Urinary System 2

Question 1

How does Dehydration/ Sweat Loss alter GFR? (10)

Answer 1

Question 2

How does the body regulate when it detects a change in blood pressure?

Answer 2

Stimulus: venous, atrial, and arterial blood pressure changes monitored by baroreceptors in each location.

Response: alter renal sympathetic firing to kidney.

Additional arterial response – altered arterial pressure can also change GFR without involving altering renal sympathetic firing.

Question 3

What are the 2 main GFR-altering hormones?

Answer 3

Angiotensin II
Atrial natriuretic peptide (ANP)

Question 4

What is Angiotensin II?
How does it affect GFR?

Answer 4

Released inactive (angiotensinogen) from liver ultimately converted to angiotensin II.

Response:
circulates in the blood to kidneys and vasoconstricts afferent and efferent arterioles; more receptors on afferent arteriole

Decrease GFR

Question 5

What is Atrial natriuretic peptide (ANP)?
How does it affect GFR?

Answer 5

Released from heart.

Response: circulates in blood to kidneys and vasodilates afferent arterioles and vasoconstricts efferent arterioles / also increases SA of glomerulus by relaxing mesangial cells –

Both Responses Increase GFR.

Question 6

In regards to Glomerular Filtration, How much do we keep? How much do we eliminate?

Answer 6

How much to keep:
During glomerular filtration, almost all substances in the blood are filtered into the glomerular space and leave in renal tubules

How much to eliminate:
Waste products, toxins, and excess substances (e.g., urea, creatinine, certain ions) are primarily eliminated through glomerular filtration into the renal tubule. These substances are meant to be eventually excreted from the body as

Question 7

In regards to Tubular Secretion, How much do we keep? How much do we eliminate?

Answer 7

How much to keep:
Tubular secretion involves actively transporting certain substances from the peritubular capillaries into the renal tubule

How much to eliminate:
The substances being secreted are meant to be eliminated from the body, as they are often waste products or need to be removed for various physiological reasons

Question 8

In regards to Tubular Reabsorption, How much do we keep? How much do we eliminate?

Answer 8

How much to keep:
Tubular reabsorption involves the reabsorption of water and various solutes from the renal tubule back into the peritubular capillaries

How much to eliminate:
Tubular reabsorption aims to retain essential substances,

Question 9

What is the Tubular lumen?

Answer 9

inner cavity of renal tubule.

Question 10

What cells make up the Renule Tubule wall?

Answer 10

Epithelial cell –
cells making up the renal tubule wall.

Question 11

Where are Epithelial Cells?

Answer 11

cells making up the renal tubule wall.

Question 12

What is the fluid surrounding the renal tubule? What are the blood vessels in the area called?

Answer 12

Interstitial fluid
- extracellular fluid surrounding renal tubule.
Blood vessel
- peritubular capillaries

Question 13

What are the 2 Tubular epithelial cell membranes?

Answer 13

Apical Membrane
- between tubule lumen and inside tubular epithelial cell.
Basolateral Membrane
- between inside tubular epithelial cell and interstitial fluid.

Question 14

Image

Answer 14

Question 15

What is a Semipermeable membrane?
(selectively permeable)

Answer 15

Semipermeable membrane
- lets some things pass and not others.

Question 16

Simple vs Facilitated Diffusion

Answer 16

Simple diffusion (SD)
Moves straight through the membrane.

Facilitated diffusion (FD)
Needs a membrane protein (MP) to provide passage.

Question 17

Osmosis

Answer 17

Osmosis (O)
Specifically for water.
Involves an aquaporin (AP; specific membrane protein) to provide passage

Question 18

What is Active Transport?

Answer 18

Low to high solute concentration.
Described as moving “up” or “against” gradient.
At least 2 DIFFERNT ions moving together:
Same direction – cotransport.
Opposite direction – counter transport

Question 19

What is PRIMARY Active Transport?

Answer 19

ATP (adenosine triphosphate) breakdown to ADP and Pi (adenosine diphosphate and inorganic phosphate) provides direct use of energy to “pump” across the membrane.

Ions moving “up” their gradients

Question 20

What is SECONDARY Active Transport?

Answer 20

Move in response to conditions created by primary (indirect use of energy).

Ions are moving “down” its gradient while another moves “up” its gradient (can be more than 2 ions involved)

(one is passively moving, one is actively moving, therefore classified as active transport not passive)

Question 21

Tubular Reabsorption and Secretion?
askq

Answer 21

Question 22

What is Obligatory water reabsorption?

Answer 22

Passive Reabosrption of Water to prevent excessive water loss
- water that moves following solutes
65% water reabsorbed in proximal tubule; lots of aquaporins so water can move fairly freely.

Question 23

Process of Obligatory Water Reabsorption:

Answer 23

Initial process:
Sodium movement creates low osmotic pressure where sodium has left and high osmotic pressure where sodium has moved (osmotic pressure gradient).
Water follows by osmosis towards sodium created high osmotic pressure.

Secondary process:
Water movement following sodium creates solute concentration gradients for other ions (like calcium, chloride, potassium, magnesium).
These ions can move by simple diffusion in latter half of proximal tubule.

As these ions move creates low osmotic pressure where left and high osmotic pressure where moved (osmotic pressure gradient).
More water movement by osmosis towards other ion created high osmotic pressure.

Question 24

What does primary transport do in the cell?

Answer 24

pumped sodium out into the interstitial fluid