Tubular Function Flashcards
How does reabosorption occur?
Active Transport and passive transport
What is obligatory osmosis?
90% of water reabsorption. it has to happen
Water follows solutes
Where does obligatory osmosis occur?
In the proximal convoluted tubule and the descending loop on henle because these areas have tubules which are permeable to water
What is facultative osmosis?
10% of water reabsorption, can increase or decrease depending on body needs
What controls facultative osmosis?
ADH which makes the cells in the collecting duct permeable to water
What is the most active area for reabsorbtion?
Proximal convoluted tubule
By the end of it 100% of organic solutes and 65% of water is reabsorbed
What are paracellular routes?
The transfer of substances across an epithelium by passing through the intracellular space between cells
What are Transcellular routes?
Into or out of he cells of tubules by following their electrochemical gradient
What does the detrusor muscle do?
Facilitates contraction of the bladder during micturation
What is the external urethral sphincter?
Voluntary control to micturate
What is the internal urethral sphincter?
Regulates involuntary control of urine flow from the bladder to the urethra
What substances are completely reabsorbed?
Glucose, amino acids and bicarbonate
What substances are partially reabsorbed?
Water, sodium, potassium and chloride
What substances are excreted as waste?
Urea, creatine and drugs
What does the nephron regulate?
Water, glucose, sodium, Uric acid and creatine
What do the interlobular arteries do?
Ascend into the cortex and branch Off into afferent arterioles
What limits reabsorption of a substance?
Transport mechanism saturation
What does glucosuria indicate?
Diabetes is present and the Tm has been reached for the sodium-glucose symporter
Where is the glucose symporter?
Proximal convoluted tubule coupled to the sodium potassium pump and facilitated diffusion of glucose
What uses an antiporter?
H+ ions with sodium
What happens when kidneys fail?
Salts and waste products build up and the ph of the blood goes down
Massive edema from salt retention and academia from inability to excrete
