The Excretory System

Functions Excretion - Filtering metabolic wastes Wastes Excess salts Carbon Dioxide Urea – produced when amino acids are used for energy

Skin Sweat Excess water, salt, small amounts of urea

Lungs Excrete CO2 when energy is produced by the mitochondria

Liver Converts amino acids to useful compounds Produces urea as waste

Kidneys Remove waste products from the blood Maintain blood pH Regulate water content of blood

Urinary System

The Urinary Organs: Kidneys: filters that take waste out of the blood and make urine

The Urinary Organs: Ureters: tubes that carry urine to the bladder

The Urinary Organs: Bladder: a muscular bag that collects urine

The Urinary Organs: Urethra: a tube that carries urine out of the body

Blood passes through the kidneys in order to deposit used and unwanted water and waste This forms urine which travels through the ureters to the bladder

Kidneys

Kidney Regions Renal Cortex Renal Medulla Renal Pelvis

Blood Flow Waste-laden blood enters kidneys through the renal artery Clean filtered blood leaves the kidney through the renal vein

Nephron Structural units of the kidney Over 1,000,000 in each kidney! 3 cm long 0.03 mm wide Filter the blood Reabsorb water, glucose, and salt Glomerulus

Nephron Glomerulus Bowman’s Capsule Loop of Henle

Filtration Blood pressure forces blood through the glomerulus All blood is filtered every 45 minutes

Filtration Filtrate Water, urea, glucose, salts, amino acids, and some vitamins Proteins, cells, and platelets are too large to pass through and remain in the blood

Reabsorption Most of the filtrate reenters the blood Active transport Amino acids, fats, glucose Osmosis – 99% of water reabsorbed

Urine Forms in Kidneys Made up of urea, excess salts, and water Loop of Henle Made up of urea, excess salts, and water Concentration variation Kidney  Ureter  Bladder Thirst your brain is telling you to get more fluids to keep your body as balanced as possible. If you don't have enough fluids in your body, the brain communicates with the kidneys by sending out a hormone that tells the kidneys to hold onto some fluids. When you drink more, this hormone level goes down, and the kidneys will let go of more fluids.

Bladder Hollow muscular organ Flexible cells Nerves tell the brain when the bladder is full. After 200 ml have accumulated After 1 minute reflex subsides Holds approximately 500 ml

Healthy Diseased Kidney Disease feel more tired and have less energy have trouble concentrating have a poor appetite have trouble sleeping have muscle cramping at night have swollen feet and ankles have puffiness around your eyes, especially in the morning have dry, itchy skin need to urinate more often, especially at night. Healthy Diseased

Dialysis http://www.kidneypatientguide.org.uk/site/HDanim.php