Human Anatomy and Physiology - The Excretory(Urinary) System
The Excretory (Urinary) System - its function is to remove waste products from the blood and
eliminate them from the body.
The Excretory system consists of:
a. Two kidneys - this organ extracts wastes from the blood, balances body fluids and form urine.
b. Two ureters - this tube conducts urine from the kidneys to the urinary bladder.
c. The urinary bladder - this reservoir receives and stores the urine brought to it by the two
ureters.
d. The urethra - this tube conducts urine from the bladder to the outside of the body for
elimination.
Major functions of the Excretory system:
1. Excretion of wastes
2. Hormonal production (renin-angiotensin and erythropoietin)
3. Acid base balancing
Kidneys
The kidneys - a pair of reddish brown, bean shaped organs located in the posterior wall of the
abdominal region, one in each side of the vertebral column.
They usually located between the transverse processes of T12-L3 vertebrae,
They are protected at least partially by the last pair of ribs and capped by the adrenal gland.
, The bean shape of the kidney is medially concave and laterally convex.
On the medial concave border is the hilum (small indented area) where blood vessels, nerves &
ureters enter and leave the kidney. Hilum is the gateway area of the kidneys.
Covering and supporting each kidney are three layers of tissue:
• Renal capsule – innermost, tough, fibrous layer
• Adipose capsule – the middle layer composed of fat, giving the kidney a protective cushion.
• Renal fascia – is the outer sub-serous membrane, connective tissue layer.
Internal Anatomy of the kidney
A sagittal section of the kidney reveals three distinct regions called pelvis, medulla and cortex
(from inside out).
The renal pelvis is the large collecting space within the kidney formed from the expanded upper
portion of the ureters.
The pelvis branch to two cavities, these are 2-3 major calyces and 8 to 18 minor calyces.
The Renal medulla is the middle portion of the kidney. It consists of 8 to 18 renal pyramids,
which are longitudinally striped, one cone shaped area.
The base of each pyramid is adjacent to the outer cortex. The apex of each renal pyramid ends
in a papilla, which opens to a minor calyx.
The Excretory (Urinary) System - its function is to remove waste products from the blood and
eliminate them from the body.
The Excretory system consists of:
a. Two kidneys - this organ extracts wastes from the blood, balances body fluids and form urine.
b. Two ureters - this tube conducts urine from the kidneys to the urinary bladder.
c. The urinary bladder - this reservoir receives and stores the urine brought to it by the two
ureters.
d. The urethra - this tube conducts urine from the bladder to the outside of the body for
elimination.
Major functions of the Excretory system:
1. Excretion of wastes
2. Hormonal production (renin-angiotensin and erythropoietin)
3. Acid base balancing
Kidneys
The kidneys - a pair of reddish brown, bean shaped organs located in the posterior wall of the
abdominal region, one in each side of the vertebral column.
They usually located between the transverse processes of T12-L3 vertebrae,
They are protected at least partially by the last pair of ribs and capped by the adrenal gland.
, The bean shape of the kidney is medially concave and laterally convex.
On the medial concave border is the hilum (small indented area) where blood vessels, nerves &
ureters enter and leave the kidney. Hilum is the gateway area of the kidneys.
Covering and supporting each kidney are three layers of tissue:
• Renal capsule – innermost, tough, fibrous layer
• Adipose capsule – the middle layer composed of fat, giving the kidney a protective cushion.
• Renal fascia – is the outer sub-serous membrane, connective tissue layer.
Internal Anatomy of the kidney
A sagittal section of the kidney reveals three distinct regions called pelvis, medulla and cortex
(from inside out).
The renal pelvis is the large collecting space within the kidney formed from the expanded upper
portion of the ureters.
The pelvis branch to two cavities, these are 2-3 major calyces and 8 to 18 minor calyces.
The Renal medulla is the middle portion of the kidney. It consists of 8 to 18 renal pyramids,
which are longitudinally striped, one cone shaped area.
The base of each pyramid is adjacent to the outer cortex. The apex of each renal pyramid ends
in a papilla, which opens to a minor calyx.
