Excretory System Biology Powerpoint 5 Excretory System Function

Excretory System Biology Powerpoint #5

Excretory System Function: The excretory system eliminates nonsolid wastes from the body. skin lungs • Through lungs, skin, and kidneys. • Lungs exhale carbon dioxide and water vapor. kidneys ureters • Sweat glands in skin release excess water and salts. urethra urinary bladder

Excretory System • The ureters are tubes that carry urine from the kidneys to the urinary bladder. skin • The urinary bladder temporarily stores urine until it is released from the body. lungs • The urethra is the tube that carries urine from the urinary bladder to the outside of the body. • The outer end of the urethra is controlled by a circular muscle called a sphincter. kidneys ureters urinary bladder urethra

Excretory System Function of the Kidney • Filter blood in order to remove cellular waste products. • At any given time, 20 % of blood is in the kidneys. Humans can function with one kidney. • If one stops working, the other increases in size to handle the workload.

Excretory System The kidneys help to maintain homeostasis by filtering the blood. cortex The kidneys are fist-sized, bean shaped structures. – two layers: medulla and cortex – filtering units called nephrons – renal artery and renal vein medulla renal artery renal vein ureter (to bladder)

Excretory System The kidney can also excrete of other waste products, such as : • 1) urea a nitrogen-based waste produced in the liver from the breakdown of protein. It is the main component of urine • 2) uric acid usually produced from breakdown of DNA or RNA • 3) creatinine waste product of muscle action.

Excretory System Kidneys have three basic functions in maintaining homeostasis. – remove waste from blood – help to maintain electrolyte, p. H, and fluid balances – release key hormones

Excretory System Nephrons clean the blood and produce urine. • Nephrons are the filtering units in the kidneys. • They clean and rebalance the blood to produce urine. • There approximately 1 million nephrons in each kidney from body to body loop of Henle from other nephrons

Excretory System • Nephrons clean the blood in a three-step process. • The first step is filtration of the blood. • Glomerulus: Network of capillaries Glomerulus 1 FILTRATION Water and other small molecules diffuse out of the blood. • Bowman’s Capsule: Encases the glomerulus Bowman’s capsule The body’s entire volume of blood is filtered every 45 minutes

Excretory System • The first step is filtration of the blood. • The second step is reabsorption of materials. from body collecting duct to body loop of Henle from other nephrons 2 REABSORPTION Most of the material is reabsorbed into the blood. Materials not reabsorbed make up the urine.

Excretory System • The first step is filtration of the blood. • The second step is reabsorption of materials. • The third step is excretion of materials. from body 3 collecting duct to body loop of Henle from other nephrons EXCRETION In the loop of Henle, water can be reabsorbed one final time to reduce the volume of urine.

Excretory System Injury and disease can damage kidney functions. • A kidney transplant can replaced damaged kidney. – recipient and donor tissue must match – drugs prevent tissue rejection The daughter and son in this photo donated a kidney and liver tissue to their mother.

Excretory System • Dialysis can be used to filter and clean the blood.

Excretory System Disorders of the Excretory System UTI (Urinary Tract Infection) • Is a very common disorder. It is an infection of the urethra or bladder. • Symptoms include painful urination (burning sensation), frequent urination (even if no urine present) and bloody or brown urine. • This can lead to chills, fever, nausea, vomiting and upper abdomen tenderness.

Excretory System Cure / Prevention : • If left untreated, all UTI’s can lead to permanent kidney damage and possible kidney failure. • Treatment is by antibiotics. A person needs to maintain good personal hygiene when eliminating wastes (liquid and solid forms) from the body. • Prevention: A person should drink lots of water.

Excretory System Kidney Infections • Result when an infection reaches the kidneys • Common causes can be infection from elsewhere in the body or obstruction of the prostate gland (usually in older men). • For children, infection can be caused by the tube that drains urine from the kidneys and the bladder.

Excretory System Kidney Stones • Cause: Crystals formed from minerals in urine. • They can be found in the kidney, ureter or bladder. • 80% of those stricken are males. • The most common crystals are: • Calcium Oxalates • Uric acid

Excretory System Kidney Stones (cont) • Symptoms include severe back or abdomen pain, blood in the urine, nausea and vomiting. • Treatment may vary from letting the stones pass through the urinary tract to ultrasound shock to disintegrate the stones to a small size that can be passed through the urinary tract. • Large stones require surgery for removal.

Excretory System Kidney Stones (cont) • Prevention: Ways to avoid kidney stones: • Increase liquid intake (more than 2 l / day) • Limit sodium intake • Limit animal protein • Limit foods high in oxalate (spinach, strawberries, nuts, dark chocolate, brewed tea)