Cambridge International A Level Biology Revision Guide

Chapter 14: Homeostasis
The structure of the kidney
Figure 14.5 shows the position of the kidneys in the body,
together with their associated structures. Each kidney
receives blood from a renal artery, and returns blood via
a renal vein. A narrow tube, called the ureter, carries
urine from the kidney to the bladder. From the bladder a
single tube, the urethra, carries urine to the outside of
the body.
vena cava
A longitudinal section through a kidney (Figure 14.6)
shows that it has three main areas. The whole kidney is
covered by a fairly tough capsule, beneath which lies the
cortex. The central area is made up of the medulla. Where
the ureter joins, there is an area called the pelvis.
A section through a kidney, seen through a
microscope (Figure 14.7), shows it to be made up of
capsule
cortex
aorta
renal artery
renal vein
kidney
ureter
bladder
urethra
ureter
pelvis
medulla
branch of
renal vein
branch of
renal artery
Figure 14.5 Position of the kidneys and associated structures
in the human body.
a
Figure 14.6 A kidney cut in half vertically.
b
305
outer epithelium
of Bowman’s
capsule
c
glomerular capillary
containing red
blood cells, and
podocyte cells
distal
convoluted
tubule
microvilli
proximal
convoluted
tubule
collecting
duct
thin section
of the loop
of Henle
thick section
of the loop
of Henle
capillary
distal convoluted
tubule
Figure 14.7 a Photomicrograph of a section through the cortex of the kidney showing a glomerulus and Bowman’s capsule
surrounded by proximal and distal convoluted tubules (× 150); b photomicrograph of a section through the medulla of a kidney
(× 300); c interpretive drawings.