Renal Physiology

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Renal Physiology

• Nermien Waly MD, PhD
• Lecturer
• School of Pharmacy
• R1339
• ACU
• nwaly_at_yahoo.com

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Overview

• Renal anatomy
• Renal functions
• Excretory function of kidneys
• Mechanism of urine formation
• micturition
• urinalysis
• Regulatory function of the kidneys
• Endocrine function of the kidneys

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Anatomy
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Kidney functions

• Excretory function
• a. urine formation,
• b. micturition,
• c. urinalysis.
• 2. Regulatory functions
• a. Water balance,
• b. Electrolyte balance,
• c. Acid-base balance (pH).
• d. Osmolarity regulation.
• 3.Endocrine function renin, erythropoietin.

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Mechanism of urine formation

• Filtration glomerular filtrate GFR
• Re-absorption
• secretion

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1.Filteration

• glomerular filtrate (GF) composition
• GFR 125 ml/min (180 L/Day)
• Renal clearance C UV/P
• Renal Blood flow (RBF) 25 of COP.
• Factors affecting RBF
• Cardiac out put (COP).
• Vasoconstriction of afferent arterioles
  (sympathetic stimulation).
• Vasoconstriction of efferent arterioles
  (angiotensinII low doses, ACE inhibitors).
• Vasodilatation of renal arterioles e.g. PGE2 and
  I2, bradykinin, nitric oxide (NO), and dopamine.

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2. Re-absorption

• 95 of water is reabsorbed from the GF at the
  PCT.
• Almost all electrolytes are reabsorbed back to
  the blood e.g. Na, K, Ca, Phosphate, Mg,
  and HCO3- (acid-base balance).
• Urea???
• 5 of water and electrolyte re-absorption is
  under hormonal control e.g. ADH, Aldosterone,
  PTH, at the distal and collecting tubules (DT
  CT).
• Glucose is completely reabsorbed (diabetes
  mellitus)

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Na K handling at the Nephron
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3. Secretion

• Urea pending the flow rate.
• Creatinine
• H (acid-base balance)

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Micturition

• Urination is an autonomic spinal reflex that is
  under voluntary control in adult humans.
• It is composed of filling phase and voiding
  phase.
• Cortical control develop around 2-3 years of age.
  

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Urinalysis

• Physical appearance
• Chemical
• albumin,
• glucose,
• pH,
• crystals
• Cells RBCs, WBCs, epithelial, Pus cells
• Culture and sensitivity tests

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Notes of the Day

• The concept of recycling and biodegradable waste.
• Chips at ACU )