Lecture 51- Urinary System Part 2

Question 1

Glomerular Filtration Rate

Question 2

Tubular reabsorption

Question 3

Tubular secretion

Question 4

What are the four carrier-mediated transport mechanisms

Answer 4

1. Facilitated diffusion
2. Active transport
3. Co-transport
4. Counter transport

Question 5

What is facilitated diffusion

Answer 5

-Carrier transport
-No ATP required down the gradient

Question 6

What is active transport?

Answer 6

Substances moved against concentration gradient

Requires ATP

Question 7

What is co-transport?

Answer 7

Does not require ATP

2 substances moved in same direction

Question 8

What is counter transport?

Answer 8

Similar to co-transport but move in opposite directions

Question 9

Transport maximum

Answer 9

The point where increasing substrate concentration will not increase transport because carriers are saturated

Question 10

Where do saturated excess substances end up?

Answer 10

Cannot be reabsorbed and is excreted and starts spilling substances into URINE

Question 11

What type of fluid does the transport occur in?

Answer 11

Tubular fluid is formed from Glomerular filtration

Question 12

What is the descending limb of the nephron loop only permeable to?

Answer 12

Water

Question 13

What is the ascending limb of the nephron loop only permeable to?

Answer 13

Solute

Question 14

How does the concentration change as filtrate moves down the descending limb?

Answer 14

Increases

Removing water

Question 15

How does the concentration change as filtrate moves up the ascending limb?

Answer 15

Decreases

Removing ions

Question 16

Countercurrent multiplcation

Answer 16

The flow of filtrate happens in opposite direction in nephron loop (down VS up)

Change in concentration is multiplied from cortex to medulla (increase VS decrease)

Question 17

How is the osmotic gradient established in the peritubular fluid?

Answer 17

Different mechanism

Question 18

What is the main solute to consider in the peritubular fluid?

Answer 18

Urea

Question 19

How does urea concentration change as the filtrate moves from the nephron loop to the conducting duct

Answer 19

Increases

This section is impermeable to urea, so filtrate can’t leave

Question 20

What duct is permeable to urea?

Answer 20

Papillary duct

Question 21

What is the role of the vasa recta?

Answer 21

Vasa recta help to prevent excessive loss of water and electrolytes in the urine, thereby helping to maintain proper fluid balance in the body

Question 22

What are the three ways to control glomerular filtration rate?

Answer 22

1. Autoregulation
2. Neural (autonomic regulation)
3. Hormonal regulation

Question 23

Autoregulation

Answer 23

Dominant regulation at rest

Question 24

Neural (autonomic regulation)

Answer 24

Activated under stress/physical activity

Constricts afferent arteriole

Question 25

Hormonal regulation

Answer 25

Initiate by kidneys/uses aldosterone system

Question 26

What makes up the juxtaglomerular complex?

Answer 26

1. Juxtaglomerular cells 2. Macula densa 3. Mesangial cells

Question 27

Juxtaglomerular cells

Answer 27

Smooth muscle cells in walls of afferent arteriole (Mechanoreceptors)

Question 28

Macula densa

Answer 28

Tall closely packed distal tubule cells (Chemoreceptors or osmoreceptors)

Question 29

Mesanglial cells

Answer 29

Phagocytic and contractile properties

Question 30

What three things happen to increase GFR after a drop has been detected, leading to decreased filtrate and urine production?

Answer 30

1. Dilation of afferent arterioles 2. Contraction of mesangial cells 3. Constriction of efferent arterioles

Question 31

Neural stimuli effects

Answer 31

1. Increased heart rate/blood pressure/metabolic rate

Question 32

Hormonal stimuli effects

Answer 32

1. Cortisol trigger 2. Aldosterone will trigger