Physiology Flashcards
How does altitude sickness present/what is the time course?
Immediately decreased O2 will cause hyperventilation in an effort to increase O2 delivery. This will cause CO2 to be blown off and thus pH to rise/become alkalotic.
Within 48 hours renal bicarbonate excretion compensates for the alkalosis to stabilize the pH and bring it within normal or near normal.
What is PSVT and how is it treated?
PSVT causes palpitations and rapid regular tachycardia most often due to a reentrant impulse traveling circularly between the slowly and rapidly conducting segments of the AV node.
Vagal maneuvers such as carotid massage, Valsalva, and cold water immersion can acutely terminate PSVT.
How does carotid massage work?
An afferent limb of the carotid sinus reflex travels with CN IX and arises from the baroreceptors in the carotid sinuses to the vagal nucleus and medullary centers. An efferent limb carries parasympathetic impulses to the SA and AV nodes via vagus (CN X). Carotid sinus massage leads to increased afferent firing from the carotid sinus, which in turn increases vagal parasympathetic tone, slowing conduction through the AV node and prolonging the AV node refractory period.
What are the fastest to slowest conduction tissues of the heart (with mnemonic)?
“Park AT VENTure AVenue”
Fastest: Purkinje Atrial Ventricular AV node Slowest^
What part of the kidney reabsorbs the majority (>60%) of water regardless of hydration status?
Proximal tubule
Absorption is isosmotic with absorption of solutes (Na, Cl, glucose) and no concentration or dilution occurs
Prolonged untreated OSA can lead to:
Pulmonary vasoconstriction -> Pulmonary hypertension -> Right heart failure
Systemic hypertension due to chronic sympathetic stimulation and elevated plasma Norepi
Loss of diurnal variation in BP
Increased risk of sudden cardiac death
Women with PCOS have an elevated ____:____ ratio.
LH:FSH
What adrenergic receptors are on the uterus? in the pupil?
Uterus = beta 2 Pupil = alpha 1
What is Neuroleptic Malignant Syndrome?
A potentially life-threatening adverse reaction to neuroleptics (antipsychotics).
4 primary features:
- Hyperthermia
- Severe generalized “lead-pipe” rigidity
- Autonomic instability
- Altered mental status
Failed fusion of the edges of the neural plate/closure of the rostral neuropore leads to:
What elevated markers will you find?
Anencephaly
Elevated AFP and AchE because they leak out
Curiously, ___ dietary calcium and ___ dietary oxalate and sodium are risk factors for calcium oxalate stones.
low calcium
high oxalate
high sodium
SERUM calcium is usually normal though.
Alkaline urine leads to formation of calcium _____ stones.
PHOSPHATE!!
What is reverse T3 (rT3)?
An inactive form of thyroid hormone that is generated almost entirely from the peripheral conversion of T4.
What is a glucagonoma?
A rare tumor arising from the alpha cells of the pancreatic islets of Langerhans. They secrete tons of glucagon leading to hyperglycemia/DM.
Characteristics:
Necrolytic migratory erythema
Erythematous papules/plaques with central clearing on face, groin, and extremities
GI symptoms (diarrhea, anorexia, abdominal pain)
What are the non-polar, hydrophobic amino acids?
GAVLIPPTM
Glycine Alanine Valine Leucine Isoleucine Phenylalanine Proline Tryptophan Methionine
Symptoms of thyroiditis (e.g. acute supperative, subacute, post-partum) are typically _______, while symptoms of a pheochromocytoma are more often _______.
Thyroiditis = constant Pheochromocytoma = (most often) episodic
What different histologies/types can craniopharyngiomas take?
Solid, cystic, calcified
Often all types seen together
