THE EXCRETORY SYSTEM

Throughout our daily activities, our bodies produce a lot of waste. Leftovers from digestive system. Carbon dioxide from cellular respiration.

Excretion is the process by which waste products are eliminated from our bodies.

Four systems are involved in this process: Integumentary: Sweat glands Digestive: fecal matter Respiratory: elimination of carbon dioxide Urinary: urine

THE ELIMINATION OF WASTE

There are roughly 2,500 sweat glands located on the surface of the human body.

These glands secrete sweat, a combination of excess water and other wastes.

Sweating is a mechanism that allows our bodies to maintain a constant temperature in hot weather, or when we exert ourselves.

SWEAT GLANDS

The urinary system is composed of the following: Kidneys Bladder Ureters Urethra

THE URINARY SYSTEM

Structure Description Function

Kidneys Two bean-shaped organs.

Filter blood. Maintain blood balance through the production of urine. Urine releases excess water and other wastes, like urea.

Ureters Two tubes, roughly 25 cm, connecting the kidneys to the bladder.

Transport urine that is produced in the kidneys to the bladder.

Bladder Reservoir with elastic walls.

Stores urine until it is released by urination. It can hold 1 L of urine.

Urethra Small channel, 3-4 cm in women, 20 cm in men.

Transports urine from the bladder to the outside.

THEIR FUNCTIONS

Inferior vena cava

Urethra

Aorta

Urethra in men and women

Kidneys are the organs which fi lter blood. Blood enters via the renal artery and leaves by the renal vein. While in the kidney, some wastes leave.

Urea is the main waste that is exited by the urinary system. Urea is made when the proteins, (amino acids), from our food mixes with oxygen from the respiratory system.

The kidneys also maintain the balance of other substances in blood. When there is too much water or minerals, some of those substances will stay behind in the kidney.

COMPOSITION OF URINE

Therefore, healthy urine is made up of:Water, 95%Urea, 2.5%MineralsOther substances in excess

Urine may also contain:Protein, glucose, fats or blood cells. These are an indication of health problems.

Traces of medications or drugs.

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The amount of urine produced depends on the concentration of minerals and water in the body.

If concentration of minerals is low, kidneys will excrete more water.

If concentration of minerals high, kidneys excrete less water and we feel thirsty!!!

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Hypertension – High blood pressure

Narrowed arteries in the kidneys can damage kidneys.Too much fluid can also raise blood pressureDamaged blood vessels may stop the removal of wastes or fluid from the body.

Diabetes Glucose found in urine.High glucose levels can damage blood vessels, stopping them from filtering blood.Can also damage nerves that tell bladder when it is full, which can lead to bladder lining being damaged and possible other infections.

Urinary Tract Infection

Caused by E.Coli bacteria.More common in women than in men.Can lead to kidney infection when it moves upwards.Symptoms include: Burning sensation during urination Increased frequency of urination Blood in urine

KIDNEY DISORDERS

Proteinuria High amounts of protein found in urine.Caused by damaged tubules in kidneys.Sign of chronic Kidney Disease.Proteins found in blood seep into urine as kidneys are filtering blood.The protein is supposed to stay within the body.

Kidney Stones Hard insoluble crystallized stones found in urinary tract.Accumulation of calcium in blood (80%), uric acid (5%) or magnesium (2%).Stones pass down ureters.Very painful, can shutdown kidneys temporarily.

Kidney Failure Kidneys stop functioning.Renal dialysis can be used on a short –term basis to filter blood.Hooked up to dialysis machine for several days a week.Major change in lifestyle.Kidney transplant eventually needed.