Mariebs Human Anatomy and Physiology Ninth Edition Marieb

Marieb’s Human Anatomy and Physiology Ninth Edition Marieb w Hoehn Chapter 25 Urinary system Lecture 15 Part 1: Urinary System Overview;

Functions of the Kidneys • Make urine • Regulate blood volume and blood pressure • Regulate plasma concentrations of Na+, K+, Cl-, HCO 3 -, and other ions • Help to stabilize blood p. H • Conserve valuable nutrients • Assist the liver in detoxification and deamination 2

Urinary System Figure from: Hole’s Human A&P, 12 th edition, 2010 Kidneys receive about 1. 2 L of blood per minute and filter nearly 180 L of fluid from the bloodstream every day! 3

Location of Kidneys Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001 Located retroperitoneally from T 12 to L 3 Left kidney is slightly higher than right kidney Adrenal glands sit on the medial and superior part of kidneys Nephro(s) = kidney 4

Location of Kidneys Helps maintain position of kidney Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001 5

Gross Anatomy of the Kidneys Renal capsule is tough, fibrous capsule (tunica fibrosa) Hilus is entry point for renal artery, vein, and nerve (mostly sympathetic fibers) [Pyel(o)-] Bases of renal pyramids face the cortex, apices face the renal pelvis and end at renal papillae Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001 6

Renal Blood Vessels (Cortical radiate arteries) Figures from: Martini, Anatomy & Physiology, Prentice Hall, 2001 Glomeruli Minor Calyx Nerves, mainly sympathetic postganglionic fibers of the ANS, follow arteries to nephrons 7

The Nephron (80%) (20%) Nephrons are the structural and functional units of the kidney 8 Figure from: Hole’s Human A&P, 12 th edition, 2010

Blood Supply of the Nephron Medulla The capillary loop of the vasa recta is a type of capillary that is closely associated with the nephron loop of juxtamedullary nephrons 9 Figure from: Hole’s Human A&P, 12 th edition, 2010

Blood Flow Through Kidney and Nephron Know this! 10 Figure from: Hole’s Human A&P, 12 th edition, 2010

Renal Corpuscle (Glomerulus + Capsule) Figure from: Hole’s Human A&P, 12 th edition, 2010 (Bowman’s) Filtrate in capsular space Notice that the efferent arteriole is smaller than the afferent arteriole This creates a high pressure (~55 -60 mm Hg) in the glomerular capillary bed 11

Visceral Glomerular Epithelium Figure from: Hole’s Human A&P, 12 th edition, 2010 Material passing out of the blood must be small enough to fit through the filtration slits (slit pores) 12

Renal Cortex and Renal Medulla Figure from: Hole’s Human A&P, 12 th edition, 2010 13