Physiology of the urinary system

The urinary system is the major system involved in the excretion of metabolic waste products which accumulate in the blood and excess of water from the body, regulates blood volume and pressure, and regulates blood pH. A type of waste called urea is removed from the blood by the urinary system. Urea is produced when foods containing protein, such as meat, are broken down in the body. Urea is carried in the bloodstream to the kidneys.

The kidneys remove urea from the blood through nephrons. And then urea, together with water and other waste substances, forms the urine and passes through the nephrons and then it is excreted from the kidney via the ureters.

Wastes in the blood come from the normal breakdown of active tissues and from food. The body uses food for energy and self-repairs. After the body has taken what it needs from food, wastes are sent to the blood.

Ureters are two narrow tubes that propel urine towards the urinary bladder, where it is stored and subsequently expelled by urination. Muscles in the ureter walls continually tighten and relax forcing urine away from the kidneys. If urine backs up or stands still, a kidney infection can develop.

The urinary bladder is a temporary storage for the urine, its reservoir. The bladder's walls relax and expand to store urine, and contract to empty it. Nerves in the bladder alert a person when it is time to urinate.

The urethra passes the urine outside of the body. The brain signals the bladder muscles to tighten, which squeezes urine out of the bladder. At the same time, the brain signals the sphincter muscles to relax to let urine exit the bladder through the urethra. When all the signals occur in the correct order, normal urination occurs.

Facts about urine:

• Average urine production in adults is about 1 – 2 l per day. The amount of urine depends on the amounts of fluid and food a person consumes and how much fluid is lost through sweat and breathing.

• Normal urine is sterile fluid. It contains fluids, salts and waste products, but it is free of bacteria, viruses and fungi.

POST-TEXT ASSIGNMENTS

Exercise 6. Find corresponding definition to the words on the left.

nerves	a colorless crystalline compound that is the main nitrogenous breakdown product of protein metabolism in mammals
nephron	a flow of bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from the same cells.
urea	a watery, typically yellowish fluid which contains nitrogen compounds such as urea and other waste substances removed from the blood by the kidneys
urine	any of the cordlike bundles of fibers that conduct sensory or motor impulses
bloodstream	each of the functional units in the kidney, consisting of a glomerulus and its associated tubule, through which the glomerular filtrate passes before emerging as urine

Exercise 7. Answer the questions.

1. What are the main functions of the kidneys?

2. What is urine?

3. What do wastes in the blood come from?

4. What organs carry urine from the kidneys to the bladder?

5. Why should kidneys remove waste products?

6. What is the function of nerves in the bladder?

7. What role does the urinary bladder play in the process of urination?

8. What part does the brain take in the process of urination?

Exercise 8. Translate word-combinations into English.

Тимчасове зберігання, виведення продуктів метаболізму, накопичуватися в крові, сечовина, надлишок води, руйнування активних тканин, бактерії та грибки, витискувати сечу з сечового міхура, регулювати об’єм крові та тиск, повідомляти мозок, виділяти сечу, сеча застоюється у сечовому міхурі, вживання їжі та рідини, нормальне сечовиділення.

Exercise 9. Find the proper continuation of the phrase and translate it into your native language:

To excrete	muscles
To alert	infection
To regulate	urine
Kidney	food and fluid
To consume	blood volume and pressure
normal breakdown	waste substances
To accumulate	the brain
Tighten and relax	of active tissues

Exercise 10. Fill in the gaps with words from the box:

nephrons urine bladder kidneys wastes urea ureters nerves

1. ________________ in the blood come from the normal breakdown of active tissues.

2. Normal ________________ contains fluids, salts and waste products.

3. _____________ usually holds 300-350 ml of urine.

4. __________________ carry urine from the kidneys to the bladder.

5. All the blood in our bodies passes through _______________ several times a day.

6. Urine is formed by ___________ together with water and other waste substances.

7. A person gets an alarm from the ____________ in the bladder when it is time to urinate.

8. In humans, a normal kidney contains 800,000 to 1.5 million ____________.

Exercise 11. Find the definitions to the terms mentioned in ex. 9:

1. It filters waste products and urea from the blood.

2. It is composed of waste products and urea and usually averages 1-2 L a day.

3. These are the materials performed as a result of a breakdown of active tissues.

4. It is an organic compound, which is colorless, odorless, solid and highly soluble in water.

5. It is an organ in the pelvis. When empty, it is about the size and shape of a pear.

6. It serves as a natural filter of the blood, and removes wastes, which are transferred to the urinary bladder.

7. They are tubes made of smooth muscle fibers that propel urine from the kidneys to the urinary bladder.

8. It is a cable-like bundle of fibers (the long projections of neurons) in the peripheral nervous system.

Exercise 12. Translate word-combinations given in italics.

1. Продукти відходів життєдіяльності appear in the blood because of порушення of muscles work.

2. If urine застоюється, a kidney infection can develop.

3. Nerves in the bladder попереджають a person about the time of urination.

4. Kidneys regulate об’єм крові та тиск.

5. Wastes products which накопичуються in the blood may greatly damage the health.

6. The body вживає food for energy and самовідновлення.

7. The muscles in the bladder розширюються to store urine.

8. Normal urine is free of бактерії, віруси та грuбки.

Exercise 13. Fill in the gaps with the words and word-combinations from the box:

Urologic disease can involve _________________________ dysfunction of the urinary system. Glomerulonephritis is a type of kidney disease in which the kidneys' filters become inflamed and ____________, and slowly lose their ability ________________________ from the blood to make urine. Patients may experience the following ____________: fatigue, high blood pressure, __________________, blood and protein in the urine.

Unfortunately, even with today's medicine, kidney disease cannot be ______________. Treatments focus on slowing ____________ of the disease and preventing ________________. Treatment may include: drug therapy, diet modification, dialysis (a medical treatment to remove wastes from __________) and kidney transplantation.

congenital or acquired, complications, scarred, the blood, to remove wastes and excess fluid, symptoms, decreased urine output, cured, the progression