Renal physiology by 3L5WADkD

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									Renal physiology
     Petra Bos
                    Objectives
   Understand and explain renal physiology
     Glomerular filtration
     Tubular reabsorption

     Tubular secretion

     Urine concentration and dilution

     Role in body homeostasis

   Understand and explain the process of
    micturition
              Kidney function
   Remove waste and excess fluid from the blood
   Homeostasis of H2O and electrolytes
   Homeostasis blood pressure
   Acid-base balance
   Produce erythropoetin
   Role in renin – angiotensin system
   Role in calcium metabolism
             Production of urine
   Glomerular filtration: 180 litres / day
   Tubular reabsorption: 178.5 litres / day
   Tubular secretion

   Urine: 1.5 litres/day




                Marieb, Human Anatomy & Physiology, 7th edition
                  Functional unit
   Nephron




              Marieb, Human Anatomy & Physiology, 7th edition
     Glomerular filtration




Marieb, Human Anatomy & Physiology, 7th edition
            Glomerular filtration
   Glomerulus
   Bowman’s capsule
   Membrane permeable:
     Plasma
     Electrolytes

   Impermeable:
     Blood cells
     Protein
     Drugs


                          Marieb, Human Anatomy & Physiology, 7th edition
Glomerular filtration




            Marieb, Human Anatomy & Physiology, 7th edition
            Glomerular forces
   Hydrostatic pressure
    glomerulus (55 mm Hg)
   Hydrostatic pressure
    Bowman’s Capsule (15
    mm Hg)
   Osmotic pressure
    glomerulus (30 mm Hg)



                            Marieb, Human Anatomy & Physiology, 7th edition
          Tubular reabsorption
   Active
   Passive
   Secondary
    active

   Maximum
    capacity

                Marieb, Human Anatomy & Physiology, 7th edition
                       Tubular reabsorption
        Na+
        Glucose
        Amino acids
        H2O
        Cl-
        K+
        HCO3-
        Ca2+
        PO3-
        Mg2+

Marieb, Human Anatomy & Physiology, 7th edition
            Tubular reabsorption




Marieb, Human Anatomy & Physiology, 7th edition
             Tubular secretion
   Acid – base balance:
       H+
   K+
   Drugs

   Active transport
              Plasma clearance
   Volume of plasma cleared of a particular
    substance
   Unit: ml/min
   Dependent on:
     GFR; does the substance get filtered?
     Reabsorption; is it reabsorbed

     Secreted; is it secreted?
                       Osmolality
   Pressure exerted by components of a liquid
   Unit milliosmol




                                          Low
           High osmolality Similar osmolality osmolality
                       Osmolality
   Pressure exerted by components of a liquid
   Unit milliosmol




                                          Low
           High osmolality Similar osmolality osmolality
                   Urine concentration
   Medullaire nephrons




    Marieb, Human Anatomy & Physiology, 7th edition
                    Urine dilution
   Descending
    loop:
       H2O transport
   Ascending
    loop:
       Na+ transport




                        Marieb, Human Anatomy & Physiology, 7th edition
           Urine concentration
   ADH
   Collecting
    duct
    permeable
    for H2O
   H2O follows
    osmotic
    gradient

                  Marieb, Human Anatomy & Physiology, 7th edition
Countercurrent mechanism




         Marieb, Human Anatomy & Physiology, 7th edition
                Urine contents
   pH 4.5 – 8.0
   No protein
   No blood cells
   No glucose
   No bacteria
   Urea, creatinine
                    Overview nephron




Marieb, Human Anatomy & Physiology, 7th edition
            Juxtaglomerular apparatus
                                 Juxta-glomerular cells
                                                           Fluid movement ↑

                                                            Juxtaglomerular
                                                               apparatus

                                                          Constriction afferent
                                                               arteriole

                                                          Hydrostatic pressure
                                                             glomerulus ↓

                                        Macula densa
                                                          Glomerular filtration
                                                                rate ↓
Marieb, Human Anatomy & Physiology, 7th edition
       Renin angiotensin system
           Blood pressure ↓

          Renin production ↑
                                      ACE
Angiotensiongen       Angiotensin 1         Angiotensin 2

                                       Aldosteron secretion ↑

                                        Na+ reabsorption ↑

                                        H2O reabsorption ↑

                                            Blood pressure ↑
              Transport of urine
   2 ureters
   Peristaltic transport
   Diagonal entrance
    in bladder
   Physiological valve




                            Marieb, Human Anatomy & Physiology, 7th edition
                                      Bladder
                                                     300-400 ml
                                                     Maximum: 1000 ml
                                                     Micturition reflex
                                                      when volume
                                                      exceeds 200 ml




Marieb, Human Anatomy & Physiology, 7th edition
                  Continence
   Internal sphincter
   External sphincter




                         Marieb, Human Anatomy & Physiology, 7th edition
                                 Continence
                                                     Bladder volume
                                                      >200 ml
                                                     Impulse to spinal
                                                      cord and pons
                                                     Inhibition detrusor
                                                      mucle contraction
                                                     Contraction
                                                      internal and
                                                      external sphincter

Marieb, Human Anatomy & Physiology, 7th edition
                    Micturition
   Bladder volume >200
    ml
   Impulse to spinal cord
    and pons
   Relaxations external
    sphincter (voluntary)
   Reflex relaxation
    internal sphincter
   Contraction detrusor
    muscle


                             Marieb, Human Anatomy & Physiology, 7th edition
Overview
Glomerular filtration
              Water
              Electrolytes
              Protein
              Glucose
              Blood cells
        Tubular reabsorption




sodium      active transport       gradient
water       follows sodium
potassium   2nd active transport   difussion
glucose     2nd active transport
Tubular secretion




      urea
      drugs
      H+
      K+
       Countercurrent principal
300    300                        300

                 100      100




1200                              1200
       1200
                          100
              Concentrating urine
300    300                                 300

                      100     100

                     ADH

                                     ADH




                    ADH
                               ADH

1200                                       1200
       1200
                              1200
                  More info
   Physiology book

   http://www.nottingham.ac.uk/nursing/sonet/rl
    os/bioproc/gfr/
   http://www.nottingham.ac.uk/nursing/sonet/rl
    os/bioproc/kidneyanatomy/index.html
   http://www.nottingham.ac.uk/nursing/sonet/rl
    os/bioproc/kidneyphysiology/index.html
       Questions?



petrabos@postgrads.unisa.edu.au
Marieb, Human Anatomy & Physiology, 7th edition
Marieb, Human Anatomy & Physiology, 7th edition

								
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