Most accurate and best test used to check for Zollinger Elison syndrome?
Secretin test....Administer secretin and see if the gastrin levels drop
Increased GI motility is an increase in...
FORCE of contractility, not frequency
Poorly controlled diabetic comes down with bloating and postprandial fullness. What is the mechanism of the defect?
Nerve damage to Vagus! It does not sense the stretch, no ACh is released, no GASTRIN is released so stomach motility does not increase.
Treatment for Diabetic Gastroparesis?
Metoclopramide (REGLAN) which increases GI motility
and
Erythromycin... leads to N/V and Diarrhea in normal people, FIXES the problem in DG
What leaves the stomach the fastest?
Normal saline>liquids> CHO>Protein> Fat
What is the cause of Irritable bowel syndrome?
Increased activity of the migrating motility complex of the gut...caused by hyperactivity of motilin
Migrating Myoelectric complex is stopped by....
Meals!
Where is the CHLORIDE pump in the body?
Salivary glands! Pumps Cl- out, Na follows but H2O cannot so it creates a hypotonic saliva
What is the only HYPOtonic GI secretion?
Saliva
What is the only part of the body that is STIMULATED by both parasympathetic and sympathetic activity?
Salivary glands! Parasympathetic, watery
Sympathetic, thick and mucinous.
What goes IN to the saliva??
Bicarb to neutralize acid
IgA...neutralizes infections
Digestive components of Saliva?
Amylase and Lipase... NOT NECESSARY FOR LIFE but allows you to TASTE food. Tofu, no taste! No protein digesting enzymes in the mouth to allow for it
Oral complication of Sjogren's syndrome?
Loss of teeth! Antibodies against salivary glands, so there is no Bicarb secreted to neutralize acid in the mouth.
Is Pepsin in the stomach essential for life?
NO
Is Salivary amylase and lipase essential for life?
NO
Is Pancreatic amylase and lipase essential for life?
YES
What is the only thing in the stomach NECESSARY for life?
Intrinsic factor
What are three stimulants for the parietal cells of the stomach and what inhibits them?
Vagal stimulation (ACh)
Gastrin
Histamine....Histamine potentiates the other two.
... Somatostatin inhibits the parietal cells.
Where is the blood with the HIGHEST pH in the body?
The venous blood leaving the stomach... CO2 from the blood combines with H2O in the GI cells...H+ goes into the lumen and bicarb enters the venous blood forming the ALKALINE TIDE
What is the function of enterokinase?
On the brush border of the duodenum, it cleaves trypsinogen to trypsen, which goes on to activate other prohormones
What is the MOA of pancreatitis?
Premature activation of trypsinogen inside the pancreas
What are two bile ACIDS??
Cholic ACID
and
Chenodeoxycholic ACID.. both are lipid soluble
What are the bile salts?
Taurocholic and Glycocholic acids... Have been conjugated with sugars, taurine and glycine, to make them water soluble.
The concentration of WHAT will decrease over time within the gall bladder?
EVERYTHING except bile salts
Where within the body are bile salts reabsorbed?
In the terminal ileum, along with B12.... Resection leads to fat malabsorption and loss of vits ADEK, hypocalcemia osteoporosis, rickets!
Where is folate reabsorbed in the body?
Jejunum...bicarb absorption occurs here too.
Where is iron absorbed in the body?
Duodenum as Fe++...also Ca++ and Mg++ are absorbed here
Greatest water absorbing section of the GI tract?
The colon...SECRETES POTASSIUM and bicarb
What components of the GI digestive enzymes are essential for life?
LIPASE..need it to break down fat....
BILE need it to absorb fat...
AMYLASE
TRYPSIN...Activates all the other protein digesting enzymes
The dipeptidases SUCRASE or LACTASE or MALTASE... deficiency in one won't kill u .
For absorption in the small intestine, everything needs to be co-transported with Na+ EXCEPT???
Fructose! ... Facilitated diffusion by GLUT 5 transporter on the lumen side...GLUT-2 on the blood side
How are glucose and galactose taken up in the small intestine?
Using Na+ cotransport using SGLT1.... Get transported thru the blood side via GLUT-2
What is the rate limiting step of Carbohydrate absorption in the Small intestine?
Oligosaccharide hydrolases that cleave oligo and disaccharides to monosaccharides.
Where is Pancreatic amylase found with the greatest concentration?
In the duodenal lumen
Does insulin affect the absorption of Glucose from the lumen of the gut into the bloodstream? (Does it affect the secondary active transport of Glucose??)
NO**
Major difference between Celiac disease and chronic pancreatitis???
Both give fat malabsorption but IRON ABSORPTION is not affected by chronic pancreatitis
What kind of acid/base imbalance is created by diarrhea??
Metabolic acidosis because the colon secretes BICARB... BUT YOU GET LOW POTASSIUM!!!! unlike in other cases where you get a transcellular shift.
Why is the anion gap NORMAL in diarrhea?
The bicarb goes down, but the Cl- goes up as it is reabsorbed and maintains the gap
What is the normal extracellular osmolarity?
300mOsm/L...
What is the TF:P ratio?
The tubular fluid to plasma ratio..Normally this is 1.0. This means that the concentration in Bowman's space is the same as in the plasma, indicating that it is freely filtered.
The concentration of ANY fluid substance in Bowman's Space will have what TF:P ratio?
1.0.....
What is true if ANY answer on the USMLE says a substance has a TF:P ratio greater than 1.0 in Bowman's space?
It is a distractor, this cannot happen
What normally happens to the Filtration Fraction in the kidney if the flow goes down?
The fraction goes UP
What is the dominant effect of Sympathetics on the kidney?
Vasoconstriction, primarily of the afferent arteriole....This decreases GFR, slowing down flow and leading to an increased filtration fraction
What are the effects of sympathetic stimulation on the kidney in the peritubular capillaries?
Afferent arteriole is constricted, slows down flow...more filtration occurs so a greater proportion of the blood in the peritubular capillaries is plasma protein... Leads to an increased ability to reabsorb.
Is there parasympathetic stimulation on the Kidney?
NO
What is the primary effect of ANG II on the kidney??
Constricts the efferent arteriole...Increases GFR....
What are the effects of ACE inhibitors and ARBs on GFR?
They decrease them, as they lead to the loss of ANG II from the body.
What is the difference between GFR and filtered load?
GFR is the rate at which fluid is filtered into Bowman's space!
Filtered load is the rate at which a SUBSTANCE is filtered into BC, usually in mg/min
What is the result of pregnancy on GFR??
It increases it!! Leads to an increased glucose concentration, leading to an increased Filtered load of glucose, so more is spilled into the urine as the transporters are saturated sooner.
What is the GOLD standard for measuring GFR?
INULIN, but it is costly and impractical so Creatinine is used instead..... These are freely filtered and not reabsorbed.
What is an increased plasma creatinine level indicative of??
Decreased GFR
What is true of Nephrotic syndrome and its relation of GFR?
GFR will go DOWN as there is a decrease in surface area available for filtration.
What is the Transport maximum for kidneys?
The transport rate of a substance at which all the carriers are saturated.
What happens to the transport maximum if you remove a kidney?
It is cut in half! There is NO compensatory increase in carriers by the other kidney.
What is the plasma THRESHOLD of a substance?
The plasma concentration, usually of glucose, at which splay begins and glucose appears in the urine.
What is the relationship between urea and water??
Urea tends to follow water, so if you increase water excretion urea goes with it... it is flow dependent.
Where is MOST OF THE O2 used up in the kidneys?
In the PCT in attempts to reabsorp up to 2/3 of the filtered sodium! This is the main metabolic activity of the kidney to GFR determines the metabolic activity of the kidney
What substance is used to measure Renal Plasma Flow?
PAH! It is filtered and under normal circumstances fully secreted.
What is true if the level of PAH is increased drastically?
This saturates the transporters to the point that the amount SECRETED is insignificant and PAH will then measure only GFR instead of RPF... Common USMLE question when an overzealous med student overinfuses a patient during experiment.
A substance is freely filtered and not transported at all by the kidney.... what is the substance?
Inulin
Mannitol
or
Sucrose... all have a filtered load that is equal to its excretion rate.
What is the reabsorption rate in the kidney equal to?
Filtered load - excreted
A substance is freely filtered and is secreted by the kidney...what is the most likely substance?
PAH! As long as it is at normal or moderate levels
Creatinine*** Only minor amount is secreted, so the answer would be a touch about the filtered load.
What is true of Urea in relation to the PCT?
It is normally partially reabsorbed.
What is true of your urine concentration if you have a free water clearance that is positive?
You are forming a hypotonic urine
What is Type II Renal Tubule Acidosis?
A metabolic acidosis caused by the breakdown of HCO3- recovery and H+ secretion in the kidney at the level of the PCT.....Leads to acidic urine
IF they ask where most anything is reabsorbed maximally in the kidney, say...
PCT if unsure... ADH activity is maximally increased, at what point in the kidney is water mostly reabsorbed..still the PCT
What is the point in the kidney at which INULIN would be at its lowest concentration??
Bowman's Space... Water is reabsorbed after this causing its fraction to be increased.
What is the point in the kidney at which INULIN would be at its greatest concentration?
The Collecting Duct.
They say the INULIN TF:P ratio is 1.0 in Bowmans and is STILL 1.0 at the end of the PCT, what does this mean and what could have caused it??
NO WATER was reabsorbed....This means that NOTHING was reabsorbed... The only thing that could cause this is complete inactivity of the Na+/K+ ATPase.
What happens to the kidney if the PCT fails to reabsorb all that it is supposed to??
The segments downstream are overloaded and the kidney begins to fail.... ADH cannot form a concentrated urine and DI occurs.
What is the point of greatest osmolarity at any point of the kidney tubule?
The TIP of the bottom of the LoH....
What point besides the tip of the bottom of the LoH can have the same (greatest) osmolality of the kidney?
The end of the CD in the presence of the maximum effect of ADH.
What is the Descending LoH permeable to?
H2O!! The osmolality in the interstitial space surrounding the Loop increases the deeper it goes, so water is constantly sucked out.
What ascending LoH is impermeable to...
Water! This is the only section of the kidney where osmolality dramatically decreases because solutes can still leave but water can't follow.
What section of the kidney tubule has the lowest osmolality?
The beginning of the DCT!....End of LoH if this is not an option.
Where are the Na+/K+ ATPase pumps located in the Distal tubule and CD, which are basically the same thing?
In the basement membrane... This pumping is what allows for the entry of Na+ thru the ENaC channels into the cells.
Function of Late DCT Principle cells?
Bring in Na+ thru ENaC channels
K+ is pumped out thru these cells
ADH via V2 receptors has action here to insert aquaporin channels
What is the function of the late DCT Intercalated cells?
These kick out the H+ ions that have been exchanged for Na+. These combine with HPO3 to form H2PO3, excreted as dihydrogen phosphate.
NH3 can also combine with the H+ here to neutralized it an is excreted as NH4+
Bicarb is also reabsorbed into the interst
Action of Aldosterone on the DCT?
Inserts ENaC channels in the lumenal side of Principle cells
What is important to know about the bicarb that enters the blood from the intercalated cells of the DCT??
It is BRAND NEWLY FORMED
What is RTA I?
When H+ ions cannot be pumped from the intercalated cells into the lumen...This leads to no Bicarb being placed into the interstitium and thus metabolic acidosis.
The urine will have an increased pH as H+ was not pumped into it.
What are two things that can place K+ into cells?
Insulin and Catecholamines!
Beta blockers therefore can cause a hyperkalemia
What is the effect of acidosis on the potassium handling of the body?
H+ must go into cells, so K+ comes out of cells and can lead to hyperkalemia..
ALSO
More bicarb must be made in the intercalated cells, so more H+ is pumped from the cell into the lumen, which means less K+ is pumped....Hyperkalemia
What is the acid based status of someone with Diarrhea??
Metabolic acidosis!! Bicarb and K+ are flushed from the body, so H+ increases. K+ decreases, so ACIDOSIS AND HYPOkalemia! Very strange
Normal anion gap because chloride is reabsorbed as Bicarb is secreted.
What must be true if on an acid-base disorder the CO2 and the bicarb move in opposite directions??
There is a mixed alkalosis, or more likely, mixed acidosis.
What are two causes of a normal anion gap metabolic acidosis?
Diarrhea
and
RTA
Which compensation takes longer, Renal or Pulmonary in acid base disturbances??
Renal
What component of breathing normally lasts longer, inspiration or expiration?
Expiration
What happens to the ventilatory rate of someone 4 weeks after moving to altitude, so they have had some time to acclimate??
STILL INCREASED... The Patm is still down so PaO2 is still down and Hb saturation is still down....breathing must be maintained at an increased level by the peripheral chemoreceptors
What is Caisson's disease?
The Bends! N2, which is 78 percent of the air we breathe, gets dissolved in blood due to increased pressure, and if that pressure is decreased too rapidly the N2 bubbles out into solution and acts as an air embolus.
Moving toward the apex of the lung is like what physiological phenomenon?
Dead space! There is extra air in the apex of the lung and it cannot be used for metabolism as the blood supply is not sufficient.
Moving toward the base of the lung is like what physiological pheonmenon?
Atelectasis, or a shunt! There is more blood available than can be oxygenated...
A PDA connects...
The aorta to the Pulmonary ARTERY
What is the most susceptible region of the kidney to ischemia?
The medulla...there is extremely low blood flow as it must move slowly.
What is the normal GFR?
120 mls/min
What happens to GFR if you lose half of your functioning nephrons, say to kidney donation?
You lost 25% of your GFR ultimately, as the other individual nephrons vasoconstrict to increase their own GFR.
What is the MAIN factor determining GFR?
Hydrostatic pressure
What is the effect of normal saline infusion on GFR??
It increases GFR as you have diluted the plasma protein concentration so there are less forces promoting reabsorption... Leads to saline induced diuresis after overwhelming PCT reabsorptive capacity.
What is the underlying mechanism behind post-renal failure?
Increasing hydrostatic pressure in Bowman's space leads to inability to filter at the capillary bed...Decreased GFR.
What is the number one way CO2 is transported in the body from tissues to the lungs?
As bicarbonate dissolved in PLASMA
What is the Chloride shift??
Movement of Cl- ions into RBCs from Plasma in exchange for the bicarb ion! Can lead to acidosis
Where are Central Chemoreceptors located and what do they monitor?
Located in the Medulla!
Monitor CO2 primarily and H+ ions...These receptors are normally the primary drive for alveolar ventilation
When do the peripheral chemoreceptors become the primary drive to breathe?
Where are they located and what do they measure?
When the PaO2 drops below 80% or the FO2 is less than 17%.
Located in the carotid sinus and Aortic Arch
Monitor ARTERIAL O2**
Why do patients with meningitis hyperventilate?
The increased amount of H+ ions formed by the infection stimulate Central Chemoreceptors
What happens to chemoreceptors on Morphine OD?
Increased PCO2 attempts to stimulate the central receptors but they are knocked out from Morphine so the Peripheral receptors take over based on low O2...DONT GIVE THIS PATIENT FULL O2 or they will stop breathing.
A normal person breathing room air is switched to a mask respirator breathing 21% O2...What are the changes to ventilation and what receptors play a role?
NO changes...this 21% is normal...
Central receptors are in charge in normal circumstances
A normal person is breathing room air, then switched to a mask breathing 100% O2 for 15 minutes... What is the ventilatory change and what receptors are responsible?
NO CHANGE! This is now FAR ABOVE NORMAL so no need to change respiration.
Central receptors are still in charge.
A normal person is breathing room air, then are switched to a mask breathing 3% CO2 and 15% O2! What are the ventilatory changes and what receptors are responsible??
INCREASED VENTILATION!
Peripheral receptors are in charge now because the FO2 is below 17%.
Rank the following WRT their affinity for O2: CO, CO2, O2.
CO> CO2> O2
Which gas is best indicated to measure the diffusion capacity of the lung?
CO! It is the most soluble and depends ONLY on the structural features of the lung. It is DIFFUSION limited, because the second it moves into the bloodstream it is bound to Hb and this its partial pressure is 0
What is the normal Venous PO2 concentration?
40 mmHg
What is the normal venous concentration of PCO2?
47 mmHG
What is the normal O2 content of blood?
20% by volume or 20 mL per 100 mL of blood
Where is most of the O2 in blood?
Bound to Hb...only .3 percent is dissolved in blood.
Does anemia effect the PaO2 of blood?
NO! you are NOT affecting that which is dissolved in plasma, and this is what the partial pressure is measuring!
It will, however, decrease Hb, decrease O2 carried by Hb and decrease O2 CONTENT!
What is PRELOAD??
Venous return..... leads to increased myocardial stretch.
What is the best way to measure preload?
End Diastolic Volume, measured by an echocardiogram
What is a normal EDV for the heart?
120 mL
What are two types of drugs that can be given to treat increased preload problems?
Diuretics
and
Dilators
What are 4 benefits of positive inotropes like Digoxin?
Increases the slope of depolarization as pressure develops faster
There is a higher peak of ventricular pressure
The rate of relaxation is faster
A shorter systole ensues, leading to decreased O2 demand.
This also allows for more coronary blood flow in di
Which axons are more conductive, Thin or Thick?
Thicker
IPSPs are caused by...
Increased Cl- conduction into the cell, hyperpolarizing it.
What type of Calcium channels are seen in the ventricular AP
L-type
What is the PR interval?
The time it takes to get thru the AV node...The beginning of P to the beginning of Q... if this is increased it can lead to heart block.
What does the QRS represent?
Ventricular depolarization.. Should be less than .12 seconds
What is an increased QT interval indicative of?
It means an arrhythmia problem is likely to be on your doorstep.
From where to where is the ST segment measure and what does it indicate?
From the end of the QRS to the beginning of T! Indicates ischemia.
How can you tell from an ECG if someone has 1st degree heart block??
The PR interval is greater than 200 ms
How can you tell from and ECG if someone has a Mobitzt I second degree heart block?
IF the PR interval increase, increases, increases until a beat is dropped.
How can you tell from an ECG if someone has a Mobitz II second degree heart block?
PR is not ever increased and then suddenly a beat is dropped.
Treatment for a 3rd degree Heart block??
Atropine and a pacemaker
What does the sarcolemma surround?
A myofibril
Bradycardia, cannon waves and syncope are signs of....
A third degree heart block!
In what two places is ATP needed during skeletal muscle excitation contraction coupling?
It is needed to get the muscle to actually MOVE and needed to remove the myosin head from actin
What are the four drugs that can be given to CHF patients that decrease morbidity and mortality?
Beta blockers
ACE-Is
ARBs
Spironolactone or Eplerenone!
ALL decrease the RAAS and lead to a decreased afterload by blocking Renin.
Where are T-tubles located on the skeletal muscle?
At the A-I band junction
Actin is covered by....
Tropomyosin
What binds Troponin to get it to pull tropomyosin off of actin?
Ca++ ions!
What is Plasma?
Blood minus the cells
What is Serum?
Plasma minus the clotting factors
What body volume is affected by loss or gain of blood volume?
ECF volume
Loss of a hypotonic solution, say in the event of Sweating or excreting a hypotonic solution, leads to...
Fluid moving from the ICF to the ECF to compensate, plus now both compartments have a higher concentration.
What will taking Na+ tablets do to the ICF or ECF volumes in your body?
Will make the ECF volume go UP
How do you measure the vascular space volume only?
With Tagged albumin
What can be used to measure the ECF volume... It must be permeable to capillary membranes but not CELL membranes!
Inulin... not secreted or reabsorbed.
What can be used to measure Total body water? Must be permeable to capillary membranes and all cell membranes?
Urea or Tritiated water
What disease can cause retention of Na+ and H2O by the kidney, due to decreased blood flow to the kidney?
CirrhoticS
NephroticS
CHF
What is a normal function of the oncotic pressure in the interstitial spaces within the lungs??
Draws any water from the alveoli to keep them dry and places it within the lymphatic channels... A raise in hydrostatic pressure and edema will occur when this mechanism is saturated.
What has occurred if it looks like the patient has CHF but the capillary wedge pressure (LA pressure) is normal??
ARDS, SEPSIS, burns, something....whatever the case you damaged the lining of the lungs leading to edema
What is the major controller of the resting membrane potential of cells?
K+....K+ channels are usually open so it can go out.
Characteristics of Action Potentials??
They are propagated without change in magnitude and are all or none!...
SUB threshold stimulations exhibit summation
What part of the arterial/venous system has the largest cross secional area?
Capillaries
What part of the arterial/venous system has the smallest cross sectional area?
Aorta
What part of the arterial/venous system has the greatest pressure drop?
Arterioles
What part of the arterial /venous system has the largest volume of blood?
The veins, which has more than the pulmonary circulation. Both are highly compliant
If you occlude a vessel by 50% by how much does the resistance go up?
16 times... Resistance = (viscosity x length)/ Radius^4
What is Reynold's number?
Diameter times velocity times elasticity, all divided by Viscosity! Most important aspect is to know that If it is greater than 2000 there is turbulent flow and if it is less than 2000 there is laminar flow.
What is the Total resistance equal to in a pipeline system set up in SERIES?
Rt= R1 + R2 + R3....+Rn...The total is always greater than the individual resistances...Flow is said to be DEPENDENT
What is the Total resistance equal to in a pipeline system set up in PARALLEL?
1/Rt= 1/R1 +1/R2 +1/R3.... The total is LESS than the value of any one resistance AND flow is said to be INDEPENDENT.
What is the effect of removing an organ, say the kidney, in a system of arteries set up in parallel??
Removing a resistor INCREASES resistance! Because 1/Rt= the sum of 1/R1 +1/R2 etc...
What will happen to Resistance, Flow, CO and HR in a system set up in parallel where a resistor is removed? (Like removing a kidney...)
Resistance INCREASES
Flow decreases
CO decreases
HR decreases
Elasticity is inversely proportional to...
Compliance
What is the main cause of DIASTOLIC blood pressure??
Comes from TPR, the resistance of the vessel itself.
What is true of measured diastolic pressure in a pt with stiff vessels due to atherosclerosis?
The diastolic pressure will be MEASURED lower than it really is....The sound is still heard as blood rushes past non-compliant vessels. True diastolic remains the same.
What is the main determinant of Systolic BP?
Stroke Volume
What are two things the MAP is equal to?
MAP = CO X TPR
MAP = Diastolic + 1/3 Pulse Pressure
Which vessel has the highest MAP in a standing person??
Will always be the LOWEST ARTERY...as gravity adds 80 mmHg in a vessel
What nerve carries information from the carotid sinus to the medulla?
The glossopharyngeal
What nerve carries information from the aortic arch to the medulla?
The Vagus
What are three organs that autoregulate blood flow and What is the chemical mediator in each organ??
Cerebral blood flow: Mediated by PaCO2
Coronary blood flow: Mediated by NO and Adenosine
EXERCISING muscle flow: Mediated by lactic acid
What will happen to cerebral blood flow based on autoregulation during exercise?
NOTHING it will remain the same..
O2 use increases, so CO2 increases, thus Breathing increases and CO2 is decreased...there is no change.
What are the changes to MAP during exercise??
MAP = CO + TPR....TPR will decrease as lactic acid vasodilates... CO is measured by HR times SV and HR goes up... SO...MAP remains the same but Systolic goes up and Diastolic goes down.
What is occurring if there is a high A-V difference in O2 within an organ?
It means there is LARGE extraction of O2, think the heart... This means low flow
What is the effect of exercise on lung PRESSURE?
Nothing, the lungs are highly compliant
What valvular event best correlates with the T-wave on an EKG?
Closure of the Aortic valve, A2
The QT interval coincides with...
The ventricular ejection! Aortic valve opening
What valvular event does the QRS complex coincide with?
Closure of the Mitral valve and the S1 sound
What makes an S3 heart sound?
Rapid filling into a dilated ventricle that is fluid overloaded...
Can be seen in children and young adults without being pathological
What makes the S4 heart sound?
Atrial contraction against a stiff ventricle....Caused by concentric hypertrophy or a previous MI
What is a typical tidal volume and what does it represent?
About 500 mLs... the measure of an normal inspiration.
What is the FRC?
Functional residual capacity... The portion of air that remains in the lungs after a normal expiration
What is the VC?
Vital Capacity! The amount that can be EXPIRED!
What is IC, the inspiratory capacity?
The amount that can be inhaled maximally after a normal exhalation.
Total lung capacity equals....
VC + RV
or
FRC+ IC
What is the result of shallow breathing???
Leads to use ONLY of the dead space, so the patient will become acidotic.
What is the total ventilation equal to??
Respiratory Rate times Tidal Volume
What is the alveolar ventilation equal to??
(Tidal Volume-Dead Space) times Respiratory Rate.
At the end of inspiration what should NOT be seen in the conducting zone breathing Atmospheric Air?
CO2! There is no CO2 in ATMOSPHERIC air
At the end of expiration what gas is LEAST likely to be found in the conducting zone?
CO2
When is the GREATEST flow of air into the alveolus??
MID inspiration when the pressure gradient is the greatest!! The intrapleural pressure goes from -5 to-8 and the pressure inside the alveolus goes from 0-->-1.
What is the definition of a restrictive lung disease?
The INABILITY to develop a negative intra-alveolar pressure
At the end of inspiration, what is the intra-alveolar pressure??
0! (or atmospheric pressure) The ATM has flowed inward as a result of the pressure difference
What is the lung volume when the Intrapleural pressure is -5 and the recoil force of the lung is 5?
Functional Residual Capacity
What is the partial pressure of a gas?
The fraction of that gas in the air times the atmospheric pressure
Which gas diffuses fastest across a capillary wall, O2 or CO2??
CO2 because even tho O2 has the greatest pressure difference CO2 is FAR more soluble!... CO is even MORE soluble
What is the definition of Obstructive Respiratory disease?
Any disease that decreases the Ability to develop a Positive intrapleural pressure... Think Emphysema, COPDs, Asthma...There is no elasticity.
What occurs at the beginning, middle and end of the Valsalva maneuver WRT BP and HR?
Beginning: Blood pressure drops as a deep breath is taken and blood pools in the lungs...Increases HR
Middle! Contraction of the intraabdominal muscles forces blood from the lungs to the LA! Increases BP and decreases HR.
END! Ultimately the decrease in b
What is PEEP used and why?
It is used in atelectasis or COPD to provide the Positive Pressure in the alveolus that the patient themselves cannot provide
What does LaPlace say about large and small alveoli?
Pressure in inversely proportional to volume, so low volume alveoli have high pressure. This forces air from small alveoli to large ones, collapsing the small ones and without surfactant the larger ones would collapse too!
3 Benefits of Surfactant!?
Decreases surface tension thus increasing compliance and allows alveoli to be filled.
Opposed the LaPlace effect collapsing small alveoli
DECREASES capillary filtration force
When does RDS occur?
When the Lecithin to Sphingomyelin ratio drops below 2:1.
The increased surface tension leads to a decreased compliance and atelectasis.
Inspiratory problems
Pulmonary edemia due to increased capillary filtration pressure
What does DHT help form in the FETUS?
The PPS, penis, prostate and scrotum
What is testicular feminization AKA?
Testosterone Insensitivity
What are the sexual structure abnormalities in Testosterone or Androgen insensitivity syndrome?
NO SEED because no testosterone
NO PPS because no testosterone means no DHT
MIF secreted by the testicles blocks the formation of fallopian tubes, uterus and upper 1/3 of vagina including the cervix.
What hormonal changes will undescended testes cause?
Increased LH because of little testosterone..
Increased FSH because the sertoli cells do not form INHIBIT to negatively feedback
Number one cause of ED?
Anxiety post MI
Number one drug cause of ED?
Beta blockers, esp given post MI
A pt Post MI is on beta blockers and is experiencing ED...They go on Sildenfil to solve the problem WHAT DRUG MUST ALSO BE STOPPED?
NTG...DONT want to double vasodilate.
Decreased FSH, Decreased LH and Anosmia are characteristic of....
Kallmans syndrome
What are the findings associated with Kallmans Syndrome?
Decreased FSH
Decreased LH
Anosmia
What hormonal changes are seen in Kleinfelter's patients?
Increased FSH and LH with no effect, sort of like male menopause.
What type of drug is Goserelin?
A GnRH agonist
What are the findings hormonally in a patient that is post menopausal?
Increased FSH
Increased LH with
Decreased sex hormones
What is characteristic of the follicular phase of the menstrual cycle?
Increased Estrogen
Endometrial hyperplasia
Thin Cervical Mucus
What is characteristic of the Luteal phase of the cell cycle?
Progesterone is the main hormone increased
LH surge causes it
It is FIXED in length, 14 days
What stimulates Thecal cells and what do they end up producing?
LH! Testosterone
What stimulates Granulosa cells that what do they end up producing?
FSH! Estrogen via aromatase
Which cells, Granulosa or Thecal cells does estrogen inhibit more while it is in its inhibitory state?
Granulosa cells, FSH receptors because you do not want to promote more than 1 follicle
What signifies the 1st day of the ovarian cycle?
BLEEDING!
What is responsible for the LH surge
At some point in the cycle, estrogen begins to have a positive feedback effect, leading to increased FSH and LH until BAM
What happens to the granulosa and thecal cells under the watchful hand of Estrogen when it is in positive feedback mode?
They both begin to produce LH receptors and together form the Corpus Luteum
What forms the progesterone needed to support the endometrial lining in the first part of pregnancy?
The Corpus Luteum! Good for the 1st 1/3 of the pregnancy
What is the function of the progesterone secreted by the CL?
Thickens cervical mucus
MAKES YOU HOT
STIMULATES APPETITE...Can be used in the treatment of wasting/cachexia
What is the effect of Progesterone from the CL on hormones?
It suppresses LH production...If no fertilization occurs the CL is not saved by the B-hCG of the syncytiotrophoblast and it dies off, Progesterone and Estrogen decrease and FSH and LH rise again!
What are the identifying characteristics of someone with Pseudohyperparathyroidism?
SHORT 4th digit
A Round Head...
The Main cause is that the tissues are resistant to PTH
What is the effect of dexamethasone on T4?
Prevents its peripheral conversion to T3
What is the main difference between T3 and rT3?
Where the one iodine was clipped off of T4...rT3 is metabolically inactive
What are the only three places in the body where metabolism is NOT determined by thyroid hormone?
BRAIN (except it is needed for neural development)
Gonads
Uterus (except it is needed for normal menstrual cycles.)
Effect of Thyroxine on Catecholamines?
They have permissive actions! Increase the number of Beta receptors
What is characteristic of Low Iodine intake effect on TSH, T3 and T4?
When iodine is in short supply more T3 is made that T4.
Peripheral T4 decreases, leading to less feedback inhibition on TSH.
TSH will be elevated
Why does prolactin excess cause amenorrhea?
It decreases GnRH and thus decreases LH and FSH
Why does loss of thyroid hormone as a child lead to dwarfism?
Because Thyroid hormone has a permissive action on GH
Why does Hyperthyroidism cause osteoporosis?
Because the excess hormones stimulate osteoclasts!
What is important regarding radioactive iodide uptake and hyperthyroidism?
Graves hyperthyroidism is the only hyperthyroid state where radioactive iodide uptake is increased.
Also only one with Eye signs and Pretibial myxedema
How do you tell the difference between subacute and silent hyperthyroidism??
Subacute HURTS! (AKA Granulomatous, AKA DeQuervains.
Why does Arginine administration enable one to check for GH release?
Arginine is an AA, it needs the effect of IGF, which comes from GH to build proteins from the AA, so GH should increase in the present of Arginine.
What is the effect of loss of growth hormone after puberty??
Not much...at that point it is mainly a stress hormone and you have three others, thyroxine, Cortisol and catecholamines
IGF Versus GH?
GH increases FFAs and Glucose after puberty...IGF is what is responsible for protein synthesis
What are somatomedins?
Insulin like growth factors, IGF...have a long half life as they are bound to proteins
What does IGF excess lead to?
Acromegaly!! It is the IGF that causes...
Colonic polyps
CHF from cardiomegaly
Sleep Apnea
Carpal Tunnel from excessive protein synthesis
What is the only stress hormone induced by sleep?
GH...slow wave sleep
What is the only stress hormone inhibited by IGF?
GH, via actions of Somatostatin, SST
Lack of thyroid hormone before puberty?
No Puberty
A highschool girl is extremely tall and over conscious of her height. What can be administered to prevent her an increased awkward ness?
Androgens...will fuse the epiphyseal plates
Sequelae of Acromegaly?
Hyperlipidemia
Dilated heart from IGF (and the other probs)
HTN
Hyperglycemia
How do you test someone for acromegaly?
Check IGF levels first....then try to suppress it with glucose (OGTT).. If they have it CUT OUT THE PITUITARY
COD of Acromegaly?
CHF from cardiomegaly