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 nephronThe 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 nerveT.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.