test 5 Flashcards
What is the food poisoning of C. perfringens like?
late onset watery diarrhea. toxin is formed when large quantities of clostridal spores are ingested. the spores germinate in the digestive tract and then begin to elaborate toxin, hence the disease’s delayed onset (contrast with S. aureus and B. cereus preformed toxins)
What are the most common metastatic tumors to the brain?
lung, renal, and melanoma
What are the biochemical consequences of total myocardial ischemia within the first 5 mins?
cessation of aerobic glycolysis and initiation of anaerobic glycolysis. this transition occurs within seconds! It results in inadequate production of high-energy phosphates (ATP and creatinine phosphate) and the accumulation of deleterious metabolites, including lactate. Although total ATP levels remain relatively normal during the first few mins of ischemia, ATP is RAPIDLY DEPLETED from areas of the cell with high metabolic demand, such as the cytosol surrounding the contraction fibers and electrolyte transport pumps. this depetion of the ATP in critical cellular areas and the accumulation of toxins results in the loss of contractility within about 60 seconds of total myocardial ischemia
What are the consequences of total myocardial ischemia in the first 30 minutes? What happens if blood flow returns to the heart in the first 30 mins? What happens if total ischemia persists for longer than 30 mins?
Contractility is lost in the first minute. As ischemia persists, ATP levels continue to fall, and lactate levels continue to rise.
If you restore blood flow in the first 30 mins, loss of contractile function is possible- but it doesn’t happen right away. Instead, the myocardium remains stunned with contractility gradually returning to normal over the next several hours to days. increased duration of ischemia prolongs the time that the myocardium remains stunned.
After 30 mins, the ATP has been degraded to ADP, AMP, and, finally adenosine. Adenosine can leak from the cells and serve as a vasodilator, but after 30 mins the adenine stores are very depleted and the damage is irreversible.
Describe HBV morphology
mature virion is a hexagonal protein core covered with a lipid bilayer envelope. HBV genome is partially double stranded circular DNA. When the virion enters the cell, the capsid is released into the cytoplasm and the viral genome is transferred to the nucleus. viral DNA is then repaired to form a fully ds circular microchromosome that may be transcribed into viral mRNAs. replication of the genome occurs within a newly synthesized capsid containing the full-length viral mRNA. reverse transcriptase (which has both RNA and DNA dependent pol activity) acts on the RNA template to create a single stranded DNA intermediate that is converted back into a circular, partially dsDNA. mature capside is then enveloped by a portion of the endoplasmic reticulum containing virally encoded proteins to form the completed virion
Describe blood supply to the arm and forearm
question 15 on test 5 has a great picture.
basically, axillary artery in the shoulder. wraps around the head of the humerus as the anterior and posterior circumflex humeral arteries. Injury to the surgical neck of the humurs may damage the axillary or anterior circumflex humeral arteries. the DEEP BRACHIAL ARTERY then runs posteriorily along the humerus with the radial nerve and can be easily injured with injuries to the shaft of the humerus. the deep brachial artery then divedes into the radial collateral artery and the middle collateral artery at the midpoint of the humerous. though the radial collateral artery also runs with the radial nerve, it is less likely to be injured becasue it originates at the lower end of the spiral groove where the deep brachial artery pierces the lateral intramuscular septum. supracondylar fractures are associated with injury to the brachial artery. the brachial artery continues more superficially and divideds into the radial and ulnar arteries just distal to the cubital fossa. the comon interosseous artery is a branch off of the ulnar artery.
Adenovirus vs. arenavirus: clinical manifestations
adenovirus: pharyngoconjunctival fever. illness of acute, self-limited febrile pharyngitis, cough, nasal congestion, conjunctivitis, and enlarged cervical lymph nodes. though rare in the general population, it can bee seen in groups of people living in crowded quarters under conditions of fatigue or stress (campers, military recruits). (example in this question is a summer camp with kids who have low-grade fever, throat pain, red eyes, and cervical LAD).
arenavirus: lymphocytic choriomenigitis virus (LCV): febrile asepctic meningoencephalitis or mild systemic flu-like illness in ppl exposed to infected mice/hamsters. No person-to-person transmission.
What happens at high altitude, including time course?
pO2 will decrease, and the body will compensate with hyperventilation (and concominant decr. in pCO2 and alkalosis). Within 48 hrs, the kidney will begin to excrete bicarb in the urine to compensate (metabolic acidosis).
Within a few hrs, the kidney will also increase EPO secretion. /the effects of EPO will kick in around 10-14 days later such that after 2 wks a patient at high altitudewill have arterial oxygen content near sea level values.
What are some key complications of Turners
short stature, shield chest, webbed neck, lymphedema (may appear at any age but is very suggestive of turner’s in a neonate), CV malformations like aortic coarctation, bicuspid aortic valve, and aortic dissection in adulthood.
volume of distribution: significance and definition
Vd = amt of drug given/plasma concentration of drug
Vd is 3-5 liters: suggests most of the drug is withing the plasma fluid (which is normally about 3 liters). A drug that is mostly in the plasma is a drug that: has a large molecular weight, or is bound extensively to plasma proteins, or is highly charge (hydrophilic).
A drug with a Vd of 14-16 L is probably hydrophilic, but is small enough to escape into the interstitial fluid
Drugs with Vd around 41 (higher than 16) can cross into the intracellular space.
Diabetic neuropathies: focus on cranial nerve mechanisms and what would be seen clinically with cranial nerve neuropathies
typically symmetric peripheral neuropathy, mononeuropathy, or autonomic neuropathy.
among cranial nerve DM neuropathies, CN III is most common. it causes ptosis and a “down and out” gaze. accomdation and the pupil’s response to light are intact (this is in contrast to a CN III compression lesion, which would affect both somatic and parasympathetic features).
CNIII neuropathy is ischemic in DM. only the somatic fibers are affected because the somatic and the parasympathetic fibers have separate blood supplies.
What are the consequences of high-oxygen-affinity hemobglobins?
Increased affinity for oxygen means that the hemoglobins have trouble releasing oxygen in the tissues. However, the body is able to compensate because low tissue oxygen stimulates the kidneys to increase EPO synthesis, which results in compensatory erythrocytosis that helps maintain normal oxygen delivery
Adenosine as a drug
drug of choice for supraventricular tachycardia (which is often dependent on a reentrant circuit). Adenosine is rapidly acting and slows conduction through the AV node by hyperpolarizing the nodal pacemaker and conducting cells (increases K out of cells). Side effects: flushing, chest burning (from bronchospasm), hypotension, and high degree AV block)
What are the stop codons?
UGA, UAG, UAA
What are key characteristics of schizophrenia? How can it be distinguished from major depression with psychotic features?
Schizophrenia: 2 or more symptoms present for at least 1 month:
Delusions, hallucinations, or disorganized speech (at least 1 of the 2 must be one of these symptoms)
May also include grossly disorganized or catatonic behavior, negative symptoms.
Continuous signs continue for at least 6 mo, including prodromal and residual symptoms.
Schizoid: voluntary social withdrawal, limited emotional expression, and contentment with social isolation.
Schizotypical: eccentric appearance, odd beliefs or magical thinking, interpersonal awkwardness
