Essay: The urinary system

The urinary system has an important role within the body maintaining homeostatic balance by ensuring the waste products get excreted, keeping water balance in the body and assisting with blood pressure and volume (Brooker and Waugh, 2013).
Water is vital for human survival, it has many important and vital functions within the body. Every cell in the body contains water and it is the water that maintains the cell’s size and shape and water is the medium for all biochemical processes in the body.
Water circulates in the blood plasma gathering toxins, waste and other substances that are not used by the cells. Blood needs to be continually cleaned and have the water content continually regulated (Hull, 2013).
The Urinary System is composed of:
• Two kidneys – produces urine by filtering blood and removing waste products, toxic substances and excess water but also restores water and solutes to the blood when they are needed. The kidneys ensure blood composition and volume is constantly regulated. The kidneys also help regulate the pH levels of blood by filtering out and excreting different amounts of hydrogen ions from the blood. The kidneys also regulate blood pressure and volume by excreting the enzyme Renin. Each kidney receives 652mL (approx) of blood/minute from branches of the renal artery. This high volume of blood is needed to maintain glomerular filtration rates (GFR) and to supply oxygen to active cells. (Brooker and Waugh, 2013)
• Two ureters – that are long, thin tubes that transports urine from the kidneys to the bladder ( Hull, 2013)
• The urinary bladder – that is a flexible muscular sac that stores urine until it is full and ready to be excreted out of the body (Hull, 2013)
• The urethra – is a thin-walled tube that transports urine out of the body from the bladder. In males the urethra is 20-25cm in length and passes through the prostate gland. The female urethra is 3-5 cm in length and because of this shortness and the closeness of the anus increases the risk of UTI’s. (Brooker and Waugh, 2013)
How age affects the urinary system.
As the body ages it becomes more prone to urinary disorders including incontinence and UTI’s because renal blood flow, glomerular filtration and urea clearance all decrease with age.
Prostate gland problems can occur in elderly men causing urinary retention and difficulties urinating. Post-menopausal women can with incontinence due to thinning of the urethral lining and weakening of the urinary sphincters caused by the decrease in oestrogen (Hull, 2013).
Other disorders that can affect the urinary system include;
• Calculi (kidney, bladder or ureteral stones), hard masses that form in the urinary tract. Theses stones are mainly calcium salts formed from excess salts or lack of stone inhibitors in the urine. Calculi commonly affect the elderly, men and people who eat a high protein diet and have a low water intake. Symptoms include renal colic, back pain, nausea, vomiting, fever and blood in the urine.
• Nephritis (Bright’s disease), inflammation of the kidney’s that causes impaired kidney function, fluid and urea retention and blood in the urine. Nephritis can be caused by bacterial infections of the kidneys, exposure to toxins or abnormal immune reactions.
• Pyelitis, inflammation of the pelvis of the kidney often caused by bacterial infection. Symptoms include pain, shivering and fever.
• Uraemia, large amounts of nitrogenous wastes such as urea in the blood. Symptoms include drowsiness, nausea and vomiting. Uraemia is usually caused by renal failure and can be fatal if left untreated.
• Renal failure, the kidneys inability to filter blood and regulate its composition and volume efficiently. Acute renal failure is the rapid decline in kidney function and is caused by kidney disease or any condition that reduces renal blood flow or obstructs urine flow. Chronic renal failure is the more gradual decline in kidney function and is caused by acute kidney failure that has been left untreated or other disease such as diabetes or hypertension. Symptoms can include oedema of the feet, ankles, face and hands, dark urine, minimal or no urination, lack of concentration, loss of appetite, nausea, and a feeling of itchiness all over. In chronic renal failure blood pressure can rise and anaemia may occur as the kidney can’t produce erythropoietin. Pain may be present if there is an obstruction in the urinary tract.
(Hull, 2013).
Fluid balance charts
If there are concerns about urinary output or renal function a fluid balance chart should be used. Fluid output will depend on several factors including fluid intake, fluid loss and renal function, an adult of 55kg should pass no less than 660mL in 24 hours but a healthy adult should be passing over 1000mL per day with 200mL being recommended to ensure the urinary system is flushed through reducing the risk of UTI’s (Brooker and Waugh, 2013)
Urinalysis
Urinalysis should be carried out to determine if there are any abnormalities. Urine normally contains;
• Water (96%)
• Electrolytes (2%)
• Waste (2%) urea, creatinine, uric acid, drug and food residues and small amounts of urobilinogen
The urine obtained for the urinalysis should be a fresh midstream specimen and should not be the first urination of the day. Other checks to carry out before performing the urinalysis include observing the colour, clarity and odour of the sample (Brooker and Waugh, 2013)
Urinalysis performed using reagent test strips test for the following;
• Specific gravity (SP) – normal range is 1.001-1.035, a high SG indicates high level of solids. High levels of SG are found when the urine is concentrated and could be an indication the person is dehydrated.
• Ph – Normal ranges are 5-8, very acidic urine could suggest stone formation and alkaline urine could suggest an infection.
• Protein – should be negative, if found could indicate glomerular/renal damage or UTI.
• Blood – should be negative, blood in urine is called haematuria and indicates an issue of the urinary tract, this could include cancer, renal damage or stones.
• Glucose – this should be negative, glycosuria can indicate diabetes mellitus but can occur in pregnancy, in physiological stress and people taking corticosteroids.
• Ketones – Ketones are formed during the abnormal breakdown of fat therefore can be detected after prolonged vomiting, fasting, starvation or poorly controlled diabetes mellitus.
• Urobilinogen – it is normal to find small amounts in the urine, elevated amounts could indicate liver damage or abnormal breakdown of red blood cells, a reduction occurs when bile fails to reach the intestines.
• Bilirubin – should be negative, if found could suggest liver disease or biliary obstruction
• Nitrates and leucocytes – should both be negative, if leucocytes are found it could indicate the presence of a UTI, if nitrates are found it suggests bacteriuria.
(Booker and Waugh, 2013)
When performing the test care should be taken not to contaminate the sample and manufacturer’s instructions should be followed (Brooker and Waugh, 2013)
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