Kidneys and Homeostasis Flashcards
1
Q
What is excretion?
A
It is the removal of metabolic waste made by the body. The main body excrete compounds using for excretory organs; the kidneys, the lungs, the skin and the liver.
2
Q
What is egestion?
A
It is the removal of undigested food material in the form of faeces.
3
Q
What is secretion?
A
It is the release of useful substances from cells.
4
Q
What are the kidneys functions?
A
Excretion – filter the blood to remove nitrogenous from metabolic waste from the body to produce urine.
Osmoregulation – the control/regulation of the water content and solute composition of body fluids e.g blood, tissue fluid and lymph.
5
Q
What is the nitrogenous waste found in plants?
A
They only synthesise Amino acid is in proteins which they need they don’t need to excrete nitrogen containing molecules. They uptake nitrates and ammonium from the soil by facilitated diffusion and active transport.
6
Q
What adaptations do plants have which enabled them not to excrete nitrogenous waste?
A
Fabaceae family plants, have nitrogen fixing bacteria.
α -keto glutarate is combined with ammonia ions into glutamate (an amino acid). Glutamate is then covered into another amino acid by transamination.
7
Q
What do you most aquatic organisms excrete their nitrogenous base in the form of?
A
Ammonia
8
Q
Why do you aquatic organisms excrete ammonia?
A
Even though ammonia is highly toxic it is extremely soluble in water. The large surface area of fish gills and amoeba allows ammonia to diffuse out rapidly and it is immediately diluted below toxic concentrations. In softbodied invertebrates the ammonia diffuses across the whole surface into the surrounding water. In freshwater fish, ammonia is lost by ammonium ions across the epithelium of the gills with the kidneys playing a minor role in excretion.
9
Q
How to birds, reptiles and insects excrete their nitrogenous waste?
A
They excrete their nitrogenous waste in the form of uric acid. Uric acid is almost insoluble in water and is non-toxic. It is excreted as a precipitate after nearly all water has been removed from the urine. In birds and reptiles the pace that urine is eliminated along with faeces from the intestine via the cloaca.
10
Q
Why do they excrete uric acid?
A
As little water is required for excretion it allows them to conserve water and live in a water shortage environment or light enough for flight.
11
Q
What do you most terrestrial organisms convert their nitrogenous waste into?
A
Urea which is then excreted as urine.
12
Q
Why is urea excreted instead of ammonia.
A
As ammonia is extremely toxic in order for a terrestrial organism to excrete ammonia, it would have to urinate loads as it can only be transported at small and dilute concentrations. However urea can be transported in more concentrated forms as it is 100,000 times less toxic than ammonia. It enables animals who excrete urea in losing less water during excretion.
13
Q
How is urea produced?
A
Dietary protein is digested into amino acids which are transported to the liver and then around the body where they are a simulated into proteins. Any excess amino acid is a deaminated, where the amino group is then converted into urea.
14
Q
What is deamination?
A
It is when the amine group is removed from a molecule with the amine group being converted into urea. The removal of the group leaves ammonia and pyruvic acid.
15
Q
What happens to the urea?
A
The ammonia is converted into urea and is released into the blood plasma and remains there until the kidneys remove it and excreted by urine.
16
Q
What can pyruvic acid be used for?
A
Respiration as a source of energy converted into fat and stored.
17
Q
What is the structure of the kidney?
A
Each kidney is covered by a tough renal capsule with both receiving blood from the renal artery and returning blood back into circulation by the renal vein. The blood from the renal artery is filtered in the outer layer, the cortex at the Bowman’s capsule. The medulla contains the loop of Henle and the collecting duct which carries urine to the pelvis. The pelvis emptied the urine into the ureter and carries the urine to the bladder.
18
Q
What is a nephron?
A
It has an individual blood filtering unit with a kidney nephron being functional unit of the kidney. They are 30 mm long so provide a large surface area. Once the blood has been filtered it is carried through the nephron and the collecting ducts of many nephrons join to carry urine to the the pelvis and ureter.
19
Q
What are the kidney blood vessels?
A
Blood is applied to each nephron in the afferent arterial where it splits into a capillary network called a glomerulus enclosed by the Bowmans capsule. From the glomerulus, blood is filtered and carried by the efferent arteriole to:
A peritubular capillary network surrounding the proximal and distal convoluted tubule
The vasa recta which is a capillary network which is surrounding the loop of Henley
20
Q
What does the blood in the vasa recta do?
A
It delivers nutrients and oxygen to the nephron cells as well as carry water and mineral ions absorbed again from the kidneys
21
Q
Where does ultrafiltration occur?
A
Bowmans capsule
22
Q
What is ultrafiltration?
A
It is the filtration of small molecules (water, glucose, urea, amino acids and mineral ions) from the blood plasma to the lumen of the bowman capsule under high pressure.
23
Q
What is the process of ultrafiltration?
A
The afferent arteriole (from the renal artery) branches into many capillaries inside the cup of the Bowman’s capsule. These capillaries reach on to form the efferent arteriole. These capillaries from a dense network called the glomerulus.
24
Q
Why is there a high-pressure produced inside the glomerulus?
A
As the contraction of the heart creates a high-pressure in the renal artery. The difference in diameter of the afferent and the efferent arterial (the efferent arteriole is narrower than the afferent arteriole).
25
What are the pores called on the bowman capillary
They are called fenetrae. The small fenestrations force small molecules through into the lumen of the Bowman's capsule.
26
What is the first layer of the Bowmans capsule?
It is a wall of capillaries which contains a single layer of epithelium cells with pores called fenestrae which are about 18 nm in diameter.
27
What is the second layer of the Bowmans capsule?
It is the capillary basement membrane which is an extracellular layer of proteins mainly collagen and glycoproteins. This layer acts as a molecular sieve as it is a filter with a selective barrier between the blood and the nephron
28
What is the final layers of the Bowmans capsule?
The wall/lining of the Bowmans capsule is made from squamous epithelium cells called podocytes. Extensions of the podocytes are called pedicels which wraps around the capillary pulling it closer to the basement membrane. The large gaps between the pedicels are called filtration slits.
29
What is the role/function of the basement membrane?
The basement membrane of the Bowmans capsule form is a selective barrier between the blood and the Bowmans capsule. It acts as a molecular sieve with only small molecules able to pass through.
30
Which molecules can't pass through the basement membrane?
Blood cells, platelets and large proteins like antibodies and albumin, these then remain in the blood.
31
Does the blood have a high or low water potential from the glomerulus into the efferent arteriole?
It has a low water potential as a lot of water has been lost with a high concentration of proteins remaining.
32
What is the filtration rate?
It is the rate at which fluid passes from the blood in the glomerular capillaries into the Bowmans capsule. Filtration occurs because of the low water potential. The net effect of high hydrostatic pressure in the capillaries and low-sodium potential in the Bowmans capsule causes water to move out the blood.
33
Where does selective reabsorption occur?
In the proximal convoluted tubule
34
What is selective reabsorption?
It is when the useful products: glucose, amino acids, ions (Na+ and Cl-), water and vitamins are reabsorbed from the filtrate in the nephron back into the blood plasma. This process is indirectly active for glucose and amino acids.
35
What is the PCT?
It is the longest and widest part of the nephron. It carries the filtrate away from the Bowmans capsule. A blood in the capillaries surrounding the PCT absorbs all glucose and amino acids, some of the urea and most of the water and Na and Cl ions from the filtrate in the proximal convoluted tubule.
36
What is the PCT made out of?
Small cuboidal epithelium cells are found in its walls with invaginations called basal channels which are in the surface facing the basement membrane and capillaries.
37
Name the adaptations of the PCT?
It has a large surface area because of the microvilli as well as it being long with a large number of nephrons in the kidney. There are numerous carrier proteins embedded in the membrane.
Numerous mitochondria to provide ATP for active transport.
They have a close association with peritubular capillaries to have a short diffusion distance between the cells and the blood.
Tight junctions between the PCT epithelium cells. These are multi protein complexes that encircle a cell which attach tightly to neighbours. This prevents seepage of reabsorbed materials back into the filtrate.
38
How does sodium ions move into the PCT?
They diffuse passively by facilitated diffusion into the PCT cell, down the concentration gradient.
39
What is sodium and glucose transport?
Glucose and amino acids are filtered and reabsorbed into the blood by secondary active transport with sodium ions. A glucose molecule and two sodium ions bind to the transport to protein in the cuboidal epithelium cell membrane. Transporting the sodium out has provided a concentration gradient which brings glucose from the filtrate to the tissues. The sodium ions are pumped into the capillary with glucose moving in by facilitated diffusion is. Glucose is taken in by the PCT cell and then into the blood.
40
What is secondary active transport?
The coupling of diffusion e.g. sodium ions down and electrochemical gradient providing energy for the transport e.g. glucose up its concentration gradient.
41
Why is secondary active transport useful?
It enhances diffusion into the cell as it keeps the sodium concentrations low in the epithelium as it carries glucose down the concentration gradient.
42
How can you test if someone was to have diabetes?
You could take a urine sample as people with diabetes have a high concentration of glucose is present this means there won't be enough available transport molecules (all are saturated with glucose molecules) in the membrane to absorb all this causes glucose to pass through the loop of Henley will be lost in the urine. Normal individuals won't have any glucose is present in the urine indicating if a patient has diabetes.
43
How is glucose and amino acids transported?
Secondary active transport/co-transport via facilitated diffusion with Na+ into the cell.
Diffusion through the cell.
Glucose diffuses via facilitated diffusion through a channel protein into the capillary and Na is taken away actively.
44
What is the percentage of ions reabsorbed in the PCT to the blood?
About 70%. Amino acid, water soluble vitamins and Cl ions across transported with any ions. Most reabsorption uses active methods i.e. active transport however some do use passive methods.
45
What happens to the solute potential/water potential in the filtrate?
As ions and glucose leave the filtrate the solute potential decreases/water potential increases. Therefore water moves freely out of the filtrate into the blood by osmosis.
46
How much water is reabsorbed?
85%
47
How much urea and small proteins are reabsorbed?
About 50% of urea and small proteins are reabsorbed back into the blood of a diffusion. So alot of water has been lost from the filtrate so has a much greater concentration in the blood resulting in the steep concentration gradient.
48
What is the water potential like at the base of the PCT?
At the base of the PCT the filtrate is isotonic with the blood plasma at the end.
49
Where is the other 15% of water reabsorbed into?
The DCT in the cortex and the loop of Henle in the medulla and 5% is reabsorbed from the collecting duct.
50
What is the loop of Henle?
It is a hairpin counter current multiplier with the function to conserve water. It concentrates salts (Na and Cl) in the tissue fluid of the Medulla of the kidney by active transport. Water is reabsorbed from the fluid into the blood to produce a concentrated urine.
51
What are the two limbs called?
Descending and ascending.
52
Is the descending limb permeable to water?
The descending is permeable to water and relatively impermeable to Na+ and Cl- ions.
53
Is the ascending limb permeable to water?
The ascending is impermeable to water but permeable to Na+ plus and Cl- ions.
54
What happens at the ascending limb?
The cells in the ascending limb actively transport Na+ and Cl- ions out of the filtrate in the tubule into the tissue fluid of the Medulla. Impermeability to water lowers the water potential of the tissue fluid in the medulla. The loop of Henle collectively concentrates salts in the tissue fluid which has a lower water potential. The apex is where it is most concentrated, as the filtrate climbs the water potential increases as it contains progressively less ions with it becoming increasingly more dilute. as ions are pumped out the limb.
55
What happens at the descending limb?
As the cells are permeable to water the filtrate flows down the limb with water diffusing out by osmosis down the water potential gradient. Water returns to the vasa recta (it doesn't raise the water potential of the tissue fluid). As the filtrate flows down it contains progressively less water therefore becoming more concentrated.
56
At which part of the loop of Henley is the most concentrated with ions?
The apex, as water has diffused out of the descending limb by osmosis so it becomes more concentrated with a lower water potential.
57
Where is the tissue fluid most concentrated?
The apex.
58
What is maintained at the tip of the loop of Henle?
An osmotic gradient is maintained. The osmotic concentration is the strength of osmosis with the value becoming high with a lower water potential this is measured in milliosmoles
59
What is the mechanism in the loop of Henle?
Counter current multiplier (as the flow in the limbs in opposite direction and the concentration of solutes is increased. The solute concentration is even higher in the Medulla)
60
Why is the counter current multiplier beneficial?
It enables a maximum concentration to be build up both inside and outside the loop.
61
What happens at the collecting duct?
The duct runs back into the medulla down area of low water potential. Water then diffuses out of the collecting duct by osmosis down a water potential gradient.
62
What happens if the loop of Henle was to be longer?
The water potential would be lower in the medulla and more water will leave the collecting duct by osmosis. The filtrate would become more concentrated in the blood (it is hypertonic to the blood) and the time it takes to reach the base of the collecting duct it is urine. Water is reabsorbed back into the vasa recta and into general circulation
63
What is the purpose of the loop of Henle?
There is to concentrate salt in the medulla lowering the water potential in the tissue. It is important in osmoregulation and in the function of the DCT and collecting duct. If the loop was longer then the medulla would be more concentrated and more water would be reabsorbed from the collecting duct. A small amount of water is also reabsorbed from the descending limb.
64
Does an animal in a wet habitat have a long or short loop of Henle?
It has a short loop of Henle as water is readily available.
65
That's an animal in a dry habitat have a long or short loop of Henle?
It has a longer loop of Henle as more salts can be transported out of the medulla by active transport this lowers the water potential so more water can be reabsorbed.
66
Where does osmoregulation occur?
It occurs in the DCT and collecting duct where the permeability of these tubes is regulated by hormones.
67
What is Osmoregulation?
It is the homoeostatic control of water and salt composition of the blood under hormonal control. It operates using a negative feedback mechanism. It also maintains a concentration of enzymes and metabolites in order for reactions to occur at a constant appropriate rate.
68
Where are the Osmo receptors?
They are in the hypothalamus
69
What do the osmoreceptors do?
They detect a fall in the water potential in the blood (monitor the salt potential). They set nerve impulses which passed to the posterior pituitary gland where ADH is released into the blood.
70
What happens during Osmoregulation?
The osmoreceptors in the hypothalamus detect the fall in water potential in the blood. They set nerve impulses which passed to the posterior pituitary gland where ADH is released into the blood. ADH then binds to the receptors found on the surface membrane of the collecting duct and DCT cells. A second signalling membrane cAMP is formed which causes vesicles containing aquaporins to bind to the cell membrane, increasing the collecting ducts permeability to water.
71
What do the endocrine glands do?
They secrete hormones into the blood.
72
What do you exocrine glands do?
It's secretes substances (often enzymes) into a duct.
73
Which gland contributes to homoeostatic balance?
Endocrine gland
74
What is antidiuretic hormone?
It is a hormone produced in the hypothalamus and is secreted by the posterior pituitary. The hormone increases the permeability of the DCT cells and the collecting ducts walls to water allowing more water to be reabsorbed.
75
What is diuresis?
It is the production of a large volume of dilute urine. A diuretic such as alcohol is a compound which causes a large production of urine. ADH causes a small production of concentrated urine and it makes the walls more permeable to water so more water can be reabsorbed from the filtrate back to the blood.
76
What controls the volume of water reabsorbed?
Negative feedback
77
What happens if there is a reduce in water intake?
A drop in water potential is detected by the Osmo receptors in the hypothalamus. Secretory granules carry ADH along the axon from the hypothalamus to the posterior lobe of the pituitary gland were ADH is secreted into the bloodstream it is carried to the kidneys where ADH increases the permeability of the walls and the DCT and collecting that. ADH causes Aqua Porins to become incorporated in the membrane from within this cytosol. Water then flows from the collecting duct into a region of high solute potential into the medulla. More water can then be reabsorbed into the vasa recta (this water is reabsorbed by osmosis from the filtrate into the surrounding hypertonic to tissue fluid around the DCT and collecting duct that this produces concentrated urine). The water is restored back to its original potential. Urine reaches the bottom of the collecting duct with a close concentration to the tissue fluid concentration near the apex of the loop of henle which is hypertonic to the general body fluids.
78
What happens if the water potential becomes too high in the blood?
The posterior pituitary gland releases less ADH. Once the ADH is broken down it's no longer bound to receptors so Aqua Porins are absorbed back into vesicles by endocytosis they move back into the cell and get removed from the membrane, so it's now impermeable to water so cannot leave the filtrate so remains in the urine. This produces a large volume of dilute urine. The blood's water potential can now return back to set point as water is getting removed from the body.
79
What are Aqua Porins?
They are intrinsic membrane proteins with a pore enabling water to move through.
80
What happens in the walls of the collecting duct and DCT?
The ADH binds to receptors as they can't pass through the membrane. These are secondary signalling messengers called cAMP which travel through the cytoplasm to cause the vesicles containing Aqua Porins to fuse with the membrane.
81
Describe what would happen if there was a decrease in water potential.
STIMULUS - Decrease in WP in the blood
DETECTOR/ RECEPTOR - Osmoreceptors in the hypothalamus detect a decrease.
CO-ORDINATOR - The posterior pituitary gland secretes ADH
EFFECTOR - Target cells in the CD and DCT in the nephron become more permeable to water (aquaporins fuse to the membrane)
RESPONSE- More water is reabsorbed into the blood and a small volume of concentrated urine is produced.
82
What happens if there is an increase in water potential in the blood plasma?
STIMULUS- Increase in WP in the plasma
DETECTOR/RECEPTOR- Osmoreceptors detect an increase
CO-ORDINATOR- The posterior lobe of pituitary gland stops the release of ADH.
EFFECTOR- Cells in the CD and DCT of the nephron become less permeable to water (as aquaporins move out of the the membrane)
RESPONSE- Less water is reabsorbed in the blood from the CD and DCT, with a large volume of urine being produced.
83
What is homoeostasis?
It describes the mechanisms by which a constant internal environment is achieved e.g. core body temperature, glucose levels, solute potential and removing waste.
84
Why is it important to keep the concentration of body fluid is constant?
It protects cells from changes in the external environment as they are kept at optimum level. It allows reactions to occur at a constant an appropriate rate allows cells to function normally despite environmental changes. Water potential, pH and body temperature can all alter but they fluctuate around a set point with the body kept in a dynamic equilibrium.
85
How does the endocrine system relate to negative feedback?
The system controls the homeostatic responses with hormones operating by negative feedback.
86
Why is homoeostasis important?
It allows cells to function efficiently and independently of fluctuations, the cells are provided with constant conditions even during different levels of activity of the organism.
87
What is negative feedback?
Negative feedback is a change in a system which produces a second change which reverses the first change. For each condition determined there is a set point which is determined by the control centre the deviations from the set point are then corrected by negative feedback was set point is restored.
88
How does the negative feedback work?
The receptor monitors the condition and detects the level of the factor and its deviation from the set point which provides an input to the coordinator. The coordinator then evaluates the information and provide output for the effective by communicating with the effectors. Effectors make a response designed to take away the deviation from the corrective procedures. The factor then returns back to normal monitored by the receptor and information is fed back to the effectors which stop making the correction
89
Give two examples of negative feedback?
Glucose concentration and core body temperature.
90
How is negative feedback use in glucose concentration?
If the glucose levels are too high above setpoint insulin is required in order to reduce the concentration as it is converted into glycogen increasing the rate at which it is respired. If the concentration falls below setpoint then glucagon is secreted which results glycogen being converted into glucose.
91
How is negative feedback used in temperature of the body?
If it falls below setpoint increased respiration generates heat and superficial blood vessels are constricted in order for the body to retain it. If the temperature was to rise above the norm superficial blood vessels dilate allowing the heat to radiate from the body reducing its temperature.
92
What systems operate in a positive feedback system?
Oxytocin and clot formation
93
How is positive feedback used in clot formation?
When the skin is cut the first stage of a clot forming is when the platelets adhere to the cut's surface. They secrete signalling molecules which attract more platelets to the site.
94
What would happen if your kidneys were to fail?
Would be unable to remove your ear which can increase the toxic levels. Excess water would also be unable to be a major body fluids would increase in volume and diluted compromising metabolic reactions.
95
What are the main causes of kidney failure?
Diabetes, high blood pressure, loss of blood pressure, autoimmune disease, infection and crushing injuries
96
Why can diabetes cause kidney failure?
High glucose concentration in the plasma results in the glomeruli losing protein especially albumin into the filtrate and causing some proteins to link together triggering scarring in a condition called glomerulosclerosis
97
How does high blood pressure cause kidney failure?
This causes damage to the glomeruli capillaries preventing ultrafiltration.
98
How does low blood pressure cause kidney failure?
Due to loss of blood or dehydration
99
Why are treatments necessary?
In order to reduce waste concentration and control the volume of bodily fluids and to regulate solute concentration.
100
What are the treatment options?
Reducing intake in certain nutrients especially protein in order to reduce the amount of urea formed and ions e.g potassium and calcium.
Using drugs to reduce blood pressure.
Dialysis.
Kidney transplant
Reducing the concentration of potassium and calcium ions
101
How is angiotensin used to reduce blood pressure?
It is a converting enzyme (ACE) inhibitors and angiotensin receptor blocker (ARBs) reduce the effect of the hormone angiotensin which constricts blood vessels increasing the blood within.
102
How does calcium channel blocker reduce blood pressure?
They dilate blood vessels reducing blood pressure.
103
How do beta blockers reduce blood pressure?
They reduce affect of adrenaline. Adrenaline causes an increase in blood pressure as the heart rate rises.
104
How does reducing the concentration of potassium and calcium ions help treat kidney disease?
The ions in the body fluids and maintained by balance of absorption in the small intestine and selective reabsorption nephron in the PCT.
105
How is high levels of potassium treated and what does it cause?
It can be treated with glucose and insulin. It can lead to heart arrhythmias (irregular heart rhythm) so intravenous calcium is use additionally to stabilise the heart muscle membranes.
106
How is high levels of calcium treated and what does it cause?
High calcium levels in the blood link to an increase in heart disease, kidney stones and osteoporosis. It is treated with biphosphonate. Biphosphonate decrease the activity of osteoclasts, the cells that break down bone in its constant recycling, releasing it into blood. More can then accumulate in the bone and less can circulate the blood.
107
What is dialysis?
It is the process of removing nitrogenous waste and its use as an artificial replacement for the loss of kidney function it also removes water that is an excess.
108
What is the dialysis fluid?
The fluid is isotonic with blood but has fewer ions and no urea which creates a concentration gradient. Ions and urea can diffuse down their concentration gradient out of the blood by the pores in the tubing into the fluid. Diffusion only occurs until equilibrium is reached. Water flows down its water potential gradient by osmosis. The fluid contains the same concentration of glucose as in the blood so none of it diffuses out. Fresh fluid is continuously passed through the machine in order to maintain the concentration gradient with the used fluid discarded.
109
What is haemodialysis?
Is a machine which separates of blood to be claimed and the dialysis fluid with a selectively permeable membrane. Blood is taken from the artery in the arm where the blood passes through thousands of narrow fibres made of selectively permeable dialysis tubing. These fibres are surrounded by the dialysis fluid. The tubing has small pores enabling small molecules to move in and out of the blood into the fluid. Large molecules like large proteins, blood cells and platelets can't past through. It uses a counter current mechanism where the blood can pass flow in opposite directions enhancing the rate of diffusion with the blood then returned to the vein.
110
What mechanism does the haemodialysis have?
A counter current mechanism
111
What is added to the blood for haemodialysis?
Heparin is added to the blood in order to thin it and prevent it from clotting.
112
Why is a sensor used in haemodialysis?
As it detects haemoglobin that would diffuse through the red blood cells if they were damaged.
113
What is continuous ambulatory peritoneal dialysis?
This dialysis is 'ambulatory' as the patient can be active and carry out normal activities during it. The patient drains a 1 to 3 dm3 bag of dialysis through a catheter and the abdomen into the body cavity. This dialysis uses the peritoneum, a thin layer of tissue which lines the abdomen. It has a rich supply of capillaries and acts as a dialysis membrane with ions and urea diffusing out of the blood into the fluid. After 40 minutes the fluid is drained from the abdomen using gravity and an empty bag. This process is repeated four times a day.
114
What must patient avoid when doing CAPD?
They must drink very little and avoid high potassium foods like tomatoes and bananas in order to prevent retention of liquid and accumulation of potassium ions.
115
State some negatives of haemodialysis?
Patient routinely use a machine for several hours at a time several days a week with patients are unable to carry activities whilst connected.
Regular hospital visits for treatment.
Expensive machinery needed which is in a short supply.
116
State some positives of haemodialysis?
Reduced risk of fluctuations in blood volume and content.
| More efficient at removing salt, urea and excess water. Infection risk is lower.
117
State some positives of continuous ambulatory peritoneal dialysis?
It is less time-consuming and patients can carry out activities whilst connected.
Fewer hospital visits as can be completed at home.
Machinery is less expensive.
118
State some negatives of CAPD?
Patients may experience fluctuations in blood volume and content.
Less efficient at removing salt, urea and excess water.
Infection risk is greater due to the catheter.
119
Who can be a donor?
They can be a living donor or could have suffered a brain or circulatory death.
120
How long does a kidney last?
Transplants can last 30 years but most file at some stage with the patient resulting back to dialysis. Kidneys from a live donor tend to work immediately and last longer. Kidneys from a deceased donor tend to take a few days or weeks to work so have to stay on dialysis until then.
121
What needs to happen in order for a recipient to receive a kidney?
They must be compatible in the ABO group and have a close tissue match in the (human leucocyte antigen) HLA.
122
Who is included in the high risk donors?
People who are 50 and over, those with high blood pressure or diabetes as their kidneys have a higher chance of failing.
123
How is the kidney transplanted?
It is placed in the lower abdomen, in the groin and the renal artery and vein emerging from the transplanted kidney are attached to the iliac artery and vein rest affectively. The circulation is restored once a kidney returns to a healthy pink colour and urine is seen emerging from the ureter, the ureter is joined to the bladder.
124
What happens after transplant?
The patient must take immunosuppressive drugs for the rest of their life as rejection may occur and is most common in the first six weeks. With a suppressed immune system patients are more susceptible infection especially in a urinary tract which can damage the kidney so low-dose antibiotics are used.
125
Why are anti-viral sometimes used?
Cytomegalovirus has infected 50% of the UK. The donor kidney may infect an infected recipient so antivirals may be used.
126
What can immunosuppressants increase the risk of?
Cancers especially skin cancer and lymphoma
127
What are Xenotransplants?
In the future animals like peas could be genetically engineered so that their cells don't carry antigens which would attack or immune system however there are ethical issues about organ sources.
