Glomerular And Tubular Dysfunctions

Front 1

Basic kidney functions

Back 1

Water and electrolyte homeostasis

Acid – base balance

Elimination of waste products and ingested chemicals

Hormone production

Front 2

Mechanisms of renal excretion

Back 2

180 l glomerular filtrate per day (2 ml/s)

99% - back reabsoption

Renal perfusion at rest = 20% of cardiac output (this is higher than in heart, brain and liver

Front 3

Glomerular filtration rate

Back 3

Balance of hydrostatic and osmotic pressures acting across diffusion barrier (endotelium fenestrae, basement nenbrane, slit diaphragms betweens the podocytes)

Front 4

Factors determining GFR:

Back 4

Surface area (1 milion nephrons within each kidney)
Permeability
Net filtration pressure (NFP) across diffusion barrier

Front 5

filtration koefficient (Kf)

Back 5

surface are and permeabiltiy

Front 6

Disturbances of glomerular function

Back 6

Decrease of glomerular filtration
Increase of glomerular permeability

Front 7

Decrease of glomerular filtration

Back 7

Decr. renal blood flow
stenosis of renal artery

Decr. glomerular capillary hydrostatic pressure (PGC)
hypovolemia, circulatory shock

Incr. hydrostatic pressure in Bowman´s capsule (PT)
block of fluid flow ( intra- and extrarenal)

Decr. concentration of plasma proteins (GC)

Decr. Kf
Decr. effective filtration surface area

Front 8

Increase of glomerular permeability

Back 8

Glomerular proteinuria

Size-selective properties of the glomerulus
Charge-selective propeties of the glomerulus
Hamodynamic forces operating across the glomerulus

Front 9

Selective proteinuria

Back 9

Albumin
Small amount of low-molecular globulins

Front 10

Non-selective proteinuria

Back 10

Albumin
Globulins of various molecular weight

Front 11

Tubular proteinuria

Back 11

Decr. excretion of low molecular proteins

alpha 1-microglobulin, beta 2-microglobulin

Front 12

Overload (prerenal) proteinuria

Back 12

Small molecular weight proteins can rise when are synthetised in excess

Tissue degraded products
Proteins of acute phase (pyretic proteinuria)
Myoglobin (rhabdomyolysis)
Ligfht immunoglobulin chains (myeloma)

Front 13

Proteinuria-Values
Healthy adult subject:
Small proteinuria:
Heavy proteinuria:

Back 13

Healthy adult subject
No more than 150 mg/day

Small proteinuria
1 g/day

Haevy proteinuria
3,5 g/day and more
Nephrotic syndrome (10 – 30 g/day)

Front 14

Renal hematuria

Back 14

Glomerular
Abnormally increased permeability

Non-glomerular
Rupture of tumor or cyst vessels

Bleading from urinary tract

Front 15

Relation between the reduction of GFR and excretion function of kidneys

Back 15

 GF   retention of substrates

1. urea, creatinín
2. phosphates, K+, H+
3. NaCl

Front 16

Reabsorption of glucose, amino acids, Na, K, Cl, H2O

Back 16

Proximal tubule (Na, Glu -Countertransport) ; (Na, H+ -Countertransport)
Thick ascending limb of loop of Henle (Na, K, Cl,)
Distal tubule (Na,Cl)

Front 17

Disturbances of tubular functions

Back 17

Tubular proteinuria
Glucosuria
Aminoaciduria
Diabetes insipidus
Osmotic diuresis

Front 18

Diabetes insipidus

Back 18

Neurogenic (Decr.ADH)
Nephrogenic (insensitivity of the renal tubule to ADH)

Front 19

Osmotic diuresis

Back 19

Pressure of large quantities of unreabsorbed solutes in the renal tubules >>increase in urine volume
Unreabsorbed solutes in the proximal tubules „hold water in the next tubules“

Front 20

Hydrogen ion secretion and bicarbonate reabsorption

Renal tubular acidosis

Back 20

- impairment of the ability to make the urine acidic
- chronic renal disease – reduction of secreted hydrogen ion
because of impaired renal tubular production of NH4+

Front 21

Disturbances of kidney ability to concentrate urine

Back 21

Disturbances of water reabsorption
Disturbances of the production of medullar

Front 22

Disturbances of water reabsorption

Back 22

diabetes insipidus

Front 23

Disturbances of the production of medullar hyperosmolarity

Back 23

- osmotic diuresis
- incr. blood flow in vasa recta
- morphologic deformations of medulla

Front 24

Proteinuria:

Back 24

3.5 g or more of protein in the urine per day
Minimal changes of glomerular membrane: 90% albumin (selective proteinuria)

Front 25

Hypoproteinemia (hypoalbuminemia)

Back 25

Mechanisms: proteinuria +
Protein loss by stool
Plasma proteins are shifted to extravascular space
Increased albumin katabolism
Inadequately increase albumin synthesis in liver

Front 26

Hyperlipidemia

Back 26

Incresed lipoprotein synthesis in liver

Front 27

Mechanisms of edema in nephrotic syndrome (NS)

Back 27

Classis theory
Hypoalbuminemia   plasma oncotic pressure  hypovolemia  R-A-A + ADH  Na + water retention

!!! But hypovolemia is present only in 30% of patients suffering from NS; plasma renin activity and aldosteron are decreased

Front 28

Two groups of patients with NS:

Back 28

1. Hypovolemia and  R-A-A activity
- small glomerular abnormalities
2.Hypervolemia without R-A-A activation
- more serious morphological abnormalities

Front 29

Pathophysiology of edema formation

Back 29

Extracellular fluid volume is determined by the balance between Na intake and its renal excretion

Common feature: renal salt retention despite progressive expaansion of ECF volume

Primary abnormality of the kidney
Secondary response to some disturbances in the circulation

Front 30

Primary edema (overfill)

Back 30

Primary defect in renal sodium excretion

Hyperevolemia leads to high cardiac output

 R-A-A,  ADH,  sympathetic activity

Examples: blomerulonephritis, renal failure

Front 31

Secondary edema (underfill)

Back 31

Response of normal kidnay to actual or sensed underfilling of the circulation

Primary disturbances within the circulation secondary triggers renal sodium retention

inr. R-A-A, incr. ADH, incr. sympathetic activity

Effective arterial blood volume