The Urinary System Chapter 26

Objective Describe the physiology of urine formation by the kidney.

Functions Excretion Elimination Homeostatic regulation removal of organic wastes from body fluid Elimination discharge of waste products Homeostatic regulation of blood plasma volume and solute concentration

Gross Dissection

Male Urinary System

Female Urinary System

Urinary Organs 2 Kidneys Urinary tract: excrete urine Ureters Urinary bladder Urethra

Kidneys Filter the blood and remove wastes Each contain 1-2 million nephrons

Kidney Dissection Outer Cortex Inner Medulla contain renal pyramids

Nephrons Functional unit of the kidneys Makes urine Controls water balance Regulates blood pressure

Nephrons Glomerulus Bowman’s Capsule Proximal Convoluted Tubule Loop of Henle Distal Convoluted Tubule Collecting Duct

Nephron Component Functions Glomerulus: mechanically filters blood Bowman's Capsule: Proximal Convoluted Tubule: reabsorbs 75% of the water, salts, glucose, and amino acids Loop of Henle: countercurrent exchange, which maintains the concentration gradient Distal Convoluted Tubule: tubular secretion of H ions, potassium, and certain drugs

Ureter Paired tubes Connects the kidney to the urinary bladder

Urinary Bladder Smooth muscle bag Stores waste solution - urine

Urethra Connects bladder to outside of the body Allows urine to pass out of the body

Basic Processes of Urine Formation Filtration Blood pressure Water and solutes across glomerular capillaries Reabsorption The removal of water and solutes from the filtrate Secretion Transport of solutes from the peritubular fluid into the tubular fluid

Incontinence (urine leakage) More than 10 million Americans experience incontinence Most do not seek treatment Treatment can improve or eliminate the problem 90% of the time Main Idea(s) of This Slide - Although over 10 million Americans suffer from some sort of incontinence, and 90% of these cases can be improved with treatment, most do not seek treatment.

Kidney Stones Solid mass of tiny crystals Form when urine contains too much of certain substances dehydration

Urinary Tract Infection (UTI) Bacteria (E. coli) from the digestive tract get in the urinary tract multiply move from the urethra to the bladder to the kidneys More common in women than men Main Idea(s) of This Slide - Urinary tract infections (UTI) are one of the most common type of infections in humans (second only to respiratory infections). UTI can occur when bacteria (commonly E. coli from the digestive tract) gets into the urethral opening and travels up the urethra towards the bladder. If the infection progresses, the bacteria can reach up into the kidneys causing damage to the nephrons. UTI are much more common in women due to the proximity of the urethral opening to the anus and the much shorter urethra found in women. This is a good time to remind students of male and female anatomy that was presented during the early lessons.