Renal Physiology Lecture Notes 2024 PDF

RENAL PHYSIOLOGY BY DR. K.S. OLANIYI Dr. Olaniyi K.S. Lecture outline ◼ Overview of renal physiology ◼ Functional anatomy of kidney ◼ Functions of kidney ◼ Functional unit of kidney (Nephron) ◼ Renal circulation ◼ Process of urine formation ◼ Renal function test ◼ Renal cleara...

RENAL PHYSIOLOGY BY DR. K.S. OLANIYI Dr. Olaniyi K.S. Lecture outline ◼ Overview of renal physiology ◼ Functional anatomy of kidney ◼ Functions of kidney ◼ Functional unit of kidney (Nephron) ◼ Renal circulation ◼ Process of urine formation ◼ Renal function test ◼ Renal clearance ◼ Micturition ◼ Clinical application Lecture objectives ◼ To understand the basis of renal physiology ◼ To know the functional anatomy of kidney. ◼ To understand the functions of kidney. ◼ To understand renal blood flow and factors that affect it. ◼ To understand the mechanism of urine formation. ◼ To know how kidney handle variable substances (Na+, K+, H+, glucose & urea). ◼ To understand the process of micturition. ◼ To understand some clinical correlates. Overview of renal physiology ❖ Branch of physiology that deals with the maintenance of constant internal environment (ECF/ICF) by regulating its volume, osmolarity, acid-base status and ionic concentration. ❖ Through removal of metabolic and nitrogenous wastes as well as toxins from the body. ❖ With the collaboration of Kidney, ureter, bladder and urethra. ❖ NB: RS is among the most vital regulatory systems in Renal corpuscle and renal tubule Renal corpuscle Renal corpuscle and renal tubule  Questions ❖Which part of the renal tubule functions more in secretion? ❖where is the Macula Densa located & what is its function? ❖Which cells of the JGA act as mechanoreceptors? ❖Which cell in the collecting tubule of the renal tubules functions in maintaining acid-base balance? ❖Which cell in the collecting tubule of the renal tubules functions in maintaining water and salt balance? ❖What is the filtration membrane, where is it located and what is it made of? Factors that affect the GFR  FACTORS THAT FAVOUR TUBULAR REABSORPTION ❖Nature of the substance -High-threshold e.g. Glucose, vitamins, amino acid -Low-threshold e.g. Electrolytes, water, minerals, fatty acids -non-threshold e.g. creatinine, inulin ❖Nature of the absorptive surface area -Proximal convoluted tubule has the highest absorptive area (65% of the tubular reabsorption). because of the flat epithelial cells and microvilli -Collecting duct has the second highest absorptive area (20% of the absorption). because of the principal and intercalated cell. -Loop of Henle has the lowest absorptive surface area (7-15% of the reabsorption), while DCT has no microvilli, but causes 5-7% under hormonal control.  FACTORS THAT FAVOUR TUBULAR REABSORPTION ❖Presence of transport mechanism -Simple diffusion -Facilitated diffusion -Active transport - PCT has numerous mitochondria which provide energy for the active transport. - Presence of SGLT2- for reabsorption of glucose, Na and water. - CDT also has a number of mitochondria that provide ATP for active transport ❖ Route of reabsorption - Transcellular-through the cytoplasm of the epithelial cell. - Paracellular- between two cells - These are abundant in PCT. ❖ Hormonal influence -Aldosterone, ADH and parathyroid hormone