Changes

The '''renal''' crest opens into the renal pelvis. The renal pelvis is an expansion where the proximal ureter begins. The renal pelvis is located within the renal sinus. The '''renal sinus''' is located within an indentation on the medial side of the kidney.  The renal sinus is a potential space, which is occupied by the ureter, branches of the renal artery and vein, lymphatics and nerves that enter the kidney at the hilus. In the horse, the renal pelvis consists of a central cavity and two large '''terminal recesses'''. The '''terminal recess''' is a long tube-like structure that collects urine from the poles of the kidneys into the renal pelvis. Most of the papillary ducts open into the terminal recesses. The renal pelvis is lined with '''transitional epithelium''' and contains '''mucous glands''' in the horse; giving urine a frothy appearence.

The '''renal''' crest opens into the renal pelvis. The renal pelvis is an expansion where the proximal ureter begins. The renal pelvis is located within the renal sinus. The '''renal sinus''' is located within an indentation on the medial side of the kidney.  The renal sinus is a potential space, which is occupied by the ureter, branches of the renal artery and vein, lymphatics and nerves that enter the kidney at the hilus. In the horse, the renal pelvis consists of a central cavity and two large '''terminal recesses'''. The '''terminal recess''' is a long tube-like structure that collects urine from the poles of the kidneys into the renal pelvis. Most of the papillary ducts open into the terminal recesses. The renal pelvis is lined with '''transitional epithelium''' and contains '''mucous glands''' in the horse; giving urine a frothy appearence.

===Vascularization===

===Vascular Supply===

The kidney receives approximately 25% of cardiac output. Each kidney is supplied by a '''renal artery''', which is a branch of the '''abdominal aorta'''. The renal artery subsequently divides at the hilus of each kidney into '''interlobar arteries''', which run to the '''corticomedullary junction'''. Here they branch into '''arcuate arteries'''. The arcuate arteries then give rise to '''interlobular arteries''' which radiate into the renal cortex. The interlobular arteries become the '''afferent arteriole''' and subsequently the capillary loops of the glomerulus.  These capillary loops then unite to become the '''efferent arteriole''', which supplies a capillary network around the nephrons. This capillary network drains blood from the renal cortex into the '''interlobular veins''', '''arcuate veins''', then '''interlobar veins'''. The interlobar veins drain into the '''renal veins''', which subsequently drain into the '''caudal vena cava'''.

The kidney receives approximately 25% of cardiac output. Each kidney is supplied by a '''renal artery''', which is a branch of the '''abdominal aorta'''. The renal artery subsequently divides at the hilus of each kidney into '''interlobar arteries''', which run to the '''corticomedullary junction'''. Here they branch into '''arcuate arteries'''. The arcuate arteries then give rise to '''interlobular arteries''' which radiate into the renal cortex. The interlobular arteries become the '''afferent arteriole''' and subsequently the capillary loops of the glomerulus.  These capillary loops then unite to become the '''efferent arteriole''', which supplies a capillary network around the nephrons. This capillary network drains blood from the renal cortex into the '''interlobular veins''', '''arcuate veins''', then '''interlobar veins'''. The interlobar veins drain into the '''renal veins''', which subsequently drain into the '''caudal vena cava'''.