Week # 15 Renal, Hepatic, and biochemistry Flashcards
Keep in mind, all of this stuff will make up <10% of the questions on the final. But it's still for KNOWLEDGE!
What are the 3 mechanisms for the regulation of acid-base balance?
the buffer system, the respiratory system, and the renal system
(all three are considered buffering systems)
What are the predominant buffers of the renal system?
phosphate and ammonia
To maintain normal pH, the kidneys must perform what 2 physiological functions?
1 - reabsorb all the filtered bicarbonate
2 - excrete the daily hydrogen ion load
Adding acid load to the body fluids results in consumption of _______ and the formation of _______ _____?
consumption of bicarbonate
formation of carbonic acid
Which buffering system can permanently eliminate excess hydrongen ions?
the renal system
Which buffering system can restore bicarbonate ions to the blood?
the renal system
What are 3 ways to lose hydrogen ions?
loss from vomiting
loss from H+ in urine
hyperventilation
(the slides said hypoventilation, but that doesn’t make sense)
What are 3 ways to gain hydrogen ions?
loss of bicarb in the GI tract
loss of bicarb in the kidneys
from protein breakdown
What is a buffer?
any substance that can reversibly bind hydrogen ions
H2O + _____ _____ _____ + H+
H2O + CO2 H2CO3 HCO3 + H+
What is the enzyme responsible for the reaction of CO2 + H2O H2CO3?
carbonic anhydrase
What percent of cardiac output goes to the kidneys?
25%
Approximately how many milliliters of urine is produced each minute?
1 - 2 mL / minute
What is the path of renal blood flow, starting with the afferent arteriole?
afferent arteriole –> glomerulus –> efferent arteriole –> peritubular capillaries –> renal vein
What is the main function of the proximal tubule?
reabsorption of the bulk of filtered fluid
What is the main function of the loop of Henle?
establishes and maintains an osmotic gradient in the medulla of the kidney
What is the main function of the distal tubule and collecting ducts?
final adjustments on urine pH, osmolality, and ionic composition
What hormone is responsible for the reabsorption of water?
antidiuretic hormone (ADH)
What hormone is responsible for reabsorption of sodium and secretion of potassium?
aldosterone
Oxidation, reduction, methylation, and hydrolysis are what type of reactions?
Phase I reactions
Phase I reactions are known as _______ or _______ reactions.
catabolic or breakdown
Glucuronidation, glutathione conjugation, sulfation, and acetylation are what type of reactions?
Phase II reactions
Phase II reactions are usually known as ________ reactions.
conjugate
The ultimate goal of both Phase I and Phase II reactions is to make a more _____-______ product.
water-soluble
for elimination purposes
What is responsible for the process of Phase I reactions?
cytochrome p-450
What are some examples of drugs metabolized by Phase II reactions?
morphine, acetaminophen, digoxin, sulfonamides, dopamine, and epinephrine
Drugs with a high hepatic extraction ratio depends on what for metabolism?
blood flow
Drugs with a low extraction ratio depend on what for metabolism?
enzyme activity and protein binding
The local anesthetics, procaine, chloroprocaine, and tetracaine are all esters. How are they metabolized?
by pseudocholinesterase
a plasma cholinesterase
How are amide local anesthetics metabolized?
by liver metabolism
What is the most important plasma protein for binding of drugs?
albumin
How are benzodiazepines metabolized?
in the liver by hepatic microsomal oxidation and glucuronide conjugation
(so, by both Phase I and Phase II reactions!)
With the exception of remifentanil, how are opioids eliminated?
by hepatic metabolism
How is remifentanil metabolized?
by ubiquitous esterases in the plasma
What are the methods of metabolism for propofol?
hepatic glucuronate and sulfate conjugation
Phase II reactions
What are the methods of metabolism for etomidate?
ester hydrolysis (major) and N-dealkylation (minor)
What is the method of metabolism for ketamine?
N-demethylation
ketamine –> (N-demethylation) –> norketamine
Are the hepatic microsomes which contain the cytochrome p-450 enzymes responsible for metabolizing anesthetic gases?
yes, yes they are
How is succinylcholine metabolized?
by pseudocholinesterase
a plasma cholinesterase. because succinylcholine is an ester
How is cisatracurium eliminated?
hofman elimination
How is vecuronium eliminated?
primarily by biliary excretion
How is rocuronium eliminated?
primarily by biliary excretion
secondarily by renal and hepatic metabolism
Hepatic blood flow is _________ with general anesthesia and regional anesthesia.
decreased
Decreased hepatic blood flow will ______ metabolism of other drugs, such as phenytoin, coumadin, ketamine, etc.
inhibit
What are 4 important functions of the kidneys?
- regulation of ECF/BP
- regulation of ionic composition
- electrolyte balance (Na, K, Ca, Mg, Cl)
- acid-base balance (H+ and HCO3)
What is the major energy macromolecule within the body?
adenosine triphosphate (ATP)
What is the net ATP production of anaerobic respiration?
2 ATP
What is the net ATP production of aerobic respiration?
34 - 38 ATP
During anaerobic metabolism, what does the end product of glycolysis (pyruvate) get converted to?
lactic acid
How much ATP is produced specifically within the Krebs Cycle?
none
ATP is formed during glycolysis and oxidative phosphorylation within the electron transport chain
How many trips around the Krebs Cycle do you get with one glucose molecule?
2
because the glucose molecule gets split into 2 parts during glycolysis
ATP production by ATP synthase is made possible by what is known as an _________ _______.
electrochemical gradient
(the electron transport chain pumps hydrogen ions across the inner matrix of the mitrochondria, creating an area of higher concentration within the cell matrix. since there is more hydrogen there, it wants to get back to the inside of the cell, but the only way it can is to do work and make some ATP!)
What are the two enzymes responsible for transporting hydrogen ions to the electron transport chain, which can then be used to create an electrochemical gradient?
NADH and FADH
(technically it’s NAD and FAD. the H on both of them stands for hydrogen. so, when they are transporting the hydrogen, you tack on the H. pretty cool, huh?)
Is hemoglobin a quaternary protein structure?
yup, sure is.
meaning, it has a heme group for each of its four polypeptides
Hemoglobin has _______ _______ with oxygen. Meaning, that there is a structural change with each oxygen bound, making it easier for more oxygen to bind to the hemoglobin.
cooperative binding
(this is also the reason that most hemes will completely fill with oxygen prior to unoxygenated hemoglobin begin to bind with oxygen)
