2. صدق الله العظيم الاسراء اية 85

3. By Dr. Abdel Aziz M. Hussein Assist Prof of Medical Physiology

4. Kidneys Urinary System

6. Kidney Functions Homeostatic Excretory Metabolic Regulatory Endocrinal

7. Kidneys keep the constancy of the internal environment (ECF) regarding; 1.Total body water 2.Tissue fluid osmolarity 3.Electrolytes Na, K, Ca etc……. 4.pH InputOutput IntakeKidney

8. Kidneys get rid of 1.Metabolic waste products e.g. urea, uric acid & creatinine. 2.Many drugs and toxins Chronic renal failure → accumulation of these metabolites (uremia)

9. Renin Drop of ABP Angiotensinogen Angiotensin I Angiotensin II ACE Through; a) Renin - angiotensin system V.C. Aldosterone ↑ ABP

10. b) Production of vasoactive substances e.g. PGs and kinins. c) Control of Na and Water excretion Vasoactive substances e.g. kinins and PGs Controlling of Na and Water excretion

11. Kidneys secrete; kinins and PGs Renin Erythropoietin from interstitial cells around PTC Activation of Vit D 1,25 DOCC

12. Gluconeogenesis in fasting and starvation Breakdown of insulin and glucagon Do not Forget (RHEEM)

14. Weight : 150 gm Capsule: tough and fibrous (limit its distension) Cross section: Outer Cortex inner Medulla Capsule

15. Cortex Medulla Glomeruli PCT DCT LH CDs Vasa recta

17. Def., It is the structural and functional unit of the kidney Number: one million nephrons in each kidney Components : A) Renal or Malpigian CorpuscleB) Renal Tubule

18. Renal Corpuscle Renal Tubule

22. Short Wide Direct branch of aorta

25. Value: 1200 ml/min or 4 ml/ 1 gm kidney tissues Significance: Is high to ensure high GFR NOT to supply excess O2 for excess metabolism

27. Components:

28. Monitor NaCl concentration in DCT (stimulated by low NaCl) ↓ GFR ↑ GFR

29. A) Synthesis, store and release of renin B) acts as Baroreceptors (detect tension in wall of afferent arterioles) Renin ↓ Renal Blood Flow ↓ wall tension JG cells

30. Form functional syncitium with macula densa and JG cells

31. Renin Angiotensinogen Angiotensin I Angiotensin II ACE The only function of JGA is synthesis and secretion of renin V.C. Aldosterone Actions of Renin: Thirst and salt appetite Stimulates Na reabsorption from PT Stimulates Na and H2O reabsorption from intestine Stimulates ACTH, ADH, etc…. Increase force of myocardial contraction

33. Filtration Reabsorption Secretion Urine

35. Def., It the membrane through which the plasma is filtered Composition: 3 layers; 1.Capillary endothelium 2.Basement membrane 3.Capsular epithelium

38. Capillary endothelium Basement Membrane Podocytes slits Blood Bowman Capsule Blood Cells Plasma proteins Plasma solutes

39. Capillary endothelium Basement Membrane Podocytes slits Blood Bowman Capsule

40. Def., It is an ultrafiltration since it is plasma minus plasma protein and cellular elements while simple filtration excludes only cellular elements.

41. Dynamics: Glomerular Filtration is formed by the forces of filtration as many capillary filtrate in the body (Starling's forces of filtration). They are 4 forces;  2 Hydrostatic pressures  2 Oncotic pressures

42. Capillary endothelium Basement Membrane Podocytes slits Glomerular capillary Bowman Capsule Glomerular Hydrostatic Pressure (Gp) Glomerular Oncotic Pressure (Gπ) Bowman Hydrostatic Pressure (Bp) Bowman oncotic Pressure (B π)

43. Gp = 60 mmHg Bπ = 0 mmHg Gπ = 32 mmHg Gp = 18 mmHg Help Filtration Oppose Filtration

45. Def., Volume of plasma filtered by both kidney per unit time Value: – 125 ml/min – 180 L/day Significance of High GFR: To ensure processing of plasma (3L) about 60 times/day (since daily GFR = 180L/day  prevents accumulation of metabolites.

46. Causes of high GFR: 1) High capillary hydrostatic P.: It is about 45- 60 mmHg in glomerular capillary High GP: 1.Efferent arteriole → narrower than afferent arteriole 2.Glomerular capillaries → present between two arteries

47. Causes of high GFR: 2) High KF (filtration coefficient) 3) High RPF.: It is about 600ml/ min. RBF

48. Factors Affecting GFR: About 45 – 60 mmHg Help GFR Glomerular hydrostatic pressure About 18 mmHg Oppose GFR Bowman’s capsular hydrostatic pressure About 32 mmHg Oppose GFR Oncotic pressure of plasma protein About 650 ml/min Help GFR Renal plasma flow (RPF) About 4 ml/min/ 1mmHg/ 100 gm Help GFR Filtration coefficient

53. 1.Glucose, amino acids, vitamins, protein → 100% 2.HCO 3 - → 90% 3.inorganic phosphate → 80% 4.Na + & water → 2/3 or 65% 5.K +, Ca 2+, Mg 2+ & urea → Variable amount Reabsorption

54. Organic solutes as PAH, drugs, various amines and ammonia. Secretion

55. a) Reabsorption of: 1.All filtered glucose, amino acids, vitamins, protein and Kreb’s cycle intermediates. 2.About 2/3 of filtered load of Na + & water. 3.About 90% of the filtered load of HCO 3 -. 4.About 80% of the filtered inorganic phosphate. 5.Variable amount of K +, Ca 2+, Mg 2+ & urea. b) Secretion of Organic solutes as PAH, drugs, various amines and ammonia.

58. 15% Water 30% Ca 65% Mg 10 % K Urea

59. a) Reabsorption of: 1.15 % of filtered water from DLH. 2.30% Ca 3.65% Mg 4.10 % K b) Secretion of Urea by thin ALH c) Concentration of urine by forming counter current multiplier system Thick ALH

62. 1.Final adjustment of urine formation. 2.Reabsorption of 7-10% of filtered load of Na +. 3.Reabsorption of 10-15% of filtered lead of water. 4.Secretion of variable amount of H + & K +. 5.Major control site for Na +, K +, Ca 2+ & acid- base balance of body. Many of these functions are controlled by hormones Na reabsorption controlled by aldosterone H2O reabsorption controlled by ADH