4.02 Understand the Functions and

Disorders of the Urinary System

4.02 Understand the functions and disorders of

the urinary system

Essential Questions

• What are the functions of the urinary system?

• What are some disorders of the urinary system?

• How are disorders of the urinary system treated?

• How do you relate the body’s hormone control to the

urinary system?

4.02 Understand the functions and disorders of the urinary system 2

Understand the functions of

the urinary system

Functions:

• Filtration

• Excretion

• Formation of urine

• Fluid and electrolyte balance

• Elimination of urine

4.02 Understand the functions and disorders of the urinary system 3

4.02 Understand the functions and disorders of the

urinary system

• Filtration: The filtering of the blood to create

a filtrate.

– This is the first step in urine formation

– Filtrate contains various substances

– These substances are either reabsorbed back into

the bloodstream, or excreted from the body as

urine.

4.02 Understand the functions and disorders of the urinary system

4

Understand the functions of

the urinary system

Excretion

• What is excretion? Removal of waste matter from the

body

• Why does the body have excretory functions?

• What is the composition of wastes excreted by the

urinary system?

– Nitrogenous wastes

– Salt

– Water

4.02 Understand the functions and disorders of the urinary system 5

Understand the functions of

the urinary system

Filtration

Reabsorption

Secretion

4.02 Understand the functions and disorders of the urinary system 6

•To form urine the nephron must perform three processes:

•Glomerularfiltration•Tubular reabsorption•Tubular secretion

4.02 Understand the functions and disorders of the urinary system 7

• Blood from renal

artery enters

glomerulus

• High pressure in

glomerulus forces fluid

into Bowman’s

capsule, where it is

filtered

BOWMAN’S CAPSULE– A tuft of capillaries

• Bowman’s capsule filters out 125cc of fluid/min.

…how many cc’s per hour is this?

• As the filtrate continues through the tubules, 99% of

water is reabsorbed back into the blood stream

4.02 Understand the functions and disorders of the urinary system 8

Reabsorption• What substances are reabsorbed?

– Water

– Glucose

– Amino acids

– Vitamins

– Bicarbonate ions

– Sodium

– Potassium

• If blood levels of certain substances are high, the substances will not be reabsorbed.

• Threshold: the term used to describe the limit of reabsorption

4.02 Understand the functions and disorders of the urinary system 9

Secretion

4.02 Understand the functions and disorders of the urinary system 10

•What is secretion? •The transport of substances from the blood into the urine in the distal and collecting tubules.

•It is the opposite of absorption.

• What substances are secreted into the

collecting tubules?– Some medications

– Ammonia

– Creatinine

– Hydrogen ions

– potassium

4.02 Understand the functions and disorders of the urinary system 11

Understand the functions of

the urinary system

Fluid and electrolyte balance

• Electrolytes are selectively secreted to maintain

body’s acid-base balance.

– What are electrolytes? Electrically charged particles

– What do they do? Help determine fluid and acid-base

balance

4.02 Understand the functions and disorders of the urinary system 12

Understand the functions of

the urinary system

Fluid and electrolyte balance

Chemical control

– ADH (Anti-diuretic hormone)- secreted by the posterior pituitary gland when blood pressure decreases

– Aldosterone- A steroid secreted by the adrenal cortex when plasma sodium decreases or plasma potassium increases.

Nervous control– Directly through the action of nerve impulses on the blood vessels leading to the kidney

– Indirect nerve control is through stimulation of certain endocrine glands whose hormone secretion will control urinary secretion.

4.02 Understand the functions and disorders of the urinary system 13

Understand the functions of

the urinary system

Fluid and electrolyte balance

Chemical control

• The amount of ADH produced is related to the

level of body hydration

4.02 Understand the functions and disorders of the urinary system 14

Understand the functions of

the urinary system

Forming more dilute urine:

Define “dilute urine”

• What are diuretics?

• What effect do they have on the production of

urine?

• Give examples of substances that have diuretic

effects.

4.02 Understand the functions and disorders of the urinary system 15

Understand the functions of

the urinary system

Fluid and electrolyte balance

4.02 Understand the functions and disorders of the urinary system 16

What effect does this cycle have on your blood pressure?

Understand the functions of the urinary system

The flow of electrolytes

4.02 Understand the functions and disorders of the urinary system 17

Review urine formation, electrolyte exchange, and some factors that effect urine volume.

Understand the functions of

the urinary system

• What do you predict will happen to blood pressure

when the blood volume increases?

• What if blood

volume decreases?

4.02 Understand the functions and disorders of the urinary system 18

Understand the functions of

the urinary system

• If more water is reabsorbed back into the body--

-what will happen to urine concentration?

• (more or less concentrated?)

4.02 Understand the functions and disorders of the urinary system 19

Understand the functions of

the urinary system

Elimination of urine

What causes the bladder to empty?

–The bladder can hold about 500 ml of fluid

–When it fills, the stretch triggers urination-emptying the bladder

Is this a voluntary or involuntary action?

What can prevent urination? Internal and external sphincters

4.02 Understand the functions and disorders of the urinary system 20

Understand the functions of

the urinary system

Elimination of urine

Urinary output

4.02 Understand the functions and disorders of the urinary system 21

Average urinary output = 1500 ml per day

*How many ounces is this?

What effects

the color of

your urine?

Urinalysis

An examination of urine

• What does normal urine look like?

• What constitutes an abnormal urinalysis?

4.02 Understand the functions and disorders of the urinary system 22

Urinalysis

4.02 Understand the functions and disorders of the urinary system 23

Urinalysis

4.02 Understand the functions and disorders of the urinary system 24

Urinalysis

4.02 Understand the functions and disorders of the urinary system 25

Disorders of the urinary

system

4.02 Understand the functions and disorders of the urinary system26

Disorders of the urinary system

Cystitis

• What is cystitis

(cyst= medical term for ____ +itis =___ )– Inflammation of the mucous membrane lining of the bladder

• Most common cause: E. Coli

• What are the major symptoms of cystitis?– Painful urination (dysuria)

– Frequent urination (polyuria)

4.02 Understand the functions and disorders of the urinary system 27

Disorders of the urinary system

Cystitis

• More common in females―Why ??

– The urethra is shorter in females

4.02 Understand the functions and disorders of the urinary system 28

Disorders of the urinary system

Glomerulonephritis

4.02 Understand the functions and disorders of the urinary system 29

� Disease which injures

the glomerulus.

� What does this mean for

my health?• When the filter is damaged, blood cells and

blood proteins enter the filtrate

• Removal of waste products is decreased

• Electrolyte balance is abnormal

• Kidney damage can occur

Disorders of the urinary system

Glomerulonephritis

• Two types:

– Acute- can occur in children after a bacterial infection, usually strep

throat

– Chronic- Occurs when the filtration membrane has been

permanently affected. May result in kidney failure.

4.02 Understand the functions and disorders of the urinary system 30

Disorders of the urinary system

Renal calculi

Also known as nephrolithiasis

nephro lith iasis

What are renal calculi made of?–Calcium phosphate

–Uric acid

What are the symptoms?–Extreme pain

–Nausea and vomiting

–Burning when urinating

–Hematuria4.02 Understand the functions and disorders of the urinary system 31

Disorders of the urinary system

Renal calculi

• What will happen if the

ureters are blocked?– The renal pelvis and calyces

become enlarged due to

excess fluid

4.02 Understand the functions and disorders of the urinary system 32

Disorders of the urinary system

Renal calculi

• How is it treated?– Increase fluids

– Medications

– Lithotripsy

4.02 Understand the functions and disorders of the urinary system 33

Disorders of the urinary system

Renal calculi

• How does lithotripsy work?

– Shockwaves are created outside the body that travel through until the

waves hit the dense stones.

• Is it a cure?

4.02 Understand the functions and disorders of the urinary system 34

Disorders of the urinary system

Renal failure

• Acute• What causes it?

– Nephritis

– shock

– Injury

– Bleeding

– Heart failure

– Poisoning

– What are the symptoms? • Oliguria- diminished production of urine

• Anuria- absence of urine

• Uremia- when the blood retains urinary waste products

4.02 Understand the functions and disorders of the urinary system 35

Disorders of the urinary system

Renal failure

chronicchronicchronicchronic

• Symptoms may be none in early stages, urinalysis may

reveal proteinuria

4.02 Understand the functions and disorders of the urinary system 36

Disorders of the urinary system

Renal Failure

• Chronic kidney

disease leads to a

buildup of fluid and

waste products in

the body.

4.02 Understand the functions and disorders of the urinary system 37

Disorders of the urinary system

Renal Failure

• How is it treated?

– Peritoneal dialysis

• Read about it! Page 587

4.02 Understand the functions and disorders of the urinary system 38

Disorders of the urinary system

Renal Failure

• How is it treated?

– Hemodialysis

• Read about it! Page 587

4.02 Understand the functions and disorders of the urinary system 39

Disorders of the urinary system

Renal Failure

• Compare the treatment of acute and

chronic renal failure.

4.02 Understand the functions and disorders of the urinary system 40

Disorders of the urinary system

How does hemodialysis mimic

glomerular function?

4.02 Understand the functions and disorders of the urinary system 41

Disorders of the urinary system

Renal transplant

• What is involved in this treatment option?

• When does a patient get a transplant?• Read about it! Page 588

4.02 Understand the functions and disorders of the urinary system 42

Disorders of the urinary system

Renal transplant

4.02 Understand the functions and disorders of the urinary system 43

What is the

major

complication of

renal

transplantation?

4.02 Understand the functions and disorders of

the urinary system

• Essential Questions

• What are the functions of the urinary system?

• What are some disorders of the urinary system?

• How are disorders of the urinary system treated?

• How do you relate the body’s hormone control to the

urinary system?

4.02 Understand the functions and disorders of the urinary system 44