TITLE/ TOPIC : EXCRETION
CONTENTS:
● Functional anatomy ( Histophysiology/ Ultrastructure) of mammalian
kidney and its renal unit (i.e: Nephron)
● Mechanism of urine formation.
● Role of antidiuretic hormones ( ADH) and aldosterone.
● Kidneys in acid- base balance.
➢Functional anatomy ( Histophysiology/ Ultrastructure)
of mammalian kidney and its renal unit ( i.e: Nephron):
❖Histophysiology/ ultrastructure of mammalian kidney:
The mammalian kidneys are compact, bean- shaped organs attached to the body wall on either
her side of the vertebral column. These are retroperitoneal and extra coelomic in position.
Kidneys originates from thr embryonic mesoderm.
There are pairs of kidneys in mammals, in which the right kidney is slightly lower ( smaller )
than the left kidney because the large area gets occupied by the liver.
Average adult kidney measures about 11 to 13 cm long and 5- 7.5 cm wide and 2.5 cm thick and
weighs about 150 grams.
Kidney is surrounded by 3 layers:
● Fibrous capsule layer (inner)
● Adipose layer (middle)→fat layers ( acts as shock absorbent proof)
● Renal fascia (outer)/ Renal capsule.
When a mammalian kidney is sliced/ dissected lengthwise, it consists of the outer reddish cortex
(renal cortex) and inner pale yellow (renal medulla) part. The renal cortex is divided into the
outer cortical zone and inner juxtamedullary zone. Within the medulla, there are pyramids.
There are about 6- 20 pyramids in humans, 1 in rabbits and other varies in different animals.
, Pyramids face the cortical area called the renal papillae, directed towards the centre of the
kidney. Together, the cortex and the renal pyramids constitute the parenchyma of the kidneys
which consist of approximately 1 million microscopic units called nephrons, collecting ducts and
vascular supply etc.
L.S of mammalian kidney
Blood supply to kidneys:
A kidney receives the blood by a renal artery arises from the dorsal aorta. In the kidney, the renal
artery is again divided and subdivided to form afferent arterioles. An afferent arterioles enters the
cavity of Bowman's capsule and forms a tuft of capillaries called glomerulus. Blood from the
CONTENTS:
● Functional anatomy ( Histophysiology/ Ultrastructure) of mammalian
kidney and its renal unit (i.e: Nephron)
● Mechanism of urine formation.
● Role of antidiuretic hormones ( ADH) and aldosterone.
● Kidneys in acid- base balance.
➢Functional anatomy ( Histophysiology/ Ultrastructure)
of mammalian kidney and its renal unit ( i.e: Nephron):
❖Histophysiology/ ultrastructure of mammalian kidney:
The mammalian kidneys are compact, bean- shaped organs attached to the body wall on either
her side of the vertebral column. These are retroperitoneal and extra coelomic in position.
Kidneys originates from thr embryonic mesoderm.
There are pairs of kidneys in mammals, in which the right kidney is slightly lower ( smaller )
than the left kidney because the large area gets occupied by the liver.
Average adult kidney measures about 11 to 13 cm long and 5- 7.5 cm wide and 2.5 cm thick and
weighs about 150 grams.
Kidney is surrounded by 3 layers:
● Fibrous capsule layer (inner)
● Adipose layer (middle)→fat layers ( acts as shock absorbent proof)
● Renal fascia (outer)/ Renal capsule.
When a mammalian kidney is sliced/ dissected lengthwise, it consists of the outer reddish cortex
(renal cortex) and inner pale yellow (renal medulla) part. The renal cortex is divided into the
outer cortical zone and inner juxtamedullary zone. Within the medulla, there are pyramids.
There are about 6- 20 pyramids in humans, 1 in rabbits and other varies in different animals.
, Pyramids face the cortical area called the renal papillae, directed towards the centre of the
kidney. Together, the cortex and the renal pyramids constitute the parenchyma of the kidneys
which consist of approximately 1 million microscopic units called nephrons, collecting ducts and
vascular supply etc.
L.S of mammalian kidney
Blood supply to kidneys:
A kidney receives the blood by a renal artery arises from the dorsal aorta. In the kidney, the renal
artery is again divided and subdivided to form afferent arterioles. An afferent arterioles enters the
cavity of Bowman's capsule and forms a tuft of capillaries called glomerulus. Blood from the
