Chapter 15 The Urinary System - Dsapresents

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					    Chapter 15
The Urinary System
    Functions of the Urinary System
1. Elimination of waste
    Nitrogenous wastes
    Toxins
    Drugs
2. Regulates homeostasis
    Water balance
    Electrolytes
    Acid-base balance in the blood
    Blood pressure
    RBC blood cell production
    Activation of vit. D
Importance of Water in Human Body
• Water helps to remove the dangerous toxins
  that our body takes in from the air, the food
  and the chemicals we use on our skin and hair.
• Water also provides cushion for our body
  joints.
• Water carries oxygen and nutrients into all our
  cells.
• Water also helps to regulate our body
  temperature.
     Our body has integrative body
               systems.
When we say “integrative”, this means that our
 body systems are interconnected to each
 other to maintain homeostasis.
    What is human homeostasis?

Word origin: from the
Greek: homeo, meaning unchanging
+ stasis, meaning standing.
• Human homeostasis refers to the body's
  ability to physiologically regulate its inner
  environment to ensure its stability, in
  response to fluctuations in the outside
  environment.
• it is the state of balance in our body.
 What will happen if you do not have
the ability to maintain homeostasis in
               our body?
Homeostatic imbalance will lead to diseases or
 even death.
Maintaining
 Chemical
Homeostasis


   The Urinary
     System
    Organs of the Urinary system


 Kidneys
 Ureters
 Urinary bladder
 Urethra
          Location of the Kidneys
 Right lower than left
 Attached to ureters, renal
  blood vessels, & nerves at
  renal hilus
 Atop kidney is adrenal
  gland
            Regions of the Kidney

 Renal cortex –
  outer region
 Renal medulla –
  inside the cortex
 Renal pelvis –
  inner collecting
  tube
Blood Flow in the Kidneys
                    Nephrons
 Structural and
  functional units of
  the kidneys
 Forms urine
 Main structures
  a. Glomerulus
  b. Renal tubule
         nephron


 renal artery

  renal vein

 Kidney
Anatomy
Nephrons
            Excess salts, water, wastes
             remain in the tubule and
             become urine
            Urine enters collecting ducts
             (tubes) in the medulla
            Collecting tubes empty into
             the renal pelvis (first section
             of the ureter)
            All the blood in the body
             passes through the kidneys
             about 20 times every hour.
                         Glomerulus

 Actual Filtration occurs here
 Excess salts, water,
  nitrogenous wastes
 Water and solutes smaller
  than proteins are forced
  through capillary walls
 Blood cells too big to filter
 Becomes urine
Renal Tubule
 Collecting tube
 Reabsorption
        Things that are useful to the
         body are brought back into
         circulation.
        water, glucose, amino acids,
         and sodium.
   NOT: Nitrogenous waste products
     - Urea
     - Uric acid
     -Creatinine
     -Excess water
            Characteristics of Urine
 Yellow due to
  pigment urochrome
  (from break-down of
  hemoglobin) &
  solutes
 Sterile
 Slightly aromatic
 Normal pH of ~ 6
 Specific gravity of
  1.001 to 1.035
                Ureters
The urine leaves
 the kidneys
 through the
 ureters, a
 muscular tubes 25
 to 30 cm long that
 moves urine from
 the kidney to the
 urinary bladder.
                 Urinary Bladder
 Smooth, collapsible,        Trigone – 3 openings
  muscular sac                  - Two from ureters

 Temporarily stores urine      - One to urethrea
                       Urethra
 Thin-walled tube
 Carries urine from bladder by peristalsis
 Release controlled by 2 sphincters
   - Internal urethral sphincter (involuntary)
   - External urethral sphincter (voluntary)
       Urethra Gender Differences
 Length
  - Females – 3–4 cm (1
    inch)
  - Males – 20 cm         (8
    inches)
 Location
  - Females – along wall of     Function
    the vagina
                                 - Females – only urine
  - Males – through the
                                 - Males –urine and sperm
    prostate and penis
                     Micturition (Voiding)
Both sphincters
 must open
-   internal relaxes after bladder
    stretches
-   Activation - impulse to spinal cord
    and back via pelvic splanchnic
    nerves
-   external voluntarily relaxes

				
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posted:4/17/2013
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