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Biology > Module 5.2 - Excretion > Flashcards

Module 5.2 - Excretion Flashcards

1
Q

What is excretion? (2)

A
  • The removal of waste products from the body
  • Excretion maintains normal metabolism and homeostasis
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2
Q

Functions of the liver? (2)

A
  • Deamination
  • Detoxification
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3
Q

Deamination? (3)

A
  • Nitrogen-containing amino groups are removed from amino acids
  • Nitrogen can’t be stored in the body
  • Forms ammonia and organic acids
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4
Q

What happens to organic acids? (2)

A
  • Organic acids are respired to give ATP
  • Converted to carbohydrate and stored as glycogen
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5
Q

What happens to ammonia? (2)

A
  • Ammonia is toxic
  • It is combined with CO2 in the ornithine cycle to create urea
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6
Q

Where does the ammonia + CO2 stage of the ornithine cycle take place? (2)

A
  • Mitochondria of liver cells
  • Other stages take place in the cytoplasm
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7
Q

What happens to urea after the ornithine cycle? (3)

A
  • Released from liver into blood
  • Kidney filters blood and removes urea as urine
  • Urine is excreted
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8
Q

Detoxification? (1)

A
  • Breaks down alcohol, drugs and unwanted hormones
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9
Q

What happens to ethanol (alcohol)? (1)

A
  • Ethanol is broken down into ethanal is broken down into acetic acid
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10
Q

What happens to the body if there is excess alcohol, drugs and unwanted hormones? (3)

A
  • Excess alcohol can cause cirrhosis (liver die and scar tissue blocks blood flow)
  • Dugs such as paracetamol can lead to liver and kidney failure
  • Unwanted hormones such as insulin can effect blood sugar levels
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11
Q

Structure of liver? (6)

A
  • Hepatic artery
  • Hepatic vein
  • Hepatic portal vein
  • Bile duct
  • Lobules
  • Sinusoids
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12
Q

Function of the hepatic artery? (1)

A
  • Oxygenated blood from heart to liver
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13
Q

Function of the hepatic vein? (1)

A
  • Deoxygenated blood from liver to heart
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14
Q

Function of the hepatic portal vein? (1)

A
  • Brings blood from duodenum and ileum which are rich in digested food to be filtered out
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15
Q

Function of the bile duct? (1)

A
  • Bile ducts takes bile to gall bladder for storage
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16
Q

Connection between hepatocytes and the bile ducts? (1)

A
  • Hepatocytes produce bile and release them into bile canaliculi which drain into bile ducts
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17
Q

Structures of the lobules? (3)

A
  • Cylindrical structures made of hepatocytes
  • Has a central vein in the middle that connects to the hepatic vein
  • Has branches of hepatic artery, portal vein and bile duct attached to each lobule
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18
Q

What are sinusoids? (2)

A
  • Capillaries that connect the hepatic artery and hepatic portal vein
  • Has Kupffer cells
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19
Q

Kupffer cells (2)

A
  • Cells that are attached to sinusoids
  • Remove bacteria and breakdown old red blood cells
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20
Q

How are sinusoids and hepatocytes involved in excretion? (2)

A
  • Blood runs through sinusoids and past hepatocytes removing harmful substances and oxygen
  • Hepatocytes breakdown harmful substances and re-enter them into the blood
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21
Q

What does the liver look like under a microscope? (4)

A
  • Central vein: white circular shape
  • Hepatocytes: spread out from central vein
  • Nucleus: red dots
  • Sinusoids: white spaces
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22
Q

Functions of the kidney? (2)

A
  • Excretion of waste products
  • Regulate water potential
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23
Q

How does the kidney excrete waste products? (6)

A
  • Blood enters kidney through renal artery
  • Ultrafiltration
  • Selection reabsorption
  • Unwanted substances pass along tubules & ureter to the bladder
  • Unwanted substances are excreted as urine
  • Filtered blood pass out of kidney through renal vein
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24
Q

Ultrafiltration? (2)

A
  • Blood passes through capillaries in the cortex from renal artery
  • Substances are filtered out into long tubules that surround capillaries
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25
Selective reabsorption? (3)
- Useful substances are reabsorbed back into the blood from tubules in medulla and cortex - Takes place when filtrate flow along proximal convoluted tubule (PCT), through the loop of Henle and distal convoluted tubule (DCT) - Epithelium of PCT has microvilli for increased larger surface area for reabsorption
26
What transport mechanism are useful substances reabsorbed by? (3)
- Glucose, amino acids, vitamins and some salts are reabsorbed via active transport and facilitated diffusion - Some urea is reabsorbed by diffusion - Water enters blood via osmosis
27
Why reabsorbed via osmosis? (1)
- Water potential of blood is lower than filtrate
28
Where is water reabsorbed from? (3)
- Loop of Henle - DCT - Collecting ducts
29
Nephrons? (3)
- Network of long tubules and capillaries - Where blood is filtered - Abundant in number
30
Role of the nephrons in blood filtration? (4)
- Blood enters the afferent arterioles in cortex from renal artery - Each afferent arterioles splits into glomerulus where ultrafiltration takes place - The efferent arterioles takes the blood out of the capillaries and into the Bowman's capsule - Filtrate pass along the rest of the nephron and useful substances are reabsorbed
31
From where are useful substances reabsorbed to and from? (1)
- Useful substances leave tubules of nephron and enter capillary network around it
32
Filtrate? (1)
- Liquid and small molecules
33
What happens to the filtrate after filtration? (2)
- Filtrate that remains after selective reabsorption is urine - Which flow through collecting duct and pass along ureter to bladder to be expelled
34
Components of urine? (5)
- Water - Dissolved salts - Urea - Hormones - Excess vitamins
35
What enters the Bowman's capsule? (2)
- Filtrate enter the nephron tubules, the capillary wall, the basement membrane before entering the Bowman's capsule through its epithelium - Larger molecules can't pass through these layers and thus stay in the blood
36
Glomerulus? (1)
- Bundle of capillaries looped inside Bowman's capsule
37
Afferent arterioles? (1)
- Takes blood into the glomerulus
38
Efferent arterioles? (2)
- Smaller in diameter and is under higher pressure than afferent - Its high pressure forces filtrate out of the capillary into the Bowman's capsule
39
The cortex under a microscope? (4)
- Glomerulus: bundle of capillaries - Bowman's capsule: white area around glomerulus - PCTs and DCTs: circular areas surrounded by squamous epithelial cells - Nuclei: purple blobs
40
What happens if the body is dehydrated? (3)
- Water potential of blood is too low - More water is reabsorbed into blood from nephron tubules - Urine is more concentrated - less water is excreted
41
What happens if the body is too hydrated? (3)
- Water potential of blood is too high - Less water is reabsorbed into blood from nephron tubules - Urine is more dilute - more water is excreted
42
By what transport mechanism is water reabsorbed by? (1)
- Water is reabsorbed via osmosis into the blood from the tubules of the nephrons
43
Loop of Henle? (3)
- Descending limb - Ascending limb - Limbs help set up counter current multiplier mechanism
44
Counter current multiplier mechanism? (1)
- Mechanism that reabsorb water
45
Counter current multiplier mechanism at the top of the ascending limb? (3)
- Na+ & Cl- diffuse out of medulla at top of ascending limb - Water stays inside tubule as ascending limb is impermeable to water - Creates low water potential in medulla
46
Counter current multiplier mechanism at the descending limb? (4)
- Water moves out of descending limb into medulla via osmosis - Due to lower water potential in medulla than in descending limb - Filtrate becomes more concentration - Water is reabsorbed into blood through capillary network from the medulla
47
Counter current multiplier mechanism at the bottom of the ascending limb? (3)
- Na+ & Cl- diffuse out of medulla at the bottom of ascending limb - Lowering watering water potential in medulla - Water stays inside tubule
48
Counter current multiplier mechanism at collecting duct? (3)
- Water to moves out of collecting duct via osmosis - Due to lower water potential in medulla than in collecting duct - Water is reabsorbed into blood through capillary network from the medulla
49
What is an adaptation of the loop of Henle for animals who live in areas of low water? (4)
- Longer loops of Henle - Long the ascending limb the more ions that can be pumped out - The more water that can be reabsorbed - Animal can save more water
50
ADH? (1)
- Antidiuretic hormone
51
ADH level when dehydrated? (8)
- Water potential of blood drops - Detected by osmoreceptors in hypothalamus - Posterior pituitary gland is stimulated to release ADH - ADH level rises - ADH makes DCT and collecting duct walls more permeable to water - More water can be reabsorbed from these tubules to medulla - Small amount of highly concentrated urine formed - Less water is loss
52
ADH level when hydrated? (8)
- Water potential of blood rises - Detected by osmoreceptors in hypothalamus - Posterior pituitary gland is stimulated to release less ADH - ADH level lower - Less ADH makes DCT and collecting duct walls less permeable to water - Less water can be reabsorbed from these tubules to medulla - Large amount of dilute urine formed - More water is loss
53
What is kidney failure? (1)
- Kidney can't carry out normal functions properly
54
Glomerular filtration rate (GFR)? (3)
- Can be detected by measuring glomerular filtration rate (GFR) - GFR is the rate at which blood is filtered into the Bowman's capsule from the glomerulus - A lower rate can indicate and faulty kidney
55
Causes of kidney failure? (2)
- Infections: inflammation which damages cells, interfering with filtration in the Bowman's capsules or reabsorption in parts of the nephron - High blood pressure: can damage the glomeruli capillaries causing larger molecules to enter capillary walls and into urine
56
Consequences of kidney failure? (4)
- Waste products build-up - Parts of the body swell as fluid accumulate in tissues - Unbalance of electrolytes - Long term kidney failure can cause anaemia
57
Consequence of too much urea in the blood? (1)
- Weight loss and vomiting
58
Examples of the consequence of unbalanced electrolytes? (2)
- Imbalance of Ca2+ and P3- can lead to brittle bones - Salt build-up can cause more water retention
59
Treatment options of kidney failure? (2)
- Renal dialysis - Kidney transplant
60
Renal dialysis? (4)
- Haemodialysis - Peritoneal dialysis - Keep a person alive until transplant is available - Less risky than surgery
61
Haemodialysis? (6)
- Blood passed through dialysis machine - Blood flows on one side of partially permeable membrane and dialysis machine flows through the other side - Waster products, excess water and ions diffuse across membrane and into dialysis fluid - Larger molecules are prevented from leaving - Sessions take two to five hours and done two-three times a week - One can feel unwell in between sessions
62
Peritoneal dialysis? (6)
- Dialysis fluid is put in a tube that passes from the abdomen into their abdominal cavity - Waste products diffuse out of patient's blood into dialysis fluid across the peritoneum - Fluid is drained out of the tube - Several times a day or one long session overnight - Risk of infection - No dialysis-free days
63
Peritoneum? (1)
- Membrane that lines the abdominal cavity
64
Kidney transplant? (5)
- Kidney needs to be same blood and tissue type of patient - Living relative or dead person donor - Transplants are cheaper than dialysis - Major operation with high risk - Immunosuppressants needed
65
How do pregnancy tests work? (5)
- Test strip containing monoclonal antibodies for hCG bound to blue bead - Urine will bind to antibodies on the beads - Urine moves up test strip taking bead up with it - Antibodies-hCG will be stuck in place - If hCG is present test strip will become blue as blue beads become concentrated in the are
66
hCG? (1)
- Human chorionic gonadotropin is a hormone only found in pregnant women's urine
67
How do drug tests for steroids work? (6)
- Anabolic steroids build up in muscle tissue - Gas chromatography/mass spectrometry (GC/MS) - In GC urine is vaporised and passed through column containing a polymer - Different substances move at different speeds - urine will sperate out - One separated MS converts them into ions and will sperate them by its mass and charge - Results will be analysed by a computer by comparing known substance to unknown substances to identify them
68
How do drug tests for recreational drugs work? (5)
- Can test for cannabis, ecstasy or cocaine - Test strip containing antibodies for the drug being tested on - Urine containing drug will bind o antibodies - Colour change will happen for positive test - If positive another test will be sent for GC/MS analysis

Biology (10 decks)

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