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Flashcards in Renal - Physiology and Diagnostics Deck (70)
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1

What is the functional subunit of the kidney?

The nephron

2

True or False: Nephron numbers increase over time.

False - they decrease over time; 10% drop in numbers every 10 years after the age of 40

3

What are the components of the nephron?

Glomerulus and tubules

4

What is the glomerulus?

a capillary bed

5

What is the glomerulus surrounded by?

Bowman's capsule

6

What does the glomerulus produce?

ultrafiltrate

7

What surrounds the tubules of the nephron?

peritubular capillaries

8

What is the function of the tubules?

To transport and alter urine

9

Where is there high hydrostatic pressure in the nephron? What occurs here? Is it selective or non-selective?

In the globerulus, there is increased filtration and it is non-selective

10

Where is there low hydrostatic pressure in the nephron? What occurs here? Is this process selective or non-selective?

In the tubules, there is increased reabsorption and it is a selective process

11

What do the two different capillary systems allow for?

individual adjustments of filtration/reabsorption

12

What are the subsections of the tubule?

Proximal tubule, loop of henle, juxtaglomerular complex, distal tubule, connecting tubule, collecting tubule, and collecting duct

13

What is the volume and composition of urine dictated by?

Glomerular filtration rate, tubular reabsorption rate, and tubular secretion rate

14

What is the filtration fraction through the glomerulus?

20 percent

15

The ultra-filtrate that the glomerulus produces is almost identical to plasma except for what?

There is a lower protein content and a lower content of protein-bound molecules (calcium and FA)

16

What are the 3 layers of the glomerulus?

Fenestrated epithelium, basement mebrane, and podocytes (epithelial cells)

17

Decribe the fenestrated endothelium.

It is composed of large pores and is negatively charged

18

Describe the basement membrane of the glomerulus.

It is composed of a collagen/proteoglycan mesh and is negatively charged

19

Describe the podocytes of the glomerulus.

It is separated by slit pores and is negatively charged

20

What are the consequences for the ultrafiltrate?

Retention of larger, negatively charged molecules within the plasma

21

What can glomerular diseases cause (think about the ultrafiltrate)?

Urinary loss of larger proteins - albumin and antithrombin

22

What determines the glomerular filtration rate (GFR)?

Glomerular hydrostatic pressure, capsular hydrostatic pressure, glomerular oncotic pressure, and filtration coefficient

23

What mechanisms are involved in reapsorbtion/secretion in the tubules?

transporters and pinocytosis

24

What occurs in the proximal tubule?

reabsorption, pinocytosis, and secretion

25

What is reabsorbed in the proximal tubule?

65% of Na+ and water, and >98% glucose and amino acids

26

What molecules undergo pinocytosis in the proximal tubule?

larger molecules

27

What is secreted in the proximal tubules?

Oxalate, urate, catecholamines, and drugs such as penicillin

28

What inibitors works at the level of the proximal tubules?

Carbonic anhydrase inhibitors

29

Normally, the proximal tubules should reabsorb all glucose in the urine. What happens in the proximal tubules in diabetes mellitus patients?

They get overwhelmed by the amount of glucose in the urine and can only reabsorb so much (transport maximum is exceeded). This results in glucosuria

30

What is Fanconi's syndrome?

An inherited/acquired disease affecting fucntion of the proximal tubules

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