renal 2 Flashcards by Jacob Amato

what can happen to tubular fluid after filtration

Reabsorption and secretion

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what are the modes of transport in secretion and reabsorption

Transcellular (through tubular cells)

Paracellular (between tubular cells

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what is the diffusion of water

Osmosis

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what regulates the rate of osmosis in membrane transport

Aquaporins

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what type of trasnport proteins are found in faciliated diffusion

Ion channels
Transport proteins
 - uni
 - symp
 - anti

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what are the types of vesicular transport

Endocytosis

Exocytosis

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where can Sodium be reabsorbed in the nephron

All but one segment

ocurs in:
- the proximal tubule(most)
- ascending limbs of loop of henle
- distal tubule
- collecting duct

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how does Glucose and amino acids get reabsorbed in the proximal tubule

Glucose and amino acids reabsored using Na symporters

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what keeps intracellular Na low in the proximal tubule

active transport on the basal side

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how does water and solutes move in the proximal tubule

paracellular transport to keep the osmolarity of the tubular fluid constant

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what does Na reabsorption occur with

With bicarbonate reabsorption using an Na/H antiporter

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how is Bicarbonate reabsorbed

Not direct since H seceretion leads to HCO3 reabsorption

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how is H secretion related to HCO non direct reabsorption

Ca reaction produces H and HCO3 in tubule cell
HCO3 transported into blood
H transported into tubular fluid where it recombines with filtered HCO3

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why is it important that the proximal tubular has transporters for organic cations and anions

to secrete drugs that are often organic ionic compounds, often bound to plasma proteins(not filtered)
- need to be secreted

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what is the pro/con of transporters in the proximal tubule for drugs

low specificity so do lots of drugs, but are easily saturated

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what all is resorbed in the proximal tubule

2/3 Na, Cl, water, and small proteins by endocytosis
K and divalent cation reabsored by solvent drag
All amino acids and glucose reabsored
Bicarbonate reabsored due to Na/H transporter

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what all is secreted in the proximal tubule

Organic ions (Drugs)

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what is reabsorbed in the loop of henle

25% of filtered Nacl

15% of water reabsorbed

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what can and cannot pass through the descending thin limb

impermeable to slat

Permeable to water

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what can and cannot pass through the ascending thin limb

impermeable to water

permeable to salt

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how does reabsorption occurin the thin desending and ascending limb

passive

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what happens to the fluid in the ascending thick limb

Fluid is diluted

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what transport protein is found in the apical membrane in the ascending thick limb

Na, K, 2Cl symporter (goes into the cells)

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what transport protein is found in the basolateral membrane in the thick ascending limb

Na K ATPase (Na out of cell, K into cell)

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does solvent drag pull monovalents and divalents in the tick ascending limb

No, paracellular transport

how does paracellular transport occur in the thick ascending limb

tubular fluid becomes positive when Cl reabsored | - cations diffuse along electrical gradient

what is the concentration of solutes in the loop

Hyopsmotic

how does fluid leveling the loop become hyperosmotic urine

Countercurrent mechanisms to create an osmotic gradient

what hormone leads to concentration of tubular fluid

acting of ADH/Vasopressin in the collecting duct

what are peritubular capillaries pereable to

NaCl and water

what happens to plasma osmolarity as the capillaries follow the loop

changes, but eventually leaves in a vein as a normal osmolarity

what does the inital segment of the distal tubule reabsorb

about 8% of filtered NaCL

how does the inital segment of the distal tubule reabsorb NaCl

NaCl symporter in apical membrane | Na K ATPase in basolateral membrane

how does sodium reabsorb in the latter half of idstal tubule and collecting duct occur

Similar to the inital segments

what are the types of cells in the collecting duct and late distal tubule

primcipal cells | intercalated cells

what is found on principle cells of the late distal tubule and collecting duct

Epithelial sodium channels

what do epiethlial sodium channels do

Reabsorb Na and secrete K

what is the importance of principle cells of the late distal tubule and collecting duct

Na reabsorption driving paracellular Cl reabsorbtion | K secreted due due to NaK APTase activity in the basal membrane

what is the roll of intercalated cell in the late distal tubule and collecting duct

Acid-base balance | reabsorb K

what hormones aid in regulate blood volume

ADH/Vasopressin | Natuiuretic pepetides

what releases Vasopressin/ADH

posterior pituitary

what causes a release of ADH

- by change in osmolality of body fluid at set point 275-290 mOsm/kgH2O - change in blood volume/pressure

what responds to a change in low blood pressure to lead to a release of Vaopressin/ADH

baroreceptors in left atrium and large pulmonary vessels

what responds to a change in high blood pressure to lead to less Vasopressin/ADH

baroreceptors in aortic arch and carotid sinus

what is the action of ADH/vasopresin

- Increase permeability of the late distal tubule and collecting duct by increasing aquaporins in the apical membrane (basolateral is freely permeable to water) - increase permeability of medullary collecting duct to urea

what is diuresis

Low ADH

what happens in Diuresis

Solutes reabsorbed in distal tubule and collecting duct, but no water reabsorption - urine dilute as 50 mOsm/Kg H2O

what is Antidiuresis

ADH high

what happens in ANtidiuresis

Water reabsored as fluid passes through collecting duct | - urine concentrated up to 1200 mOsm/kg H2O

what does the renin-angiotensin-aldosterone system stimulate

Events that increase reabsorption of sodium and water (combat volume contraction)

what is renin release

responding to a drop in perfusion pressure decrease in NaCL delivery to macula densa Sympa input to juxtaglomerular cells

what does renin do

Converts angiotensinogen to angiotensin I

what converts Angiotensin I to Angiotensin II

angiotensin converting enzyme

what is the effect of angiotensin II

Vasoconstriction Stimulates release of ADH increase sympa activity Stimulate aldosterone secretion

what does aldosterone from the adrenal cortex do

increase NaCl reabsorption in the distal tubule and collecting duct by increasing transport protein synth

when are natriuretic peptides secreted

when the heart dilates (during volume expansion)

where does atrial natriuretic pepetide come from

the atria

where does brain natriuretic peptide come from

Ventricles

what are the effects of natriuretic peptides

vasodilation of afferent arterioles Vasoconstriction of efferent arterioles inhibit renin and aldosterone inhibit ADH secretion

what is the net efffect of natriuretic peptides

increase excretion of NaCl and water

why is it important to regulate potassium

major determinant of membrane resting potential | - affect electrically excitable cells

what does hyperkalemaia lead to

depolarize V

what does hypokalema

hyperpolarize V

what does a change in K do to the heart

causes cardiac arrhythmias

what happens to ingesting K

fast shifted into cells mediated by insulin, epinephrine, and aldosterone

how much ingested K is excreted by the kidney

90-95%

is K freely filtered in the Glomerulus

yes

where is K reabsorbed

67% in the proximal tubule | Thick ascending limb

how is K reabsorbed in the proximal tubule

paracellular transport/solvent drag like Na

how K reabsorbed in the thick ascending limb

Na, K, 2Cl symporter and paracellular transport (non solvent drag)

how is K secreted in the late distal tubule and collecting duct

- K secreted by principal cells depending on ATPase activity, K gradient, apical K permeability - intercalated cells reabsorb K when Potassium is depleted

what are the factors that affect excretion of Potassium

Plasma K | Flow rate of tubular fluid

how does plasma K change the excretion of Potassium

increased K simulates Aldosterone release | aldoserone increase Na/K ATPases in principle cells

what does an increase in flow rate do to K secreteion

Increases K secertion

why does in creased flow lead to an increase in K secretion

local response to bending of cilia

how does increased flow increase K secretion

increased flow increased Na in collected Na reabsorption favors increased K secretion

does reabsorption of K in proximal tubule and thick ascending limb change a lot dpending on poassium presence

wha does secretion increase if plasma K is high

increases in distal tubule and cortical collection

where does reabsorption of K occure when plasma concetrations are low`

distal tubule | cortical collecting duct

renal 2 Flashcards

(79 cards)