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Z MD1 Renal block > Physiology > Flashcards

Flashcards in Physiology Deck (107)
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main functions of the kidneys (7)

- water and sodium homeostasis
- acid/base balance
- control of ECF Ion conc
- excretion of waste products and xenobiotics
- endocrine functions
- formation of concentrated urine
- formation of dilute urine

1

what is uremia

the accumulation of dozens of toxic metabolites (not only urea)

2

which hormones do the kidneys make

EPO
renin
Vitamin D3
PGI2

3

what is the difference between superficial cortical glomeruli and juxtamedullary glomeruli

SCG - LOP penetrates only a short distance into the medulla and their efferent arterioles give rise to cortical capillaries surrounding the PCT and DCTs
JMG - LOP penetrates deep into the medulla and their efferent arterioles become the vasa recta that also penetrate deep into the medulla parallel to the LOH

4

what is the proportion between SCG and JMG?

JMG only make up 10% of glomeruli

5

main function of JMG

give the greatest responsibility to concentrating the urine - increase the osmolarity of the urine

6

what are the two parts of the proximal tubule

pars recta and PCT

7

what is the difference in the thin and thick parts of the ascending limb of the LOH between SCG and JMG?

SCG - thin is very short
JMG - thin is very long

8

how many nephrons do we have

2 million (1 million in each kidney)

9

what is the filtration fraction at the kidney

20% of the renal plasma flow

10

what is the GFR?

125ml/min

11

what is the volume of fluid that is passed through the kidneys a day

180L

12

at what point do you start to get problems if your GFR starts to drop

when it drops down to 30-40ml/min

13

where are the macula densa cells

epithelial cells of the thick ascending that lie against the afferent and efferent arterioles

14

what are the 2 components of renal autoregulation

myogenic response
tubuloglomerular reflex

15

what what range of MAP can the nephron keep the pressure constant in the glomerulus

70-180mmHg

16

How do macula densa cells participate in renal autoregulation

sense the NaCl that is delivered to it (if pressure too high, NaCl will be higher) --> releases adenosine and thromboxane to constrict the afferenent arteriole

17

what is the pressure in the glomeruli kept at

50mmHg

18

where are the cells that make renin?

they are the granular cells lining the afferent arteriole

19

three parts of the filtration complex of the glomerulus

fenestrations
basal lamina
slits between foot processes of podocytes

20

what stops most proteins moving through the glomerulus

their negative charge is repelled by the negative charge on the basal lamina and fenestrations

21

why in diabetes, does the amount of albumin increase in the urine

because in the diabetes the negative charge of the basal lamina is lost and so a disproportionate amount of albumin is allowed through the glomerulus and lost in the urine

22

what are the normal values of the forces acting towards filtration at the glomerulus

hydrostatic pressure in the glomerular capillary = 50mmHg
hydrostatic pressure in the bowmans capsule = 10mmHg
Oncotic pressure in the glomerular capillary = 25-40mmHg
oncotic pressure in the Bowmans capsule = 0mmHg

23

what is the net filtration pressure at the glomerules

10-15mmHg

24

what happens to GFR when the afferent arteriole is constricted? What about the efferent arteriole?

afferent - GFR decreases due to decreased hydrostatic pressure
efferent - GFR increases due to increased hydrostatic pressure

25

where does angiotensin 2 act in the kidney primarily

primarily on the efferent arteriole - constricts them (supporting filtration)

26

Ang2 inhibitors and their effect on the kidney

dilation of the efferent arteriole - decreases GFR

27

what is the equation for renal blood flow

change in pressure from renal artery to capillary / resistance of the afferent and efferent arterioles

28

what is the myogenic response

afferent arteriole constricts in response to stretch by increased pressure

29

three things that can cause renin release

- sympathetic activation
- decreased BP in afferent arteriole
- decreased NaCl delivery at the macula densa