Our sense organs 45

➡
ment, followed by the thin loop of Henle. This
leads into another convoluted segment, the distal
tubule (see the left diagram on page 69). This discharges
urine into a minor collecting duct, which
becomes a larger collecting tube (the papillary
duct). Bundles of these end in bulges of the renal
medulla (renal papillae). These in turn are incorporated
in cuplike extensions (renal calyces) of
the renal pelvis (diagram page 68), where they
discharge their urine. This is subsequently carried
to the bladder by the ureter.
Continual contemplation of God’s Word acts in
our lives like purifying kidneys, as Jesus told his
disciples: “You are already clean because of the
word I have spoken to you” (John 15:3). The
redemptive power of the blood of Jesus is the
foundation of purification; in the Word of God
the church is told that “Christ loved the church
and gave himself up to her to make her holy,
cleansing her by washing with water through the
Word” (Eph 5:25-26).
We cannot live without kidneys. If someone’s sins
have not been forgiven, and all the accumulated
dross is not eliminated, then he is spiritually dead.
Nobody can have everlasting life without spiritual
kidneys, as Jesus said: “Let the (spiritually) dead
bury their own (physically) dead” (Matt 8:22).
➡
➡
Convoluted segments
of a renal tubule
Glomerulus
Incoming blood
Outgoing blood
Vascular pole
Bowman’s capsule
(diameter 0.17 mm)
Urinary pole
Primary urine
Glomerular tuft
(capillaries)
Straight (ascending
and descending)
segments of the tubule
Loop of Henle
Papillary duct
Detail of a human kidney.
Left: A nephron, the functional unit
Right: Enlarged cross-sectional view
of a renal glomerulus
69