Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

COB Physiology I > Lecture 16: Tubular Reabsorption and Secretion > Flashcards

Lecture 16: Tubular Reabsorption and Secretion Flashcards

1
Q

Paracellular route of reabsorption

A

Transport of filtrate between cells; diffusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Transcellular route of reabsorption

A

Transport of filtrate through cells; transporters and channels involved

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Aquaporins

A

Specific channel for water transport which can be removed or inserted onto membrane, regulating H2O reabsorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Aquaporin-1

A

Widespread, including in renal tubules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Aquaporin-2

A

Present in apical membranes of collecting tubule cells, CONTROLLED BY ADH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Aquaporin-3

A

Present in basolateral membranes of collecting tubule cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

ATPases

A

Establish ionic gradients across nephron cell membranes which drive reabsorption or secretion of many solutes; SECONDARY active transport; Na+ gradient powers movement (symporters, antipoers)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

ENaC channel

A

Found in apical membrane of nephron cells, closed by amiloride, opened by several hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Facilitated transport

A

Transport occurring through channels or uniporters; example: glucose transport

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Active transport

A

Transport directly coupled to an energy source; example: Na+/K+ ATPase pump, Ca2+ ATPase pump, H+ATPase pump, etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Secondary active transport

A

Transport coupled indirectly to an energy source; example: Ion gradient, Na+/glucose cotransporters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

SGLT2

A

Reabsorbs 90% of glucose in early proximal tubule (sodium glucose cotransporter on brush border of PCT cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

SGLT1

A

Reabsorbs 10% of glucose in late proximal tubule (sodium glucose cotransporter on brush border of PCT cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What substances are actively secreted into the renal tubules?

A

Creatinie, para-aminohippuric acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Transport maximum

A

There is a limit to the rate at which the solute can be transported due to saturation of a specific transport system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Transport maximum for glucose

A

375 mg/min; if we exceed this amount, all glucose will be excreted in urine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Solvent drag

A

Solutes dragged along with solvent regardless of gradient due to osmotic movement of water

18
Q

Which of the following in L/day represents the GFR in the average adult human?

A. 3
B. 125
C. 180
D. 360

A

C. 180

19
Q

An increase in which of the following factors will result in a decrease in glomerular hydrostatic pressure?

A. Arterial pressure
B. Afferent arteriolar resistance
C. Efferent arteriolar resistance
D. Both B and C
E. All of the above
A

B. Afferent arteriolar resistance

20
Q

Almost 90% of glucose reabsorption occurs in the early proximal tubule. Which of the following mechanisms is responsible for moving glucose from the tubular lumen into the cytoplasmic compartment?

A. Primary active transport via glucose ATPase pump

B. Secondary active transport via Na+/glucose cotransporter

C. Secondary active transport via Na+/glucose antiporter

D. Diffusion due to concentration differences between tubular fluid and cytoplasm

A

B. Secondary Active Transport via a sodium/glucose cotransporter

21
Q

Transport characteristics of proximal tubule

A

highly metabolic, many mitochondria, extensive brush borders (lumen), extensive channels (interstitial)

22
Q

What substances are reabsorbed in proximal tubule?

A

65% filtered sodium, chloride, bicarbonate, and potassium; all filtered glucose and amino acids

23
Q

What substances are secreted into lumen by proximal tubule?

A

H+, organic acids, bases

24
Q

Transport characteristics of thin descending limb of Loop of Henle

A

Highly permeable to H2O, moderately permeable to most solutes (urea, sodium)

25
Q

What substances are reabsorbed by the thin descending segment of the Loop of Henle?

A

20% of filtered H2O

26
Q

Thin ascending segment of Loop of Henle

A

IMPERMEABLE TO WATER

27
Q

Thick ascending segment of Loop of Henle

A

Na+/K+ ATPase pump in basolateral membranes, Na+/K+/Cl- cotransporter, slight leak of K+ into lumen; IMPERMEABLE TO WATER

28
Q

Distal tubule

A

Contains macula densa, reabsorbs most ions but is IMPERMEABLE to WATER and UREA (diluting segment)

29
Q

Principal cells

A

Reabsorb Na+, H2O from lumen; secrete K+ into lumen using Na+/K+ ATPase pump (late distal/collecting ducts)

30
Q

Intercalated cells

A

Reabsorb K+ (HCO3-?) from lumen; secrete H+ into lumen via H_ ATPase transporter

31
Q

Medullary collecting duct

A

Cuboidal epithelium, smooth surface with few mitochondria; ADH controls permeability to H2O; permeable to urea via transporters; can secrete H+ against large concentration gradient (acid/base control)

32
Q

What substances are reabsorbed in medullary collecting duct?

A

Sodium, Chloride, H2O in presence of ADH, Urea, Bicarbonate

33
Q

Aldosterone

A

Source: adrenal cortex
Function: increases Na+ reabsorption, stimulates K+ secretion
Site of action: principal cells of cortical collecting ducts
Stimulus for secretion: increased extracellular K+, increased levels angiotensin II

34
Q

Addison’s Disease

A

Occurs due to the absence of aldosterone, results in marked loss of sodium and accumulation of potassium

35
Q

Conn’s Syndrome

A

Hypersecretion of aldosterone (few symptoms)

36
Q

Angiotensin II

A

Function: increased Na+, H2O reabsorption, returns blood pressure and extracellular volume toward normal
Effects: stimulates aldosterone secretion, constricts efferent arterioles, stimulates Na+ reabsorption in proximal tubules

37
Q

ADH

A

Source: posterior pituitary
Function: increases H2O reabsorption
Effects: binds to V2 receptors in late distal tubules, collecting tubules/ducts; increases formation of cAMP stimulating movement of aquaporin-2 proteins

38
Q

Atrial Natriuretic Peptide (ANP)

A

Source: cardiac atrial cells in response to distension
Function: inhibits reabsorption of Na+, H2O

39
Q

Parathyroid Hormone (PTH)

A

Source: Parathyroid glands
Function: increases Ca2+ reabsorption

40
Q

Renal clearance

A

Volume of plasma that is completely cleared of the substance by the kidneys per unit time
Cs = (Us x V)/Ps

41
Q

Inulin

A

Polysaccharide that is not produced in body; used to measure GFR via renal clearance (125 ml/min = normal)

COB Physiology I (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions