HideShow resource information
  • Created by: Amira200
  • Created on: 06-06-16 11:03
Define the term excretion
The removal of unwanted waste of metabolism
1 of 67
Which two main products need to be removed from the body
CO2 and Nitrogen containing compounds such as urea
2 of 67
How and where is carbon dioxide produced
Produced by every living cell in the body as a result of respiration
3 of 67
Where is urea produced
In the liver from excess amino acids
4 of 67
Where is carbon dioxide excreted
In the alveoli in the lungs. Excreted as we breath out
5 of 67
Where is urea excreted
At the kidneys
6 of 67
Why must CO2 be removed from the body
CO2 binds to water to form H2CO3 (carbonic acid). This dissociates into HCO3- ions and H+ ions. H+ ions contribute to respiratory acidosis. H+ ions also combine with Hb in RBC competing with O2.Most of CO2 carried around blood in form of HCO3-.
7 of 67
Where in the body detects extra H+ ions
The respiratory centre in the medulla oblongata of the brain detects extra H+ ions and causes an increased breathing rate to help remove extra CO2
8 of 67
What happens if blood pH drops below 7.35
Slowed breathing, headache. This is respiratory acidosis.
9 of 67
Why must nitrogenous compounds be removed from the body
Body can't store excess proteins or amino acids. But AA contain as much energy as carbs so they are transported to the liver to be deaminated and then undergo the ornithine cycle to be converted into urea
10 of 67
Describe the process of deamination
Occurs in the liver. AA combines with oxygen to produce a keto acid + ammonia.
11 of 67
Why does the ornithine cycle have to be carried out
Ammonia produced in deamination is highly toxic and highly soluble. Therefore the ornithine cycle combines 2NH3 with CO2 to form urea (a less toxic and less soluble nitrogenous compound) and water
12 of 67
Which reaction is a veto acid formed and what happens to it
It is produced during deamination in the liver and is used in Krebs cycle to be respired to produce ATP. as it contains a lot of energy so shouldn't be wasted
13 of 67
What is the liver made out of
14 of 67
What does the hepatic artery supply to the liver
Supplies liver with oxygenated blood which is very low in waste/no waste. Blood comes from aorta.
15 of 67
What does the blood from the hepatic artery supply the liver with
Oxygen that is essential for aerobic respiration. Liver cells are very active s they carry out many metabolic processes which require ATP so it is important that they receive a good supply of oxygen
16 of 67
What does the hepatic portal vein supply the liver
Deoxygenated blood which is high in waste and potentially toxic products. Blood comes from the digestive system i.e. the small intestines
17 of 67
How does blood leave the liver
Via the hepatic vein. It rejoins onto the vena cava which returns blood to normal circulation
18 of 67
What is the name of the fourth vessel which isn't a blood vessel and is connected to the liver and what does it do
It is the bile duct. Bile duct carries bile to the gall bladder when bile is stored or alternatively to the small intestines to emulsify fats and neutralise acidic pH
19 of 67
Why must the cytoplasm of liver cells be very dense
As it carries out many metabolic processes meaning that it must be specialised in terms of the amounts of certain organelles that it contains
20 of 67
List some functions of the liver cells
Formation of cholesterol. Detoxification of alcohol. Formation of urea.Destruction of RBC. Breakdown of hormones
21 of 67
What are kupffer cells
Specialised macrophages. Involved in the breakdown and recycling of old RBC. Breakdown of Hb forms bilirubin which is excreted as part of the bile and in faeces. They act as phagocytes also also.
22 of 67
What is the role of the enzyme catalase
It is an enzyme used as part of detoxification in the liver and break hydrogen peroxide into hydrogen and oxygen
23 of 67
Describe the detoxification of alcohol in the liver
Ethanol depresses nerve activity. Ethanol is dehydrogenated by ethanol dehydrogenase to form ethanal and NADH. Ethanal is dehydrogenated by ethanal dehydrogenase to form ethanoate (acetate) + NADH. Acetate combines with CoA and is used in Krebs.
24 of 67
NAD is also required to oxidise and break down fatty acids. What happens if too much alcohol is being taken
NAD is being used to accept H atoms from dehydrogenation of alcohol. Fatty acids converted into lipids and steroids hepatocytes. This causes cirrhosis where the liver becomes enlarged "fatty liver"
25 of 67
Name the parts of the kidney from the outside to the inside
Capsule. Cortex. Nephron Medulla. Pelvis. Renal artery(red). Renal Vein (blue
26 of 67
Which parts of the nephron are located in the cortex
Glomerulus. PCT. DCT
27 of 67
Which parts of the nephron are located in the medulla
Loop of Henle. Collecting duct which connects to pelvis aiding in removal of urine out of ureter
28 of 67
Briefly describe ultrafiltration
Blood flows into the glomerulus from afferent arteriole. Pressure in glomerulus higher than in the Bowmans capsule so fluid pushed into bowmans capsule.Molecules with an RM of
29 of 67
What are the 3 barriers that decide what is pushed from glomerulus into bowmans
Endothelium which has narrow pores that blood plasma and dissolved substances can pass through. Basement membrane with collagen and glycoprotein which act as a filter to prevent entry of molecules >69000. Podocytes (major processes).
30 of 67
What is filtered out of blood during ultra filtration
Salts (inorganic ions e.g. Na, K and Cl), Water, Amino Acids, Glucose, Urea
31 of 67
What is left in the capillary during ultrafiltration
Protein and blood cells because they have a RM >69000. Presence of proteins mean that blood has a v low WP ensuring that some fluid is retained in blood. Important to help reabsorb water later on
32 of 67
Briefly describe selective reabsorption
Some ions removed e.g. Na+ ions from Na-K pumps into tissue fluid. Na conc in cytoplasm decreases. Glucose + amino acids also leave PCT by facilitated diffusion. Reabsorption of salts increases WP in tubule fluid so water leaves by osmosis.
33 of 67
What is the cell surface membrane in contact with the tubule fluid called and what is its function
Microvilli. Highly folded to increase surface area for reabsorption
34 of 67
How is glucose and amino acids retuned into the blood during selective reabsorption
Co transporter proteins by facilitated diffusion
35 of 67
What does the cell cytoplasm having many mitochondria indicate
Active or energy requiring process involved as many mitochondria will produce a lot of ATP
36 of 67
Describe the composition and general structure of the loop of henle
Contains a descending limb and ascending limb. Arrangement allows salts to be transferred from ascending limb to descending limb to increase concentration of salts in tubule fluid.
37 of 67
Describe movement of substances down descending loop of henle
Loss of water by osmosis to surrounding tissue fluid. Diffusion of sodium and chloride ions into tubule from surrounding tissue fluid. Decreased water potential
38 of 67
Describe the movement of substances up the ascending limb of Loop of henle
Water potential higher. At base, Na + Cl- ions diffuse out of tubule. Higher up, Na + K ions actively transported out of tubule. Wall impermeable to water so water cannot leave.
39 of 67
What is the arrangement of the loop of henle known as
Hairpin countercurrent multiplier
40 of 67
What occurs at the DCT
Readjustment of salts in the tubule by active transport
41 of 67
What occurs at collecting duct
Tubule fluid contains a lot of water. As fluid moves down collecting duct, water removed from tubule by osmosis into tissue fluid and then blood capillaries. Amount of water reabsorbed depends on permeability of walls of collecting duct
42 of 67
Which has a lower WP the pelvis or medulla
Medulla. As you go further down the medulla, the water potential decreases even further
43 of 67
What is osmoregulation
The control of water levels and salt levels in the body.
44 of 67
On a cool day what is the permeability of the collecting duct
Need to conserve less water so collecting duct less permeable
45 of 67
On a hot day what is the permeability of the collecting duct
Need to conserve more water so collect duct is going to be more permeable
46 of 67
What and where is the water potential in the blood monitored
Osmoreceptors in the hypothalamus
47 of 67
What happens to the osmoreceptors when WP is low
Osmoreceptor cells lose water so cells shrink causing them to stimulate neurosecretory cells.
48 of 67
What are neurosecretory cells
Specialised neurones that produce and release ADH.
49 of 67
Where is ADH manufactured
In the cell body of neurosecretory cells in the hypothalamus. ADH flows down the axon of the terminal bulb in the posterior pituitatry gland where it is stored until needed
50 of 67
How is ADH released
When neurosecretory cells stimulated, they send action potentials down their axons and cause the release of ADH
51 of 67
What does ADH act on
It acts on the cells of the collecting duct.
52 of 67
Describe what happens when there is a high water potential in the blood
Detected by osmoreceptors in hypothalamus. Less ADH released by pituitary gland. CD walls less permeable. Larger volumes of dilute urine is produced
53 of 67
Describe what happens when there is a low water potential in the blood
Detected by osmoreceptors in the hypothalamus More ADH released. CD walls more permeable. More water reabsorbed into blood. Less and more concentrated volumes of urine produced
54 of 67
List 3 reasons why kidney failure occurs
Diabetes. High BP. Infection
55 of 67
What happens when the kidneys fail completely
Body unable to remove excess water and certain waste products from the blood like urea and salts. It is unable to regulate watering salt levels in blood rapidly leading to death
56 of 67
What are the main two treatments for kidney failure
Dialysis and kidney transplant
57 of 67
Describe dialysis
Removes waste, excess fluid and salt from blood by passing blood over a dialysis membrane. The membrane is partially permeable and allows exchange of substances between blood and dialysis fluid. Any excess diffuses across membrane into dialysis fluid
58 of 67
Briefly describe haemodialysis
Blood passed into a machine that contains artificial dialysis membrane. Heparin added and bubbles removed. Performed 3 x a week lasting several hours
59 of 67
Briefly describe peritoneal dialysis
Permanent tube implanted in abdomen and dialysis solution poured through tubes and fills space between abdominal wall and organs. Solution then drained from abdomen afterwards. Many times daily.
60 of 67
Describe kidney transplant
Kidney implanted into lower abdomen and attached to blood supply and bladder.
61 of 67
Why do immunosuppresents have to be given after a transplant
To make sure that the bodies immune system doesn't reject the new kidney which it recognises as foreign
62 of 67
Discuss advantages of kidney transplant
Less limited diet. Physically feel better. Better quality of life. Freedom from time consuming dialysis
63 of 67
Discuss disadvantages of kidney transplant
Need immunosuppressants for life of kidney. Major surgery. Risks of surgery. Frequent check ups. Side effects of medicines e.g. high BP, fluid retention, increased susceptibility to infections
64 of 67
Describe how a pregnancy test works
Specific monoclonal antibodies bind to hCG. Antibody has marker. hCG-antibody complex binds to immobilised antibodies forming a coloured line. Second line indicates pregnant
65 of 67
What are anabolic steroids and how do you test for them
Increase protein synthesis within cells. Analyse urine sample in lab using GC or MS
66 of 67
Discuss advantages and disadvantages of anabolic steroids
Unfair advantage in sport. Harmful side effects e.g. depression. Have to keep up with competition of athletes.
67 of 67

Other cards in this set

Card 2


Which two main products need to be removed from the body


CO2 and Nitrogen containing compounds such as urea

Card 3


How and where is carbon dioxide produced


Preview of the front of card 3

Card 4


Where is urea produced


Preview of the front of card 4

Card 5


Where is carbon dioxide excreted


Preview of the front of card 5
View more cards


No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Cellular processes resources »