functional characteristics of nephron
TRANSCRIPT
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A male patient, age 60 presents to medical OPD with the complaints of Body Swelling, generalized weakness and anorexia. He is diabetic and hypertensive for the last about 5 years.On examination and investigations, it was found that he was having:1.Edema2.Metabolic acidosis3.Increased levels of Urea, Potassium, creatinine and uric acid4.Anemia5.Osteomalacia 6.Hypertension ©Prof. Dr. Rashid Mahmood 1
What is the probable Cause/ Diagnosis?
3 ©Prof. Dr. Rashid Mahmood3
OBJECTIVES• Goal /Aim
– By the end of this session students should be able to understand the Basic Concepts of Functional characteristics of nephron
• Specific objectives• At the end of the lecture students should be able to
• Describe the Functions of the Kidneys • Outline Physiologic Anatomy of the Kidneys and
Nephron• Describe The nephron as the functional unit of the
kidney• Differentiate between Cortical and juxtamedullary
nephron
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Lesson contents• Multiple Functions of the Kidneys in
Homeostasis– Excretion – Regulation of water and electrolyte balance– Regulation of arterial pressure– Regulation of acid-base balance– Regulation of erythrocyte production
– Regulation of 1,25-Dihydroxyvitamin D2 production
– Glucose synthesis
• Physiologic Anatomy of the Kidneys– General organization of the kidneys and urinary tract– Renal blood supply– The nephron is the functional unit of the kidney– Regional differences in nephron structure: Cortical and
juxtamedullary nephron ©Prof. Dr. Rashid Mahmood
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5 ©Prof. Dr. Rashid Mahmood5
OBJECTIVES• Goal /Aim
– By the end of this session students should be able to understand the Basic Concepts Functional characteristics of nephron
• Specific objectives• At the end of the lecture students should be able to
• Describe the Functions of the Kidneys • Outline Physiologic Anatomy of the Kidneys and
Nephron• Describe The nephron as the functional unit of the
kidney• Differentiate between Cortical and juxtamedullary
nephron
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FUNCTIONS OF KIDNEY
• Primary function
• REGULATORY FUNCTIONS
• EXCRETORY FUNCTIONS
• SECRETORY/ENDOCRINE FUNCTIONS
• OTHER FUNCTIONS
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Functions of kidney• Primary function
1. Maintenance of the normal volume and composition of body fluids2. To get rid of body waste
materials
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Functions of kidney1. REGULATORY FUNCTIONS (Maintenance of Homeostasis)
i. Regulation of water balanceii. Regulation of electrolyte concentrationiii. Regulation of acid-base balanceiv. Regulation of arterial pressure
i. Long-term: salt and water excretionii. Short-term: renin
v. Regulation of blood volume
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Functions of kidney2. EXCRETORY FUNCTIONS
i. Excretion of metabolic waste productsUrea, creatinine, uric acid, bilirubin etc
i. Excretion of drugs, hormone metabolites
ii. Excretion of foreign chemicals. ToxinsPesticides, food additives etc
--contd--
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Functions of kidney3. SECRETORY/ENDOCRINE
FUNCTIONS (Hormonogenesis)i. Erythropoietinii. Vitamin D-3 (1,25-dihydroxyvitamin
D3; calcitriol)
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Functions of kidney3. Other FUNCTIONS
i. Gluconeogenesisii. Detoxification of free radicals and drugs
(Peroxisomes)iii. PROSTAGLANDIN Synthesis and
metabolism i. Dilatation of blood vesselsii. Water and sodium excretioniii. Autoregulation of renal blood flow
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OBJECTIVES• Goal /Aim
– By the end of this session students should be able to understand the Basic Concepts Functional characteristics of nephron
• Specific objectives• At the end of the lecture students should be able to
• Describe the Functions of the Kidneys • Outline Physiologic Anatomy of the Kidneys and
Nephron• Describe The nephron as the functional unit of the
kidney• Differentiate between Cortical and juxtamedullary
nephron
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Physiological anatomy
• One million nephrons in each kidney
• Cannot be regenerated
• Decrease by 10% every 10 years after the age of 40 years
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RENAL BLOOD FLOW• 1200 ml/min
• 21% of Cardiac Output
• Weight: 0.4% of total body weight
• Q= P/R
Renal Blood Flow =(Renal Artery Pressure)-(renal vein Pressure)
÷
Total Renal Vascular Resistance
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Q. 2
• Calculate the Renal Blood Flow if – Renal Artery Pressure= 1100 mmHg– Renal vein Pressure = 5 mmHg– Total Renal Vascular Resistance= 0.1
» Also write calculations
©Prof. Dr. Rashid Mahmood 28
29 ©Prof. Dr. Rashid Mahmood29
OBJECTIVES• Goal /Aim
– By the end of this session students should be able to understand the Basic Concepts Functional characteristics of nephron
• Specific objectives• At the end of the lecture students should be able to
• Describe the Functions of the Kidneys • Outline Physiologic Anatomy of the Kidneys and
Nephron• Describe The nephron as the functional unit of the
kidney• Differentiate between Cortical and juxtamedullary
nephron
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Total length of all
Nephrons in both
kidneys= 100 km
Diameter of nephron=
10-60 microns
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Q. 3
1. Can you identify a portal system in the renal circulation? (Yes/ No)
2. From which Ganglion the renal nerves arise?
©Prof. Dr. Rashid Mahmood 33
34 ©Prof. Dr. Rashid Mahmood34
OBJECTIVES• Goal /Aim
– By the end of this session students should be able to understand the Basic Concepts Functional characteristics of nephron
• Specific objectives• At the end of the lecture students should be able to
• Describe the Functions of the Kidneys • Outline Physiologic Anatomy of the Kidneys and
Nephron• Describe The nephron as the functional unit of the
kidney• Differentiate between Cortical and juxtamedullary
nephron
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Summary • The urinary system is well known for eliminating wastes from
the body, but its role in homeostasis goes far beyond that.• Each kidney contains about 1.2 million functional units called
nephrons
• A nephron consists of two principal parts: a renal corpuscle, where the blood plasma is filtered and a long renal tubule that processes this filtrate into urine.
• Nephrons just beneath the renal capsule, close to the kidney surface, are called cortical nephrons
• Nephrons close to the medulla are called juxtamedullary nephrons
• Juxtamedullary nephrons are responsible for maintaining an osmolarity gradient in the medulla that helps the body conserve water.
• About 15% of the nephrons are juxtamedullary39
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Learning Resources
• Guyton and Hall (Text book of physiology), 12th Edition
• Ganong (Text book of physiology), 24th Edition• Berne & Levy Principles of Physiology (Koeppen BM),
6th Edition, 2014 • Human Physiology Stuart Fox, 13th Edition, 2012 • Human Physiology : from cells to system with Power
Lecture DVD Lauralee Sherwood, 8th edition, 2012
• Internet
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