excretory system Flashcards

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1
Q

what is excretion

A

removal of the waste product of metabolism, and substances in excess of requirements from the body.

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2
Q

why must carbon dioxide be excreted

A

Carbon dioxide must be excreted as it dissolves in water easily to form an acidic solution which can lower the pH of cells. which reduces activity of enzymes

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3
Q

what is the process of breaking down excess amino acids called

A

deanimation

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4
Q

how does the liver split up the amino acid

A

carbon is turned into glycogen
nitrogen is turned into ammonia (highly toxic) so converted to urea which is less toxic

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5
Q

where does the urea go

A

The urea dissolves in the blood and is taken to the kidney to be excreted
A small amount is also excreted in sweat

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6
Q

what do the lungs excrete

A

carbon dioxide

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7
Q

what is the main blood vessel that brings blood into the kidneys

A

renal artery

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8
Q

what is the main blood vessel that brings blood out of the kidney

A

renal vein

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9
Q

what carries urine from the kidney to the bladder

A

ureter

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10
Q

what are the waste substances that need to be removed from the blood

A

creatinine
urea
excess hormones
excess water
ammonia
uric acid
salts

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11
Q

in the kidney which structures help transport glucose

A

artery, vein

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12
Q

summarise the livers main 4 roles

A

assimilation of amino acids to form proteins
break down of the nitrogen containing parts of excess amino acids
forms urea which is excreted by the kidneys
breakdown of red blood cells

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13
Q

what is urine

A

mineral salts and urea dissolved in water

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14
Q

what is the urine pathway

A

Liver (urea) –> kidney –> ureter (urine) –> bladder –> urethera

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15
Q

temperature and exercise affect on volume and concentration of urine

A

temperature and exercise increase leads to increased dehydration and hence less volume and more concentrated urine as water content will be less.

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16
Q

high hydration means…

A

more volume and less concentrated urine

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17
Q

how does temperature and exercise increase dehydration

A

as temperature and exercise increase, more sweat is released causing the body to lose water and salts through sweat

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18
Q

what are the kidney’s function in the body

A

regulate the water content in the blood (vital for maintaining blood pressure)
excrete toxic waste products of metabolism

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19
Q

what is a nehpron

A

nephron acts as a filterate in the kidney and is the functional unit of the kidney

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20
Q

where is glucose reabsorbed in the nephron

A

proximal convuluted tube

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21
Q

where is urea reabsorbed in the nephron

A

not absorbed, excreted through urine

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22
Q

where are salts reabsorbed in the nephron

A

loop of henle

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23
Q

where is water reabsorbed

A

loop of henle
collecting duct

24
Q

why does ultrafiltration take place

A

capilaries get narrower as they go further into the glomerulus which increases the pressure of the blood in the vessels
this causes the smaller molecules in the blood to be forced out of the capilaries and into the bowmans capsule

25
Q

how is glucose reabosrbed

A

through active transport in the proximal convuluted tube

26
Q

how are salts reabsorbed

A

through diffusion in the loop of henle

27
Q

how is water reabsorbed

A

through osmosis in the distal convuluted tube

28
Q

where is urine formed

A

in the collecting duct

29
Q

how is the nephron adapted to its function

A

the nephron reabsorbs glucose through active transport, has many mitochondria to provide energy for the glucose moleucules to move against the concentration gradient

30
Q

in a normal patient which structures transports glucose

A

renal artery
renal vein

31
Q

if both kidneys are damaged what are the consequences

A

build-up of toxic wastes in the body which will be fatal if not removed

32
Q

what happens if no treatment is done for both kidneys being damaged

A

toxins such as urea build up and salt and water balance is upset
causing death

33
Q

what is kidney dialysis

A

artificial machines carry out the functions of the kidney outside the body

34
Q

what is kidney transplant

A

one healthy kidney from a willing donor will replace the 2 diseased kidneys

35
Q

how do kidney dialysis machines work

A

Patients are connected to a dialysis machine which acts as an artificial kidney to remove most of the urea and restore/maintain the water and salt balance of the blood

dialysis fluid contains same conc of salts, water and glucose, hence only excess or some of the salts/water/glucose is filtered out. no urea conc so all urea diffuses out

36
Q

how is blood transported in a kidney dialysis machine

A

Unfiltered blood is taken from an artery in the arm, pumped into the dialysis machine and then returned to a vein in the arm

37
Q

how does the dialysis machine work inside the machine

A

Inside the machine the blood and dialysis fluid are separated by a partially permeable membrane
- the blood flows in the opposite direction to dialysis fluid, allowing exchange to occur between the two where a concentration gradient existsw

38
Q

what is dialysis fluid made up of

A

Dialysis fluid contains:
-a glucose concentration similar to a normal level in blood
-a concentration of salts similar to a normal level in blood
-no urea

39
Q

how does the dialysis glucose concentration and the human body’s blood glucose concentration interact with eachother

A

As the dialysis fluid contains a glucose concentration equal to a normal blood sugar level, this prevents the net movement of glucose across the membrane as no concentration gradient exists

40
Q

how does the dialysis urea conc and the urea conc in the blood interact with eachother

A

As the dialysis fluid has no urea in it, there is a large concentration gradient - meaning that urea diffuses across the partially permeable membrane, from the blood to the dialysis fluid.

41
Q

how does the dialysis salt conc and the blood salt conc interact with each other

A

As the dialysis fluid contains a salt concentration similar to the ideal blood concentration, movement of salts across the membrane only occurs where there is an imbalance (if the blood is too low in salts, they will diffuse into the blood; if the blood is too high in salts, they will diffuse out of the blood)

42
Q

what is an additive of the dialysis solution

A

An anticoagulant is added to blood before it runs through the machine to prevent the blood from clotting and slowing the flow

43
Q

what happens to urine after exiting the collecting chamber

A

goes into ureter through peristalsis then stored in bladder then excreted through unrinary system

44
Q

describe the functions of the liver in excretion

A

deamination
excess amino acids, converted to ammonia which is then quickly converted to urea as ammonia is highly toxic

45
Q

1 adv and 1 disadv of kidney transplant compared to dialysis

A

ADV: patients do not need to return to clinic for dialysis
DISADV: need immunosuppressant drugs

46
Q

explain the function of the renal capsule

A

ultrafiltration
high blood pressure assists filtrate to pass through
glomerulus
filtrate small enough to move through the glomerulus
filtrate contains dissolved salts, urea and glucose

47
Q

where is urea formed

A

liver

48
Q

what is the function of the proximal convoluted tube

A

selective reabsorption
back into the blood
e.g glucose

49
Q

what is the function of the glomerulus

A

ultrafiltration
small molecules from blood
are pushed out under high pressure

50
Q

why might the concentration of sodium ions be higher in the liquid that flows out of the liver than the concentration in urine

A

water has been reabsorbed by osmosis
in collecting duct
more water makes the liquid dilute, hence less water will make the liquid concentrated

51
Q

name two components of the blood that is not in dialysis fluid

A

red blood cells
white blood cells

52
Q

Amino acids are processed by the liver. describe the process

A

deanimation
nitrogen component of amino acids are converted to ammonia
quickly converted to urea
as ammonia is too toxic and can be harmful
carbon component of amino acids are converted to glucose.
Some amino acids are used to make protiens (eg fibrinogen)

53
Q

how does excretion differ in diabetic patients

A

when the glucose concentration in blood becomes too high
all the glucose isnt able to be reabsorbed in the PCT
glucose has a strong osmolarity and pulls water with it
causing patients to pee excessively and lose a lot of water

54
Q

what does the glomerulus do

A

ultrafilteration
small molecules are forced out from blood into glomerulus due to high pressure
large molecules don’t pass

55
Q

what does the proximal convoluted tubule do

A

selective reabsorption
back into blood
eg glucose