The Nephron Function
What is secreted (moved back) into the Distal Convoluted Tubule?
- Potassium (K) - Hydrogen Ions (H+)
Secreted in the Proximal Convoluted Tubule
- Uric Acid (waste product) - Organic Acids (include many antibiotics) This is how they're removed from the body
Creatinine and Urea
- Waste products - Should be removed from circulation before they become toxic
Components of Excretion/Urine contains
- Water (H2O) - Sodium Chloride (NaCl) - Potassium (K) - Bicarbonate (HCO3) - Creatinine - Urea
Normal Filtrate contains
- Water (H2O) - Sodium Chloride (NaCl) move together - Potassium (K) - Bicarbonate (HCO3) - Glucose - Amino Acids - Creatinine - Urea
How much Urea is reabsorbed into the blood at the Proximal Convoluted Tubule?
50% - Not all Urea leaves the Nephron in the Urine
Glomerulus
A network of Capillaries
How many Nephrons are in each Kidney?
Approximately 1 million
How much Sodium Chloride (NaCl) is reabsorbed from the Loop of Henle?
Approximately 25%
Afferent Arteriole
Blood enters the Glomerulus through this
Efferent Arteriole
Blood exits the Glomerulus through this
At the end of the Collect Duct
Blood reabsorbs what is needed and any additional wastes are removed
How does water (H2O) leave the Nephron?
By Osmosis
How do the Kidneys help to maintain Homeostasis in the body?
By regulating: - Water balance - Ion balance - Acid-bade levels in fluids
As blood enters and exits the Glomerulus
Components of the blood are filtered out into an area called the Bowman's Capsule
The Loop of Henle
Concentration of Urine - Descending limb: filtrate travels down - Ascending limb: filtrate travels up
Medulla
Highly salty as Sodium Chloride (NaCl) is actively pumped out of thick ascending limb and water cannot follow
The Ascending Limb
Is impermeable to water (H2O)
The Descending Limb
Is permeable to water (H2O)
What is Homeostasis?
Maintaining a stable internal environment
The Distal Convoluted Tubule is
Normally impermeable to water, however small amounts may be reabsorbed
Water leaves the descending limb by what?
Osmosis, due to the salty environment of the Medulla
The Collecting Duct
Reabsorbs: - Urea - About 5% of the filtered Sodium Chloride (NaCl) - Water (H2O)
Proximal Convoluted Tubule (Proximal Tubule)
Reabsorption of: - Potassium (K) - Sodium Chloride (NaCl) (65%) - Water (H2O) (65%) - Amino Acids (100%) - Glucose (100%) - Bicarbonate (HCO3) (90%) Back into the blood
The first part of the journey where filtration takes place
The Glomerulus
The simple way to think about the Nephron
The Proximal Convoluted Tubule = Reabsorption The Loop of Henle = Secretion The Distal Convoluted Tubule = the fine-tuning
Sodium Chloride (NaCl) leaves which limb?
The Thin Ascending Limb and is actively pumped out of the Thick Ascending Limb which causes the filtrate to be dilute
What is the Nephron?
The unit of the Kidney responsible for: - The production of Urine in order to get rid of excess water and toxic waste products.
The Distal Convoluted Tubule
Under the influence of the hormone Aldosterone: - Sodium Chloride (NaCl) (5%) is reabsorbed. Also reabsorbed: - Water (H2O) - Bicarbonate (HCO3)
