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60 Cards in this Set
- Front
- Back
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What concept do I use to answer all questions about steroid hormones?
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Look for the protein made by that hormone. If I don't see the protein, work backwards and look for the RNA, DNA, etc.
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What is the only limiting factor to diffusion of fat soluble proteins across a membrane?
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Concentration gradient
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How do water soluble hormones cross a membrane?
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They don't, they must use a 2nd messenger to transport their signal
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How do I set up Fick's principle?
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Easy to get through membrane if increased/hard to get through membrane if increased
(concentration)(surface)(flux)/(charge)(size)(thickness)(reflection coefficient) |
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What is the definition of reflection coefficient?
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Amount of particles that return/Amount ofo particles I sent out
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Which two fats can we only get from our diet?
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Linolenic
Linoleic --> used to make arachidonic acid --> prostaglandins |
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How do we connect drug information to what we have learned about membranes?
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We use the half-life of the drug!
If long half-life: fat soluble If short-half-life: water soluble |
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All membranes have a resting potential of ____ except ____ and ____ which have a resting potential of ____
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-90
neurons and Purkinje cells -70 |
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The ion needed to cause cells to depolarize is ____
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Na+
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Ca++ is used for depolarization of membranes in what two locations?
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atria and thalamus
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Under physiological conditions, how do Na+ and CL- relate to each other?
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Na and Cl must always travel in the same direction!
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When a membrane depolarizes, does it become more positive or more negative?
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More positive
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What is required for All Primary Active Transport? In what direction may things be transported?
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ATPase
against a concentration gradient |
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How does Secondary Active Transport occur?
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It uses the Na+ gradient
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What is the most common second messenger?
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C-AMP
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What happens when a water soluble hormone stimulates it's receptor?
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adenylate cyclase --> cAMP -->Protein kinase A
PDE breaks down CAMP into Inosine when pathway no longer necessary |
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When are sympathetic proteins active?
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When they are phosphorylated
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When are parasympathetic proteins active?
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When they are de-phosphorylated
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Does cAMP stimulate sympathetic or parasympathetic pathways?
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cAMP stimulates sympathetic pathways at low levels and parasympathetic pathways at high levels
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What drugs are PDE inhibitors?
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caffeine and theophylline - cause increase in cAMP --> sympathetic pathways are stimulated
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Who are the "fils"? how do they work?
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Sildenafil (Viagra)
Vardenafil (Cialis) Tadalafil (Levitra) - most priapism They block the PDE that degrades cGMP thereby stimulating the parasympathetic pathway |
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What precautions should be given to patients on one of the 'fils'?
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Don't take within 24 hours of taking Niacin
Don't take within 4 hours of taking alpha1 blockers - because they also cause venodilation |
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How does IP3-DAG work?
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Protein binds to receptor--> Phospholipase C splits PIP2 into IP3 and Dag.
Dag binds calcium at the sarcoplasmic reticulum IP3 causes calciums release ---Protein kinase C |
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Which hormones use IP3-DAG? In what tissues does IP3-DAG function?
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All hypothalamic hormones except CRH
All SMOOTH MUSCLE CONTRACTION by hormone or neurotransmitter |
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In what tissues does the Ca-Calmodulin system function? What is required to stimulate Ca-Calmodulin?
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All SMOOTH MUSCLE CONTRACTION by distention only!!
4 calciums:1 calmodulin are needed for this system to function |
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What hormone uses CA++ as a 2nd messenger?
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Gastrin
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What hormones use Tyrosine kinase as a 2nd messenger?
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Insulin and all growth factors
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How does Nitric Oxide function as a 2nd messenger?
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Nitric Oxide --> Guanylate cyclase --> elevates c-GMP
Causes venodilation first |
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What molecules use Nitric Oxide as a 2nd messenger?
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Nitrates
Endotoxin ANP --> dilates renal arteries to increase blood flow |
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All cells have what phases of depolarization?
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0, 3, and 4
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What ion is responsible for Phase 0? Phase 3? Phase 4?
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0: Na+
3: K+ 4: Na+ |
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Describe depolarization of a membrane from beginning to end
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M-channel opens-->Na leaks into cell down conc gradient --> when cell reaches -60 H gate opens--> Na rushes in until membrane reaches +135 --> M gate closes b/c it is timed --> K rushes out until membrane reaches -96 --> Na/K pump restores conc grad (3 Na Out/2 K in) --> Na/Ca exchange pump restores membrane potential (3 Na in/1 Ca out)
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What drug should I use to block depolarizations of any membrane?
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Na-channel blocker
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What drug should I use to block depolarization of Atria or thalamus?
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Ca-channel blocker
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Which Na-channel blocker is attracted to ischemic tissue?
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Lidocaine - that's why we use it for ventricular arrythmias
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Extracellular Ca+ is responsible for what type of depolarization?
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Depolarization of atria
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Intracellular Ca++ is responsible for what type of depolarization?
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contraction of smooth muscle
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What part of the heart controls HR? How is it able to do so?
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SA node
It resets faster than all other parts of the heart 2/2 having the fastest Phase 4 |
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What part of the heart has the longest ARP of any heart fiber?
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AV node
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What is unique about the contraction of heart muscles? How does this translate to the tracing of depolarizing heart fibers?
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All muscles of the Atria or all muscles of the ventricle must contract at once
The Phase 2 part of depolarization is elongated in cells that depolarize earlier and shorter in cells that depolarize later |
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How can I distinguish between atrial tracings and ventricular tracings?
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Atrial tracings have a sloped Phase 0
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What is the concept that explains Absolute Refractory Period?
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Another signal may not be propagated until a threshold number of channels have been reset
Therefore, no signal may be propagated no matter how strong |
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What is the concept that explains Relative Refractory Period?
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A signal may be propagated b/c a threshold number of channels have been reset
The signal, however, must be stronger than usual and the amplitude of the response will be decreased |
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Why is K able to reach its Nernst number and other ions aren't able to reach theirs?
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Because half of K channels are regulated and half are wide open
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How can I diagnose arrythmia by pulse alone?
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A patient's maximal HR = 220-age
If pulse is even 1 greater than that number, patient has an arrythmia |
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What is pathognomonic for atrial arrythmias?
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Heart block of any kind (b/c atria keeps firing, but AV node, which controls ventricular rate, only lets signals through at a certain rate)
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Height of an EKG tracing reflects what character of the depolarization?
Width of the EKG tracing reflects what character of the depolarization? |
Height = voltage
Width = duration |
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A p wave is indicative of...
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Phase 0 of Atrial depolarization
Ca is rushing into the cells |
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A pr segment is indicative of...
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Signal moving through AV node/contraction of atria
Ca moving into cells/moving out of SR |
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a qrs segment is indicative of...
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Phase 0 Ventricular depolarization (NA moving in)
Q=signal moves through septum R = signal moves down anterior of heart S = signal moves up posterior heart |
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an st segment is indicative of...
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Ventricular contraction
Ca moving into cell/out of SR |
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a t wave is indicative of...
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Phase 3 Repolarization of Ventricles
K moving out of cell |
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a peaked t wave is indicative of...
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Hyperkalemia
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an inverted t wave is indicative of...
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Big Trouble!! Cells lrepolarizing in same way that they depolarized (anterior to posterior) --> V fib is pending
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Which coronary artery is the dominant artery in most people?
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The one that supplies the SA node - R coronary in 90% of ppl
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What parts of the heart are supplied by the R coronary artery?
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R main - back of R atrium then splits in half
R post descending - upper 2/3 of both ventricles AV nodal branch - anastomoses with LAD to supply inferior ventricles |
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What parts of the heart are supplied by the L coronary?
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Left main --> anterior and branches to give off L circumflex then continues to form LAD
Left circ - Left atrium then --> L marginal supplies lateral wall of L vent LAD - Ant wall of septum, anterior of both ventricles, feeds inf wall |
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What are 3 clues that someone is having a L coronary infarct?
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1. Sudden death
2. Heart failure (>40% of heart muscle not working) 3. Massive ventricular arrythmias |
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What are the clues that someone has had a R coronary infarct?
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1. Heart block
2. Wide P wave, widened PR segment |
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What are the four main complications of anterior wall MI?
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1. Cardiac tamponade - entire part of heart dies and sac fills with fluid
2. aneurysm 3. VSD 4. mitral valve insufficiency --> regurg |
