This document outlines the functions and physiological anatomy of the kidneys, including their excretory, homeostatic, and endocrine functions. It describes the nephron structure and types, as well as the renal circulation and blood flow dynamics. Additionally, it details the nervous supply to the kidneys, indicating how sympathetic and parasympathetic inputs can affect renal blood flow and potential sensory pain referral.

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RENAL PHYSIOLOGY
(I)
m
KIDNEY FUNCTION &
PYSIOLOGICAL ANATOMY
Mohammed Abdel Gawad

2. OBJECTIVES
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 Introduction
 Functions of the kidney
 Physiological anatomy of the kidney
 Nephron & its types
 Renal circulation & renal blood flow
 Nervous supply of the kidney

3. INTRODUCTION – THE KIDNEY
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 A retroperitoneal organ
 T11-L3
 Normal size: 11-15cm
in adults.
 Right kidney usually
shorter than the left
(upper limit of variation
in length between right
& left 1.5 cm)

4. FUNCTIONS OF THE KIDNEY
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 1- Execratory function:
 a. metabolites
 b. drugs
 c. toxins
 2- Homeostatic function:
 a. Maintenance of water balance.
 b. Maintenance of electrolyte balance.
 c. Maintenance of acid-base balance.
 3- Endocrine (hormonal) secretory function:
 a) Renin by the juxtaglomerular cells (JG)
 b) Erythropoietin hormone by endothelial cells of peritubular capillaries of renal
cortex
 c) Prostaglandins.
 4- Endocrine (hormonal) metabolic function:
 The kidney converts vitamin D3 → active 1,25­dihydroxycholecalciferol by
alpha one hydroxylase enzyme in cells of PCT under effect of PTH.

5. PHYSIOLOGIC ANATOMY
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OF THE KIDNEY

6. NEPHRON
(Renal malpighian corpuscle & Renal tubules)
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7. NEPHRON
(Renal malpighian corpuscle)
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8. NEPHRON
(Renal malpighian corpuscle)
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9. TYPES OF NEPHRON
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10. TYPES OF NEPHRON
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(85-90%)
(10-15%)

11. RENAL CIRCULATION
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 See the video
on our facebook group
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12. RENAL CIRCULATION
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13. RENAL CIRCULATION

14. KIDNEYS BLOOD FLOW RATE
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 - One fourth (25%) of the cardiac output
passes into the kidney/minute (1300 ml
blood/minute).
 - The high renal blood flow does not reflect a
high O2 consumption (kidneys utilize 8% of the
total O2 consumption of the body).
 - This high blood flow is related to the
homeostatic function of the kidney → allows a
high rate of glomerular filtration

15. NERVE SUPPLY
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 The renal blood vessels are supplied by
splanchnic nerves, vasoconstrictors → renal
blood is reduced in stress condition due to
sympathetic stimulation → blood is shifted
to vital organs
 The kidney also receives input from the
parasympathetic nervous system, by way of
the renal branches of Vagus nerve (Cranial
nerve X), the function of this is yet unclear.
 Sensory input from the kidney travels to the
T10-11 levels of the spinal cord and is
sensed in the corresponding dermatome.
Thus, pain in the flank region may be
referred from corresponding kidney

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Gawad