Exrectory System
Excretory System Review
Main Concepts: Describe the major gross anatomical structures of the excretory system.
Kidneys: receive about 25% of the cardiac output; produce urine (a fluid containing water, ions, and small soluble compounds)
Ureters: receive urine from the kidneys and conduct it to the urinary bladder. Urine movement involves a combo of gravity and the peristaltic contractions of smooth muscle in the walls of the ureters
Urinary Bladder: receives and stores urine prior to elimination from the body. Urination is driven by the contraction of smooth muscle layers in the walls of the bladder
Urethra: passageway that conducts urine from the urinary bladder to the exterior
List and describe the functions of the excretory system.
Adjusting blood volume and blood pressure
Regulating plasma concentrations of sodium, potassium, chloride, and other ions
Stabilizing blood pH
Conserving valuable nutrients
Removing drugs and toxins from the bloodstream
Explain the functions of the components of a nephron, and relate those functions to cellular and histological specializations.
Segment General Functions Specific Functions
Renal Corpuscle Filtration of plasma; generates approximately 180 L/day of filtrate similar in composition to blood plasma but without proteins Filtration:
Water and inorganic and organic solutes from plasma
Retention:
Plasma proteins and blood cells
Proximal Convoluted Tubule Reabsorption of 60-70% of the water (108-116 L/day), 99-100% of the organic substrates, and 60-70% of the sodium and chloride ions in the original filtrate Active Reabsorption: glucose, other simple sugars, amino acids, vitamins, ions (including sodium, potassium, calcium, magnesium, phosphate, and bicarbonate
Passive Reabsorption: urea, chloride ions, lipid-soluble materials, water
Secretion: hydrogen ions, ammonium ions, creatinine, drugs and toxins
Nephron Loop Reabsorption of 25 % of the water and 20-25% of the sodium and chloride ions
Main Concepts: Describe the major gross anatomical structures of the excretory system.
Kidneys: receive about 25% of the cardiac output; produce urine (a fluid containing water, ions, and small soluble compounds)
Ureters: receive urine from the kidneys and conduct it to the urinary bladder. Urine movement involves a combo of gravity and the peristaltic contractions of smooth muscle in the walls of the ureters
Urinary Bladder: receives and stores urine prior to elimination from the body. Urination is driven by the contraction of smooth muscle layers in the walls of the bladder
Urethra: passageway that conducts urine from the urinary bladder to the exterior
List and describe the functions of the excretory system.
Adjusting blood volume and blood pressure
Regulating plasma concentrations of sodium, potassium, chloride, and other ions
Stabilizing blood pH
Conserving valuable nutrients
Removing drugs and toxins from the bloodstream
Explain the functions of the components of a nephron, and relate those functions to cellular and histological specializations.
Segment General Functions Specific Functions
Renal Corpuscle Filtration of plasma; generates approximately 180 L/day of filtrate similar in composition to blood plasma but without proteins Filtration:
Water and inorganic and organic solutes from plasma
Retention:
Plasma proteins and blood cells
Proximal Convoluted Tubule Reabsorption of 60-70% of the water (108-116 L/day), 99-100% of the organic substrates, and 60-70% of the sodium and chloride ions in the original filtrate Active Reabsorption: glucose, other simple sugars, amino acids, vitamins, ions (including sodium, potassium, calcium, magnesium, phosphate, and bicarbonate
Passive Reabsorption: urea, chloride ions, lipid-soluble materials, water
Secretion: hydrogen ions, ammonium ions, creatinine, drugs and toxins
Nephron Loop Reabsorption of 25 % of the water and 20-25% of the sodium and chloride ions