Urinary System
Urinary system consists of -
KIDNEYS-2
URETERS -2
URINARY BLADDER
URINOGENITAL TRACT/URETHRA
Kidneys
Kidneys are the main organs of urinary system.They are 2 bean shaped
organs lying on the posterior wall of upper abdomen, one on each side of vertebral column. They lie at the level of twelfth thoracic to third lumbar vertebrae. Right kidney is located slightly lower than left kidney. Dimensions of each kidney are 11 x 5 x 3 cm3. Each kidney weighs 150g. approximately.On each kidney, an adrenal gland is present.
Each kidney is embedded by fat called perirenal fat.Right kidney bears the impression of part of duodenum on its front.Pancreas crosses the left kidney transversely in its front. Each kidney is convex on its outer border and concave in the centre of its inner border. At this point, blood vessels, nerves and ureter enter and leave kidney. This point of kidney is called Hilus. Ureters transport urine formed in kidneys to urinary bladder.From urinary bladder, urine is passed to the exterior through urethra.Urethra in males is also passage for semen.Hence it is also called urinogenital tract in males. In females, it is independent.
Structure of Kidney
Longitudinal section of Kidney :
Kidney is surrounded by a fibrous capsule. It can be stripped off easily.
Portion inside this fibrous capsule can be divided into-
1) Cortex 2) Medulla
Cortex is the outer reddish brown coloured portion and medulla is the inner lighter area.
Medulla is subdivided into 10 to 15 conical areas called renal pyramids.
Pyramids have their broad base towards cortex and apex projecting into lumen of minor calyx. Columns of Bertin are the projections of cortex. They form the boundaries of the pyramids.
Ureters
There are two ureters carrying urine from kidneys to urinary bladder.
They are continuous from renal pelvis to urinary bladder and are about 25-30 cm long. Diameter is about 3 mm.Ureter is slightly constricted at three places.Ureter has three layers and they are-
1. Outer fibrous coat which is continuous with the fibrous coat of kidney.
2. Muscular coat containing outer circular layer and inner longitudinal layer.
3. Lining of mucous membrane continuous with that of bladder.
Urinary bladder
Urinary bladder is sac serving as distensible reservoir of urine evacuating its contents at suitable intervals of time. It lies in pelvic cavity behind symphisispubis. Urinary bladder consists of two portions.
1. Body - sac of detrussor muscle.
2. Trigone - triangular region connecting the three openings of bladder -
two of ureters and one of urethra.
Urinary bladder has two sphincters.They are
1. Internal sphincter
2. External sphincter
Internal sphincter is formed by smooth muscles surrounding the opening of urethra. External sphincter is formed by striated muscle of urogenital diaphragm
Urethra
Urethra is the canal through which urine from bladder is passed to the
exterior. It extends from base of the bladder. It has two sphincters.They are-
1. Internal sphincter - involuntary
2. External sphincter - voluntary
It has two orifices .They are-
1. Internal urethral orifice in the bladder.
2. External urethral orifice.
Male urethra serves as common tract for urinary and reproductive systems and thus it is called urinogenital tract. In females it serves for urinary system only. Male urethra : It is about 20 cm. long. It is divided into three portions.
1. Prostatic portion - surrounded by prostate gland and 3 cm. long. Prostatic and ejaculatory ducts open into this point.
2. Membranous portion - passing through pelvic floor and 1-2 cm. long.
3. Spongy portion - lying within penis and 15 cm. long.
Female Urethra : It is about 4 cm. long. It serves for urinary system only. It extends from the base of the bladder. It passes downwards behind symphisis pubis. It opens to the exterior in front of vaginal orifice.
Urinary system consists of -
KIDNEYS-2
URETERS -2
URINARY BLADDER
URINOGENITAL TRACT/URETHRA
Kidneys
Kidneys are the main organs of urinary system.They are 2 bean shaped
organs lying on the posterior wall of upper abdomen, one on each side of vertebral column. They lie at the level of twelfth thoracic to third lumbar vertebrae. Right kidney is located slightly lower than left kidney. Dimensions of each kidney are 11 x 5 x 3 cm3. Each kidney weighs 150g. approximately.On each kidney, an adrenal gland is present.
Each kidney is embedded by fat called perirenal fat.Right kidney bears the impression of part of duodenum on its front.Pancreas crosses the left kidney transversely in its front. Each kidney is convex on its outer border and concave in the centre of its inner border. At this point, blood vessels, nerves and ureter enter and leave kidney. This point of kidney is called Hilus. Ureters transport urine formed in kidneys to urinary bladder.From urinary bladder, urine is passed to the exterior through urethra.Urethra in males is also passage for semen.Hence it is also called urinogenital tract in males. In females, it is independent.
Structure of Kidney
Longitudinal section of Kidney :
Kidney is surrounded by a fibrous capsule. It can be stripped off easily.
Portion inside this fibrous capsule can be divided into-
1) Cortex 2) Medulla
Cortex is the outer reddish brown coloured portion and medulla is the inner lighter area.
Medulla is subdivided into 10 to 15 conical areas called renal pyramids.
Pyramids have their broad base towards cortex and apex projecting into lumen of minor calyx. Columns of Bertin are the projections of cortex. They form the boundaries of the pyramids.
Ureters
There are two ureters carrying urine from kidneys to urinary bladder.
They are continuous from renal pelvis to urinary bladder and are about 25-30 cm long. Diameter is about 3 mm.Ureter is slightly constricted at three places.Ureter has three layers and they are-
1. Outer fibrous coat which is continuous with the fibrous coat of kidney.
2. Muscular coat containing outer circular layer and inner longitudinal layer.
3. Lining of mucous membrane continuous with that of bladder.
Urinary bladder
Urinary bladder is sac serving as distensible reservoir of urine evacuating its contents at suitable intervals of time. It lies in pelvic cavity behind symphisispubis. Urinary bladder consists of two portions.
1. Body - sac of detrussor muscle.
2. Trigone - triangular region connecting the three openings of bladder -
two of ureters and one of urethra.
Urinary bladder has two sphincters.They are
1. Internal sphincter
2. External sphincter
Internal sphincter is formed by smooth muscles surrounding the opening of urethra. External sphincter is formed by striated muscle of urogenital diaphragm
Urethra
Urethra is the canal through which urine from bladder is passed to the
exterior. It extends from base of the bladder. It has two sphincters.They are-
1. Internal sphincter - involuntary
2. External sphincter - voluntary
It has two orifices .They are-
1. Internal urethral orifice in the bladder.
2. External urethral orifice.
Male urethra serves as common tract for urinary and reproductive systems and thus it is called urinogenital tract. In females it serves for urinary system only. Male urethra : It is about 20 cm. long. It is divided into three portions.
1. Prostatic portion - surrounded by prostate gland and 3 cm. long. Prostatic and ejaculatory ducts open into this point.
2. Membranous portion - passing through pelvic floor and 1-2 cm. long.
3. Spongy portion - lying within penis and 15 cm. long.
Female Urethra : It is about 4 cm. long. It serves for urinary system only. It extends from the base of the bladder. It passes downwards behind symphisis pubis. It opens to the exterior in front of vaginal orifice.
No comments:
Post a Comment