A&P Test 1 Flashcards
Where is cholesterol found?
In the cell wall
Is the cell wall a good place for storage?
Yes, of fatty things.
When is cholesterol fluid rather than rigid?
in low temperatures <37c
*think icecream
How much cholesterol is endogenous?
80%
How much cholesterol is exogenous?
20%
What does statins do?
Reduces the amount of cholesterol being produced by the endogenous system by interfering with the whole cholesterol synthesis pathway.
What is acetyl-CoA?
Big sugary compounds (byproducts of metabolism) that the body can take to use as a substrate to build other things, including cholesterol.
(note that the body often has similar chemical precursors for many outcomes)
How does acetyl-CoA produce ATP?
From glucose and oxygen
What is at the top of the list of things that cholesterol can be turned into?
Sex hormones
What are the sex hormones?
Estradiol E2
Testosterone
Progesterone
What is a precursor to testosterone?
Androstenedione
an·drow·stee·nuh·dee·own
What are the hormones that we talked about that come from cholesterol?
sex hormones
sex hormones precursors
stress hormones
Where are stress hormones made?
The adrenal glands
What are the stress hormones?
Aldosterone
Cortisol
Why don’t stress hormones have “distinct activity”?
They are so similar in shape that their activity isn’t relegated to one kind of receptor. The compound may have different effects on different receptors.
What is required to change a parent compound of cholesterol to a specific hormone?
Enzymes
What does Phosphatidyl refer to?
phospholipid
What are the 4 phosphatidyl compounds?
Phosphatidylinositol
Phosphatidylserine
Phosphatidylethanolamine
Phosphatidylcholine
What is the abbreviation for Phosphatidylinositol?
PI
What is the abbreviation for Phosphatidylserine?
cytosolic
What is the abbreviation for Phosphatidylethanolamine?
PE
What is the abbreviation for Phosphatidylcholine?
PCh
What to do the phosphatidyl groups play a role in?
surfactant
Besides surfactant, what can the phosphatidyl groups be involved in?
Signal transduction processes inside of the cell, or storage of something that can be used for signal transduciton.i.e.inositol is used for smooth muscle contraction
What signal transduction is PI involved in?
smooth muscle contraction
IP3
phosphatidylcholine is used to stash choline in the cell wall, and is eventually used to make _______
acetylcholine
What is Phosphatidylserine used for? How does it work?
Immune marking.
It stays on the inside of healthy cell walls.
Sometimes it can get disoriented and try to cross over to the outside of the cell wall, but typically flipase catches it and puts it back inside.
If the immune system catches it on the outside, the immune system destroys whatever it is attached to.
What keeps Phosphatidylserine inside of the cell wall?
An enzyme called Flipase
In what instance does flipase not catch Phosphatidylserine and flip it back to the inside of the cell?
In a sick cell when the cell itself is using a lot of ATP so no energy is available for Flipase to work.
What is sphingomyelin?
a fatty compound found within the cell wall that is used to create myelin in the nervous system.
What are the precursors found within the cell membrane?
Polyunsaturated fats/lipids
arachidonic acid AA
Phosphatidylinositol
Phosphatidylserine
Phosphatidylethanolamine
Phosphatidylcholine
sphingomyelin
cholesterol
What is an example of a polyunsaturated fat?
arachidonic acids
What is arachidonic acid a parent compound to?
prostaglandins
Name the prostaglandins
PGG2
PGH2
PGE2
PGI2
PGF2alpha
What does TXA2 do?
It mediates the healing of a vessel injury by causing vasospasms. They are released when you injury a blood vessel along with the clotting cascade.
What are the enzymes called that work on the prostaglandin pathway of arachidonic acid?
COX1 and COX2
What do prostaglandins do in the body?
They increase sensitivity to pain
How do we as clinicians reduce pain?
Through the inhibition of the enzymes COX1 and COX2 which then decrease the amount of prostaglandins in the body and therefore reduces sensitivity to pain.
What does COX1 and COX2 do to arachidonic acid?
It catalyzes two chemical reactions to turn arachidonic acid into the precursors pGG2 which turns into PGH2
what does PG(insert letter)2 synthase do?
it is the enzyme that turns PGH2 into one of the other prostaglandins.
What is the difference between COX1 and COX2?
COX1- widespread in the body
COX2- Turned on in response to painful stimuli
What is cyclooxygenase?
The enzymes COX1 and COX2
What is an example of a drug that inhibited COX2?
Vioxx
Which of the 2 COX’s is more useful in treating pain?
COX2
Is COX2 only found where pain is?
No, it also is found in the heart and kidneys.
Why was Vioxx taken off the market?
A bunch of people were having cardiovascular events.
(70-80yr olds finally getting off the couch and being active = increase in cardiovascular events)
What is an example of an OTC COX2 drug
Naproxen
Delete
Me
Why does aspirin make you bleed?
It blocks COX1 which therefore inhibits the production of TXA2
What drugs effect the COX1 pathway?
Aspirin
NSAIDS
Tylenol
Tylenol targets
Neurons
What is the prostaglandin pathway from arachidonic acid?
arachidonic acid
cox1 cox2
PGG2
cox1 cox2
PGH2
PGE2 PGI2 PGFalpha2 TXA2
What is the leukotriene pathway from arachidonic acid?
arachidonic acid
5-lipo oxygenase
LTA4
LTC4
LTD4
LTE4
Which pathway is an important effector of our immune response?
The Leukotriene arm
(think leukocytes)
What does LT stand for?
Leukotriene
What are the inflammatory mediators that we’re studying?
LTC4
LTD4
LTE4
what is a leukotriene receptor antagonist example?
Singulair
What are lipoxegenases?
The enzymes that drive the leukotriene arm of the arachidonic pathway.
Takes arachidonic acid and turns it into Leukotrienes
How long do HETE’s and EET’s last?
not long, very short lived.
Are HETE’s and EET’s big or small?
They are really large fatty compounds.
What are HETE’s and EET’s involved in?
Acute renal failure and other acute inflammatory disease processes.
What does the third arm of the arachidonic pathway do?
produces the HETE an EET compounds
Why are HETE’s and EET’s difficult to manipulate?
They are unstable and short lived
Where are Leukotrienes and prostaglandins okay to hang out?
In the water content on the inside of the cell.
Because they are so distinct, just little pieces from arachidonic acid, they don’t look like a big fatty compound anymore.
Where are HETE’s and EET’s found?
Inside of the cell wall. They don’t change much from arachidonic acid so they still have big fatty characteristics.
What aids in chemical messages getting from the outside of the cell into the cell?
proteins in the cell wall
What moves across the cell wall very easily without needing any kind of pore, channel or pump?
Gas
What is simple diffusion?
When something i.e. gas, can move across the cell wall very easily and doesn’t require energy. Usually following the concentration gradient and/or electrical gradient.
Are proteins used in simple diffusion?
Sometimes. Gas doesn’t need them, but ions use proteins channels. (like a hallway from the EFC to ICF where the proteins make up the walls)
Are resting cells net negative or net positive?
net Negative
Are active cells net negative or net positive?
net positive
What type of diffusion utilized a carrier protein but doesn’t require energy?
Facilitated diffusion
Describe facilitated diffusion
Net movement down a concentration diffusion by the protein binding to a compound, a confirmation change happening, and then the release of the compound on the inside of the cell.
i.e. Glut-4 transporter
Does water have issues getting into and out of the cell wall?
No. Water sneaks in through the electrolyte channels in the cell wall, or goes through water dedicated channels called AQP (aqua porin)
Why are pumps needed?
To move compounds across the cell wall that don’t want to go there.
What does the Na+/K+ pump use to create energy?
ATP. it is a ATPase pump
Describe how the Na+/K+ pump works.
The pump pulls an ATP from the inside of the cell and rips a phosphate off of it. Turning ATP into ADP. This generates energy. The energy that’s formed is used to shift 3 Na+ ions out and 2K+ in
How many Na+ ions are moved, and in what direction with the Na+/K+ pump?
3 ions are moved out of the cell
How many K+ ions are moved, and in what direction with the Na+/K+ pump?
2 ions are moved inside of the cell
Almost all of the other gradients are somehow linked to which pump in the body?
Na+/K+ pump
In a cell that doesn’t do a lot of work other than just sending messages, the energy requirement of the Na+/K+ pump is how much of the energy in that type of cell? What is an example of this type of cell?
60-70%
a neuron
What is the single most energy requiring process within the body, providing that we’re not running a marathon?
the Na+/K+ pump
What is a pump called that metabolizes ATP?
Primary active transport, or 1st degree active transport.
Describe how the ca++ pump works.
Ca++ is moved inside of the cell to “Turn it on” and therefore has to be pumped back out to “turn is back off”. The Ca++ pump burns ATP to pump the used Ca++ back out of the cell.
Describe how a Proton pump or acid pump works.
The cell creates acid and the acid pump burns ATP to move it across the cell wall into the ECF.
What are 3 examples of primary active transport?
Na+/K+ pump
Ca++ pump
Proton or Acid pump
If you have more Ca++ inside of the cell than the Ca++ pump can handle, what kicks in to get Ca++ out?
Na+/Ca++ exchanger
NCX
What does the Na+/Ca++ exchanger rely on instead of ATP to make the “pump” work?
The electrical gradient of Na+. Set up by the Na+/K+ pump.
How many Na+ ions are exchanged for Ca++ ions in the Na+/Ca++ exchanger?
3 Na+ moving into the cell for 1 Ca++ moving out (like a turn style)
What is are examples of secondary active transports?
Na+/Ca++ exchanger, Sodium glucose transporter SGLT
Muscle cells primarily use which “pump” to get Ca++ outside of the cell?
Na+/Ca++ exchanger
How do we move glucose into the cell faster?
By coupling glucose with sodium movement.
What percentage of glucose movement across the cell wall happens by something grabbing it from the cell wall, it undergoing a confirmation, and then being released on the inside of the cell?
98%
Why doesn’t glucose use the electron channels/pumps or simple diffusion to get into the cell?
It’s too large and charged
Is energy required to move glucose into the cell via the Glut-4 Transporter?
What is required?
No. (Acts like a like a gear. Glucose pushes on one end and the gear turns into the cell, no electricity needed)
Insulin! They are insulin dependent
How does insulin effect the glut-4 transporter?
Insulin is the signal that tells the cell to move the glut-4 transporter to the wall. More insulin=more transporters=more glucose that can be moved into the cell.
The net movement of a compound via facilitated diffusion depends on what 2 things?
The number of transporters available at the cell wall
The concentration gradient (how bad is the destination lacking the compound being moved?)
What does the glut-1 transport system do?
They supply glucose to red blood cells.
Non-insulin dependent
What is an example of facilitated diffusion?
Glut transporters
