(03) - Renal Blood Flow

Question 1

answer this…

Answer 1

A

sodium is focusing solely on volume

the way you fix volume is change amount of Na (water follows sodium)

“the point of this question is to recognize that what the body is measuring in terms of how much sodium is excreted in the urine is based on the volume - not on the plasma concentration”

concentration based on water balance

the volume on absolute amount of Na in ECF

going to try to fix the osmolality at a fixed level

there’s only 1 sodium amount (and thus volume) that will give you the correct concentration

Question 2

(What happens if intae exceeds Use + Excretion)

1. proteins (nitrogen) –> increased what?
2. salt + water –> ?
3. if salt > water –> ?
4. If Water > salt –> ?

Answer 2

1. increased nitrogenous waste in the blood (azotemia)
2. ECF volume expansion and increased bp and/or edema
3. hypernatremia, decreased ICF volume (water shifts into extracellular space)
4. hyponatremia, increased ICF volume

Question 3

The kidney will correct all of your fuckups (if it is working well…)

Question 4

(three basic mechanisms)

1-3. What are they?

Answer 4

1. filtration
2. reabsorption
3. secretion

Question 5

(Who Came up with this???)

read this

(two biggest things is plasma is water and sodium - bascially salt water)

1. answer the question at the bottom…

Answer 5

1. reabsorption of sodium

Question 6

(Key Concepts)

1. excretion means what?
2. substance is present in what?
3. Does urine change from renal pelvies to the tip of the urethra?

Answer 6

1. the exit of substance from the body
2. the final urine produced by the kidneys
3. no

Question 7

Answer 7

1. glomerulus
2. tubules

Question 8

(Key concepts)

1. What is the process by which water and solutes in blood leave the vascular system thorugh the filtration barrier and enter Bowman’s space

Answer 8

1. glomerular filtration

Question 9

(Key Concepts)

1. What is the process of moving substances from the lumen across the epithelial layer into the surrounding renal interstitium and then on to the bloodstream?

2-3. What are the two steps?

Answer 9

1. reabsorption
2. removal from tubular lumen (to interstitium)
3. movement into blood (from interstitium)

Question 10

this is proximal tubule

moves in stuff from side with villi - pumps out other side

takes stuff out of tubular lumen and puts it in interstitium

Question 11

(Key Concepts)

1. What is the process of moving substances into the tubular lumen from the cytosol of epithelial cells that line the walls of the nephron?

2-3. Substances may originate from what two places?

4. most cross what?

Answer 11

1. secretion
2. synthesis within the cell
3. by crossing the epithelial layer from the surrounding renal interstitium
4. the epithelial layer

Question 12

this is a schmatic to illustrate the three different functions

Question 13

name these processes from left to right

actually - watch this - 25:00 at 8AM 4/29

Answer 13

1.

Question 14

(Structure-Function)

the intact neprhon hypothesis = overall kidney function is the sum of the function of all individual nephrons

glomeruli close to medulla have tubules that go really deep into the medulla that create a really concentrated urine

those towards the surface don’t goes as deep - aren’t exposed to high pressure gradient - can’t produce as concentrated as urine

Question 15

reason all urea isn’t excreted is because every time the blood flows through the nephron only about a third of it ends up in the filtrate - so its hard to completely excrete something

urea is one of the two things we use to create concentation in the medulla (salt and urea) - used for making concentrated urine

Question 16

(Summary of Key Points)

1. the major function of the kidney is what?
2. each nephron consists of what two components?
3. The kidneys “handle” substances by a combo of three basic methods
4. also metabolize substances
5. also produce hormones

Answer 16

1. to regulate the composition of the ECF
2. a filtering glomerular component and a transporting tubular component

Question 17

Answer 17

1. first to produce filtrate, second for reabsorption
2. hydrostatic pressure

Question 18

(Glomerular Filtration)

(Filtration is selective)

1. Small substances enter what (like what)?
2. Do larger substances pass the glomerular filter? (like what?)

Answer 18

1. urinary space (electrolytes, glucose, peptides)

(without regulation - just free flowing)

2. no (albumin, globulins, cells)

Question 19

protein amount in afferent and efferent are the same

but a bunch of stuff gets extracted (fluid, electrolytes)

so concentration of albumin increases

what effect does this have on second capillary bed (the higher protein concentration)

this influences starling forces (oncotic pressure) - the fact that there are more conc proteins draws fluid in

this facilitates movement of fluid from intersitium back to the peritubular capillaries

Answer 19

Question 20

(Filtration Fraction)

1. What is the definintion?
2. FF = ?
3. the percentage of renal plasma flow that ends up as what?

Answer 20

1. the fraction of plasma flowing throught eh glomerulus that is dvierted into Bowman’s space by filtration
2. GFR/RPF (glomerular filtration rate/renal plasma flow)
3. glomerular filtrate

Question 21

Answer 21

A

Question 22

(Urine Concentration)

desert rodents have long loops of henle

dogs and cats good at concentrating urine - humans not so great

specific gravity = density in comparison to water (if water is 1)

(the kidneys separate salt and water)