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2014-05-08 07:11:14

Extra Stuff For Unit 4
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  1. Outline The Main Features Of The Two Types Of Dialysis
    • Hemodialysis
    • - Haemodialysis is the most common form. blood from a vein is passed over a dialysis membrane in an external machine.
    • - Heparin is added to prevent clotting of the blood externally

    • Peritoneal
    • - The dialysis is done internally, A permanent catheter is inserted into the abdomen.
    • The filter is the patient’s own abdominal membrane, the peritoneum.
    • - Dialysis fluid is inserted through the catheter into the space between the abdominal wall and surrounding organs.
    • - After a couple of hours, the fluid is drained from the abdomen, and this process must be performed in several consecutive sessions daily.
  2. Outline How The Cells That Line The PCT Are
    Specialised To Achieve Ultrafilteration
    There are tight junctions between each cell which prevent substances from moving between cells (instead they have to go through them.

    The plasma membrane in contact with the tubule fluid is highly folded to form microvilli which increases surface area for reabsorption

    Membrane also contains special cotransporter proteins that transport glucose or amino acids in association with sodium ions

    there are many mitochondria to provide energy for the active processes
  3. How Does Water Reabsorption Take Place In The Loop Of Henle
    • The descending limb is highly permeable to water, and so water is lost to the surrounding medullary fluid by osmosis more and more as the fluid flows down the limb, and the water
    • which is lost is reabsorbed back into the blood by surrounding capillaries – this concentrates the tubule fluid The descending limb does not actively lose any sodium or chloride ions

    • At the bottom section of the ascending limb, the concentration gradient of salts causes sodium chloride to diffuse from the ascending limb into the medullary interstitial fluid,
    • lowering the solute concentration of the filtrate and adding to the solute
    • concentration of the surrounding fluid.

    Near the top of the ascending limb, sodium chloride is actively transported out into the medullary fluid. As the walls of the ascending limb are impermeable to water, the movement of salts does not cause water to osmotically follow along. 

    • As the tubule fluid moves along the loop of
    • Henle, the transport of sodium chloride out of the ascending limb, coupled with the osmosis of water out of the descending limb, establishes an osmotic concentration in the medullary interstitial fluid which becomes increasingly hypertonic as the loop drops in towards the medulla
  4. Outline The Process Of Selective Reabsorption
    On the plasma membrane closest to the blood capillary, there are sodium-potassium pumps which actively transport sodium ions out of the cell and potassium ions into the cell.  As sodium ions are pumped out, the concentration of sodium ions inside drops

    This allows the transport of sodium ions back in from the plasma membrane in contact with the PCT – the ions flow in through specialised co-transporter proteins which couple the movement of sodium ions into the cell with the movement of glucose and amino acids As sodium moves in, taking glucose and amino acids in with it, the concentration of glucose and amino acids within the cell increase, and so these substances diffuse out and into the blood capillary via facilitated diffusion, using transport proteins

    • The movement of substances from the PCT into the cells leads to an increased water potential inside the PCT and so water diffuses, by osmosis, into the cells, which increases the water potential of those cells,
    • and so water diffuses into the blood capillary

    Larger proteins will be reabsorbed by endocytosis
  5. Adrenaline cannot enter the cell so how does it cause an effect?
    Adrenaline is the first messenger

    • The adrenaline receptor on the plasma membrane is a complementary shape to the
    • shape of the adrenaline. This receptor is associated with an enzyme on the inner surface of the plasma membrane called adenyl cyclase.

    The adenyl cyclase converts ATP to cyclic AMP CAMP – the cAMP is therefore the secondary messenger which goes on to cause effects inside the cells by activating enzyme actions
  6. Give the evaluation for undergoing dialysis
    • No need for major surgery, even the implantation of peritoneal dialysis is only minor surgery
    • no chance of rejection or need for immunosuppresents

    • but....
    • negative impact on quality of life
    • constant need for dialysis is a burden
    • diet is strictly limited if your on dialysis
    • physiological drawback of seeing yourself as chronically ill
  7. Give the evaluation for undergoing kidney transplants
    • Does not effect your life as much - no need for time consuming dialysis all the time
    • better quality of life and diet is less limited
    • physchologically no longer see yourself as ill

    • but....
    • requires major surgery including the risk of general aesthesia and surgery itself
    • possible risk of rejection and must take immune drugs and there also side effects to the drugs themselves
  8. State Where Both Aldosterone And Adrenaline Are Made
    Aldosterone – Adrenal Cortex

    Adrenaline – Adrenal Medulla
  9. Give The Effects Of Adrenaline Hormone
    • - Increases heart rate and stroke volume
    • - Stimulates glycogenolysis in the liver
    • - Decreases blood flow to the gut and skin by vasoconstriction
    • - Increases blood flow to muscles and brain by vasodilation
    • - Increases blood pressure – vasoconstriction
    • - increases resistance to flow
    • - Increases air flow to alveoli by contracting smooth muscle
    • - Contraction of radial muscles in iris – dilate pupil
    • - Increases secretion from apocrine sweat glands
  10. How Does The Pregnancy Test Work?
    Urine passes into the reaction zone and some of the monoclonal antibodies bind to the hCG, though some do not and carry on down the strip also

    When the urine carrying the monoclonal antibodies (some bound to hCG and others not) reaches the testing zone, the hCG binds from a separate area to the polyclonal antibodies immobilised here, so that the blue beads on the original anditbodies are fixed – this zone goes blue

    those monoclonal antibodies without hCG attached continue to move along the strip with the urine when they reach the control antibodies and bind to them, likewise here turning this zone blue