Uworld Physio Flashcards
euthyroid sick syndrome lab values
low T3, normal TSH and T4
pathophysio of euthyroid sick syndrome
Suppression of 5’-deiodinase by glucocorticoids and inflammatory cytokines (eg, TNF-alpha, IL-1, IFN-beta) Decreased peripheral conversion of T4 to T3 Decreased hypothalamic TRH secretion
A PFO is a one-way tissue valve in the atrial septum that opens only when right atrial pressure exceeds left atrial pressure; venous return to the right atrium increases during what manuever?
the release (ie, relaxation) phase of a Valsalva maneuver and encourages opening of a PFO.
The pO2 in the left atrium and ventricle is lower than that in the pulmonary capillaries due to
mixing of oxygenated blood from the pulmonary veins with deoxygenated blood from the bronchial circulation and thebesian veins.
pregnancy causes increased/decreased plasma volume, rbc mass and hemoglobin conc
increase in plasma volume, rbc mass
decrease in hemoglobin
ADH is secreted in response to
plasma hyperosmolality and, to a lesser extent, depletion of the effective circulating volume.
Water deprivation initially increases plasma osmolality, resulting in increased ADH secretion. This causes the kidney to produce concentrated urine, which helps to counteract the rise in plasma osmolality by reducing urinary free water excretion.
Antidiuretic hormone acts on what nephron segment?
the medullary segment of the collecting duct to increase urea and water reabsorption, allowing for the production of maximally concentrated urine
cause of hypocalcemia from high volume blood transfusion
Citrate anticoagulants in high-volume blood transfusion can chelate plasma calcium, leading to hypocalcemia which causes peripheral neuromuscular excitability (eg, paresthesia, muscle spasms). This is most common with very rapid transfusion rates, but it can also be seen at lower rates in patients with hepatic insufficiency because citrate is metabolized by the liver.
every time GFR halves, serum creatinine —–
doubles
Obstruction of the pulmonary circulation by an embolus causes ———- dead space ventilation
increased
Patients being weaned from mechanical ventilation typically breathe at —- tidal volumes, with a compensatory ———in respiratory rate to maintain minute ventilation.
low
increase
low tidal volumes —- dead space vetilation and resp rate
increase dead space & resp rate
happens in pts weaning from vent
what hormone increases the most in concentration after ovulation?
progesterone
During the latter half of the menstrual cycle, the corpus luteum secretes high levels of progesterone, which thickens the endometrium and prepares it to receive and nourish a blastocyst.
Both LH and FSH surges are mediated through changes in the level and pulsatility of——, which is also highest before ovulation.
GnRH
Circadian rhythms are maintained by the ——— nucleus
suprachiasmatic
The primary functions of the SCN are to
modulate body temperature and produce hormones such as cortisol (stress hormone) and melatonin (sleep-inducing hormone).
—– tendon circuit is a negative feedback system that regulates and maintains muscle tension. When a muscle exerts too much force, the —– inhibit contraction of the muscle, causing sudden muscle relaxation.
Golgi
———- are thin, myelinated nerve fibers whose free nerve endings detect temperature and nociceptive stimuli. They are associated with acute (sharp) pain and constitute the afferent portion of the reflex arc that mediates withdrawal from noxious stimuli (e.g., retracting the hand away from a hot stove).
A-delta fibers
Pacinian corpuscles are ——- adapting mechanoreceptors located in the subcutaneous tissue of the skin as well as the mesentery, peritoneum, and joint capsules. Ruffini’s end organs are —— adapting mechanoreceptors that exist in the skin, subcutaneous tissue, and joint capsule. Both help to mediate touch, proprioception, and vibratory sensation and are innervated by myelinated A-beta fibers.
rapidly
slowly
PTH is a polypeptide hormone that is produced by the —– cells of the parathyroid glands in response to hypocalcemia
chief
3 primary effects of PTH:
Increases osteoclastic bone resorption, which releases calcium and phosphate into the circulation
Increases renal calcium reabsorption and reduces phosphate reabsorption
Increases formation of 1,25-dihydroxyvitamin D (by upregulating renal 1-alpha-hydroxylase), which increases intestinal calcium absorption
Both perfusion and ventilation are highest in the ——- of the lung.
However, the ventilation/perfusion (V/Q) ratio is lowest in the ———
base
CO poisoning causes a —— shift of the hemoglobin-oxygen dissociation curve, reflecting a decreased tendency for oxygen to unload in the tissues
leftward
Carbin dixoide poisonig causes an ——- in carboxyhemoglobin, PaO2 and methemoglobin
increase in carboxyhemoglobin
no change in PaO2 or meth
Type ———- (fast-twitch or white fibers) primarily use glycolysis and specialize in rapid bursts of high force contraction. Their function is amplified by resistance training.
Type II muscle fibers
—— muscle fibers (slow-twitch or red fibers) primarily use oxidative phosphorylation and contain high quantities of lipids, myoglobin, and mitochondria. They specialize in sustained, low force contraction, and their function is amplified by endurance training.
Type I
increase in ——- in a patient’s large skeletal muscle groups after a prolonged period of regular endurance training
mitochondrial content
TSH resistance due to a mutation in the TSH receptor gene presents with ———- hypothyroidism, which is characterized by increased TSH and low thyroxine. The thyroid gland is normal in size and location
congenital
breast milk lacks vitamin — and —
vitamin D and K
The most common cause of secondary hyperthyroidism is a ————–
In addition to hyperthyroid symptoms, TSH causes generalized hypertrophy of the thyroid gland (diffuse goiter). Laboratory evaluation shows elevated levels of thyroid hormone (triiodothyronine and thyroxine) and TSH.
TSH-secreting pituitary adenoma
——— stimulates the release of testosterone from the Leydig cells of the testes
LH
—— stimulates the release of inhibin B from the Sertoli cells in the seminiferous tubules
FSH
Defective FSH receptors will prevent spermatogenesis and cause low ——– levels
inhibin B
In chronic kidney disease, conversion of —- to ——– vit D is impaired.
25-hydroxyvitamin D to 1,25-dihydroxyvitamin D
The ——— phases stimulate gastric acid secretion, while ——— influences tend to reduce gastric acid secretion
cephalic and gastric
intestinal
Hypoglycemia can be precipitated by ——– in patients with insulin-treated diabetes due to the persistent effects of exogenous insulin.
exercise
Cause of maligent pleural effusions
Localized lung inflammation can cause increased vascular permeability, resulting in increased inflow of fluid into the pleural space. Once malignant cells have metastasized to the pleural space, they can occlude the pleural lymphatic stoma located on the parietal surface and prevent pleural fluid reabsorption.
Disruption of the thoracic lymphatic duct is an occasional cause of malignant effusion that leads to a chylothorax (milky white pleural fluid with high triglyceride content). This mechanism is most commonly seen with lymphoma;
what section has only thick filaments?
The H band is the region of the sarcomere that contains only thick (myosin) filaments. The H band is the part of the A band (which is on either side of the M line) where thick filaments have no overlapping thin (actin) filaments
During skeletal muscle contraction, calcium is released from the sarcoplasmic reticulum and binds ——–, thereby allowing the binding of actin to myosin
troponin C
Graves disease is an autoimmune disorder triggered by ——— receptor antibodies (TRAb)
thyrotropin
Chronic kidney disease can cause hyperphosphatemia due to impaired renal excretion of phosphorus. Elevated blood phosphate triggers the release of fibroblast growth factor 23, which lowers calcitriol production and intestinal calcium absorption. The resulting hypocalcemia, along with hyperphosphatemia, leads to ————
secondary hyperparathyroidism
—————— increases maternal insulin resistance during the second and third trimesters, leading to a rise in serum glucose that helps provide adequate nutrition to the growing fetus.
Human placental lactogen
Prolactin is responsible for —— production and lactation in postpartum women.
milk
——– plays an important role in uterine contraction and the milk letdown reflex
Oxytocin
Primary nocturnal enuresis (ie, bed-wetting at age ≥5 without prior nighttime urinary continence) is caused primarily by ————–
a brain maturational delay in the development of bladder control
———– is the persistence of glandular columnar epithelium in the vagina and is a precursor for clear cell adenocarcinoma of the vagina. Female offspring exposed to ————- in utero are at increased risk and may present with vaginal discharge or vaginal cysts/fleshy colored lesions.
Vaginal adenosis
diethylstilbestrol
Polycystic ovary syndrome (PCOS) is associated with oligomenorrhea, hirsutism, and polycystic ovaries. Disruption in intraovarian steroidogenesis causes anovulatory cycles and results in chronic estrogen stimulation with decreased progesterone secretion, placing PCOS patients at risk for —————-
endometrial hyperplasia/carcinoma
which of the following side effects will happen during the first few months following a vastecomy?
viable sperm in ejaculation, up to 3 months
Adverse effects associated with the use of excessive doses of ————- include acne, gynecomastia, azoospermia, decreased testicular size, and increased aggression. When measured, serum testosterone is typically normal or elevated. However, endogenous testosterone production and spermatogenesis are decreased
anabolic steroids (androgen use)
———– deficiency results in an inability to convert testosterone to dihydrotestosterone in the peripheral tissues. Affected males are born with ambiguous genitalia. Following puberty, affected patients have normal or elevated levels of serum testosterone.
5-alpha reductase
————- syndrome is a common cause of male hypogonadism. Small, firm testes and a decreased serum testosterone level are characteristic. Patients may exhibit diminished secondary sexual characteristics.
Klinefelter (XXY seminiferous tubule dysgenesis)
32 yr old female, SOB.
Normal PaO2 saturation
normal % saturated (SaO2)
low oxygen content.
what can be the cause?
chronic blood loss (low hemoglobin conc)
——– inhibits cellular oxidative phosphorylation by inhibiting Fe3+ in cytochrome c oxidase, lowering peripheral tissue oxygen consumption. Arterial PaO2, SaO2, and CaO2 remain unchanged, but venous oxygen content rises and the arterial-venous oxygen gradient falls.
Cyanide
