Module 5.6 Tubular Reabsorption

Question 1

Define tubular reabsorption

Answer 1

the movement of solute and water from the tubules back into the plasma in the peritubular capillaries

Question 2

With the exception of ________\_, all solutes are in the same concentration in the glomerular filtrate as in the plasma

Answer 2

With the exception of plasma proteins, all solutes are in the same concentration in the glomerular filtrate as in the plasma

Question 3

Most reabsorption occurs in the _______\_and is (regulated/not regulated)

Answer 3

Most reabsorption occurs in the proximal tubule and is (regulated/not regulated)

Question 4

Reabsorption is a highly ___\_process, with most solutes requiring the presence of a _______\_ to facilitate movement across the reabsorption barrier

Answer 4

Reabsorption is a highly selective process, with most solutes requiring the presence of a transport protein to facilitate movement across the reabsorption barrier

Question 5

The reabsorption barrier consists of the

1. _______\_,
2. _______\_,
3. _______\_, and
4. _______\_, as shown in the following diagram.

Answer 5

The reabsorption barrier consists of the

1. tubular epithelial cell,
2. basement membrane,
3. peritubular space, and
4. capillary endothelial cell,

as shown in the following diagram.

Question 6

Reabsorption can occur _____\_or ____\_

Answer 6

Reabsorption can occur passively or actively

Question 7

In _____\_ reabsorption, no energy is required for reabsorption to occur

Answer 7

In passive reabsorption, no energy is required for reabsorption to occur

Question 8

Provide an example of a solute that moves passively:

Answer 8

The protein metabolism waste product urea is passively reabsorbed as it freely diffuses down its concentration gradient across the tubular epithelial cell

Question 9

In ____\_ reabsorption, energy is required at one or more steps in the reabsorption process

Answer 9

In active reabsorption, energy is required at one or more steps in the reabsorption process

Question 10

Provide an example of a solute that is actively reabsorbed:

Answer 10

Glucose is actively reabsorbed as it is transported across the apical membrane of the tubular epithelial cell by a secondary active transport protein and then across the basolateral membrane by a facilitated diffusion carrier protein.

Question 11

To be reabsorbed, a substance must pass 5 barriers in a process called?

Answer 11

Transepithelial transport

Question 12

What are the five steps of Transepithelial Transport?

1. Substance must leave the __________by crossing the _______\_ of the tubular cell
2. Must pass through _______\_ from one side of the tubular cell to the other
3. Must cross the _______\_of the tubular cell to enter the _______\_
4. Must diffuse through the _______\_
5. Must penetrate the _______\_to enter the _______\_

Answer 12

What are the five steps of Transepithelial Transport?

1. Substance must leave the tubular fluid by crossing the luminal membrane of the tubular cell
2. Must pass through cytosol from one side of the tubular cell to the other
3. Must cross the basolateral membrane of the tubular cell to enter the interstitial fluid
4. Must diffuse through the interstitial fluid
5. Must penetrate the capillary wall to enter the blood plasma

Question 13

Fill in the % for each reabsorbed substance

Answer 13