Uworld Physio

Question 1

euthyroid sick syndrome lab values

Answer 1

low T3, normal TSH and T4

Question 2

pathophysio of euthyroid sick syndrome

Answer 2

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

Question 3

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?

Answer 3

the release (ie, relaxation) phase of a Valsalva maneuver and encourages opening of a PFO.

Question 4

The pO2 in the left atrium and ventricle is lower than that in the pulmonary capillaries due to

Answer 4

mixing of oxygenated blood from the pulmonary veins with deoxygenated blood from the bronchial circulation and thebesian veins.

Question 5

pregnancy causes increased/decreased plasma volume, rbc mass and hemoglobin conc

Answer 5

increase in plasma volume, rbc mass

decrease in hemoglobin

Question 6

ADH is secreted in response to

Answer 6

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.

Question 7

Antidiuretic hormone acts on what nephron segment?

Answer 7

the medullary segment of the collecting duct to increase urea and water reabsorption, allowing for the production of maximally concentrated urine

Question 8

cause of hypocalcemia from high volume blood transfusion

Answer 8

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.

Question 9

every time GFR halves, serum creatinine —–

Answer 9

doubles

Question 10

Obstruction of the pulmonary circulation by an embolus causes ———- dead space ventilation

Answer 10

increased

Question 11

Patients being weaned from mechanical ventilation typically breathe at —- tidal volumes, with a compensatory ———in respiratory rate to maintain minute ventilation.

Answer 11

low

increase

Question 12

low tidal volumes —- dead space vetilation and resp rate

Answer 12

increase dead space & resp rate

happens in pts weaning from vent

Question 13

what hormone increases the most in concentration after ovulation?

Answer 13

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.

Question 14

Both LH and FSH surges are mediated through changes in the level and pulsatility of——, which is also highest before ovulation.

Answer 14

GnRH

Question 15

Circadian rhythms are maintained by the ——— nucleus

Answer 15

suprachiasmatic

Question 16

The primary functions of the SCN are to

Answer 16

modulate body temperature and produce hormones such as cortisol (stress hormone) and melatonin (sleep-inducing hormone).

Question 17

—– 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.

Answer 17

Golgi

Question 18

———- 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).

Answer 18

A-delta fibers

Question 19

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.

Answer 19

rapidly

slowly

Question 20

PTH is a polypeptide hormone that is produced by the —– cells of the parathyroid glands in response to hypocalcemia

Answer 20

chief

Question 21

3 primary effects of PTH:

Answer 21

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

Question 22

Both perfusion and ventilation are highest in the ——- of the lung.

However, the ventilation/perfusion (V/Q) ratio is lowest in the ———

Answer 22

base

Question 23

CO poisoning causes a —— shift of the hemoglobin-oxygen dissociation curve, reflecting a decreased tendency for oxygen to unload in the tissues

Answer 23

leftward

Question 24

Carbin dixoide poisonig causes an ——- in carboxyhemoglobin, PaO2 and methemoglobin

Answer 24

increase in carboxyhemoglobin

no change in PaO2 or meth

Question 25

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.

Answer 25

Type II muscle fibers

Question 26

—— 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.

Answer 26

Type I

Question 27

increase in ——- in a patient’s large skeletal muscle groups after a prolonged period of regular endurance training

Answer 27

mitochondrial content

Question 28

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

Answer 28

congenital

Question 29

breast milk lacks vitamin — and —

Answer 29

vitamin D and K

Question 30

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.

Answer 30

TSH-secreting pituitary adenoma

Question 31

——— stimulates the release of testosterone from the Leydig cells of the testes

Answer 31

LH

Question 32

—— stimulates the release of inhibin B from the Sertoli cells in the seminiferous tubules

Answer 32

FSH

Question 33

Defective FSH receptors will prevent spermatogenesis and cause low ——– levels

Answer 33

inhibin B

Question 34

In chronic kidney disease, conversion of —- to ——– vit D is impaired.

Answer 34

25-hydroxyvitamin D to 1,25-dihydroxyvitamin D

Question 35

The ——— phases stimulate gastric acid secretion, while ——— influences tend to reduce gastric acid secretion

Answer 35

cephalic and gastric

intestinal

Question 36

Hypoglycemia can be precipitated by ——– in patients with insulin-treated diabetes due to the persistent effects of exogenous insulin.

Answer 36

exercise

Question 37

Cause of maligent pleural effusions

Answer 37

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;

Question 38

what section has only thick filaments?

Answer 38

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

Question 39

During skeletal muscle contraction, calcium is released from the sarcoplasmic reticulum and binds ——–, thereby allowing the binding of actin to myosin

Answer 39

troponin C

Question 40

Graves disease is an autoimmune disorder triggered by ——— receptor antibodies (TRAb)

Answer 40

thyrotropin

Question 41

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 ————

Answer 41

secondary hyperparathyroidism

Question 42

—————— 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.

Answer 42

Human placental lactogen

Question 43

Prolactin is responsible for —— production and lactation in postpartum women.

Answer 43

milk

Question 44

——– plays an important role in uterine contraction and the milk letdown reflex

Answer 44

Oxytocin

Question 45

Primary nocturnal enuresis (ie, bed-wetting at age ≥5 without prior nighttime urinary continence) is caused primarily by ————–

Answer 45

a brain maturational delay in the development of bladder control

Question 46

———– 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.

Answer 46

Vaginal adenosis

diethylstilbestrol

Question 47

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 —————-

Answer 47

endometrial hyperplasia/carcinoma

Question 48

which of the following side effects will happen during the first few months following a vastecomy?

Answer 48

viable sperm in ejaculation, up to 3 months

Question 49

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

Answer 49

anabolic steroids (androgen use)

Question 50

———– 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.

Answer 50

5-alpha reductase

Question 51

————- 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.

Answer 51

Klinefelter (XXY seminiferous tubule dysgenesis)

Question 52

32 yr old female, SOB.

Normal PaO2 saturation

normal % saturated (SaO2)

low oxygen content.

what can be the cause?

Answer 52

chronic blood loss (low hemoglobin conc)

Question 53

——– 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.

Answer 53

Cyanide