The Urinary System
I. Introduction
A. The Kidneys. Position
1. Are reddish organs that are shaped like “kidney beans”. There are
two, a right and left, located above the waist, between the
peritoneum and the posterior wall of the abdomen. Since the
kidneys are behind the abdominal peritoneum they are said to be
retroperitoneal (others being the adrenal gland and the ureters for
the urinary system).
2. Partially protected by the 11th and 12th pair of ribs.
3. The Left Kidney is slightly higher the Right Kidney.
B. Kidney tissue layers. Three layers surround the kidney (Going deep
to superficial)
1. The Renal Capsule- smooth ,transparent, fibrous membrane
continuous with the outer coat of the Ureter. Deepest of the three layers.
This layer serves to protect against trauma and maintains the shape of
the kidney.
2. Adipose Capsule
3. Renal Fascia
II. External and Internal Anatomy
A. Size. The Kidney is approx. 12 cm (5inches) long, 12-15 cm wide and
2-3 cm thick.
, B. Renal Hilum is a deep vertical fissure near the center of the concave
border in which the ureter leaves the kidney. Blood and lymphatic
vessels also enter and exit the kidney via the hilum
C. Renal Sinus is a cavity within the kidney. Contains the renal pelvis
and minor & major calyces
D. Renal Cortex is one of three general regions of the internal kidney.
The most outermost region.
E. Renal Medulla is the innermost layer with eight to eighteen cone
shaped structures called pyramids.
F. Renal Pyramids,are located in the renal medulla.
G. Renal Columns are projections of the renal cortex extending between
the pyramids.
H. Nephron is the functional unit of the kidney . There are
approx 1-1.25 million nephrons in each kidney. A person is born with
all the nephrons they possess. Nephrons can grow larger.
I. The cortical and medullary collecting ducts are ducts which receive
filtrate from many nephrons which in turn drain into papillary ducts
These in turn empty into the minor calyces
J. Minor Calyces are ducts that drain into Major calyces. Each kidney has
8 to 18 minor and 2 to 3 major calyces. Located in the Renal Sinus.
I. Introduction
A. The Kidneys. Position
1. Are reddish organs that are shaped like “kidney beans”. There are
two, a right and left, located above the waist, between the
peritoneum and the posterior wall of the abdomen. Since the
kidneys are behind the abdominal peritoneum they are said to be
retroperitoneal (others being the adrenal gland and the ureters for
the urinary system).
2. Partially protected by the 11th and 12th pair of ribs.
3. The Left Kidney is slightly higher the Right Kidney.
B. Kidney tissue layers. Three layers surround the kidney (Going deep
to superficial)
1. The Renal Capsule- smooth ,transparent, fibrous membrane
continuous with the outer coat of the Ureter. Deepest of the three layers.
This layer serves to protect against trauma and maintains the shape of
the kidney.
2. Adipose Capsule
3. Renal Fascia
II. External and Internal Anatomy
A. Size. The Kidney is approx. 12 cm (5inches) long, 12-15 cm wide and
2-3 cm thick.
, B. Renal Hilum is a deep vertical fissure near the center of the concave
border in which the ureter leaves the kidney. Blood and lymphatic
vessels also enter and exit the kidney via the hilum
C. Renal Sinus is a cavity within the kidney. Contains the renal pelvis
and minor & major calyces
D. Renal Cortex is one of three general regions of the internal kidney.
The most outermost region.
E. Renal Medulla is the innermost layer with eight to eighteen cone
shaped structures called pyramids.
F. Renal Pyramids,are located in the renal medulla.
G. Renal Columns are projections of the renal cortex extending between
the pyramids.
H. Nephron is the functional unit of the kidney . There are
approx 1-1.25 million nephrons in each kidney. A person is born with
all the nephrons they possess. Nephrons can grow larger.
I. The cortical and medullary collecting ducts are ducts which receive
filtrate from many nephrons which in turn drain into papillary ducts
These in turn empty into the minor calyces
J. Minor Calyces are ducts that drain into Major calyces. Each kidney has
8 to 18 minor and 2 to 3 major calyces. Located in the Renal Sinus.
