Kidney By Dr Abdel Aziz M Hussein Lecturer
Kidney By Dr. Abdel Aziz M. Hussein Lecturer of Medical Physiology
Urinary System • Urinary system consists of 1. 2 Kidneys 2. 2 Ureters 3. Urinary bladder 4. Urethra • The kidneys are the major excretory organs of the body. • The skin, liver, lungs, and intestines eliminate some waste products
Kidneys Ureters Urinary Bladder Urethra
Overall Functions of Kidneys
Overall Functions of Kidneys Homeostatic Excretory Endocrinal Kidney Functions Regulatory Metabolic
1. Homeostatic Function • Kidneys keep the constancy environment (ECF) regarding; 1. Total body water 2. Tissue fluid osmolarity 3. Electrolytes Na, K, Ca etc……. 4. p. H Intake Input of the Kidney Output internal
2. Excretory Function • 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)
3. Regulation of ABP Through; a) Renin - angiotensin system V. C. ↑ ABP Aldosterone Angiotensin II ACE Angiotensin I Renin Angiotensinogen Drop of ABP
3. Regulation of ABP 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
4. Endocrinal Function • Kidneys secrete; Erythropoietin from interstitial cells around PTC Activation of Vit D 1, 25 DOCC kinins and PGs Renin
5. Metabolic Functions Breakdown of insulin and glucagon Gluconeogenesis in fasting and starvation Do not Forget (RHEEM)
Functional Anatomy of Kidney
Functional Anatomy of Kidney Weight : 150 gm Capsule: tough and fibrous (limit its distension) Cross section: Capsule Outer Cortex inner Medulla
Functional Anatomy of Kidney Cortex • Lie next to capsule • Red and granular Medulla • Inner part of kidney • Pale and striated
Functional Anatomy of Kidney • Glomeruli • PCT • DCT • LH • CDs • Vasa recta Cortex Outer Medulla Inner Medulla
Functional Anatomy of Kidney Renal papilla Cortical tissue Columns of Bertini Renal pyramid Renal Lobe
Nephron
Nephron Def. , • It is the structural and functional unit of the kidney Number: • one million nephrons in each kidney Components : A) Renal or Malpigian Corpuscle B) Renal Tubule
Renal Corpuscle Renal Tubule Nephron Components
Renal Corpuscle Blind end of renal tubule Tuft of capillaries 20 - 40 loops
Renal Tubule S 1 DCT CT S 2 S 3 Thick ALH DLH Thin ALH CD
Types of Nephrons
Types of Nephrons Cortical Juxta medullary 85% 15% Glomeruli: -Small in size -In outer 2/3 of cortex Efferent arterioles give PTC only Loop of Henle Glomeruli: -Large in size -In inner 1/3 of cortex Efferent arterioles give PTC and vasa recta Loop of Henle -Short -Reach outer medulla -Make bend at junction ( ) outer and inner medulla -Has no thin ALT -Long -Dip deep into inner medulla -Make bend at inner medulla -Have thin ALT Renal tubules have low reabsorptive capacity high reabsorptive capacity
Juxta-medullary Nephron Superficial Cortical Nephron
Superficial cortical Nephron Juxta-medullary Nephron
Renal Blood Supply
• Short • Wide • Direct branch of aorta
Blood Supply N. B. • Diameter of efferent arteriole is smaller than afferent arteriole → favour high hydrostatic pressure in glomerular capillary → favour high filtration of plasma through glomerular capillaries
Nerve Supply • The kidney is supplied mainly by sympathetic fibers; 1 -Renal blood vessels: VC via alpha 1 adrenergic receptors 2 -Renal tubules : increase Na reabsorption 3 - Juxtaglomerular apparatus cells: release of renin via Beta 1 adrenergic receptors
THANKS
- Slides: 42