Urinary System (Chart)

7/27/2019 Urinary System (Chart)

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ORGANS OF THE HUMAN URINARY SYSTEM

1. The principal systemof excretion is the

urinary system, which

is considered far more

efficient than themost modern sewage

disposal system in the

world. The urinary

system, consisting of

the kidneys, ureter,

urinary bladder, and

urethra, disposes

such metabolic

nitrogenous wastes as

urea, uric acid, and

creatinine.

2. Organs of the Urinary Systema. The kidneys are two bean-shaped

organs, each about four inches long and lying near

the base of the spinal cord. Each contains about half

a million tubules called nephrons, which are the filter

devices of the kidneys. The function of the kidneys is

primarily to eliminate nitrogenous wastes, excess

water, sugar, mineral salts, and other toxic or

unnecessary substances. As blood passes through

the glomerulus, a ball of capillaries on top of the

nephrons, the wastes are collected by the tubules

and sent for temporary storage to the urinary

bladder through the ureter.

b. The ureter is the long tube that leads from the kidneys to the urinary bladder.c. The urinary bladder is the bag that temporarily holds the urine.d. The urethra is the tube exit for the urine.

3. Blood and urine are two body fluids associated with kidneys. Each of these fluids can provideinformation about the health condition of the body.

4. A urine analysis is often performed in order to determine the state of a patients health. Thisanalysis consists of tests that can detect various substances in the urine that can provide clues

to various disorders and ailments. These tests are as follows:

a. Acidity Test. Normal urine is slightly acidic.b. Protein Test. The presence of protein may indicate kidney infection.c. Blood Test. The presence of blood may indicate chemical poisoning or internal bleeding.d. Glucose Test. The presence of sugar may indicate diabetes or kidney infection.


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COMMON AILMENTS OF THE URINARY SYSTEM

1. The urinary tract may sometimes get infected by microorganisms, which usually enter the bodythrough the urethra, other body organs, or the blood. Some infections can be treated by

drinking lot water, resting, cushioning your diet, or taking antibiotics. Other infections are

more serious and need medical attention.

2. Nephritis. When the nephrons of the kidneys become infected, a disease called nephritis mayresult. The disease causes inflammation of some parts of the kidney, reducing its ability to

filter blood. if untreated or if it occurs repeatedly, the infection can damage the kidneys to the

point that they cannot remove wastes anymore. The body becomes poisoned with its own

waste, resulting in a condition called uremia.

3. A person with severe kidney damage may have to be connected to an artificial kidney, called adialysis machine. During dialysis, the patients blood is pumped into special tubing made ofsemipermeable membrane and surrounded by a special fluid. Wastes and other unneeded

materials diffuse from the tubing into the fluid. At the same time, certain substances from the

fluid diffuse into the blood. in this way, the blood is cleansed and replenished. The blood then

flows back into the person.

4. If the kidneys no longer function, a new kidney may have to be transplanted. Fortunately, onekidney is enough to do the work of two.

5. Kidney Stones. Thesestones form in the

kidneys when salts in

the urine form

crystals. The stones

may be as small as

gravel or large enough

to block the ureter

and keep urine from

leaving the kidneys.This can be a very

painful experience. If

the stone is not

removed, it can lead

to the destruction of

the kidneys.

6. Kidney stones areoften treated with atechnique called

ultrasound. The ultrasonic vibrations break up the stones into smaller pieces so they can pass

out of the ureter.


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THE SKIN

1. The skin is the largest organ of the human body, weighing up to 4.5 kg, with a surface area ofabout 17,000 sq.cm. in the average adult. It is divided into three tissue layers: epidermis (outer

layer), dermis (inner layer), and the subcutaneous layer.

2. Structures ofthe Skin

a. TheEpidermis. The

epidermis is

subdivided into 4

layers. The top layer

is made up of dead

cells containing

keratin, which

toughens the skin.

The bottom layer is

made up of live,

reproducing cells

whose main purpose

is to replenish the top

layer. These cells move up through the two intermediate layers until they arrive, dead at

the surface. The bottom layer also contains cells producing a brown pigment called

melanin, the bodys adaptation against ultraviolet radiation. The greater the melanin, the

darker is the skin. Exposure to sunlight and artificial ultraviolet tends to increase the

melanin production.

b. The Dermis. The dermis contains nerve endings, blood vessels, fatty tissue, and glands. Thedermis has tiny projections called papillae, which help join the dermis to the epidermis.

c. Under the dermis is a flexible tissue containing many spaces called areolar tissue whichconnects the skin to the body and helps the skin intact.

3. The skin has two kinds of glands:a. Sebaceous glands. Sebaceous glands secrete oil called sebum, which lubricate the hairs and

surface.

b. The Sweat Glands. The sweat glands are of two kinds: eccrine and apocrine. The eccrineglands secrete sweat that cools the body. The apocrine glands secrete a small amount of

fluids that give odor to the skin.

4. The skin can be considered another organ of excretion of the human body for excess water,urea, and mineral salts. The sweat gland is the principal excretory structure of the skin. It

consists of a long tubule which is partly coiled at the lower end. The upper end is straight andleads to an opening on the skin called pore.

5. The excretion of the fluid waste through the pores of the skin is called perspiration. The fluidwaste is also called sweat.

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Urinary System (Chart)