Human Excretory System

Human Excretory System Excretion is the removal of metabolic wastes from the body, including toxic chemicals, excess water, carbon dioxide and salts. Excretory Organs Skin Lungs Kidneys Human Excretory System Normal metabolic activity generates waste products that must be eliminated to sustain homeostasis. Ammonia (a product of protein metabolism) is converted to urea for elimination. Carbon dioxide, generated from cellular respiration, is removed from the lungs. Excess water and salts must be eliminated in order to maintain osmotic and pH balance. The skin removes water, salts and nitrogen wastes in the form of sweat. The lungs eliminate carbon dioxide, water vapor and heat in exhaled air. The kidneys excrete the majority of metabolic waste products from the body. Each kidney contains about one million functional filtering units called nephrons. References: Campbell, N.E. & Reece, J.B. (2002). Biology,(6th ed.). San Francisco: Benjamin Cummings. Raven, P.H. & Johnson, G.B. (2002). Biology, (6th ed.). McGraw-Hill.

Human Urinary System Diagram Nephron Kidney Ureter Urinary Bladder Urethra Human Urinary System The urinary system, consisting of the kidneys, ureters, urinary bladder and urethra, is responsible for eliminating the majority of metabolic wastes from the body. The functional unit of the kidney is the nephron. Each nephron is made of a cup-shaped portion called Bowman’s capsule, tubules and a network of capillaries. Blood pressure within a knot of capillaries (called the glomerulus) increases, causing most of the fluid of the blood to enter Bowman’s capsule. This fluid is called filtrate. As the filtrate passes through the tubule portion of the nephron, materials needed by the body are reabsorbed and the remainder of the filtrate becomes urine. Proper functioning of the kidney is essential to maintaining homeostatsis in the body. References: Raven, P.H. & Johnson, G.B. (2002). Biology, (6th ed.). McGraw-Hill. Image References: LifeART. (1998). Super Anatomy Collection 1-9. Baltimore, MD: Williams & Wilkins, All rights reserved.

Urinary system The urinary system, consisting of the kidneys, ureters, urinary bladder and urethra, is responsible for eliminating the majority of metabolic wastes from the body The functional unit of the kidney is the nephron. Each nephron is made of a cup-shaped portion called Bowman’s capsule, tubules and a network of capillaries

Inside the Kidney Blood pressure within a knot of capillaries (called the glomerulus) increases, causing most of the fluid of the blood to enter Bowman’s capsule This fluid is called filtrate. As the filtrate passes through the tubule portion of the nephron, materials needed by the body are reabsorbed and the remainder of the filtrate becomes urine Proper functioning of the kidney is essential to maintaining homeostatsis in the body