The outermost layer of kidney wall is called cortex. It is divided into two parts. Supercial cortex and juxtamedullary cortex. The outer layer of the cortex is called the superficial cortex and the inner layer of the cortex is called the juxtamedullary cortex. The supracial cortex contains 85% and the juxtamedullary cortex 15% of nephrons. The cortex contains the renal corpuscle, proximal convoluted tubule, and distal convoluted tubule of the nephron.

The outermost layer of kidney wall is called cortex. It is divided into two parts. Supercial cortex and juxtamedullary cortex. The outer layer of the cortex is called the superficial cortex and the inner layer of the cortex is called the juxtamedullary cortex. The supracial cortex contains 85% and the juxtamedullary cortex 15% of nephrons. The cortex contains the renal corpuscle, proximal convoluted tubule, and distal convoluted tubule of the nephron.

Three regions are seen in the longitudinal section of the kidney. These are-
(i) Cortex : The outermost layer of kidney wall is called cortex. It is divided into two parts. Supercial cortex and juxtamedullary cortex. The outer layer of the cortex is called the superficial cortex and the inner layer of the cortex is called the juxtamedullary cortex. The supracial cortex contains 85% and the juxtamedullary cortex 15% of nephrons. The cortex contains the renal corpuscle, proximal convoluted tubule, and distal convoluted tubule of the nephron.
(ii) Medulla: The central part of kidney wall is called medulla. It is light red in color. It consists of 8-18 pyramidal structures. It is called renal pyramid. The base of the pyramid faces the cortex and the apex faces the renal sinus. The top of the pyramid is called Papilla. Papilla with 10-25 pores. Apex of papilla opens into minor calyx. The minor calyxes open together into the major calyx. Also, the pillar-like part of the cortex between the two renal pyramids is called the Renal column. (iii) Pelvis: The large collecting space inside the kidney is called the pelvic floor. There are two types of branchial parts in the pelvis. There are 2-3 main branches. Major branches are called major calyxes. 8-14 minor calyxes arise from the major calyx.

Kidneys look like bean seeds and are reddish-brown in color. Its length is 10-12 cm, width is 5-6 cm and thickness is 3 cm. Male kidney weighs 125-170 grams and female kidney weighs 115-155 grams. Its outer side is convex and inner side is concave. The fold in the concave part is called Hilus. The hilus is attached to the ureter. Each kidney is covered by a fibrous connective tissue called the renal capsule or tunica fibrosa. Outside the renal capsule is a fatty layer that protects the kidney from friction. At the tip of the kidney are the cap-like adrenal glands.

Kidney is the main excretory organ of human body. This is called a body filter. In 1842, Sir William Bowman first explained the exact structure of the kidney. The structure of kidney can be described in two ways. External structure and internalization.
1. External Structure
Kidneys look like bean seeds and are reddish-brown in color. Its length is 10-12 cm, width is 5-6 cm and thickness is 3 cm. Male kidney weighs 125-170 grams and female kidney weighs 115-155 grams. Its outer side is convex and inner side is concave. The fold in the concave part is called Hilus. The hilus is attached to the ureter. Each kidney is covered by a fibrous connective tissue called the renal capsule or tunica fibrosa. Outside the renal capsule is a fatty layer that protects the kidney from friction. At the tip of the kidney are the cap-like adrenal glands.
2. Internal Structure
Three regions are seen in the longitudinal section of the kidney. These are-
(i) Cortex : The outermost layer of kidney wall is called cortex. It is divided into two parts. Supercial cortex and juxtamedullary cortex. The outer layer of the cortex is called the superficial cortex and the inner layer of the cortex is called the juxtamedullary cortex. The supracial cortex contains 85% and the juxtamedullary cortex 15% of nephrons. The cortex contains the renal corpuscle, proximal convoluted tubule, and distal convoluted tubule of the nephron.
(ii) Medulla: The central part of kidney wall is called medulla. It is light red in color. It consists of 8-18 pyramidal structures. It is called renal pyramid. The base of the pyramid faces the cortex and the apex faces the renal sinus. The top of the pyramid is called Papilla. Papilla with 10-25 pores. Apex of papilla opens into minor calyx. The minor calyxes open together into the major calyx. Also, the pillar-like part of the cortex between the two renal pyramids is called the Renal column. (iii) Pelvis: The large collecting space inside the kidney is called the pelvic floor. There are two types of branchial parts in the pelvis. There are 2-3 main branches. Major branches are called major calyxes. 8-14 minor calyxes arise from the major calyx.

The narrow tube behind the urinary bladder is called the urethra. The length of the urethra is 18-20 cm in males and 3.5-4.0 cm in females. Urine is released through it.

Urinary bladder is a triangular sac. Its wall is thin, elastic and composed of involuntary muscles called detrusors. It acts as a urinary reservoir. The bladder can hold 700-750 ml of urine. However, only when 280-320 ml of urine accumulates, the urge to urinate arises. Patients with hyperuricosuria develop stones in the urinary bladder.

The tube that originates from the pelvis and opens into the urinary bladder is called the ureter. Its length is about 25-30 cm. It carries urine from the kidneys to the bladder.

Kidney looks like a bean seed. Its outer side is convex and inner side is concave. Below the ribcage in the lumbar region of the abdominal cavity are two kidneys on either side of the spine. The left kidney is slightly larger than the right kidney. The upper edge of the kidney lies below the 12th thoracic vertebra and is protected by the 11th and 12th vertebrae. The lower edge of the kidney lies above the third lumbar vertebra. The left kidney lies slightly above the liver and the right kidney slightly below.

The system through which nitrogenous wastes are excreted from the body is called the excretory system. Different parts of excretory system are-
1. Kidney: Kidney looks like a bean seed. Its outer side is convex and inner side is concave. Below the ribcage in the lumbar region of the abdominal cavity are two kidneys on either side of the spine. The left kidney is slightly larger than the right kidney. The upper edge of the kidney lies below the 12th thoracic vertebra and is protected by the 11th and 12th vertebrae. The lower edge of the kidney lies above the third lumbar vertebra. The left kidney lies slightly above the liver and the right kidney slightly below.
2. Ureter: The tube that originates from the pelvis and opens into the urinary bladder is called the ureter. Its length is about 25-30 cm. It carries urine from the kidneys to the bladder.3. Urinary bladder: Urinary bladder is a triangular sac. Its wall is thin, elastic and composed of involuntary muscles called detrusors. It acts as a urinary reservoir. The bladder can hold 700-750 ml of urine. However, only when 280-320 ml of urine accumulates, the urge to urinate arises. Patients with hyperuricosuria develop stones in the urinary bladder.
4. Urethra: The narrow tube behind the urinary bladder is called the urethra. The length of the urethra is 18-20 cm in males and 3.5-4.0 cm in females. Urine is released through it.