Urinary system
Biology 106
Kidney
• Two bean shaped kidneys are attached to the
posterior abdominal wall, one on each side of
the vertebral column.
• Urine production and filtrate blood plasma
• Consists of 3 parts, outer thin layer called
Capsule followed by Cortex and Medulla.
• The functional unit of the kidney is the
nephron.
The nephron
The nephron is the functional unit of the kidney. Each
nephron consists of one renal corpuscle and its associated
tubule.
• The renal corpuscles are the sites where the process of
urine formation begins with a filtrate of blood plasma.
• Renal tubules are differentiated into several segments.
 A proximal convoluted tubule drains filtrate away from a
renal corpuscle.
 A loop of Henle descends into the medulla, makes a hairpin
turn, and returns to the cortex.
 The distal convoluted tubule passes near to the original
corpuscle then leads to a collecting duct.
 A collecting duct receives fluid from several distal tubules,
then passes through the medulla and drains into the pelvis.
Renal Cortex, with renal corpuscles
Renal tubules
Nerves system
Biology 106
Outline
• Sciatic nerve
T.S. of the sciatic nerve of cat
• Spinal cord
 T.S. of the spinal cord the rabbit
T.S. of the sciatic nerve of cat
• Neurons (Nerve cells) are specialised cells that
conduct electrical impulses.
• Composed of bundles of nerve fibers bounded
togther by C.T. called endoneurium.
• Each bundle is surrounded by C.T. called
perineurium.
• All bundles collected by C.T. called
epineurium.
Magnification X10
Magnification X100
T.S. of the spinal cord the rabbit
• The function of the spinal cord is to carry sensory
information from the periphery to the brain along
the ascending sensory fiber tracts and to carry
motor information from the brain to the
peripheral tissues along the descending motor
fiber tracts.
• Composed of nerve bodies (Gray matter), and
nerve fibers ( White matter).
• Have dorsal and ventral fissures, dorsal and
ventral horn and central canal. Surrounded by pia
mater.
CNS
• The CNS has a
characteristic tissue
arrangement called grey
matter and white matter.
• Grey matter contains the
cell bodies (perikarya) of
neurons and the
supporting cells
(neuroglia) as well as
unmyelinated dendrites.
• White matter does not
contain any cell bodies,
but mostly contains
myelinated nerve fibres.