Chapter 9.2 Flashcards
(43 cards)
Where are the upper portions of each nephron located?
The renal correct of the kidney
Where are the lower portions of each nephron on located?
The renal medulla of the kidney
What are the nephrons surrounded by?
Tissues of the medulla and the cortex
Where do any substances that are secretes by nephrons go?
They are absorbed by the surrounding tissues of the kidney and return to the bloodstream or turn into urine
What 4 processes are crucial to the formation of urine?
Glomerular Filtration
Tubular Filtration
Tubular Secretion
Water Reabsorption
What does Glomerular Filtration do?
Moves water and solutes (except proteins) from blood plasma into the nephron. This is called filtrate
What does tubular reabsorption do?
Removes useful substances such as sodium from the filtrate and returns them into the blood for reuse by body systems
What does tubular secretion do?
Moves additional wastes and excess substances from the blood into the filtrate
What happens in water reabsorption?
Removes water from the filtrate and returns it to the blood for reuse by body symptoms
What process does the formation of urine start with?
Glomerular filtration
What does glomerular filtration do?
Forces the water and dissolved substances in plasma from the glomerulus into the bowman’s capsule
What 2 factors contribute to glomerular filtration?
Permeability of the glomerular and capillaries
Blood pressure
What is special about capillaries in the glomerulus?
They have many pores in their walls large enough to allow things to pass through and into the bowman’s capsule. They are also small enough to prevent blood and proteins from exiting
What is BP like in the glomerulus?
About 4x greater than capillaries elsewhere in the body`
Why is BP high in the glomerulus?
Because it provides the force for filtration
What is the composition of filtrate from the glomerulus to the plasma?
It is essentially plasma without the proteins and blood cells
Where does the filtrate go after it reaches the glomerulus?
The proximal tube
What happens as much of the filtrate enters the proximal tube?
About 65% is reabsorbed and returned to the body
Through what is means is much of the filtrate absorbed from the proximal tubule?
Through passive and active transport
What are the cells of the proximal tubule lined with?
Mitochondria
What does the mitochondria in the proximal tubule do?
They use the power of ATP to drive the active transport of sodium ions, glucose, and other solutes back into the blood
What else is reabsorbed into the bloodstream in the proximal tubule, besides salt?
Negatively charged ions tag along passively and water follows by osmosis
What is the function of the loop of henle?
Reabsorb water and ions from the glomerular filtrate
What does the loop of henle encounter when it descends?
An increasingly salty environment
