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Hole’s Human
Anatomy and Physiology
Eleventh Edition
Shier w Butler w Lewis
Chapter
20
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1
URINARY SYSTEM
Consists of

kidneys

ureters

urinary bladder

urethra
2
URINARY SYSTEM
3
EXSTROPHY OF THE BLADDER
4
REPAIRING EXSTROPHY OF THE BLADDER
5
KIDNEYS

Reddish brown,
bean-shaped organ

Enclosed in tough,
fibrous capsule


Approximately
 12 cm high
 6 cm wide
 3 cm thick
Left slightly larger
6
LOCATION OF KIDNEYS

positioned retroperitoneally - behind
the parietal peritoneum
7
LOCATION OF KIDNEYS




Lie on either side of
the vertebral column,
High on the posterior
wall of the abdominal
cavity, just at the
12th rib
Left slightly higher
than right
Surrounded by fat
8
KIDNEY STRUCTURE
Renal Sinus

Concave area

Contains Renal Pelvis

Is entrance for blood
vessels and ureter –
area is called hilum
9
KIDNEY STRUCTURE
3
Main areas
1.
Renal Cortex – outer
shell
2.
Renal Medulla – main
area of tissue
3.
Renal Pelvis -2 types
of funnel shaped
calyces (major calyx
and minor calyx)
10
KIDNEY STRUCTURE
Cortex and
Medulla
contain
functional
units of
kidneys
called
nephron
11
FUNCTIONS OF THE KIDNEYS
 removal of metabolic wastes (contain nitrogen
and sulfur hence smell of urine) from the blood and
excretion to the outside of the body
 regulation of
 red blood cell production (by hormone
erythropoietin)
 blood pressure (by enzyme renin)
 calcium ion absorption (activates Vitamin D)
 volume, composition, and pH of the blood
12
RENAL BLOOD VESSELS
Kidneys receive 15-30% of cardiac output
(blood pumped with each heart beat)
13
RENAL BLOOD VESSELS
Interlobular vessels go to nephron.
Two types:
1. Afferent –
incoming vessel
2. Efferent –
outgoing vessel
14
URINE FORMATION
• nephrons remove wastes from the blood and
regulate water and electrolyte concentrations
• urine is the final product of the processes of:
• glomerular filtration
• tubular reabsorption
• tubular secretion
•
https://www.youtube.com/watch?v=OkyFPMXa28c
15
STRUCTURE OF A NEPHRON



Functional unit of
kidney
About 1 million per
kidney
Consist of 2 parts
 Renal
Corpuscle
 Renal
Tubule
16
NEPHRON POSITION
17
2 PARTS OF RENAL CORPUSCLE
Glomerulus
1.


cluster of blood
capillaries
Where filtration of
blood occurs
Bowman’s capsule
2.



Glomerular capsule
Saclike structure
Catches the filtrate
from the glomerulus
18
GLOMERULUS
19
GLOMERULAR FILTRATION



As a result of the smaller
Efferent arteriole the
blood in the Glomerulus is
under great pressure.
The pressure forces
substances out of the
capillaries and into the
Bowman Capsule
Proteins are too large to
pass and are not normally
filtered out
20
GLOMERULAR FILTRATE AND
URINE COMPOSITION
21
GLOMERULAR CAPSULE
Collects the
filtrate
from the
glomerulus
and directs
it into the
tubule.
22
AMOUNTS OF GLOMERULAR
FILTRATE AND URINE
average amounts over a 24 hour period
180 L of filtrate
produced each 24
hours. Would
dehydrate if
reabsorption
didn’t take place.
23
CONTROL OF FILTRATION RATE
• Primarily three
Renin-Angiotensin system
mechanisms are responsible
for keeping the GFR
constant
• Increased
sympathetic impulses
decrease GFR by
causing afferent
arterioles to constrict
• Renin-angiotensin
system
• Autoregulation
24
TUBULAR REABSORPTION
• transports substances from the glomerular filtrate into
the blood within the peritubular capillary
Most of the
fluids and
particles filtered
out initially will
be returned to
the blood. This
happens in the
proximal
convoluted tubule
and Loop of
Henle.
25
SODIUM AND WATER REABSORPTION
• osmosis reabsorbs
water in response
to reabsorbing
sodium and other
solutes by active
transport in the
proximal portion of
the renal tubule
26
SODIUM AND WATER FILTRATION,
REABSORPTION, AND EXCRETION
27
TUBULAR SECRETION
• transports substances from the blood within
the peritubular capillary into the renal tubule
28
TUBULAR SECRETION
In distal convoluted tubules, potassium ions or hydrogen
ions may be passively secreted in response to active
reabsorption of sodium ions
29
REGULATION OF URINE
CONCENTRATION AND VOLUME
• the distal convoluted tubule and collecting duct are impermeable
to water, so water may be excreted as dilute urine
• if ADH is present, these segments become permeable, and water
is reabsorbed by osmosis into the hypertonic medullary interstitial
fluid
30
URINE FORMATION
• Glomerular Filtration
• substances move from blood to glomerular capsule
• Tubular Reabsorption
• substances move from renal tubules into blood of
peritubular capillaries
• glucose, water, urea, proteins, creatine
• amino, lactic, citric, and uric acids
• phosphate, sulfate, calcium, potassium, and sodium
ions
• Tubular Secretion
• substances move from blood of peritubular capillaries
into renal tubules
• drugs and ions
•https://www.youtube.com/watch?v=oCQ-5iwTQvM
31
ROLE OF ADH IN REGULATING URINE
CONCENTRATION AND VOLUME
32
FUNCTIONS OF NEPHRON COMPONENTS
33
UREA AND URIC ACID EXCRETION
Urea
• by-product of amino
acid catabolism
Uric Acid
• product of nucleic
acid metabolism
• plasma concentration
reflects the amount or
protein in diet
• enters renal
tubules through
glomerular filtration
• enters renal tubules
through glomerular
filtration
• most reabsorption
occurs by active
transport
• contributes to the
reabsorption of water
from the collecting duct
• ~10% secreted and
excreted
34
URINE COMPOSITION
• about 95% water
• usually contains urea, uric acid, and
creatinine
• may contain trace amounts of amino
acids and varying amounts of
electrolytes
• volume varies with fluid intake and
environmental factors
35
ELIMINATION OF URINE
Flow of urine:
1. nephrons
2. collecting ducts
3. renal papillae
4. minor and major
calyces
5. renal pelvis
6. ureters
7. urinary bladder
8. urethra
9. outside
36
URETERS
• 25 cm long
• extend downward posterior to the parietal peritoneum
• parallel to vertebral column
• in pelvic cavity, join urinary bladder
• Peristaltic waves move urine
• wall of ureter
• mucous coat
• muscular coat
• fibrous coat
37
URINARY BLADDER
• hollow, distensible, muscular organ located within the
pelvic cavity, posterior to the symphysis pubis and
inferior to the parietal peritoneum
38
URINARY BLADDER
• the internal floor of the bladder includes a
triangular area called the trigone which has an
opening at each of three angles
39
URETHRA
• tube that conveys urine from the urinary bladder
to the outside of the body
40
MICTURITION
• urination reflex
•Distension of the bladder walls stimulates the
urge to urinate.
•Urethral sphincters (internal & external) relax to
open passageway
41
CROSS SECTION OF URETHRA
42
MICTURITION
43
LIFE-SPAN CHANGES
• kidneys appear scarred and grainy
• kidney cells die
• by age 80, kidneys have lost a third of their mass
• kidney shrinkage due to loss of glomeruli
• proteinuria may develop
• renal tubules thicken
• harder for kidneys to clear certain substances
• bladder, ureters, and urethra lose elasticity
• bladder holds less urine
44
KIDNEY STONES
45
CLINICAL APPLICATION
Glomerulonephritis
• inflammation of glomeruli
• may be acute or chronic
• acute glomerulonephritis usually occurs as an immune
reaction to a Streptococcus infection
• antigen-antibody complexes deposited in glomeruli and
cause inflammation
• most patients recover from acute glomerulonephritis
• chronic glomerulonephritis is a progressive disease and
often involves diseases other than that caused by
Streptococcus
• renal failure may result from chronic
glomerulonephritis
46