URINARY SYSTEM

FUNCTIONS:

Excretion

Regulation of blood volume and pressure

Regulation of the concentrated of solutes in the blood

Regulation of extracellular fluid pH

Regulation of red blood cell synthesis

Vitamin D synthesis

Ureters transport urine urine from the kidneys to the Urinary bladder

Urinary bladder stores urine and expels into the Urethra

It discharges urine from the body

o KIDNEYS: They lie on the posterior abdominal wall, behind the peritoneum, with one kidney

on either side of the vertebral column

Small dark red organ, bean shaped 12 cm long, 6 cm wide, 3m thick

FUNCTION:

Cleanse the blood and adjust pH composition.

3 REGIONS OF KIDNEY

1. RENAL CORTEX

-Comes from Latin word meaning “bark”

-outer light red Region

2. RENAL MEDULLA

Dark red brown region

-medulla has many triangular regions with a striped appearance called

MEDULLARY PYRAMIDS.

APEX-tip of the boarder base of each pyramid faces toward the cortex.

RENAL COLUMN- extension of renal cortex

3. RENAL PELVIS

-Funnel shape cavity

MAJOR AND MINOR CALYCES- cup like structure and extension of

pelvis that collect urine.

BLOOD SUPPLY IN THE KIDNEY

RENAL ARTERY- arterial supply of each kidney. Renal artery approaches the

hilus, it divides into SEGMENTAL ARTERIES. Inside the pelvis, segmental

arteries break up into LOBAR ARTERIES. Each of which has a branches called

INTERLOBAR ARTERIES give off the ARCUATE ARTERIES. Venous

blood INTERLOBULAR VEIN to ARCUATE VEINS to INTERLOBAR

VEINS to RENAL VEIN.

http://www.austincc.edu/apreview/PhysText/Renal.html

ROLES OF KIDNEY:

1. Excretion of nitrogen containing waste

2. Maintaining waste

3. Electrolyte balance of the blood

4. Ensuring proper blood pH

NEPHRONS Structural units of kidney

Responsible for forming the urine

TWO PARTS OF NEPHRON:

1. RENAL CORPUSCLE – blood plasma is filtered

2. RENAL TUBULE

-extra length

-more surface area, more filtration

- reabsorb water, sodium, potassium

- secrete waste

TWO COMPONENTS OF A RENAL TUBULE

1. GLOMERULUS- knot of capillaries

Fed and drained by ARTERIOLES (EFFERENT & EFFERENT

ARTERIOLE)

AFFERENT ARTERIOLE- arises from interlobular artery

- Feeder vessel

EFFERENT ARTERIOLE – receives blood that passed through the

glomerulus.

2. GLOMERULAR/ BOWMAN’S CAPSULE- portion of renal tubule that is

enlarged and cup-shaped surrounds the glomerular capillaries.

PODOCYTES-visceral layers consists of modified simple squamous

epithelial cells.

REGIONS OF RENAL TUBULE

1. PROXIMAL CONVOLUTED TUBULE- lumen surface covered with

dense microvilli that increases surface area.

-Simple cuboidal epithelial cells

-denotes part of the tubule attached to the glomerular capsule

2. LOOP OF HENLE- links ascending limb and descending limbs

- Connects distal and proximal convoluted tubule.

- Simple squamous epithelial cell

TWO PARTS OF LOOP OF HENLE

1. DESCENDING LIMB OF THE LOOP OF HENLE- first part

2. ASCENDING LIMB OF THE LOOP OF HENLE- makes the

hairpin turn.

3. DISTAL CONVOLUTED TUBULE- denotes part of the tubule that is

further away.

-Simple cuboidal epithelial cells

COLLECTING DUCT- delivers the urine

NEPHRONS ARE CALLED:

CORTICAL NEPHRONS- nephrons located within the cortex

JUXTAMEDULLARY NEPHRONS- nephrons closely to the cortex- medulla junction.

RENAL PHYSIOLOGY

http://moodle.rockyview.ab.ca/mod/book/view.php?id=56711&chapterid=20684

1. GLOMERULAR FILTRATION

First step urine production, water and most solutes in blood plasma move across

the wall of glomerular capillaries into the glomerular capsule and then into the renal

tubule. Glomerulus acts as filter.

OLIGURIA- abnormally low urinary output

2. TUBULAR REABSOPRTION

As filtered fluid flows along the renal tubule and through the collecting duct,

tubule cells reabsorb about 99% of the filtered water and many useful solutes. The water

and solutes return to the blood as it flows through the peritubular capillaries and vasa

recta. Reabsorption refers to the return of substances in the bloodstream. Absorption

means entry of new substances into the body, as occurs in the gastrointestinal tract.

Tubule cells are transporters.

3. TUBULAR SECRETION

As fluid flows along the renal tubule and through the collecting duct, the tubule

and duct cells secrete other materials, such as wastes, drugs, and excess ions, into the

fluid. Notice that tubular secretion removes a substance from the blood.

SITE OF REABSORPTION AND SECRETION IN A NEPHRON

http://manashsubhaditya.blogspot.com/2012/07/urinary-system-filter-system-of-human_04.html

*urine contains most of the wastes and unneeded substances.

CONTROL OF BLOOD COMPOSITION BY THE KIDNEY

*Blood composition depends on THREE MAJOR FACTORS: diet, cellular metabolism and

urine output

* kidney filters 150 to 180 litters of blood plasma through their glomeruli.

EXCRETION OF NITROGENOUS WASTES

MOST IMPORTANT NITROGENOUS WASTES

1. Urea- formed by the liver when amino acids are used to produce energy. End

product of protein breakdown

2. Uric acid- released when nucleic acids are metabolized.

3. Creatinine- associated with creatine metabolism in muscle tissue

MAINTAINING WATER AND ELECTROYLTE BALANCE OF BLOOD

FLUID COMPARTMENTS- 3 location which water occupies

INTRACELULLAR FLUIDS- body fluids contained within the living cells

EXTRACELLULAR FLUIDS- body fluids located outside the cells.

ANTIDURETIC HORMONE (ADH)- Increase osmolarity of extracellular fluid

or decreased blood volume promotes release of ADH from the posterior pituitary

gland

ALDOSTERONE- major factor regulating sodium ion content of the ECF and in

the process helps regulate the concentration of other ions such as chlorine,

Potassium, Magnesium.

SODIUM ION- electrolyte responsible for osmotic water flow

JUXTAGULOMERULAR APPARATUS- helps regulate blood pressure within

the kidneys

RENIN- catalyze the series of reactions that produce , angiotensin II, cause

vasoconstriction and promotes aldosterone release

POLYURIA- excrete large volumes of urine

MAINTAINING ACID-BASE BALANCE OF BLOOD

ALKALOSIS- arterial blood rise above 7. 45

ACIDOSIA- arterial pH to below 7. 35

PHYSIOLOGICAL ACIDOSIS- arterial pH between 7.35-7.0

BLOOD BUFFER

RESPIRATORY SYSTEM CONTROL

RENAL MECHANISMS

CHARACTERISTICS OF URINE -clear and pale to deep yellow

UROCHROME- pigment that results from the body’s destruction of haemoglobin.

Cause a normal yellow color

-more solutes the deeper the yellow color

- sterile and slightly aromatic odor.

-allow to stand, ammonia odor caused by the action of bacteria on the urine.

-pH is slightly acid (around 6)

ACID-ASH FOODS- diet contains large amounts of proteins and whole-wheat products

causes urine to become quite acid.

ALKALINE-ASH FOODS- vegetarian diets

- water plus solute equals urine

- more dense than distilled water

- specific gravity is 1. 001 to 1.035

PHELONEPHITIS- kidney inflammation

SOLUTES IN THE URINE

-Sodium and potassium ions

-urea

-uric acid

-creatinine

-ammonia

-bicarbonate ions

URINALYSIS

-tells much about the state of the body

-analysis of the volume and physical, chemical and microscopic properties of urine

-volume of urine 1-2 L per day

-water 95% volume of urine

o URETERS

-transport urine from the renal pelvis in the kidney to the urinary bladder

-slender tube 25-30 cm long, 6 mm in diameter

THREE LAYERS OF TISSUE FORM THE WALL OF THE URETER

1. MUCOSA- deepest coat

2. TRANSITIONAL EPITHELIUM

3. LAMINA PROPRIA

MUSCULARIS- intermediate coat, inner longitudinal and outer circular layers of

smooth muscle

ADVENTITIA- superficial coat layer of areolae connective tissue containing

blood vessel

RENAL CALCULI- crystals/ kidney stones

-uric acid salts

o URINARY BLADDER -smooth collapsible muscular sac that stores urine temporarily

-located retroperitoneally in the pelvis just posterior to the pubic symphysis

TRIGONE- small triangular area

INTERNAL URETHRAL ORIFICE- the opening into the urethra. lies anterior corner

THREE COATS MAKE UP THE WALL OF URINARY BLADDER

1. MUCOSA- deepest coat

2. TRANSITIONAL EPITHELIUM

3. LAMINA PROPRIA

RUGAE- fold in the mucosa is present

INTERMEDIATE MUSCULARIS/ DETRUSOR MUSCLE- surrounding of mucosa

INTERNAL URETHRAL SPHINCTER- around the opening to the urethra by the

circular fibers

EXTERNAL URETHRAL SPHINCTER -inferior to internal urethral sphincter.

involuntary

ADVENTITIA- most superficial coat of the urinary bladder.

THE MICTURATION REFLEX

MICTURATION/ urination/ voiding -discharge of urine from the urinary bladder

Impuses propagate to the Micturation center in sacral spinal cord segments S2 and S3

and trigger a spinal reflex called Micturation reflex.

o URETHRA

-Thin walled tube that carries urine by peristalsis from the bladder to the exterior of

the body

-female urethra lies directly posterior to the pubic symphysis, us directed obliquely,

inferiorly and anteriorly and has length of 4 cm. EXTERNAL URETHRAL ORIFICE,

located between the clitoris and the vaginal opening. The wall of female urethra consists

of deep mucosa composed of epithelium and lamina propria (areolar connective

tissue) and superficial muscularis .

male urethra extends to internal urethral orifice to the exterior. Consists of deep mucosa

and a superficial muscularis has three anatomical regions:

1. Prostatic urethra- passage through the prostate

2. Membranous (intermediate)urethra-shortest portion passes through the deep

muscle of peritoneum.

3. Spongy urethra- longest portion passes through penis

DEVELOPMENT OF THE URINARY SYSTEM

In the third week of fetal development the intermediate mesoderm, differentiates into the

kidneys. The intermediate mesoderm is located in paired elevations called urogenital ridges.

Three pairs of kidneys form within the intermediate mesoderm in succession: the pronephrons,

the mesonephrons, and the metanephros. Last pair remains as the functional kidneys of newborn.

PRONEPHROS first kidney form the most superior of the three and has an associated pronephric

duct. Ducts empties into the cloaca, the expanded terminal part of the hindguts, which function s

as a common outlet for the urinary, digestive, and reproductive ducts. The pronephrons begins to

degenerate during the fourth week and is completely gone by the sixth week.

MESONEPHROS the second kidney, replaces pronephros of the pronephric duct, which

connects to the meseonephros, develops into the mesonephric duct. The mesonephros beginds to

degenerate by the sixth week and gone by eight week.

URETERIC BUD fifth week, a mesodermal outgrowth. By the third month, the fetal kidneys

begin excreting urine into the surrounding amniotic fluid: indeed, fetal urine makes up most of

the amniotic fluid. During development, the cloaca divides into a urogenital sinus, into which

urinary and genital ducts empty, and a rectum that discharges into the anal canal. The urinary

bladder develops from the urogenital sinus. ultimate destination in the abdomen. As they do so,

they receive renal blood vessels. Although the inferior blood vessels usually degenerate.

Consequently, some individuals (about 30%) develop multiple renal vessels

http://mednotesforyou.blogspot.com/2010/06/indiana-university-school-of-medicine.html

Diseases of the Urinary System

NEPHROLOGY - branch of medicine concerned with the diagnosis and treatment of conditions

related to the kidneys, and physicians who specialize in kidney disease are called nephrologists.

Other health professionals who treat kidney problems include primary care physicians,

pediatricians, transplant specialists, and urologists

Benign Prostatic Hyperplasia

Benign prostatic hyperplasia (BPH) is a condition in which the prostate gland is enlarged,

making urination difficult for men with this disease

Bladder Cancer

Bladder cancer is the result of uncontrolled, abnormal cell growth within the bladder. According

to the American Cancer Society, there are three major types of bladder cancer: transitional cell

carcinoma, squamous cell carcinoma and adenocarcinoma. Of these, the most common is

transitional cell carcinoma, which is also called urothelial carcinoma.

Cystocele (Fallen Bladder)

Cystocele is a disease affecting females in which the wall between the bladder and vagina

becomes weak, allowing the bladder to fall into the vagina.

Hematuria (Blood in the Urine)

The Mayo Clinic describes hematuria as the presence of red blood cells in urine. Though the

blood might not be visible to patients with this disease, a doctor will be able to see the red blood

cells under a microscope.

Interstitial Cystitis

Interstitial cystitis is described by the Interstitial Cystitis Association as chronic and often painful

inflammation of the bladder. This disease is also referred to as Painful Bladder Syndrome or

Frequency-Urgency-Dysuria Syndrome.

Kidney Stone

Kidney stone is a term used to describe a solid piece of material---most commonly made up of

calcium from the urine--that forms in one or both of the kidneys. These can cause harmful and

painful blockages that require the stone(s) to be broken into pieces by lasers for easier passage.

Neurogenic Bladder

Neurogenic bladder is caused by the malfunction of nerve signaling in the muscles that control

the bladder. When these nerves fail to transmit messages properly to the brain, an individual may

lose the ability to urinate normally.

Prostate cancer

Prostate cancer is the result of uncontrolled, abnormal cell growth within the prostate gland. It is

highly curable in the early stages, so men should be checked routinely.

Prostatitis

Prostatitis is a condition that results in inflammation of the prostate gland. Men with prostatitis

may find it difficult or painful to urinate, and can also experience pain in the back or genital area.

Proteinuria

Proteinuria is a term used to describe the presence of protein in the urine at levels that are

deemed abnormal. Urine with a high concentration of protein may be indicative of more

complicated kidney problems.

Renal (Kidney) Failure

Renal failure occurs when the kidneys malfunction, preventing the normal removal of waste

from the body. There are three major diseases that can lead to renal failure: Acute renal failure,

chronic kidney disease and end-stage renal disease.

Urinary Incontinence

Urinary incontinence is a condition that results in the involuntary loss of bladder control. This

condition can be remedied through surgical procedures, and sometimes by exercising the

muscles of the pelvic floor.

URINE TRIVIA

A study in Finland demonstrated that human urine mixed with wood ash makes a good fertilizer

for tomatoes.

In May 2009 a system for recycling astronauts urine and sweat into drinking water finally

became operational after months of repeated mechanical failures. Out one end and in the other

(sorry, I couldn't resist that). The system recycles 93% of the astronauts' sweat and urine.

The Cow Protection Department of India's oldest Hindu nationalist group (Rashtriya

Swayamsevak Sangh) announced in 2009 that is was developing a new soft drink made from

cow urine. The soft drink, flavored with herbs, is expected to be ready for sale in a few months.

The healthy beverage is being developed in part to counteract what many in India consider the

corrupting influence of Western food imports. Many in India believe that cow urine has strong

healing properties, and is capable of even curing cancer.

There is a lot of frozen urine floating around in space. For years, most of the urine produced by

astronauts has just been dumped overboard. When it hits the cold vacuum of space, it instantly

freezes into tiny pee crystals. With a new urine recycling system installed on the International

Space Station that turns urine into drinking water, there should be a decrease in the quantity of

pee ice debris in orbit.

Some individuals have odorous urine after eating asparagus, and it was long thought to be a

genetic trait since some people seemed to be immune to this effect. The odor is caused by a

asparagusic acid which the body converts into methanethiol (closely related to skunk spray!). It

now appears that there are exceptions on both sides of the phenomenon. Due to genetic

differences, most but not all people produce methanethiol after eating asparagus, and most but

not all people can detect the odor.

According to my friend and his wife in Thailand, slices of the kafir lime are used as a deodorant

in urinals.

Research at the University of Kuopio in Finland has shown that human urine used as fertilizer

increases the yield of cabbage over conventional fertilizers. The cabbages were also bigger and

had fewer germs. The urine had been stored for 6 months before use as fertilizer. It also works

with cucumbers.

Science News 10/6/07

Both the ancient Egyptians and the Aztecs rubbed urine on their skin to treat cuts and burns.

Urea, a key chemical in urine, is known to kill fungi and bacteria.

REFERRENCES:

Essentials of Anatomy and Physiology 6th Edition,. Rod R. Seeley, Trent D. Stephens, Philip

Tate

Introduction to the Human Body the Essentials of Anatomy and Physiology 7th

Edition and 12th

Edition ., Gerard J. Tortora, Bryan Derrickson,

Essentials of Anatomy and Physiology 6th Edition., Elaine N. Marieb, R.N., Ph.D.

http://www.livestrong.com/article/46314-diseases-urinary-system/#ixzz27ZfyoCNy

http://pinnaclehealthresources.staywellsolutionsonline.com/Library/DiseasesConditions/Adult/Kidney/

85,P08231

http://www.foodreference.com/html/f-urine-trivia.html