Chapter 13: The Urinary System
Urologists: specializes in the diagnosis and treatment of
diseases of the urinary system
Nephrologists: specializes in the diagnosis and treatment
diseases of the kidney
The urinary system (urinary tract) carries the wastes of
the body, and the kidney eliminates them
The kidney removes wastes products from the blood
Urine consists of excess water, electrolytes, and urea
6 Organs of the Urinary System:
1.2 kidneys
2.2 ureters
3.One urinary bladder
4.One urethra
The process of removing metabolic wastes is called
excretion and it maintains homeostasis
Metabolic wastes: CO2, excess water, electrolytes,
nitrogenous compounds like ammonia, and urea – if they are
not eliminated, they will poison the body
The Kidneys:
One kidney on each side of vertebral column that lies
against deep muscles of the back
Blood with wastes enters the kidney at its hilum through the
renal artery
Nephrons in the kidney filter the blood
Glomerulus: plexus of capillaries, part of a nephron
Blood goes into the tubules tubules go into the
calyces calyces join to form the ureter ureters
, carry the filtered waste which is now called urine to
the urinary bladder
Functions of the kidneys:
o Filter blood to eliminate waste
o Regulate blood volume and pressure by eliminating or
conserving water
o Maintaining homeostasis by controlling the amount of
water and electrolytes that are eliminated
The Ureters:
Carry urine from renal pelvis to the urinary bladder
As pressure builds up in the filling bladder, the muscle wall
compresses the ureters to prevent urine from being forced
back up to the kidneys
Uses gravity and peristalsis
Urinary Bladder and Urethra
The urinary bladder is a temporary storage for urine before it
is evacuated through the urethra
Moderately full bladder contains about 1 pint of urine
Maximum capacity is about 1.5 pints
Urination is also called micturition
External Urethral Sphincter: provides voluntary control of
urination
Males: 7-8 inch long urethra
Females: 1.5 inches long
External urinary meatus: opening of the urethra to the
outside
Micturition
When the bladder contains about 200 mL of fluid the stretch
receptors trigger the micturition reflex
Parasympathetic nerves stimulate the bladder’s muscle walls
to provide the urgent feel of needing to pee
Disorders of the Urinary System
Urologists: specializes in the diagnosis and treatment of
diseases of the urinary system
Nephrologists: specializes in the diagnosis and treatment
diseases of the kidney
The urinary system (urinary tract) carries the wastes of
the body, and the kidney eliminates them
The kidney removes wastes products from the blood
Urine consists of excess water, electrolytes, and urea
6 Organs of the Urinary System:
1.2 kidneys
2.2 ureters
3.One urinary bladder
4.One urethra
The process of removing metabolic wastes is called
excretion and it maintains homeostasis
Metabolic wastes: CO2, excess water, electrolytes,
nitrogenous compounds like ammonia, and urea – if they are
not eliminated, they will poison the body
The Kidneys:
One kidney on each side of vertebral column that lies
against deep muscles of the back
Blood with wastes enters the kidney at its hilum through the
renal artery
Nephrons in the kidney filter the blood
Glomerulus: plexus of capillaries, part of a nephron
Blood goes into the tubules tubules go into the
calyces calyces join to form the ureter ureters
, carry the filtered waste which is now called urine to
the urinary bladder
Functions of the kidneys:
o Filter blood to eliminate waste
o Regulate blood volume and pressure by eliminating or
conserving water
o Maintaining homeostasis by controlling the amount of
water and electrolytes that are eliminated
The Ureters:
Carry urine from renal pelvis to the urinary bladder
As pressure builds up in the filling bladder, the muscle wall
compresses the ureters to prevent urine from being forced
back up to the kidneys
Uses gravity and peristalsis
Urinary Bladder and Urethra
The urinary bladder is a temporary storage for urine before it
is evacuated through the urethra
Moderately full bladder contains about 1 pint of urine
Maximum capacity is about 1.5 pints
Urination is also called micturition
External Urethral Sphincter: provides voluntary control of
urination
Males: 7-8 inch long urethra
Females: 1.5 inches long
External urinary meatus: opening of the urethra to the
outside
Micturition
When the bladder contains about 200 mL of fluid the stretch
receptors trigger the micturition reflex
Parasympathetic nerves stimulate the bladder’s muscle walls
to provide the urgent feel of needing to pee
Disorders of the Urinary System
