physiology

Question 1

what area the starling forces that oppose filtration?

Answer 1

hydrostatic interstitium(bowman’s space) pressure
oncotic glomerular capillary pressure

Question 2

what area the starling forces that favors filtration?

Answer 2

hydrostatic glomerular capillary pressure

Question 3

urine concentration is regulated by …….?

Answer 3

vasa recta

Question 4

the renal corpuscle is made up of?

Answer 4

glomerulus and bowman’s capsule

Question 5

glomerulus contains what type of capillary?

Answer 5

fenestrated

Question 6

what is the glomerular filtration rate?

Answer 6

125ml/
180L/

Question 7

why is the glomerular basement membrane important?

Answer 7

it is made up of 3 layers
: 2 layers of negatively charged heparin sulfate glycosaminoglycans called lamina Rera interna and Rera externa and in the middle is a type 4 collagen lamina densa layer
–
proteins are -vely charged–>repelled by basement membrane

Question 8

Where does the glomerulus bowmans capsule drain?

Answer 8

The filtrate that has passed through the three-layered filtration unit enters Bowman’s capsule. From there, it flows into the renal tubule—the nephron—which follows a U-shaped path to the collecting ducts, finally exiting into a renal calyx as urine.

Question 9

which layer of the glomerulus filtrate barrier does not permit the filtration/passing of plasma proteins?

Answer 9

basement layer

Question 10

the basement layer doesn’t allow for the passing of the plasma proteins creating …….?

Answer 10

ultrafiltrate fluid(has no plasma proteins or blood cells)

Question 11

what are the molecules that are freely filtered through the basement membrane?

Answer 11

glucose
amino acids
lipids
Ca2+
Cl-
Na+
K+
HCO3-
Mg2+
H2O
creatinine
urea

Question 12

which molecules are repelled away from the basement membrane is absorbed back into the blood?

Answer 12

plasma proteins are not filtered (absorbed back into blood): albumin, fibrinogen, IgG globulin

Question 13

Filtration fraction=

Answer 13

GFR/RPF

As filtration fraction increase, GFR increase and renal plasma flow decrease

Question 14

What occurs to the RPF,GFR,& Filtration fraction when afferent arterioles constrict?

Answer 14

RPF: dec
GFR: dec
Filtration fraction: no change

Question 15

What occurs to the RPF,GFR,& Filtration fraction when efferent arterioles constrict?

Answer 15

Rpf: dec
Gfr: inc
Filtration fraction: increase

Question 16

What occurs to the RPF,GFR,& Filtration fraction when there’s increased plasma protein concentration?

Answer 16

Rpf: no change
Gfr: dec
Filtration fraction: decrease

Question 17

What occurs to the RPF,GFR,& Filtration fraction when there’s decreased plasma protein concentration?

Answer 17

Rpf: no change
Gfr: inc
Filtration fraction: increase

Question 18

What occurs to the RPF,GFR,& Filtration fraction when there’s constriction of the ureter?

Answer 18

Rpf: no change
Gfr: dec
Filtration fraction: dec

Question 19

Low levels of angiotensin 2 results in …… bcz……

High levels of angiotensin 2 results in …… bcz …..

Answer 19

1) inc GFR bcz it’s only affecting the efferent arterioles
2) decrease GFR bcz it’s spreading to both efferent and afferent arterioles

Question 20

Podocytes are found in which layer?

Answer 20

Epithelialof glomerular filtration barrier

Question 21

Nephrotic syndrome results from…..

Answer 21

Loss of charge barrier in glomeruli causing albuminuria, edema hyperlipidemia

Question 22

Where is heparen sulfate found and what charge does it posses?

Answer 22

It is found in the basement membrane and it has a negative charge which repels negatively charged proteins

Question 23

The clearance of …… is used to estimate renal plasma flow
The clearance of …… is used to estimate GFR

Answer 23

Para-aminohippurate
Inulin

Question 24

If filtration > excretion =

If filtration < excretion =

Answer 24

Reabsorption
Secretion

Question 25

Glucose is filtered across glomerular capillaries and reabsorbed by the epithelial cells of the …….

Answer 25

proximal convoluted tubule.

Question 26

Fill in the channels:
Glucose reabsorption is a two-step process involving ……….. across the luminal membrane and ………. across the peritubular membrane.

Answer 26

Na+-glucose cotransport (in the membrane of tubule)

facilitated glucose transport (in the blood vessel)

Question 27

………..—> Na+-glucose cotransporter channel

……….—> Na+-K+ ATPase and the facilitated glucose transporter channel

Answer 27

Luminal membrane of the epithelial cells

Peritubular membrane(blood vessel)

Question 28

The proteins involved in ………….. of glucose are called GLUT 1 and GLUT 2, which belong to a larger family of glucose carriers.

Answer 28

facilitated diffusion

Question 29

…….. patients have glucose plasma concentration that exceeds Tm causing Glycosuria(glucose in urine)

Answer 29

Diabetes

Question 30

Filtered load. Glucose is freely filtered across glomerular capillaries, and the filtered load is the product of GFR and plasma glucose concentration (filtered load = GFR × [P]x).

• Thus, as the plasma glucose concentration is increased, the filtered load ………

Answer 30

increases linearly.

Question 31

Reabsorption.

At plasma glucose concentrations less than 200 mg/dL, all of the filtered glucose can be ……. because Na+-glucose cotransporters are plentiful.

At plasma concentrations above 350 mg/dL, the carriers are completely saturated and reabsorption levels off at its maximal value, Tm.

Answer 31

reabsorbed

Question 32

……. plasma glucose concentrations of 200 mg/dL, all of the filtered glucose is reabsorbed and none is excreted.

• At plasma glucose concentrations above 200 mg/dL, the carriers are nearing the saturation point.
—>Most of the filtered glucose is reabsorbed, but some is not; the glucose that is not reabsorbed is excreted.
• The plasma concentration at which glucose is first excreted in the urine is called threshold, which occurs at a lower plasma concentration than does Tm. phenomenon called splay.
• Above 350 mg/dL, Tm is reached and the carriers are fully saturated.

Answer 32

Below

Question 33

Because of …….., glucose is excreted in the urine (i.e., at threshold) before reabsorption levels off at the Tm value.

Answer 33

splay

Question 34

In contrast to glucose, which is reabsorbed by carrier-mediated (facilitated)mechanisms, urea is reabsorbed or secreted by ……….

Answer 34

diffusion (simple diffusion and facilitated diffusion).

Question 35

The rate of reabsorption or secretion is determined by the ……………….. for urea between tubular fluid and blood and by the permeability of the epithelial cells to urea.

Answer 35

concentration difference

Question 36

Reabsorption occurs mainly in the …….

Answer 36

Proximal convoluted tubule

Question 37

When medulla cortical duct becomes permeable to urea and there’s high concentration of urea, …… will aid in reabsorption of water, which will automatically cause reabsorption of urea.

Answer 37

ADH (vasopressin);(aids in water reabsorption- > triggering reabsorption of urea)

Question 38

the greater the ……. reabsorption, the greater the urea reabsorption and the lower the urea excretion.

Answer 38

water

Question 39

Where are water and urea reabsorbed ?

Answer 39

Proximal convulated tubule

Question 40

In the ………, urea is secreted.

Answer 40

thin descending limb of Henle’s loop

Question 41

The ………… limb of Henle, distal tubule, and cortical and outer medullary collecting ducts are impermeable to urea (&water), so no urea transport occurs in these segments

Answer 41

thick ascending

Question 42

More urea is secreted into the ……………… than was reabsorbed in the proximal tubule; thus, at the bend of the loop of Henle, 110% of the filtered load of urea is present.

Answer 42

thin descending limbs

Question 43

in the presence of …………, water is reabsorbed in the late distal tubule and the cortical and outer medullary collecting ducts—consequently, in these segments, urea is “left behind” and the urea concentration of the tubular fluid becomes quite high.

Answer 43

antidiuretic hormone (ADH)

Question 44

Vasopressin creates a (hyper/hypo) osmotic urine?

Answer 44

Hypo-osmotic urine (bcz ADH allows for the reabsorption of water and NaCl back to blood)

Question 45

in the presence of ADH/vasopressin , water is reabsorbed in the …………….. tubule and the cortical and outer medullary collecting ducts

Answer 45

late distal tubule

Question 46

in which part of the nephron is urea reabsorbed?

Answer 46

in the proximal tubule, 50% of the filtered urea is reabsorbed by simple diffusion

Question 47

where is the urea filtered?

Answer 47

glomerulus, which is where filtration occurs