230
UNIT 3
Organ Systems
Figure 12-7.
Glomerulus and podocyte.
SEM,
3
9,677
This scanning electron microscopy (SEM) image shows that the surface of the
glomerulus
is entirely covered by
podocytes
and their
processes
. Each
podocyte
is composed of a cell body (with nucleus) and several
branching processes
. The small terminal branches
that cover the capillaries are called
foot processes
or
pedicles
. The pedicles from two podocytes interdigitate with each other. The
gaps between adjacent pedicles are referred to as
± ltration slits
, which are bridged by
±
ltration slit diaphragms
. The inner core of
the pedicles is supported by actin F laments. The inner core of the primary processes is supported mainly by microtubules and inter-
mediate F laments. The podocytes and their unique arrangement are important components in establishing the glomerular F
ltration
barrier.
Podocyte
Podocyte
Podocyte
Pedicles
Pedicles
Pedicles
Filtration slits
Filtration slits
Filtration slits
Branches of
Branches of
primary processes
primary processes
Branches of
primary processes
Primary
Primary
process
process
Primary
process
Pedicles
Pedicles
Pedicles
Primary
Primary
process
process
Primary
process
Podocyte
Podocyte
Podocyte
Primary
Primary
process
process
Primary
process
Branches of
Branches of
primary processes
primary processes
Branches of
primary processes
Filtration slits
Filtration slits
Filtration slits
Bowman space
(filtrate into the space)
Glomerulus
(filters blood)
Urinary
pole
Proximal
convoluted
tubule
Thick descending limb
(proximal straight
tubule)
Thin descending limb
(descending
thin segment)
Ascending thin limb
(ascending
thin segment)
Thick ascending limb
(distal straight
tubule)
Distal
convoluted
tubule
cortical
collecting
tubule
Collecting
duct
Papillary
duct
Minor
calyx
Area
cribrosa
Major
calyx
Renal
pelvis
Ureter
Urinary
bladder
(store)
Urethra
(to outside)
Loop of Henle
Renal corpuscle
Collecting system
Production and Drainage of Urine
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