Session 3 - Filtration Flashcards Preview

Semester 3 - Urinary > Session 3 - Filtration > Flashcards

Flashcards in Session 3 - Filtration Deck (95)
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31

Give three examples of things actively secreted

• Protons
• Potassium
• Creatinine

32

What are two methods of secretion into the PCT?

• Entry by passive carrier
• Secretion into the lumen

33

What is entry by passive carrier?

• Diffusion across basolateral membrane down conc grad created by Na+/K+ ATPase

34

How does entry by active secretion differ to passive?

• Directly uses ATM and H+ gradient creat by Na+-H+ antiporter

35

Give two forms of reabsorption?

• Transcellular
• Paracellular

36

How easy is it for a cation to get through the filter compared to an anion?

• Positive charge of cation allows slighty bigger molecules through than anions

37

What is reabsorption in PCT driven by?

• Sodium uptake

38

How is Na+ reabsorbed in tubular cells

• 3Na-2K-ATPase (Na into ECF, K+ into cell)
• Na+ moves across the apical membrane from tubule lumen down its concentration gradient
• Water follows into cell

39

In what way do solutes move in the PCT?

• Tubular lumen -> Intersticium -> Capillaries

40

What are the three mechanisms via which tubular reabsorption occurs?

• Osmosis
• Diffusion
• Active transport

41

What does iso-osmotic mean when applied to reabsorption?

• Osmosis does not take effect

42

Where does unregulated absorption occur?

• Proximal convoluted tubule

43

What is the method via which reabsorption occurs?

• Co-transport, following active transport

44

What is the transport maximum?

• If plasma conc exceeds Tm, the rest spills over into urine

45

What is the reabsorption path?

• Lumen -> Intersticium -> Peritubular capillaries

46

How is reabsorption different from glomerula filtration?

• Occurs primarily through cells

47

What 7 main substances are secreted into glomerula filtrate?

• Protons
• Potassium
• Ammonium ions
• Creatinine
• Urea
• Some hormones
• Some drugs

48

Why do we need kidney secretion?

• Only 20% of plasma filtered in renal corpuscle each time

49

From where does tubular secretion occur?

• From the epithelial cells that line the renal tubules and collecting duct into the glomerular filtrate

50

How are organic cations secreted?

1) Entry by passive carrier into tubular lumen cell
a. Positive cation from ECF moves into negative cell down electrical gradient. This is as a result of basolateral 3 Na+/2 K+ ATPase
2) Secretion into the lumen
a. H-OC exchanger driven by H+ gradient created by the Na+-H+ antiporter
b. Na+ into cell from lumen, H+ out cell into lumen
c. Drives H+ into cell from lumen by creating conc grad
d. Organic Cation out by active transporter

51

Name three endogenous cations

• Dopamine
• Adrenaline
• Histamine

52

Name three cationic drugs

• Morphine
• Atropine
• Sulfonamides

53

Name three endogenous anions

• Urate
• Bile salts
• Fatty acids

54

Name two anionic drugs

• Penicillin
• Salicylate

55

What is secondary active transport?

• Na+/K+ ATPase used to generate Na+ gradient

56

Where is glucose reabsorbed in the nephron?

• Proximal convoluted tubule

57

Through what transporter is glucose reabsorbed in the proximal convoluted tubule?

SGLUT

58

What is SGLUT?

• 2 Na+ ions and 1 glucose
• Glucose travels from lumen of tubule to the peritubular capillaries (moves into peritubular capillaries by facillitated diffussion

59

What is Tm?

• Transport maximum from tubule to capillaries

60

What is the renal threshold for glucose?

• 200mg/100ml