Sweep 1.1

Question 1

Resting O2 consumption is

Answer 1

~250 ml/min, and the amount of dissolved O2 in the blood is less than 10% of what is needed to support basal metabolism.

Question 2

Respiratory alkalosis

Respiratory rate faster

Answer 2

than normal or hyperventilation results in decreases in

[H+] and PCO2

Question 3

Respiratory acidosis

Respiratory rate

Answer 3

lower than normal or hypoventilation results in increases in
PCO2 and [H+]

breath-holding is extreme hypoventilation

Question 4

Effects of Hb on blood pH

Hb buffers

Answer 4

most of the H+ produced by the CA reaction
arterial pH = 7.4
venous pH = 7.36

Question 5

H+ binds to —— residues on Hb, but affinity depends on ——

Answer 5

histidine

PO2

Question 6

then in the lung, Hb releases

Answer 6

H+ to combine with HCO3- and CA reaction runs in reverse

CO2 + H2O ⇐ H2CO3 ⇐ HCO-3 + H+

Question 7

CO2 is more —– in plasma than O2

Answer 7

soluble

Question 8

increase Hb affinity for O2

Answer 8

à shift curve to left and Hb is saturated at a lower PO2

Question 9

decrease Hb affinity for O2

Answer 9

à shift curve to right and Hb is less saturated for a given PO2

Question 10

according to Vander, CO also shifts Hb-O2 dissociation curve to the

Answer 10

left (binding of CO will increase Hb’s affinity for whatever O2 is has).

Question 11

peripheral chemoreceptors are stimulated by

Answer 11

↑ [H+] or ↓ PO2

Question 12

central chemoreceptors are stimulated by

Answer 12

↑ [H+] in extracellular fluid in brain

Question 13

ventilation rate increases below PO2 of about

Answer 13

60 mm Hg

Question 14

central chemoreceptor response to

Answer 14

decrease in brain pH is primary regulator

Question 15

Ventilation rate can be modified by

Answer 15

non-respiratory sources of H+

Question 16

Immediate responses T

stimulate

Answer 16

ventilation –

increased dependence on anaerobic glycolysis –

Question 17

hypoxic hypoxia or hypoxemia -

Answer 17

decreased arterial PO2

Question 18

anemic hypoxia –

Answer 18

normal arterial PO2; decreased hemoglobin and O2 content of blood

Question 19

ischemic hypoxia–

Answer 19

blood flow to tissues is too low

Question 20

histotoxic hypoxia -

Answer 20

cells unable to utilize O2

Question 21

renin – part of renin-angiotensin-aldosterone cascade to regulate

Answer 21

blood pressure

Question 22

ESRD patients have a reduced ability to

Answer 22

eliminate nitrogenous wastes (urea) and excess nitrogen is converted to ammonium. The excess ammonium has direct effects on health – the blood is alkalized which leads to an increased pH in the oral cavity.

Question 23

Contraindications for ESRD patients:

nephrotoxic drugs such as

Answer 23

tetracycline, acyclovir, aspirin, NSAIDs

Question 24

Contraindications for ESRD patients:

increased susceptibility to bleeding due to

Answer 24

destruction of platelets

Question 25

response of the juxtaglomerular apparatus (JGA) located at the intersection of the

Answer 25

macula densa of distal tubule with afferent and efferent arterioles – the JGA secretes the hormone renin which regulates systemic blood pressure, and, therefore, glomerular blood flow

Question 26

Inulin and creatinine are substances that can be used to

Answer 26

measure renal clearance

Question 27

inulin –

Answer 27

small polysaccharide; freely filtered and not secreted or absorbed

Question 28

creatinine –

Answer 28

product of muscle metabolism; freely filtered, not reasbsorbed, almost no secretion; normal creatinine levels < 1+ 0.5 mg/dl; if > 10 → requires dialysis

Question 29

Autoregulation involves

Answer 29

intrinsic mechanisms that adjust bloodflow through the glomerulus; it is achieved by two primary mechanisms

Question 30

1. myogenic mechanism –

Answer 30

vascular smooth muscle tends to contract when it is stretched, and relax when not stretched

constriction or dilation of smooth muscle in afferent or efferent arterioles has contrasting effects on RBF

Question 31

2. tubuloglomerular feedback –

Answer 31

feedback from the JGA adjusts afferent arteriole diameter and, thus, GFR

Question 32

CA inhibitors – reduce

Answer 32

Na+ reabsorption; proximal tubule is major site of action

Question 33

Loop diuretics – act in thick ascending limb to

Answer 33

inhibit Na+ reabsorption via the Na+ K+ 2Cl- symporter

Question 34

Thiazides – block

Answer 34

Na+Cl- symporter in early distal tubule

Question 35

K+ - sparing – two classes that both act in

Answer 35

late distal tubule and cortical collecting duct to inhibit sodium reabsorption AND potassium secretion

Question 36

K+- sparing

Answer 36

1. aldosterone antagonists

2. ENaC blockers

Question 37

Aquaretics –

Answer 37

ADH receptor antagonists

Question 38

Osmotic diuretics increase the osmotic pressure in the

Answer 38

tubular fluid, and, thus, impair Na+ reabsorption.

Question 39

Osmotic diuretics Examples include

Answer 39

mannitol and pathologically elevated glucose.

Question 40

Acetazolamide is an example of a

Answer 40

CA inhibitor.

Question 41

CA inhibitors gain access to the proximal tubule via

Answer 41

secretion

Question 42

Most of the diuretic effect is in the proximal tubule where ~1/3 of Na+ reabsorption relies on the

Answer 42

Na+/H+ antiporter

Question 43

Diuretic effect is not large

downstream segments will increase

Answer 43

Na+ reabsorption when tubular Na+ increases

typically increases Na+ excretion to 5-10% of filtered load

Question 44

Loop diuretics are the most powerful of all diuretics; they inhibit

Answer 44

Na+ reabsorption in the ascending limb of the loop of Henle.

Question 45

Loop diuretics

Inhibit ———- in the thick ascending limb which inhibits ————-

Answer 45

Na+K+2Cl- symporter

Na+ reabsorption

Question 46

Loop diuretics

urine leaving loop is

Answer 46

not dilute

Question 47

Loop diuretics

no osmotic gradient established in the

Answer 47

medulla interstitium so water is not reabsorbed along collecting duct → urine is dilute (500 mOsm instead of 1400 mOsm)

Question 48

Can increase Na+ excretion to as much as

Answer 48

25% of filtered load, because Na+ reabsorption capacities downstream of their site of action are limited.

Question 49

Thiazide diuretics

Thiazide diuretics like

Answer 49

chlorothiazide are secreted into the proximal tubules, and they act in the early distal tubule to block the Na+Cl- transporter

Question 50

Using EPO to treat anemia in

Answer 50

dialysis patients

Treatment of anemia typically uses Procrit ® to stimulate erythropoiesis (rather than rely on transfusions).

Question 51

Side effects of Procrit ® treatment include

Answer 51

flu-like symptoms, headaches, high BP, and cardiovascular problems