Excretion
Anatomy, lecture 01
The excretion system consists of kidneys, ureters, bladders and urethra.
Kidneys and ureters present in posterior abdominal region
Distal end of ureters, bladders and urethra are pelvic urinary organs, kidneys and
abdominal part of ureters are retroperitoneal.
- Retroperitoneal structures (retro means behind)
Structures that lie posterior to the parietal peritoneum (peritoneum is a
membrane that covers the abdominopelvic cavity)
Primary retroperitoneal are structures that develop posterior to peritoneum
such as kidneys and suprarenal gland (also called adrenal glands)
Perinephric fat protects the kidneys along with the peritoneum
- The kidneys
Filters blood to produce urine, 2 kidneys, T12-L3 vertebrae, right kidney
slightly lower than left due to presence of live
The right kidney has a suprarenal gland on its anterior and diaphragm on its
posterior along with a subcostal nerve
The left kidney also has a suprarenal gland but also has spleen, stomach,
pancreas on its anterior, and same things on its posterior as with the right
kidney
Anatomy of the kidney
1. Has red/brown fibrous capsule
2. Hilum which contains renal vein, branches form renal artery, and renal
pelvis
3. A lymphatic system around the vessels
Kidney consists of an outer renal cortex completely surrounding the inner
renal medulla
Renal cortex projects INTO the inner part of the kidney forming renal columns
These columns divide renal medulla into renal pyramids
,Minor calyces receive urine from papillary ducts
Nephrons are the functional unit of the kidney, each kidney has 800,000 to a
million nephrons
Kidneys CANNOT regenerate nephrons following injuries
Cortical nephrons are nephrons that have glomeruli located in the outer
cortex, enveloped by peritubular capillaries to transport blood
Juxtamedullary nephrons have glomeruli that lie deep in the renal cortex near
the medulla, associated with organized set of blood vessels called vasa recta
,- Renal arteries in the kidneys
Right and left renal arteries from the aorta between L1-L2 level
Divides into anterior and posterior branches and segmental arteries that
enter hilum
Right artery is longer than the left
Arteries INSIDE the kidney include- lobar arteries, interlobar, interlobular,
arcuate and afferent glomerular arterioles
, - Veins and lymph of the kidneys
Renal veins empty into the inferior vena cava, left vein which is longer than
the right passes behind the splenic vein and body of the pancreas. Made by
the connection the L gonadal and L suprarenal vein.
R renal vein passes behind the descending duodenum
The L vein can be compressed of there is an aneurysm in any of those 2
vessels. This is called nutcracker syndrome
Lymph drains to the aortic nodes around the origin of the renal artery
- The ureters
Ureters convey urine from the kidney to the bladder
They are muscular ducts
Urine is propelled by the contractions of the ureter wall and by filtration
pressure from the glomeruli
Pathway- from hilum over the psoas muscle surface, crosses the bifurcation
at common iliac artery at the sarco-iliac joint enter the bladder at trigone
area
Areas of constriction-
1. Junction between the ureters and renal pelvis
2. Where ureters cross the pelvic brim
3. At the trigone where they enter the wall of the bladder
These areas are important as they can be sites of obstruction
Anatomy, lecture 01
The excretion system consists of kidneys, ureters, bladders and urethra.
Kidneys and ureters present in posterior abdominal region
Distal end of ureters, bladders and urethra are pelvic urinary organs, kidneys and
abdominal part of ureters are retroperitoneal.
- Retroperitoneal structures (retro means behind)
Structures that lie posterior to the parietal peritoneum (peritoneum is a
membrane that covers the abdominopelvic cavity)
Primary retroperitoneal are structures that develop posterior to peritoneum
such as kidneys and suprarenal gland (also called adrenal glands)
Perinephric fat protects the kidneys along with the peritoneum
- The kidneys
Filters blood to produce urine, 2 kidneys, T12-L3 vertebrae, right kidney
slightly lower than left due to presence of live
The right kidney has a suprarenal gland on its anterior and diaphragm on its
posterior along with a subcostal nerve
The left kidney also has a suprarenal gland but also has spleen, stomach,
pancreas on its anterior, and same things on its posterior as with the right
kidney
Anatomy of the kidney
1. Has red/brown fibrous capsule
2. Hilum which contains renal vein, branches form renal artery, and renal
pelvis
3. A lymphatic system around the vessels
Kidney consists of an outer renal cortex completely surrounding the inner
renal medulla
Renal cortex projects INTO the inner part of the kidney forming renal columns
These columns divide renal medulla into renal pyramids
,Minor calyces receive urine from papillary ducts
Nephrons are the functional unit of the kidney, each kidney has 800,000 to a
million nephrons
Kidneys CANNOT regenerate nephrons following injuries
Cortical nephrons are nephrons that have glomeruli located in the outer
cortex, enveloped by peritubular capillaries to transport blood
Juxtamedullary nephrons have glomeruli that lie deep in the renal cortex near
the medulla, associated with organized set of blood vessels called vasa recta
,- Renal arteries in the kidneys
Right and left renal arteries from the aorta between L1-L2 level
Divides into anterior and posterior branches and segmental arteries that
enter hilum
Right artery is longer than the left
Arteries INSIDE the kidney include- lobar arteries, interlobar, interlobular,
arcuate and afferent glomerular arterioles
, - Veins and lymph of the kidneys
Renal veins empty into the inferior vena cava, left vein which is longer than
the right passes behind the splenic vein and body of the pancreas. Made by
the connection the L gonadal and L suprarenal vein.
R renal vein passes behind the descending duodenum
The L vein can be compressed of there is an aneurysm in any of those 2
vessels. This is called nutcracker syndrome
Lymph drains to the aortic nodes around the origin of the renal artery
- The ureters
Ureters convey urine from the kidney to the bladder
They are muscular ducts
Urine is propelled by the contractions of the ureter wall and by filtration
pressure from the glomeruli
Pathway- from hilum over the psoas muscle surface, crosses the bifurcation
at common iliac artery at the sarco-iliac joint enter the bladder at trigone
area
Areas of constriction-
1. Junction between the ureters and renal pelvis
2. Where ureters cross the pelvic brim
3. At the trigone where they enter the wall of the bladder
These areas are important as they can be sites of obstruction
