UNIT 7: CHAPTER 26
URINARY SYSTEM
Name the organs of the urinary system.
The urinary system is the major excretory system of the body. It consists of;
o 2 kidneys, which are the primary excretory organs.
o Each kidney’s excretory products are carried by a ureter (1 for each kidney)
o To a single urinary Bladder.
o The bladder is emptied of the waste liquid by the urethra (1 urethra).
Describe the main function of the kidneys.
Each kidney filters large volumes of blood- wastes from the blood are collected- and form
urine.
Urine consists of; (1) excess water, (2) excess ions, (3) metabolic wastes and (4) toxic
substance.
The kidneys are important for many other important metabolic activities, which include;
1. Excretion: The kidneys filter waste products from blood. Nearly 21% of blood
pumped out of the heart is filtered by the kidneys each minute. Fluid and waste are
captured by an extensive network of tubes found throughout each kidney. As fluid
moves through the kidneys, it is slowly modified until it is converted to urine.
2. Regulation of blood volume and pressure: The kidneys play a major role in controlling
the extracellular fluid volume of the body. Depending on the hydration level of our
bodies, the kidneys can produce a large amount of dilute or a small amount of
concentrated urine. Through urine production, the kidneys regulate blood volume
and blood pressure.
3. Regulation of blood solute concentrations: The kidneys help regulate the
concentration of major ions such as Sodium (Na), Potassium (K) and Calcium (Ca).
4. Regulation of extracellular fluid pH: The kidneys secrete variable amounts of
Hydrogen (H)to help regulate the extracellular pH.
5. Regulation of red blood cell synthesis: The kidneys secrete a protein called
erythropoietin, which stimulates the syntheses of red blood cells in the bone
marrow.
6. Regulation of Vitamin D synthesis: the kidneys play an important role in controlling
blood levels of calcium by regulating the synthesis of Vitamin D.
Identify the location and external anatomy of the kidneys.
o The kidneys are bean shaped organs which are retroperitoneal.
o They are located on each side of the vertebral column near the psoas muscle.
o Each kidney is approximately the size of a clenched fist.
o The kidneys extend from the lower portion of the rib cage at the level of the last
thoracic vertebra (T12) to the third Lumbar (L3) vertebra.
o The liver lies superior to the right kidney causing the right kidney to sit lower than
the left.
o Each kidney is about 11 cm long, 5 cm wide and 3 cm thick.
o Each kidney is surrounded by an outer layer of connective tissue called the renal
capsule.
, o Surrounding the outside of each capsule is a thick layer of adipose tissue which
cushions and protects each kidney.
o A thin layer of connective tissue called renal fascia surrounds the adipose tissue and
helps anchor the kidneys to the abdominal wall.
Identify the inner regions of the kidney.
o Cortex
o Medulla
o Pyramids
o Papilla
o Pelvis
o Calyx
URINARY SYSTEM
Name the organs of the urinary system.
The urinary system is the major excretory system of the body. It consists of;
o 2 kidneys, which are the primary excretory organs.
o Each kidney’s excretory products are carried by a ureter (1 for each kidney)
o To a single urinary Bladder.
o The bladder is emptied of the waste liquid by the urethra (1 urethra).
Describe the main function of the kidneys.
Each kidney filters large volumes of blood- wastes from the blood are collected- and form
urine.
Urine consists of; (1) excess water, (2) excess ions, (3) metabolic wastes and (4) toxic
substance.
The kidneys are important for many other important metabolic activities, which include;
1. Excretion: The kidneys filter waste products from blood. Nearly 21% of blood
pumped out of the heart is filtered by the kidneys each minute. Fluid and waste are
captured by an extensive network of tubes found throughout each kidney. As fluid
moves through the kidneys, it is slowly modified until it is converted to urine.
2. Regulation of blood volume and pressure: The kidneys play a major role in controlling
the extracellular fluid volume of the body. Depending on the hydration level of our
bodies, the kidneys can produce a large amount of dilute or a small amount of
concentrated urine. Through urine production, the kidneys regulate blood volume
and blood pressure.
3. Regulation of blood solute concentrations: The kidneys help regulate the
concentration of major ions such as Sodium (Na), Potassium (K) and Calcium (Ca).
4. Regulation of extracellular fluid pH: The kidneys secrete variable amounts of
Hydrogen (H)to help regulate the extracellular pH.
5. Regulation of red blood cell synthesis: The kidneys secrete a protein called
erythropoietin, which stimulates the syntheses of red blood cells in the bone
marrow.
6. Regulation of Vitamin D synthesis: the kidneys play an important role in controlling
blood levels of calcium by regulating the synthesis of Vitamin D.
Identify the location and external anatomy of the kidneys.
o The kidneys are bean shaped organs which are retroperitoneal.
o They are located on each side of the vertebral column near the psoas muscle.
o Each kidney is approximately the size of a clenched fist.
o The kidneys extend from the lower portion of the rib cage at the level of the last
thoracic vertebra (T12) to the third Lumbar (L3) vertebra.
o The liver lies superior to the right kidney causing the right kidney to sit lower than
the left.
o Each kidney is about 11 cm long, 5 cm wide and 3 cm thick.
o Each kidney is surrounded by an outer layer of connective tissue called the renal
capsule.
, o Surrounding the outside of each capsule is a thick layer of adipose tissue which
cushions and protects each kidney.
o A thin layer of connective tissue called renal fascia surrounds the adipose tissue and
helps anchor the kidneys to the abdominal wall.
Identify the inner regions of the kidney.
o Cortex
o Medulla
o Pyramids
o Papilla
o Pelvis
o Calyx
