Tubular reabsorption Flashcards
Where does the filtrate move along?
Renal tubule
What happens to the useful substances needed by the body?
Reabsorbed back into blood in the capillaries surrounding renal tubules
Where does reabsorption take place?
Proximal tubule
How is the proximal tubule adapted for reabsorption?
- Long and coiled – maximum reabsorption
- Dense capillary network closely surrounds – substances move easily into bloodstream and transported
- Wall of tubal are made up of specialised cuboidal epithelium cells
What adaptations does the cuboidal epithelium cells have?
- Brush border of microvilli on inner surface - inc SA
- Outer surface is folded - in SA
- Many mitochondria - produce ATP - active transport
How does reabsorption take place?
Sam substances are actively reabsorbed from the filtrate in the nephron into the bloodstream in the surrounding capillaries
How does active reabsorption work?
Molecules move active leak, they combine with a carrier molecule and move against the concentration gradient
What type of energy does active reabsorption need?
Adenosine triphosphate
Define concentration gradient
The gradual difference in the concentration of solute in a solution between two regions
Name the substances that are actively reabsorbed
All organic nutrients – glucose, proteins and most water soluble vitamins
Fat soluble vitamins and many irons – selectively absorbed
Why are fat soluble vitamins and many ions selectively absorb?
The needs of the body
What is they know of any urine?
No glucose and protein molecules
How much water is passively reabsorbed?
65% reabsorbed from the filtrate into the blood by osmosis
What else is passively reabsorbed?
Chloride ions and sodium ions
What is not reabsorbed?
Yeah area, uric acid and creatinine
What is the function of the loop of Henle?
Create a high concentration of salt in the Medulla area
What is the high concentration of salt are necessary for?
I was Moteck withdrawal of water from the distal tubeles and the collecting ducts
Where are sodium irons actively transported out of?
Out of the filtrate in the ascending limb into the tissue fluid surrounding the limbs
What is the process of sodium irons actively transported named?
Sodium pump which uses energy
What is the result of the sodium pump?
Tissue fluid in the Madella of the kidney becomes highly concentrated (hypertonic)
Why does water flow in the ascending limb of Henle?
The sounds are impermeable to water
Why does the filtrate become hypotonic?
Loser salt but not water
What is the final outcome of the loop of Henley?
Water is actively conserved and pass back into the blood – not lost in urine
What colour is urine when there is this your informed?
Concentrated in dark yellow in colour
What does the longer the loop of Henley mean?
The greater concentration of salt in Medulla area
Why is urine highly concentrated?
More urine is reabsorbed in loop of Henle
Adaption of proximal convoluted tube for reabsorption
- Very long and convoluted - transport is slow, maximum reabsorption
- Surrounded by dense capillary network - transport of substances
- Specialised cuboidal epithelium
Descending loop of Henle
Water passively reabsorbed - osmosis
How does water move in the ascending limb of Henle?
Osmosis - filtrate of distal convoluted tubules
Define tubular secretion
Molecules transported from blonde to distal convoluted tubule
What molecules are transported in tubular secretion?
Urich acid, urea, creatinine, hydrogen irons, ammonium
