final

Question 1

Na and associated ions account for what fraction of the solutes in the blood plasma

Answer 1

280/300 mOsm

Question 2

what is the primary extracellular ion

Answer 2

Na

Question 3

hormonal and neural influences on Na balance (4)

Answer 3

1. Aldosterone
2. ADH
3. Atrial natriuretic peptide (ANP)
4. other hormones -> estradiol, progesterone and cortisol
5. cardiovascular baroreceptors

Question 4

high concentrations of K+ are ______

Answer 4

toxic

Question 5

K+ moves in the opposite direction as _____

Answer 5

H+

Question 6

K+ concentrations affect _________ especially in _______

Answer 6

membrane potential, cardiac muscle

Question 7

What percent of K+ is lost in the filtrate

Answer 7

10%

Question 8

Where is most potassium reabsorbed in the nephron?

Answer 8

65% in the proximal convoluted tubule (PCT)

25% in the thick ascending limb of the loop of Henle

Question 9

How much K⁺ is typically lost in the filtrate before fine-tuning?

Answer 9

Only ~10% remains after the bulk of it is reabsorbed early in the nephron

Question 10

What happens if more K⁺ is reabsorbed than the body needs?

Answer 10

Tubular secretion of K⁺ is triggered to maintain balance.

Question 11

Where does K⁺ secretion occur in the nephron?

Answer 11

Distal convoluted tubule (DCT)

Principal cells of the collecting duct

Question 12

What factors increase K⁺ secretion?

Answer 12

High K⁺ in blood (hyperkalemia)

Aldosterone (promotes K⁺ secretion in exchange for Na⁺ reabsorption)

Question 13

2 factors that determine rate and extent of K+ excretion

Answer 13

plasma k+ concentration

aldosterone concentration

Question 14

where is 99% of ca found

Answer 14

bone

Question 15

what is ca important for (3)

Answer 15

neuronal signalling, second messenger, heart muscle contraction

Question 16

2 hormones involved in Ca regulation

Answer 16

PTH and calcitonin

Question 17

PTH

Answer 17

increases ca levels in the blood

Question 18

calcitonin

Answer 18

Decreases Ca levels in blood by stimulating bone deposition and inhibiting bone reabsorption

Question 19

how much of filtered ca is reabsorbed

Answer 19

98%

Question 20

PTH 3 targets

Answer 20

1. bone - osteoclasts
2. small intestine (activation of vit D)
3. kidneys

Question 21

Why does PTH stimulation of the kidneys have opposing effects on ca and phosphate

Answer 21

if both are pulled back it won’t be available in the blood -> it will become ca salts and become part of the bone instead of being free in the blood for cell signaling

Question 22

____% of phosphate is reabsorbed in the PCT by ______

Answer 22

75, active transport

Question 23

No PTH

Answer 23

phosphate is reabsorbed to transport max

Question 24

high PTH

Answer 24

reduced active transport of phosphate

Question 25

PTH activates ________ to promote ca reabsorption in the GI

Answer 25

Vit D

Question 26

how many hydrolats are required to get the active form: 1,25-dihydroxy vitamin D

Answer 26

2 hydroxylations

Question 27

what is calcitonin secreted by

Answer 27

parafollicular cells in the thyroid

Question 28

what does calcitonin inhibit

Answer 28

osteoclasts

Question 29

Alkalosis

Answer 29

7.45 or more

Question 30

acidosis

Answer 30

7.35 or less

Question 31

sources of acid (4)

Answer 31

1. Breakdown of phosphorus-containing proteins - phosphoric acid 2. Anaerobic metabolism of glucose - lactic acid 3. fat metabolism - fatty acids and ketone bodies 4. loading and transport of co2 as bicarb - H+ ions

Question 32

blood H+ concentrations are regulated by (3)

Answer 32

- Chemical buffer systems - the respiratory center and the brain stem renal mechanism

Question 33

chemical buffer eq.

Answer 33

CO2 + H20 <-> H2CO3 <-> H+ +HCO3-

Question 34

renal mechanism

Answer 34

involved in reabsorbing or generating new bicarbonate (getting rid of H+) or in rare cases the opposite

Question 35

How does the collecting duct regulate H⁺ secretion?

Answer 35

It responds to the pH of the extracellular fluid (ECF) — if ECF is too acidic, H⁺ secretion increases.

Question 36

Where does the secreted H⁺ in the nephron come from?

Answer 36

It is generated from carbonic acid (H₂CO₃) inside the tubule cells.

Question 37

What ion is reabsorbed for every H⁺ secreted into the tubule? Why?

Answer 37

One Na⁺ is reabsorbed to maintain electrochemical balance.

Question 38

What happens when H⁺ combines with HCO₃⁻ in the tubule lumen?

Answer 38

they form CO₂ and H₂O → CO₂ diffuses back into the tubule cell, promoting more H⁺ secretion.

Question 39

How does bicarbonate get back into the bloodstream?

Answer 39

HCO₃⁻ is reabsorbed into the peritubular capillaries along with Na⁺.

Question 40

how much phosphate is reabsorbed?

Answer 40

75% except during acidosis

Question 41

type a intercalated cells of the collecting duct secrete

Answer 41

H+

Question 42

NH4+ secretion

Answer 42

weak acid lost in the urine

Question 43

bicarb ion excretion

Answer 43

more rare only happens when someone is hyperventilating

Question 44

type B cells

Answer 44

reverse reabsorption by reabsorbing H+ while excreting bicarb

Question 45

respiratory acidosis

Answer 45

PCO2 >45 mmHg, pH<7.35

Question 46

respiratory alkalosis

Answer 46

PCO2 <35 mmHg, pH >7.45

Question 47

metabolic acidosis

Answer 47

HCO3- < 22 mEq/L, pH <7.35

Question 48

metabolic alkalosis

Answer 48

HCO3- >26 mEq/L, pH >7.45