Urinary bladder fills with urine. Nerve impulses from spinal cord cause urinary bladder muscles to contract and sphincters to relax making urination possible. Brain controls this reflex in older children and adults. Three Regions a. On concave side, there is depression where renal blood vessels and ureter enter.
Renal cortex is outer granulated layer that dips down between the renal medulla.
Renal medulla has radially striated cone-shaped masses called renal pyramids . Renal pelvis is central space or cavity continuous with ureter. Nephrons a. Nephrons are microscopic, sometimes called renal or kidney tubules. Each kidney contains over one million nephrons. Several nephrons enter one collecting duct.