33627137 urinary system anatomy and physiology

8/4/2019 33627137 Urinary System Anatomy and Physiology

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Urinary System Anatomy and PhysiologyPart I


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Urinary System

Kidneys (2)

Most important excretory organ Eliminate waste

Ureters (2) Bladder (1) Urethra (1) Nephron Unit

Functional unit of the kidney Formation of urine Tubular and vascular structures


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Kidney Location and Protection

Kidneys are located in the posterior wall of the abdominal cavity In the retroperitoneal space Connective tissue (renal fascia) hold the kidneys in place Adipose tissue cushion the kidneys The lower rib cage partially enclose the kidney andprotect them


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Urinary System Anterior/Posterior Views


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Kidney Structures

Kidney is reddish-brown Looks like a bean Approximately 4 inches x 2 inches Hilus indentation where blood vessels and structures enter or exit the kidney Three

Regions in the kidney if sliced in half renal cortex, renal medulla, renal pelvis


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Average adult kidney weighs 113-170 g. 10 12 cm long. 6 cm wide. 2.5 cm thick. Right kidney is lower than the left due to location of liver.


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Adrenal gland lies on top of each kidney. Renal parenchyma is divided into two parts: ~ Cortex ~ Medulla


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Renal Cortex

Light, outside region Cortex means bark Contains: Nephron


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Renal Medulla

Dark, triangular structure Form small cone shaped regions called renal pyramidsEach pyramid is separated by renal columns The lower ends of the pyramids pointto the renal pelvis


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Renal Medulla

Contains: Loops of Henle, Vasa Recta and collecting ducts of the juztamedullarynephrons.

Each kidney contains 8 -18 pyramids. Pyramids drain into 4 13 minor calices. 2 3major calices.


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Renal pelvis

A basin that collects the urine made by the kidney and helps form the upper endof the ureter The edges of the renal pelvis closest to the renal pyramids are called calices Calices collect the urine formed in the kidney


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Renal pelvis

Is the beginning of collecting system and composed structures that are designedto COLLECT and TRANSPORT URINE.


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How do they work?

Need a blood supply Brought to the kidney via the renal artery Renal artery stems from the abdominal aorta 20-25% of cardiac output goes to the kidneys Smaller

arteries supply blood to the nephron unit Blood leaves the kidney via the renalveins The renal veins empty into the inferior vena cava


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Functions of the Kidneys

Excrete nitrogenous waste from the bodyUrea Ammonia Creatinine

Regulate blood volume Help regulate electrolyte content of the blood Regulate acid-base balance (pH) Regulate blood pressure Regulates red blood cell production


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The Formation of Urine

The Nephron Unit Each kidney contains about 1 million nephron units The number does not increase after birth They cannot be replaced if damaged 2 parts

Tubular component (renal tubule) Vascular component


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Renal Tubules

Glomerular capsule (Bowmans Capsule) C shaped capsule surrounding the glomerulus Glomerulus cluster of capillaries

Proximal convoluted tubule Loop of Henle ascending and descending limb DistalConvoluted tubule Collecting duct


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Nephron


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Renal Vasculature

Receives blood from the renal artery Renal artery branches into the afferent arterioles (Branches to form glomerulus) Afferent arterioles feed into Bowmans capsule The efferent arterioles exit Bowmans capsule The efferent arterioles form theperitubular capillaries The peritubular capillaries empty into the venules, large veins, and then into the renal veins It is imperative you know the relationship between the tubular and vascular structures.


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Urine Formation

Formed in the nephron unit Water and dissolved substances move through the renaltubules and vessels Three processes are involved in urine formation

Glomerular filtration Tubular reabsorption Tubular secretion


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Normal Urine

Clear and pale to deep yellow or amber Slightly aromatic in odor Slightly acidic5.0 8.0 With a sp. Gravity of 1.010 1.030 (+) NA, K ions, urea uric acid, creat

inin, ammonia, and HCO3 ions (-) Glucose, CHON, RBC, and WBC and bile pigments


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Composition of Urine

Sterile 95 % water Nitrogen containing waste urea, uric acid, ammonia, creatinine Electrolytes Light yellow color of urine is due to a pigment called urochromeUrochrome is formed from the breakdown of hemoglobin in the liver


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Urine Specific Gravity

Ratio of the amount of solute to the total volume Solute = substance dissolved in the urine The greater the solute = greater the specific gravity Concentrated Urine = high specific gravity

Ex. dehydration Ex. Overhydration, diabetes insipidus

Dilute Urine = low specific gravity


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Urine Characteristics

Amount 1500 ml in 24 hours pH average 6.0 Specific Gravity heavier than water (1.0101.030) Color yellow (amber, straw colored, concentrated, orange, brown, red,sediment, clear or cloudy) Dehydrated = deep yellow, dark Overhydrated = pale yellow, colorless


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Abnormal Constituents of Urine

Albumin (protein) Glucose Red blood cells Hemoglobin White blood cells Ketone bodies Bilirubin


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Urine Testing

Urinalysis Microscopic exam Culture and sensitivity Urine dipstick Urine Drug and alcohol screening 24 hour urine testing


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Your Plumbing The Urinary Tract (Ureters, Urinary bladder, Urethra)

Ureters Transport urine, they do not alter it in any way Urine moves in responseto gravity and muscular movements called peristalsis through ureters.


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Your Plumbing


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The Bladder

Stores urine temporarily until elimination Located behind the symphasis pubis Adistended bladder or full bladder can be palpated above the syphasis in the abdo

minal cavity. Bladder has 4 layers

Mucous membrane Submucosa Detrusor muscle involuntary smooth muscle Serosa

Contain rugae to allow for stretching Trigone triangular area in the floor of the bladder


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Urination Micturition

Expelling urine from the bladder The urge to urinate (void) happened at about 200 ml of urine in the bladder At about 300 ml urine in the bladder, the urge becomes more uncomfortable Moderately full = 500 ml urine Overdistended bladder mayhave over 1000 ml urine Bacteria in your bladder doubles every 4 hours. Stimulated by stretch receptors


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Urethra

Carries urine from the bladder to the outside of the body Internal sphincter prevents urine from emptying; composed of smooth muscle; involuntary External sphin

cter at the upper portion of the urethra allows you to resist the urge to urinate; composed of skeletal muscle; voluntary Female short, opens to the outside atthe urethral meatus Male longer, passes through the prostate gland; carries urine and sperm


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Urinary Retention and Suppression

Retention - Inability to voidPost operative; anesthesia Bladder dysfunction

Suppression no urine formation

Kidney dysfunction


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Data Collection & Documentation

Characteristics of urine

Color Sediment Clear or cloudy Odor

How does the patient/resident void? Urinary diversions? Signs and symptoms

Urgency Frequency Burning sensation Hesitancy


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What is the Costovertebral Angle?T11R. Kidney

T12 L1

L. Kidney

12th Rib

Costovertebral AngleRegion to assess for kidney tenderness


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Disorders of the Urinary System

Glomerulonephritis Polycystic Kidney Pyelonephritis Renal Calculi kidney stonesRenal Failure UTI urinary tract infection


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As We Age

By age 80 there is a 50% reduction in nephron units; therefore a decreased ability to concentrate urine Urinary bladder shrinks and becomes less able to contract and relax; therefore the elderly must void frequently Bladder infection incidence increases Increase in bladder incontinence due to weakened muscles


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Functions of Genitourinary System

Filtration Reabsorption Secretion Excretion Regulation


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33627137 urinary system anatomy and physiology

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