Excretion

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  • Created by: Phil
  • Created on: 15-05-13 20:14
Excretion
Is the removal of metabolic waste from the body.
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What is metabolic waste?
Unwanted by-products from normal cell processes.
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Main substances that need to be excreted
Nitrogen containing compounds such as urea and Co2.
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Where are the main waste products produced.
Co2 is produced as a by-product of respiration and urea is produced in the liver from excess amino acids.
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What is deamination?
The removal of the amine group from an amino acid to produce ammonia.
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What 3 main effects does high amounts of co2 have on the body?
1. Slows down o2 trans. 2.Increases ammounts of carbaminohaemoglobin. 3.Can cause respiratory acidosis.
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What causes respiratory acidosis?
Co2 combines with water to produce carbonic acid. Carbonic acid dissociates & releases H ions. This lowers pH in the blood. If there is too much co2 and the pH drops to lower than 7.35 then ra occurs.
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Symptoms of respiratory acidosis?
Drowsiness, headaches, difficulty in breathing, confustion.
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What diseases/conditions can cause respiratory acidosis?
Emphysema, chronic bronchitis, asthma.
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What does the hepatic artery do, why is this important?
Carried oxygenated blood to the liver. Many metabolic processes occur in the liver so a good supple of o2 is needed to make ATP.
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What does the Hepatic portal vein do?
Carries deoxygenated blood from th digestive sysem to the liver.
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Hepatic vein.
Deoxy blood leaves the liver via the hapatic vein.
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What does the bile duct do?
Carried bile from the liver to the gall bladder.
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What is a sinusoid?
A special chamber that contains both deoxy and oxy blood. Runs from the outside to the inside.
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What is a canaliculus?
A channel that flows inside to outside and carries bile.
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What are kupffer cells?
Special macrophages that move out in the sinusoids.
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What are the main functions of kupffer cells?
To breakdown and recycle old RBC.
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What is Bilirubin?
one of the waste products from haemoglobin breakdown.
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What does the liver control? 3.
Blood glucose levels, animo acid levels and lipid levels
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What 4 things do livers synthesise?
RBC in the fetus, bile, plasma proteins and cholesterol.
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What does the liver store?
Vit A, D and B12, iron and glycogen
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What do livers detoxify?
Alcohol and drugs.
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What do livers breakdown?
Hormones
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What do livers destroy?
RBC.
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DIAGRAM THE KIDNEY.
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What supplies and drains blood to the kidney?
Renal vein drains and renal artery supplies.
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Describe the structure of the kindey
Surrounded by a capsule, outer region is the cortex and inner region is the medulla. The central region is the pelvis which leads into the ureter.
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What is the Nephron?
The bulk of the kidney made up of tiny tubules, the functioning unit of the kidney.
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What is the glomerulus?
A fine network of capillaries that is surrounded by the Bowman's Capsule. Fluid from the blood is pushed into the Bowman's capsule by the process of ultrafiltration. The capule leads into the nephron.
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What are the four parts of the nephron?
The proximal convoluted tubule. The distal convoluted tubule. The loop of Henle. The Collecting guct.
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DIAGRAM NEPHRON AND ASSOCIATED BLOOD CAPILLERIES.
..
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What is the overall function of the nephron?
To alter the fluid recieved from the renal artery in the cortex, to urine, in the collection duct.
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How is fluid altered in the nephron?
By Selective reabsorption (mostly occuring in PCT) and the changing of water potenital in the loop of Henle.
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What is selective reabsorption
When useful substances are reabsorbed into from the nephron in to the bloodstream, while other excretoy substances reamin in the nephron.
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What is a convoluted tubule and where are the proximal and distal tubules located?
A convoluted tubule is one that is bent and coiled. Proximal - closest to the glomerulus. Distal-furthest away from the glomerulus.
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PROCESS ULTRAFILTATION
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What is ultrafiltration?
Filtration at a molecular level - Larger mols/cells are left in the blood and smaller mols pass through into the Bowmna's Capsule.
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What are Podocytes?
Specialised cells that make up the lining of the Bowman's Capsule.
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What's the difference between the afferent and the efferent arteriole and what is the significence of this?
The afferent arteriole is wider in diameter. Blood enter through the arteriole and the difference in diameters ensures that the blood in the glomerulus is under increased pressure, causing it to be pushed into the Bowman's Capsule.
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During ultrafiltration, what is filtered out of the blood?
Water, Amino acids, glucose, urea, inorganic ions
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What is left in the capillary, what is the significance of this?
Blood cells and proteins, proteins = Very low water potential, this means some fluid is still retained in the blood with water and the other substances list above, the low wp also important for the reabaroption of water later on.
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PROCESS SELECTIVE REABSORPTION.
F
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DIAGRAM PCT
/
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How are the cells lining the pct specialised?
Microvilli, Co-transporter proteins, sodim-potassium pumps, Many Mitochondria.
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How does the structure microvilli help pct in it's function?
CSM highly folded to form the microvilli. This increases SA.
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How do co-transporter proteins help the pct carry out it's function?
In the membrane, transport amino acids/glucose/sodium ions from the tubule into the cell via faciltates diffusion.
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How do sodium/potassium pumps help the pct carry out it's function?
Actively transport sodium ions out of the cell and potassium ions into the cell.
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What is osmoregulation?
The contol and regulation of the water potential of the blood and body fluids. Done by the kidney in Humans;
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What is the role of the loop of Henle?
To create a very low water potential in the tissue of the medulla.
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What is the function of the descending limb of the Loop of Henle?
Causes the water potenital of the fluid to become lower, this is due to loss of water by osmosis to surrounding tissue and the diffusion of sodium and chloride ions into the tubule from the surrounding tissue.
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What occurs at the base of the tubule?
Sodium and chloride ions diffuse out into the tissue fluid.
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What is the function of the ascending limb of the Loop of Henle?
Causes the water potential of the fluid inside the tubule to increase, due to the active transport of sodium/chloride ions out, The tube is impermeable to water, so water does not leave.
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What occurs at the distal convoluted tube?
Active transport is used to adjust the concentrations of various salts.
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What happens in the collecting duct and why?
Water leaves the fluid by osmosis, this happens due to the low water potenital in the surrounding tissue fluid in the medulla caused by the loop of henle.
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What happens to the water that leaves from the collecting duct?
Enters blood cappilleries and is carried away.
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PROCESS OMSO
...
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What is ADH?
Antidiuretic Hormone, released from the pit gland and acts on the collecting duct to increase their reabsorption of water.
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What are osmoreceptors?
Receptor cells that monitor the wp of the blood. it wp is low then water is moved out of osmoreceptor cells causing them to shrink and causing the stimulation of neuroscretory cells.
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What are Neurosecretory cells?
Specialised cells that act like nerve cells but release a hormone into the blood.
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What does the hypothalamus control in terms of osmoregulation?
Contains neurosecretory cells and various receptors that monitor the blood.
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DIAGRAM CONTROL OF WATER POTENITAL VIA NEG FEEDBACK.
...
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What are the most common causes of kidney failure?
Diabetes Mellitus, hypertension and infection
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What issues are caused by kidney failure?
The inability to remove excess water and certain waste products from the body, the inability to regulate water levels and slat levels in the body, will lead to death.
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What are the two main treatments of kidney failure?
Dialysis and kidney transplant
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What is dialysis?
The use of a partially permeable membrane to treat the blood.
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What is Dialysis fluid?
A complex solution that matches the composition of body fluids.
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What is the dialysis membrane
A partially permeable membrane that seperates the dialysis fluid from the patien'ts blood in a dialysis machine.
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What are the two types of dialysis?
Heamodialysis and Peritoneal dialysis.
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What occurs during haemodialysis?
Blood from a vein is passed through a machine containing the dialysis membrane. Heparin is added to avoid blood clot and any air bubbles are removed before the blood is returned to the body.
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How often does haemodialysis happen?
3 times a week for several hours, usually at a clinic.
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What occurs during Peritoneal dialysis?
The filter is the body's own abdominal membrane. A permanent tube in implanted in the abdomen and dialysis fluid is added to the tube. After several hours fluid is drained.
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How often does peritoneal dialysis occur?
Usually daily, however patient can walk about while it occurs.
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4 advantages to kidney transplant?
1.No dialysis. 2.Less limited diet. 3.Better physical feeling. 4.Better qual of life.
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4 disadvantages to kidney transplant?
1.Need immunosuppressants for lift of the kidney. 2.Major surgery. 3.Risk of infection. 4.Need frequent checks in case of rejection.
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Other cards in this set

Card 2

Front

What is metabolic waste?

Back

Unwanted by-products from normal cell processes.

Card 3

Front

Main substances that need to be excreted

Back

Preview of the front of card 3

Card 4

Front

Where are the main waste products produced.

Back

Preview of the front of card 4

Card 5

Front

What is deamination?

Back

Preview of the front of card 5
View more cards

Comments

Swallowtail

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A good collection of over 70 flash cards which will give you the information you need to revise thoroughly the process of excretion and the kidney. Adding some diagrams to this set of cards of key structures and flow diagrams of the main processes would make them a more complete resource. Print them off and test yourself.

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