthy persons urine/

A

no

55
Q

Summarise how pregnancy tests work

A

-Urine applied to stick
-If pregnant, hCG will be present in urine
hCG will bind to mobile monoclonal antibodies attached to coloured bead ( antibodies are complementary to hCG)
-Form hCG/antibody complex

-hCG/antibody complex is carried up test
hCG/antibody complex binds to line of immobilised antibodies- forms coloured line AT RESULT WINDOW

-Excess mobile antibodies bind to second line of immobilised antibodies- forms second coloured line to show test is working AT CONTROL WINDOW

56
Q

How is urine tested for testosterone

A

gas chromotography

-Urine sampel is vaporised and passed through a column containing a polymer.
-the different substances move at different speeds which seperates the substances in urine.
-A mass spectrometer then converts them into ions and separates them

  • results analysed by a computer
57
Q

GFR?
used to ..?

A

Glomerular filtration rate,
used to measure and to indicate kidney disease

58
Q

Haemodialysis description

A

In haemodialysis the patient’s blood is passed through a dialysis machine —
the blood flows on one side of a partially permeable membrane and dialysis
fluid flows on the other side. The blood and dialysis fluid flow
in opposite directions in order to maintain a steep concentration gradient
between the two fluids, to increase the rate of diffusion.

During haemodialysis, waste products and excess water and ions
diffuse across the membrane into the dialysis fluid, removing them from the
blood. Blood cells and larger molecules like proteins are prevented from
leaving the blood.

59
Q

peritoneal Dialysis description

A

Before a patient can have peritoneal dialysis for the first time, an operation
is needed to insert a tube that goes from outside the patient’s body into their
abdominal cavity (the space in the body where the intestines, stomach,
kidneys, etc. are found). The abdominal cavity is lined with a membrane
called the peritoneum. During peritoneal dialysis, dialysis fluid is put through
the tube into the abdominal cavity . The fluid remains in the
body while waste products from the patient’s blood diffuse out of capillaries
and across the peritoneum into the dialysis fluid. After several hours, there’s
an exchange — the fluid inside the body is drained out, and a fresh lot of
dialysis fluid is put in. This fluid is left there until the next exchange.

60
Q

Transplant description

A

A kidney transplant is where a new kidney is implanted into a patient’s body
to replace a damaged kidney. The new kidney has to be from a person with
the same blood and tissue type. They’re often donated from a living relative,
as people can survive with only one kidney. They can also come from other
people who’ve recently died — organ donors.

61
Q

Advantages of Haemodialysis

A

-Have dialysis free days
-keep alive until transplant
-Less risky than transplanmt
-no surgery

62
Q

Advantages of peritoneal Dialysis

A

-Can be done by patient at home
-Keep alive until transplant #
-Less risky than transplant

63
Q

Advantages of kidney transplant

A

-Cheaper than long term dialysis
-More convenient, don’t feel unwell between sessions

64
Q

Disadvantages of haemodialysis

A

-patients feel increasingly unwell between haemodialysis sessions = build up of waste
-Sessions = 3-5 hours , 2-3 sessionns a week, in hospital
-Expensive
-Inconvenient
-Must control diet = protein and starch

65
Q

Disavdantages of Peritoneal dialysis

A

-Risk of infection at the tube
-No dialysis free days
-4 exchanges daily or overnight

66
Q

Disadvantages of Peritoneal dialysis

A

-Risk of infection at the tube
-No dialysis free days
-4 exchanges daily or overnight

67
Q

Disadvantages of Transplants

A

-Risky, Major operation
-Immune system may reject transplant
-Must take immunosuppressants

68
Q

Explain how the structure of a liver lobule aid the functions of the liver. (4)

A

Blood from hepatic artery and hepatic portal vein mix
In sinusoid
Hepatocytes arranged in thin blocks
Every hepatocyte has a good blood supply to get enough oxygen and break down any harmful materials in the blood quickly
Hepatocytes close contact to bile canaliculi
Aids diffusion

69
Q

Detoxification of alcohol

in liver

A

Ethanol is converted to ethanal by ethanol dehydrogenase

Ethanal is converted to ethanoic acid ( also known as acetic acid) by ethanal dehydrogenase

Ethanoic acid dissociates to produce ethanoate and hydrogen ions

Ethanoate combines with coenzyme A to form acetyl coenzyme A

Acetyl coenzyme A involved in respiration as a source of energy

70
Q

Liver cirrhosis

A

The liver tissue is irreversibly damaged.
Hepatocytes dies and are replaced with fibrous tissue.
This means the hepatocytes can no longer divide and replace themselves so the liver shrinks.

71
Q

Monoclonal antibodies

A

antibodies from a clone of cells that are produced to be specific to a specific antigen/ chemical

72
Q

Cells in the proximal convoluted tubule have adaptations for reabsorption:

A

They are covered with microvilli increase S.A
They have many mitocohondria provide ATP for active transport

Biology (45 decks)

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