GTL (Gym, Tan, Lipids)
Bloody Spaces
Rome Wasn't Built in a Day!
Acid Base Balance
Case on Case
100
Which of the following lipids is involved in gut-brain axis communication?
a. Propionate
b. Cholesterol
c. Sphingomyelin
d. Thromboxane
e. Androgen
A: What is Propionate?
It is a short-chain FA involved in both gut-brain axis communication along with butyrate and acetate. It also contributes to the development of neuropsychiatric disorders along with butyrate.
100
Which of the following are contents of the triangular interval?
a. Axillary nerve, circumflex scapular artery & vein
b. Radial nerve, posterior circumflex artery & vein
c. Axillary nerve, deep brachial artery/vein
d. Radial nerve, deep brachial artery/vein
e. No nerve, circumflex scapular artery & vein
D: What is Radial nerve, deep brachial artery/vein?
Note: A is quadrangular space
100
Fibrillar collagen is responsible for providing mechanical strength in which structures?
a. Fetal tissue, uterus, placenta
b. Lens, retina, cochlea
c. Glomerulus, skin, renal tubules
d. Bones, tendons, ligaments
D: What is Bones, tendons, ligaments?
100
A 32-year-old mountain climber is training at high altitude. After 3 days, she notices she becomes short of breath with mild exertion. Arterial blood gas shows:
pH: 7.46
PaCO₂: 30 mmHg
PaO₂: 65 mmHg
Which of the following best describes the change in her hemoglobin–oxygen dissociation curve at this time, and the physiologic reason for it?
a. Left shift — decreased 2,3-BPG due to hyperventilation
b. Right shift — increased 2,3-BPG due to chronic hypoxia
c. Left shift — increased affinity for O₂ to improve tissue delivery
d. Right shift — decreased temperature from cold exposure
e. Left shift — increased pH from lactic acid accumulation
B. What is Right shift — increased 2,3-BPG due to chronic hypoxia?
100
You went to Arkansas and had a wild night out in the town. You’re back at your Air B&B and you get up to go pee late at night. Unfamiliar with the Air B&B, you wander around looking for the bathroom when you accidentally run into a giant glass door, shattering it. A giant piece of glass gets lodged into the posterolateral aspect of your neck and you suddenly realize you are unable to raise the tip of your shoulder on the injured side. Which nerve is damaged?
a. Dorsal scapular
b. Thoracodorsal
c. Accessory
d. Spinal nerve C3
e. Greater occipital
C: What is Accessory nerve?
Your trapezius muscle is posterolateral to your neck. The glass shard pierces the acromion of the scapula and accessory nerve innervates the trapezius. The hint is that you are unable to raise the tip of your shoulder.
200
What contributes to plasma membrane fluidity?
a. Hydrogen bonds between the phospholipids allows a higher melting point
b. Liposomes fuse and weaken the van der waals forces contributing to more fluidity
c. Weak van der waals forces among unsaturated fats allows for a higher melting point
d. Cholesterol stored within the membrane allows for a lower melting point
e. Transmembrane ion channels make the membrane more flexible to water and ions
D: What is Cholesterol?
Both cholesterol and unsaturated fats contribute via weakened van der waals forces due to the kink of a double bond (unsat) and the properties of cholesterol (not in detail in this lecture) LOWER the melting point allowing for more fluidity! (important in cold climates!)
200
Which of the following makes the floor of the cubital fossa?
a. Pronator teres
b. Bicipital aponeurosis
c. Brachialis
d. Radial head
e. Superficial fossa
C: What is brachialis?
The supinator muscles also make up the floor (aka the deep edge of the space)
200
In collagen synthesis, in the formation of the triple helix structure (Gly-X-Y) is formed in which cellular structure?
a. Cytoplasm
b. Smooth endoplasmic reticulum
c. Rough endoplasmic reticulum
d. Golgi apparatus
e. Extracellular matrix
C: What is Rough endoplasmic reticulum?
The triple helix of procollagen is assembled inside the RER before secretion.
200
This condition causes pH to decrease due to increased [H+] and or decreased [HCO3-] and is compensated via what mechanism (also name the condition)
What is “hyperventilation” for metabolic acidosis?
200
A 46-year-old construction worker sustains a penetrating injury to the medial aspect of his distal humerus. He develops clawing of the fourth and fifth digits, sensory loss over the medial hand, and weakened wrist flexion. Which muscle is most likely spared in this patient?
a. Flexor carpi ulnaris
b. Medial two lumbricals
c. Adductor pollicis
d. Flexor digitorum superficialis
e. Palmar interossei
D: What is Flexor digitorum superficially?
FDS is innervated by the median nerve; all others are ulnar nerve–dependent.ulnar nerve–depende
300
A 22-year-old weightlifter presents with upper back pain after heavy overhead lifting. The physician suspects trapezius strain. Which of the following best describes the muscle’s origin?
a. External occipital protuberance, medial superior nuchal line, nuchal ligament, and spinous processes of C7–T12
b. Spinous processes of T2–T5 vertebrae
c. Spinous processes of T7–T12 and thoracolumbar fascia
d. Transverse processes of C1–C4 vertebrae
e. Supraspinous fossa of scapula
A:What is External occipital protuberance, medial superior nuchal line, nuchal ligament, and spinous processes of C7–T12?
300
The median cubital vein is a content of the cubital fossa as well as a common site for blood draws. Which of the following veins proximally branch off of it?
a. Basilic, cephalic
b. Brachial, cephalic
c. Basilic, radial
d. Brachial, ulnar
e. Radial, ulnar
A. What is Basilic, cephalic?
300
A 45-year-old man is brought to the emergency department after a high-speed motor vehicle accident. He complains of severe upper neck pain and difficulty turning his head. Neurologic exam reveals bilateral upper extremity weakness and decreased sensation below the C2 dermatome. CT of the cervical spine shows widening of the atlantodental interval and anterior displacement of the atlas relative to the axis.
Which of the following structures is most likely injured in this patient?
a. Alar ligaments
b. Apical ligament
c. Cruciform ligament
d. Ligamentum flavum
e. Posterior longitudinal ligament
C. What is Cruciform ligament? This is super important to know for this class and even OPP!
300
A patient is treated with fluoroacetate, a toxin that forms fluorocitrate in vivo. This compound inhibits aconitase. Which TCA intermediate will accumulate first in this patient’s cells?
a. Isocitrate
b. Citrate
c. Malate
d. Succinyl-CoA
e. Oxaloacetate
B: What is Citrate?
Aconitase converts citrate → isocitrate; inhibition → citrate accumulation
300
A 27-year-old man presents to the clinic with progressive fatigue, loose teeth, and poor wound healing. He mentions that over the last two months, his gums have become swollen and bleed easily. He also has frequent bruises on his legs without any known trauma. His diet consists mostly of instant noodles and canned foods, as he has been unemployed and living alone. On exam, you observe multiple ecchymoses on the lower limbs, gingival swelling, and small perifollicular hemorrhages with corkscrew hairs.
Laboratory evaluation shows a normal platelet count and coagulation profile. A deficiency in which of the following enzymatic processes is most likely responsible for this patient's condition?
a. Lysyl oxidase activity
b. Collagen triple helix formation
c. Proline and lysine hydroxylation
d. Collagen fibril cross-linking
e. Elastin fiber assembly
C: What is Proline and lysine hydroxylation?
This patient has scurvy, caused by vitamin C deficiency, which impairs the hydroxylation of proline and lysine residues in collagen synthesis. Hydroxylation is essential for stable triple helix formation. Without it, collagen is weak, leading to the bleeding, poor wound healing, and skin findings described.
400
Multiple components of which organic molecule make cholesterol?
a. Citric acid
b. Acetate
c. Isoprene
d. Retinol
e. Butyrate
C: What is Isoprene?
Isoprene is a 5-carbon organic molecule that is a building block of all sterols, cholesterol included.
400
Which of the following best describes the role of CRP in this patient's condition?
a. CRP neutralizes bacterial toxins directly
b. CRP activates B cells to produce antibodies
c. CRP promotes phagocytosis by opsonization
d. CRP binds iron to limit bacterial growth
e. CRP inhibits complement activation
C: What is CRP promotes phagocytosis by opsonization?
CRP is a positive acute-phase protein produced by the liver in response to inflammation, especially from bacterial infections like pneumonia.
It binds to phosphocholine on bacterial surfaces and damaged host cells, acting as an opsonin and enhancing phagocytosis. CRP also activates the classical complement pathway, which further helps in pathogen clearance.
400
Which soft tissue structure anchors the deep back muscles?
a. Flexor retinaculum
b. Linea alba
c. Thoracolumbar fascia
d. Subscapular ligament
e. Infrascapular ligament
C. What is Thoracolumbar fascia?
400
A scientist is studying the regulation of the TCA cycle in vitro. She observes that high concentrations of NADH inhibit multiple enzymes. Which of the following enzymes is not directly inhibited by NADH?
a. Citrate synthase
b. Isocitrate dehydrogenase
c. α-Ketoglutarate dehydrogenase
d. Malate dehydrogenase
A. What is Citrate synthase?
Citrate synthase is NOT inhibited directly by NADH.
400
A 1-month-old infant is brought to the pediatrician due to poor feeding, lethargy, and episodic seizures. On examination, the baby is tachypneic and has hepatomegaly. Labs show hypoglycemia, elevated lactate, and metabolic acidosis. A deficiency in which of the following enzymes is most likely responsible for the patient’s symptoms?
a. Glucose-6-phosphatase
b. Pyruvate kinase
c. Phosphofructokinase-1
d. Glucose-6-phosphate dehydrogenase
e. Hexokinase
C: What is PFK-1 deficiency?
Classic presentation of pyruvate kinase deficiency (RLS of glycolysis), a glycolytic enzyme defect. It leads to:
↓ ATP in red blood cells → hemolytic anemia
Backup of glycolysis intermediates → ↑ lactate
↓ Pyruvate → impairs aerobic metabolism
Hepatosplenomegaly from extramedullary hematopoiesis
500
What is the medial border of the suboccipital triangle?
a. Rectus capitis minor
b. Obliquus capitis superior
c. Semispinalis capitis
d. Longissimus capitis
e. Rectus capitis major
E. What is Rectus capitis major?
500
A 25-year-old male is brought to the emergency department after being tackled during a football game. He landed on his right shoulder and now complains of weakness in lifting his arm and numbness over the lateral shoulder region. On physical exam, he is unable to abduct his right arm beyond 15 degrees. There is noticeable atrophy of the deltoid muscle. Sensation is decreased over the lateral aspect of the upper arm (regimental badge area). X-rays reveal no fracture.
Which of the following structures was most likely injured?
a. Suprascapular nerve
b. Axillary nerve
c. Radial nerve
d. Musculocutaneous nerve
e. Long thoracic nerve
B: What is Axillary nerve?
The axillary nerve passes through the quadrangular space of the shoulder and can be injured by anterior shoulder dislocation or trauma to the surgical neck of the humerus.
It innervates the deltoid and teres minor muscles and provides sensation over the lateral shoulder (regimental badge sign).
Loss of abduction beyond 15° and deltoid atrophy are key findings.
500
What structurally stabilizes the link between two cysteine residues?
a. Covalent disulfide bonds between the sulfur residues
b. Hydrogen bonding between the ammonia residues
c. Ionic disulfide bonds between the sulfur residues
d. Peptide bond between two cysteines
A. What is Covalent disulfide bonds between the sulfur residues?
500
A 68-year-old man with a history of chronic obstructive pulmonary disease (COPD) presents for routine follow-up. His arterial blood gas shows:
pH: 7.38
PaCO₂: 52 mmHg
HCO₃⁻: 30 mEq/L
Despite the elevated CO₂, the patient is asymptomatic and hemodynamically stable. Which of the following best explains the maintenance of near-normal pH in this patient?
a. Increased pulmonary ventilation
b. Hemoglobin binding excess acid
c. Renal retention of hydrogen ions
d. Renal compensation via bicarbonate retention
e. Phosphate buffering in the urine
D. What is Renal compensation via bicarbonate retention?
This patient has chronic respiratory acidosis due to elevated PaCO₂ from COPD. His near-normal pH indicates metabolic (renal) compensation, specifically retention of bicarbonate (HCO₃⁻) to buffer the excess acid from CO₂.
The kidneys compensate over days to retain bicarbonate, which neutralizes the extra hydrogen ions.
500
A 22-year-old woman is brought to the emergency department with complaints of lightheadedness, tingling in her fingers, and chest tightness. Her roommate states that the symptoms began after a stressful phone call with her parents. On the physical exam, she is alert but anxious and breathing rapidly at 28 breaths per minute. ABG shows:
pH: 7.52 (normal range: 7.35-7.45)
PaCO₂: 28 mmHg (normal range 35-45 mmHg)
HCO₃⁻: 24 mEq/L (normal range: 22-26 mEq/L)
What is the most likely acid-base disorder?
a. Metabolic alkalosis
b. Respiratory alkalosis
c. Respiratory acidosis
d. Metabolic acidosis
e. Mixed disorder
B: What is Respiratory alkalosis?