Exam 1 Flashcards
What are the waste products that are created from metabolism and enter into the venous system from the capillary bed?
CO2, H+, Heat, Urea
What mechanism is the major control system of the body?
Negative Feedback mechanism.
What mechanism is characterized by the body perceiving a change in stimulus and amplifying this change?
Positive Feedback Mechanism
What are two examples of positive feedback mechanisms?
- Oxytocin induced uterine contraction via amplification via stretch of cervix
- The clotting cascade
What are positive feedback mechanism “checkpoints”? Give examples after defining.
These are “safety valves” that prevent the positive feedback mechanism from turning in to vicious cycles.
- Birthing a baby that stops the oxytocin-induced uterine contractions.
- Bleeding coagulation stops the clotting cascade from continuing.
What ion spills from the intracellular fluid when tissue dies and causes further damage? What mechanism does this process exhibit?
Potassium; Pathologic positive feedback mechanism.
How many cells does the body have? What proportion of these cells are red blood cells (RBCs) ?
- 35 trillion cells
- 25 trillion RBCs
What is the pathology behind SIDS? What mechanism fails to cause this pathology?
SIDS occurs when a baby does not respond to elevated CO2 levels. This occurs because the baby lacks the necessary “safety valve” to increase respirations in response to increased CO2.
Approximately how many nephrons do humans have at birth? What causes these to decrease over time and what mechanism is involved?
2 million nephrons
- damage occurs over time which decreases the number of nephrons which places further stress on the remaining nephrons. This is an example of a pathologic positive feedback mechanism and is exemplified in Diabetic Renal Inflammation.
What type of bonds help proteins to hold their structures (folding and such)?
Sulphur bonds
What are the components of the glycocalyx?
Glycolipids and glycoproteins
What are cell “ID tags” and what are they composed of?
Cell ID tags are carb groups located on the outer portion of the cell membrane. These tags let the immune system know if the cell needs to be targeted or not.
How does high blood glucose interface with cellular ID tags?
- Hyperglycemia sticks extra glucose molecules to the carb groups and makes the cell ID tags “bad” this makes the immune system target these cells despite their health.
Where are serine molecules located? What is the result if the location changes?
Serine molecules SHOULD be located intracellularly. If the serine molecule presents itself extracellularly, then the immune system targets the cell.
What are Integral proteins usually pair to? What is the pairing’s purpose?
Integral proteins usually pair with intracellular peripheral proteins. This pairing allows the peripheral protein to “break off” and exert some function based on the interaction of an agonist with the integral protein.
What is the relevance of a C=C (carbon-carbon double bond) in regards to the phospholipid bilayer?
- The C=C bond makes the cell wall more fluid by “nudging” the cells away from each other.
- This helps make the cells flexible (ex. RBCs)
What is a micele and what is its significance?
- Micele’s are phospholipid spheres that function as carrier objects to move hydrophobic drugs around a system. (Ex. Propofol)
What is the process of lipid rescue?
- This is a technique where a bunch of micele’s are given to hopefully capture a lipid soluble drug onto the carrier micele’s.
How is cholesterol “grabbed” from the cell membrane?
- The cholesterol has a hydroxyl group (-OH) that sticks out of the cell membrane and can be used as a point for other proteins to attach to and pull the entire cholesterol molecule out of the cell membrane.
How much of cholesterol is ingested vs created by the body?
- 20% of cholesterol is exogenously ingested.
- 80% is produced endogenously.
How is the process of cholesterol synthesis interrupted? What are the steps that led to the point of interruption?
- Cholesterol synthesis is interrupted using Statins by inhibiting HMG-CoA reductase.
- Acetyl-CoA & Acetoacetyl-CoA → HMG-CoA → HMG-CoA reductase 🔚 Statin
Do statin’s have any benefits aside from reducing endogenous cholesterol production?
Yes, statins are also antiinflammatory.
What the important cholesterol derivatives? Which of these derivatives are sex hormones?
- Progesterone
- Aldosterone (causes retention of Na+ and H20)
- Cortisol
- Estradiol
- Testosterone
- Progesterone, estradiol and testosterone are sex hormones.
What other molecule has a -OH “grabber” like cholesterol?
Arachidonic Acid
Are saturated or polyunsaturated lipid fats considered better? Why?
Polyunsaturated fats are considered better because they make the cell wall more fluid and less rigid.
What are the 4 phosphatidyl compounds?
- Phosphatidylinositol
- Phosphatidylserine
- Phosphatidylethanolamine
- Phosphatidylcholine
What is the purpose of phosphatidylinositol?
Inositol is a signaling compound and does signaling by being phosphorylated 1-3 times, IP, IP2, IP3 (IP3 involved in smooth muscle).
Which of the phosphatidyl compounds is an immune marker?
Phosphatidylserine
What is the purpose of a flippase enzyme? What causes flippase to not work?
- Flippase “flips” extracellular serine back to an intracellular position.
- ATP shortages or cell death can cause this enzyme to not work.
In what system is phosphatidylethanolamine pertinent?
The nervous system.
Thought to be important for cell division and replication.
What are the two purposes of phosphatidylcholine?
- PCh is stored in the cell wall as a precursor to ACh, to be “grabbed” when needed.
- Pertinent at the neuromuscular junctions and for nerve signaling.
Does cholesterol make the cell wall more fluid?
No, it makes the cell wall more rigid.
What is sphingomyelin? Where is it pertinent?
- sphingomyelin is a myelin precursor which is important as insulation for the nerve sheath for nerve signaling.
In the AA pathway out of PGG2 and PGH2 which of the two prostaglandins comes first and which is more stable?
- PGG2 comes first (AA → COX 1 & 2 → PGG2 → PGH2)
- PGG2 is unstable and has to be converted to PGH2 to be useful.
Between COX1 and COX2, which one is related more to pain?
COX2
What converts phospholipids into arachidonic acid?
PhospholipaseA2. This enzyme can be inhibited by corticosteroids.
What component of AA metabolism is the allergy response pathway? What is the main enzyme that starts this pathway?
- Leukotriene pathway
- 5-LipoOxygenase (LOX)
Where do your Leukotriene receptor antagonists work in regards to the AA metabolism pathway?
AA → 5-LOX → 5-HPETE → LTA4
Lukast drugs work to inhibit at the LTA4 level.
Where does Aspirin inhibit the AA pathway?
At the COX1 and COX2 level.
What characteristic do all of the prostaglandin (PGH2) derivatives share? Which of the PGH2 derivatives are particularly important and why?
- All prostaglandin derivatives are proinflammatory.
- TXA2 is most important and activates coag cascade and causes vasoconstriction.
- PGI2 promotes anticoagulation and vasodilation.
- PGE2 mediates fever and pain.
What are the negative attributes of COX inhibition?
- Worsening of heart disease by inhibiting PGI2 but not TXA2. This causes increased endothelial clotting essentially.
- The kidneys are affected microvascularly in much the same way as the heart.
What organ has relevance in regards to cytochrome P450 in the AA pathway?
Liver
What is the normal serum Na+ level and what is its concentration gradient?
140-150 mEq/L and the gradient is 10:1 with most Na+ being extracellular
What is the normal serum K+ level and what is it’s concentration gradient?
Serum K+ = 4 mEq/L, and it’s concentration gradient is 1:35 favoring the ICF.
Where is Ca2+ stored intracellularly, what are the functions of Ca2+, and what is its gradient?
- Stored in ER
- Signaling compound that “turns” cell on
- Gradient is 10,000 : 1 favoring the ECF.
What is the function of Mg2+ and what should we know about its gradient?
- Antagonizes Ca2+ by competing for its receptor sites.
- More Mg2+ is present in the ICF.
What should we know about Cl- and it’s concentration gradient?
- Chloride follows Na+
- Much higher concentration outside than inside (because it follows Na+?)
What should be known about phosphate compounds (HPO4 & H2PO4-) and their gradient?
- Phosphates are used inside cell for energy (ATP) and as signaling compounds.
- More Phosphate is intracellular than extracellular
What other molecule functions in much the same way as ATP?
GTP (Guanine TriPhosphide)
What is Phosphocreatine and what should be known about it?
- Phosphocreatine is a high energy phosphorylated creatine molecule.
- Phosphocreatine replenishes ADP to ATP
- Helps in high energy activities (lifting weights, sprints, etc)
Are amino acids primarily located intracellularly or extracellularly?
Intracellularly
Is creatine located mainly intracellularly or extracellularly?
Intracellularly