NBCE Part I flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Brachial plexus roots

Formed by ventral rami C5 through T1; divides into roots, trunks, divisions, cords, and terminal branches, supplying the shoulder and upper limb.

Coronal plane

Vertical plane dividing the body into anterior and posterior portions; also called the frontal plane and perpendicular to the sagittal plane.

Sesamoid bone

Small bone embedded within a tendon that reduces friction and alters the direction of muscle pull; the patella is the largest example in the body.

Serous pericardium layers

Parietal and visceral (epicardium) layers separated by the pericardial cavity, which holds a thin film of serous fluid for lubrication during cardiac motion.

Atlantoaxial joint rotation

The median atlantoaxial joint between the dens of C2 and the anterior arch of C1 provides roughly 50 percent of total cervical rotation.

Ligamentum flavum

Elastic ligament connecting the laminae of adjacent vertebrae; it limits flexion, protects the spinal cord, and assists return to extension.

Conus medullaris level

In adults the spinal cord terminates at approximately L1-L2; below this level the cauda equina continues within the lumbar cistern.

Uncinate processes

Lateral upward projections on cervical vertebral bodies C3-C7 that form uncovertebral (Luschka) joints, a common site of osteophyte formation.

Cardiac output formula

Cardiac output equals heart rate multiplied by stroke volume, normally about 5 L/min; stroke volume equals end-diastolic volume minus end-systolic volume.

Resting membrane potential

About -70 mV in neurons, maintained mainly by the Na+/K+ ATPase, which pumps three sodium ions out and two potassium ions in.

Frank-Starling law

Increased ventricular preload stretches cardiac muscle fibers, raising contractile force and stroke volume up to a limit beyond which further stretch reduces output.

Henderson-Hasselbalch equation

pH = 6.1 + log([HCO3-] divided by 0.03 x PaCO2); used to interpret acid-base disorders from bicarbonate and carbon dioxide values.

Michaelis-Menten equation

v = Vmax[S] / (Km + [S]); Km is the substrate concentration at half-maximal velocity, and a lower Km indicates higher enzyme affinity.

Gibbs free energy

ΔG = ΔH - TΔS; a negative ΔG means the reaction is spontaneous and exergonic, positive means nonspontaneous, and zero means equilibrium.

Chargaff base pairing rules

In double-stranded DNA, adenine pairs with thymine by two hydrogen bonds and guanine pairs with cytosine by three; adenine equals thymine and guanine equals cytosine.

Osmolarity versus molarity

Osmolarity counts all dissolved particles per liter of solution, so 1 M NaCl is about 2 osmolar, while molarity counts only intact solute molecules.

Coagulative necrosis

Most common necrosis pattern, caused by ischemia except in brain; tissue architecture is preserved temporarily with eosinophilia and nuclear pyknosis, karyorrhexis, and karyolysis.

Virchow triad

Three factors promoting thrombosis: endothelial injury, abnormal blood flow such as stasis or turbulence, and hypercoagulability of the blood.

Granulomatous inflammation

Chronic inflammation with activated macrophages (epithelioid cells) and multinucleated giant cells, characteristic of tuberculosis, sarcoidosis, and foreign-body reactions.

Type I collagen

Predominant collagen of skin, bone, tendon, and mature scars; type III collagen is deposited early in healing and later replaced by type I.

Endotoxin properties

Lipopolysaccharide of the gram-negative outer membrane; heat stable, not converted to a toxoid, and causes fever and shock through TLR4 and cytokines.

Incidence versus prevalence

Incidence counts new cases over a period; prevalence counts all existing cases at a point or over a period, approximately incidence multiplied by duration.

Autoclave standard cycle

Sterilization at 121°C (250°F) and 15 psi for 15 minutes; kills spores and all microorganisms and is monitored with biological indicators.

Immunoglobulin IgG

Most abundant immunoglobulin; the only class crossing the placenta, giving passive fetal immunity; mediates the secondary response and opsonization of microbes.

First and second heart sounds

S1 is closure of the mitral and tricuspid (atrioventricular) valves at the start of systole; S2 is closure of the aortic and pulmonic valves ending systole.

S3 heart sound

Low-pitched early diastolic sound from rapid ventricular filling; normal in children and pregnancy but indicates volume overload or heart failure in adults.

Murmur grading scale

Grade I is barely audible and grade VI is audible without a stethoscope; thrills accompany grade IV and higher, and grade V is heard with the stethoscope edge.

Deep tendon reflex grading

0 absent, 1+ diminished, 2+ normal, 3+ exaggerated, and 4+ hyperactive with clonus; recorded during the deep tendon reflex examination.

Upper motor neuron signs

Spasticity, hyperreflexia, positive Babinski sign, and clonus with minimal atrophy; caused by lesions above the anterior horn cell.

C6 nerve root level

C6 radiculopathy affects thumb sensation, biceps and brachioradialis reflexes, and wrist extension strength; it often follows a C5-C6 disc herniation.

Achilles reflex root

S1 reflex tested by ankle plantar flexion from gastrocnemius and soleus contraction; S1 sensation lies on the lateral foot, and loss suggests S1 root involvement.

Straight leg raise test

Passive hip flexion with the knee extended; pain radiating below the knee between 30 and 70 degrees suggests L4-S1 nerve root irritation.