FREE HESI A2 Study Guide 2026: All Sections

This free HESI A2 study guide walks through every section the Elsevier HESI A2 (Admission Assessment) tests for nursing and allied-health admissions — Mathematics, Reading, Vocabulary, Grammar, Anatomy & Physiology, Biology, Chemistry, and (for some programs) Physics.^[2]

The single most important thing to know first: the HESI A2 is a modular exam. Each program chooses which sections you take (commonly four to six) and sets its own passing score— so there is no single national form, length, or pass mark. Confirm your program’s required sections and cutoff before you study.^[3]

It’s interactive, not a wall of text: every section has high-yield notes, worked scenarios, labeled diagrams, flashcards, and practice questions, so you learn by doing — not just reading. Drill gaps with our free practice test and flashcards.

HESI A2 Exam Snapshot

Because the HESI A2 is school-configured, the counts and times below are typical ranges, not a single official blueprint. Each scored section also carries about five unscored pilot questions, so the administered count exceeds the scored count.^[4][5]

A common four-section exam (Math, Reading, Vocabulary, Grammar) runs roughly 200 scored questions in about 210 minutes; adding sciences raises the total. There is no universal passing score — programs commonly require around 75–80%, and many gate on each section individually. Two non-scored modules (Learning Style and Personality Profile) are diagnostic only and never affect your academic score.^[4]

Mathematics

Mathematics is a near-universal core section — about 50 scored questions in roughly 50 minutes. It is applied arithmetic for nursing, not algebra: the exam rewards fast, accurate fraction, decimal, and percent work, cross-multiplication, and memorized conversions. By community report, roughly 30 of 50 questions are ratio/proportion or conversion based.^[12]

Two facts shape your whole strategy: there is no formula or conversion sheet, and many testing centers provide no calculator — so equivalents must be memorized cold. Read each question carefully to decide whether to multiply or divide; that direction error is a top failure mode.^[5]

How the Math section is built (read this first)

Spend your hours where the points are. Ratios, proportions, and unit conversions dominate, followed by fraction/decimal/percent fluency and a few nursing-flavored dosage problems. Roman numerals, military time, and basic algebra are lower-frequency “sleepers” worth a quick review.^[1]

Follow PEMDAS on every multi-step problem: Parentheses, Exponents, Multiplication/Division (left to right), then Addition/Subtraction. The most-missed order-of-operations error is doing addition before multiplication — $2 + 3 \times 4 = 14$, not 20.^[12]

Fractions, decimals, and percents

Convert fluently in every direction. A fraction becomes a decimal by dividing top by bottom; a decimal becomes a percent by multiplying by 100; a percent becomes a fraction over 100, then reduce. The single most common careless error is not simplifying the final answer — answer choices are usually in lowest terms.^[12]

To add or subtract fractions, find a common denominator first ($\frac{1}{4} + \frac{1}{6} = \frac{3}{12} + \frac{2}{12} = \frac{5}{12}$); to multiply, go straight across and simplify; to divide, multiply by the reciprocal ($\frac{1}{2} \div \frac{3}{4} = \frac{1}{2} \times \frac{4}{3} = \frac{2}{3}$).^[12]

For percents, anchor on one relationship: $\text{part} = (\text{percent} \div 100) \times \text{whole}$. The classic HESI “12 of 50” score pattern is just $\frac{12}{50} = 0.24 = 24\%$. Percent change is a separate formula: $\frac{\text{new} - \text{old}}{\text{old}} \times 100$.^[12]

Ratios, proportions, and dosage — the highest-yield topic

A proportion sets two ratios equal; solve by cross-multiplication: $\frac{a}{b} = \frac{c}{d} \Rightarrow ad = bc$. Keep matching units in matching positions (mg over mL on both sides) — a mismatched setup is the top failure mode.^[12]

Treat dosage problems as proportions. The core dosage formula is $\text{Amount to give} = \frac{\text{Dose Ordered}}{\text{Dose on Hand}} \times \text{Quantity}$ — and always convert to a common unit before computing.^[13]

Measurement and unit conversions (memorize cold)

No reference sheet is provided, so the equivalents must be automatic. Use the metric ladder for metric-to-metric moves, and memorize the household and metric↔household equivalents below. One HESI convention to note: 1 grain = 60 mg on the HESI (not the ~64.8 mg pure value).^[12]

Roman numerals, military time, and basic algebra

Roman numerals: I=1, V=5, X=10, L=50, C=100, D=500, M=1000; a smaller symbol before a larger one subtracts (IV=4, IX=9, XL=40, XC=90, CM=900), so XCVI = 96. Military (24-hour) time adds 1200 to PM hours — 1 p.m. = 1300, 11 p.m. = 2300, and midnight = 0000.^[1]

Basic algebra is light: solve for the variable with inverse operations, e.g. $3x + 5 = 20 \Rightarrow 3x = 15 \Rightarrow x = 5$.^[12]

Reading Comprehension

Reading is a near-universal core section — about 47–55 scored questions in roughly 60 minutes. Passages are short-to-medium and often health, science, or general-interest. The dominant skill is disciplined reading: every answer must be supported by the passage, so using outside knowledge is the single biggest trap.^[14]

Main idea, supporting details, and inference

Separate three things questions deliberately blur. The main idea is the single point the whole passage supports; a supporting detail is a stated fact that backs it; and an inference is a conclusion the passage logically supports but does not state. The classic trap is a true detail dressed up as the main idea.^[14]

The main idea is often stated in the first or last sentence of a paragraph. For detail questions (“according to the passage…”), locate the exact sentence by scanning for keywords. For inference, stay one small stepfrom the text — reject any choice that adds outside facts, even if it “could be true in real life.”^[14]

Author's purpose, tone, and text structure

Identify the author's purpose: to inform, persuade, entertain, describe, or instruct. Most informational and health passages are written to inform, so beware reading them as persuasive. Tone is the author's attitude, judged from word choice (connotation) — most health passages are neutral and objective.^[14]

Recognize organization from signal words: because/therefore (cause–effect), however/unlike (contrast), first/next/finally (sequence), for example (illustration). Separate fact (verifiable) from opinion (a judgment, often marked by best, should, or unfortunately).^[14]

Reading strategy and common traps

Read the question first, then scan the passage for the relevant spot — efficient with roughly a minute per question. Eliminate choices that are too broad, too narrow, not stated, or contradicted. For “EXCEPT/NOT” questions, find the three that ARE supported; the odd one out is the answer.^[14]

Vocabulary & General Knowledge

Vocabulary is a near-universal core section — about 50 scored questions in roughly 50 minutes. It tests academic and medical/health-contextvocabulary, frequently framed in a clinical sentence (“The patient was admitted for an acutecough”). It is often called the easiest section to study for, yet it is a sleeper failure section because the official review book omits many commonly tested everyday words.^[17]

High-yield medical vocabulary

Because the framing is clinical, the same word carries its medical sense. Know the high-frequency clinical words such as acute vs. chronic, patent vs. occluded, benign vs. malignant, and contraindication.^[17]

Academic vocabulary and word parts

Many tested words are everyday academic English — abate, abstain, ambiguous, candid, discrepancy, exacerbate, prudent, virulent. When a word is unfamiliar, decode it with word parts: a prefix changes meaning at the front, a root carries the core meaning, and a suffix often marks a condition.^[17]

Context-clue and elimination strategy

Use context cluesin the sentence: a definition clue restates the meaning, a contrast clue (“but/unlike”) signals the opposite, and an example clue illustrates it. Read the sentence’s charge (positive or negative) and pick a matching-charge answer.^[14]

Grammar

Grammar is a near-universal core section — about 50 scored questions in roughly 50 minutes. The format is heavily “find the error” and best-usage: pick the correct option or the word that fixes a sentence. It tests standard formal written English, not casual speech.^[15]

Agreement and parts of speech

Know the parts of speech (noun, pronoun, verb, adjective, adverb, preposition, conjunction) and that an adverb modifies a verb (“She did well,” not “good”). Subject-verb agreementis tested on nearly every form: ignore words between the subject and verb (“The box of supplies ishere”), and treat indefinite pronouns (each, every, everyone, neither) as singular.^[15]

For pronoun case, use subject pronouns (I, he, she, we, they) as subjects and object pronouns (me, him, her, us, them) as objects — “between you and me,” never “I.” Use who for subjects and whom for objects.^[15]

Sentence structure and punctuation

A fragment is missing a subject or verb (“Because she studied.”); a run-on or comma splicewrongly joins two independent clauses (“She studied, she passed.”) — fix with a period, semicolon, or a conjunction. Keep items in a list parallel (“reading, writing, and studying”).^[15]

Use the apostrophe for possession (nurse’s) and contractions (don’t), never for plain plurals; a semicolon joins two related independent clauses. Capitalize sentence starts and proper nouns.^[15]

Commonly confused words

High-yield homophones and confusables recur on nearly every form: affect (verb) vs. effect(noun), their/there/they’re, your/you’re, its/it’s, than/then, accept/except, principal/principle, and fewer/less.^[16]

Anatomy & Physiology

Anatomy & Physiology is the most commonly added science (about 25–30 questions, ~25 minutes) and the single most-feared section because of its breadth and applied physiology. The #1 community warning: the official review book’s A&P chapter does not fully prepare you — study broad system function and cause-and-effect, not just definitions. Highest-yield clusters are cardiac blood flow, the endocrine gland→hormone map, and directional terms.^[7]

Directional terms, planes, and tissues

Know directional terms (anterior/posterior, medial/lateral, proximal/distal, superior/inferior) and the three body planes: sagittal (left/right), frontal/coronal (front/back), and transverse (top/bottom). The levels of organization run chemical → cell → tissue → organ → organ system → organism, and the four tissue types are epithelial, connective, muscle, and nervous.^[7]

Cardiovascular system and blood flow (highest-yield)

The heart appears on virtually every form, so know it cold. It has four chambers — right and left atria (receive) and right and left ventricles (pump). The left ventricle is the strongest because it pumps to the whole body. Valves: tricuspid (right, 3 cusps) and bicuspid/mitral (left, 2 cusps) — mnemonic LAB RAT (Left=Bicuspid, Right=Tricuspid).^[6]

Trace the blood-flow path: body → right atrium → tricuspid → right ventricle → pulmonary valve → pulmonary artery → lungs → pulmonary veins → left atrium → mitral → left ventricle → aortic valve → aorta → body. The pulmonary artery (deoxygenated) and pulmonary vein (oxygenated) are the two famous exceptions to the arteries-carry-oxygen rule.^[6]

Endocrine glands and hormones (high-yield)

The endocrine system is a frequent trap because students confuse which gland makes which hormone. The pituitaryis the “master gland”; theparathyroid(PTH) raises blood calcium when it drops, while the thyroid’s calcitonin lowers it; and the pancreas releases insulin (lowers blood sugar) and glucagon (raises it).^[8]

Other body systems

Cover the rest broadly. The respiratory path ends at the alveoli (gas exchange), driven by the diaphragm. Digestion runs mouth → esophagus → stomach → small intestine (most absorption) → large intestine (water).

The urinary path is kidney → ureter → bladder → urethra, with the nephron as the filtering unit. In the nervous system, afferent neurons are sensory (toward the CNS) and efferent are motor (away) — mnemonic SAME.^[7]

Biology

Biology is a school-dependent science section (about 25–30 questions, ~25 minutes) at intro-college level. The highest-confidence “this was on my exam” cluster is cellular respiration and photosynthesis (reactants, products, and ATP yields), mitosis vs. meiosis, transcription/translation, and Punnett squares.^[10]

Cells, organelles, and transport

Separate prokaryotes (bacteria — no nucleus) from eukaryotes (nucleus + organelles). Match each organelle to its job: the mitochondria make ATP, ribosomes build proteins, the nucleus holds DNA, and the Golgi apparatus packages and ships proteins. Transport: diffusion and osmosis are passive, while active transport needs ATP.^[9]

Cellular respiration vs. photosynthesis

Memorize the two energy equations cold — telling them apart is the most-asked Biology item. Cellular respiration burns glucose to make ATP: $\ce{C6H12O6 + 6O2 -> 6CO2 + 6H2O + ATP}$, running glycolysis (cytoplasm) → Krebs cycle → electron transport chain, for ~36–38 ATP per glucose. Photosynthesis is the reverse, building glucose with light: $\ce{6CO2 + 6H2O + light -> C6H12O6 + 6O2}$.^[10]

Cell division, DNA, and genetics

Distinguish mitosis (one division → two identical diploid cells, 2n = 46 in humans) from meiosis (two divisions → four unique haploid gametes, n = 23). The central dogma flows DNA → RNA → protein; DNA pairs A-T and G-C, while RNA uses uracil (U) instead of thymine. A codon is three mRNA bases for one amino acid (AUG = start).^[9]

For Mendelian genetics, a genotype is the genetic makeup (Bb) and a phenotype is the observed trait. A monohybrid cross $Bb \times Bb$ gives a genotype ratio of 1:2:1 and a phenotype ratio of 3:1 (dominant:recessive) on a 2×2 Punnett square.^[9]

Chemistry

Chemistry is an uncommon section (about 25–30 questions, ~25 minutes), required by programs with a chemistry prerequisite. It is more conceptual than calculation— atomic structure, the periodic table, bonding, reaction types, and pH — and light on multi-step stoichiometry, so don’t over-drill hard math.^[11]

Atomic structure and the periodic table

An atom has protons (+) and neutrons (0) in the nucleus and electrons (−) in shells. The atomic number (number of protons) defines the element, and mass number A = protons + neutrons. Isotopes share an element but differ in neutrons. Valence electrons (outer shell) drive bonding.^[11]

On the periodic table, atomic radius decreases left→right and increases down; electronegativity and ionization energy increase toward the top-right (fluorine is most electronegative). Group 18 noble gases are inert (full shell); group 17 halogens are very reactive.^[11]

Bonding and reaction types

An ionic bond transfers electrons (metal + nonmetal, e.g., $\ce{NaCl}$); a covalent bond shares electrons (nonmetals, e.g., $\ce{H2O}$). Balance equations by changing coefficients only, never subscripts — required by conservation of mass.^[11]

Acids, bases, the mole, and pH

The pH scale runs 0–14: below 7 acidic, 7 neutral, above 7 basic, and pH + pOH = 14. Strong acids ($\ce{HCl}$, $\ce{HNO3}$, $\ce{H2SO4}$) fully dissociate; strong bases include $\ce{NaOH}$ and $\ce{KOH}$.

A mole is $6.022 \times 10^{23}$ particles (Avogadro’s number), and molarity is moles of solute per liter. Remember OIL RIG for redox.^[11]

Physics

Physics is rare — required only by programs with a physics prerequisite, and it is not in the official Elsevier review book. Confirm your program even requires it before studying. It tests conceptual + light-calculation intro physics: motion, forces, energy, and basic waves and electricity.^[18]

Motion, forces, and energy

Distinguish speed (a scalar, distance ÷ time) from velocity (a vector with direction), and distance (total path) from displacement (straight-line). Acceleration is the change in velocity over time. Newton’s second law is $F = ma$, weight is $W = mg$ with $g \approx 9.8\ \text{m/s}^2$, and work is $W = F \times d$.^[18]

Energy is conserved (it transforms, never disappears). Kinetic energy is $KE = \tfrac{1}{2}mv^2$, gravitational potential energy is $PE = mgh$, and power is $P = \frac{W}{t}$. Momentum is $p = mv$ and is conserved in collisions.^[18]

Waves and electricity

A wave transfers energy; wave speed is $v = f\lambda$. Transverse waves (light) vibrate perpendicular to travel; longitudinal waves (sound) vibrate parallel, and sound needs a medium while light travels through a vacuum. Ohm’s law is $V = IR$; in a series circuit current is the same throughout, while in a parallel circuit voltage is the same across branches.^[18]

How to Use This Study Guide

Because the HESI A2 is modular, your first move is to confirm which sections your program requires and what cutoff it sets — then study only those, one at a time. Use this guide alongside our free practice tools, not on its own:

HESI A2 Glossary

Quick definitions for the terms you’ll see most across the HESI A2 sections:

acceleration

The change in velocity over time, in m/s².

active transport

Movement of substances from low to high concentration, requiring ATP.

acute

Sudden in onset and short but often severe in course; opposite of chronic.

affect

Usually a verb meaning to influence (an Action).

afferent

Sensory neurons carrying signals toward the CNS (mnemonic SAME: Sensory-Afferent).

allele

A version of a gene; dominant (uppercase) masks recessive (lowercase).

anterior

Toward the front of the body (ventral).

aorta

The largest artery; carries oxygenated blood from the left ventricle to the body.

atomic number

The number of protons in an atom's nucleus; it defines the element.

author's purpose

Why a text was written: to inform, persuade, entertain, describe, or instruct.

benign

Not harmful; not cancerous.

cellular respiration

Converting glucose and oxygen into ATP, CO₂, and water; glycolysis in the cytoplasm, Krebs and the ETC in the mitochondria.

central dogma

The flow of genetic information: DNA → RNA → protein.

chronic

Long-lasting and persistent.

codon

Three mRNA bases that code for one amino acid; AUG is the start codon.

comma splice

Two independent clauses joined by only a comma; fix with a period, semicolon, or a conjunction.

conservation of mass

Principle that matter is neither created nor destroyed, so atoms must balance in a chemical equation.

context clue

A hint in the surrounding sentence — definition, contrast, example, or restatement — that reveals a word's meaning.

contraindication

A reason NOT to use a particular treatment.

covalent bond

A bond formed by sharing electrons, typically between nonmetals.

cross-multiplication

Solving a proportion $a/b = c/d$ by setting $a \times d$ equal to $b \times c$, then solving for the unknown.

diffusion

Movement of particles from high to low concentration (passive, no ATP).

diploid

Having the full chromosome number (2n = 46 in humans).

distal

Farther from the point of attachment or origin.

dosage formula

Amount to give = (Dose Ordered $\div$ Dose on Hand) $\times$ Quantity; convert to the same unit first.

effect

Usually a noun meaning a result (the rEsult).

efferent

Motor neurons carrying signals away from the CNS to muscles (Motor-Efferent).

Elsevier

The education company that owns and publishes the HESI (Health Education Systems, Inc.) exams, including the A2; the official content guide is the Admission Assessment Exam Review, 6th edition (2024).

endocrine gland

A ductless gland that secretes hormones directly into the blood.

fact

A statement that can be verified as true or false.

fragment

An incomplete sentence missing a subject, a verb, or a complete thought.

frontal plane

The coronal plane; divides the body into front and back.

genotype

An organism's genetic makeup (e.g., Bb).

glucagon

A pancreatic hormone that raises blood glucose.

Golgi apparatus

The organelle that packages, modifies, and ships proteins.

grain

An apothecary mass unit; on the HESI A2 use 1 grain = 60 mg (the pure value is ~64.8 mg, but HESI rounds to 60).

haploid

Having half the chromosome number (n = 23 in humans), as in gametes.

HESI A2

The Health Education Systems, Inc. Admission Assessment (A2), Elsevier's modular nursing- and allied-health-program admission exam. Schools choose which sections applicants take and set their own passing score.

homophone

A word that sounds like another but differs in spelling and meaning, such as their, there, and they're.

inference

A conclusion a passage logically supports but does not state outright; on HESI A2 it must stay close to the text.

insulin

A pancreatic hormone that lowers blood glucose.

ionic bond

A bond formed by transferring electrons, typically between a metal and a nonmetal.

isotope

Atoms of the same element with different numbers of neutrons.

kinetic energy

The energy of motion, $KE = \tfrac{1}{2}mv^2$.

lateral

Away from the midline of the body.

left ventricle

The largest, strongest heart chamber; pumps oxygenated blood to the whole body through the aorta.

main idea

The single most important point a passage makes; it covers the whole passage, broader than any one detail.

malignant

Cancerous; tending to worsen or spread.

medial

Toward the midline of the body.

meiosis

Cell division producing four genetically unique haploid gametes for reproduction.

metric ladder

Kilo-Hecto-Deca-base-Deci-Centi-Milli, each step a factor of 10 (mnemonic: King Henry Died By Drinking Chocolate Milk).

mitochondria

The 'powerhouse' organelle; site of cellular respiration and ATP production.

mitosis

Cell division producing two genetically identical diploid cells for growth and repair.

mitral valve

The bicuspid (two-cusp) left atrioventricular valve (the L in LAB RAT).

modular exam

An exam built from selectable sections; each nursing program picks which HESI A2 sections (typically 4–6) its applicants must take, so there is no single fixed length.

molarity

Concentration in moles of solute per liter of solution, $M = \text{mol} \div \text{L}$.

mole

An amount equal to Avogadro's number, $6.022 \times 10^{23}$ particles.

nephron

The functional filtering unit of the kidney.

Newton's second law

Force equals mass times acceleration, $F = ma$.

occluded

Blocked or closed off.

Ohm's law

Voltage equals current times resistance, $V = IR$.

OIL RIG

Oxidation Is Loss, Reduction Is Gain — of electrons.

opinion

A belief or judgment that cannot be verified; often signaled by best, should, or unfortunately.

organelle

A specialized structure within a cell, such as the mitochondria or nucleus.

osmosis

The diffusion of water across a selectively permeable membrane.

parathyroid

The gland whose hormone (PTH) raises blood calcium when it drops.

patent

Open and unobstructed (a patent airway).

PEMDAS

Order of operations: Parentheses, Exponents, Multiplication/Division (left to right), Addition/Subtraction (left to right).

percent change

(new value $-$ old value) $\div$ old value $\times 100$; positive is an increase, negative a decrease.

pH scale

A 0–14 logarithmic scale of acidity; below 7 acidic, 7 neutral, above 7 basic.

phenotype

An organism's observed physical trait.

photosynthesis

Using light to build glucose from CO₂ and water in chloroplasts; the reverse of respiration.

pilot question

An unscored trial question (about 5 per section) that does not count toward your score but is mixed in so the administered count exceeds the scored count.

pituitary

The 'master gland' that controls other endocrine glands; anterior secretes GH/TSH/ACTH/FSH/LH/prolactin, posterior releases ADH and oxytocin.

posterior

Toward the back of the body (dorsal).

prefix

A word part added to the front of a root that changes meaning, such as hyper- (over) or hypo- (under).

proportion

An equation stating that two ratios are equal, such as $a/b = c/d$; solved by cross-multiplication.

proximal

Closer to the point of attachment or origin.

pulmonary artery

The one artery carrying deoxygenated blood, from the right ventricle to the lungs.

pulmonary vein

The veins carrying oxygenated blood from the lungs to the left atrium.

Punnett square

A grid used to predict offspring genotype and phenotype ratios from a genetic cross.

ratio

A comparison of two quantities, written $a:b$ or $a/b$; ratios and proportions are the heaviest-weighted HESI A2 math topic.

ribosome

The site of protein synthesis.

root

The core part of a word carrying its base meaning, such as cardi (heart).

run-on

Two independent clauses joined without proper punctuation or a conjunction.

sagittal plane

Divides the body into left and right.

subject-verb agreement

The rule that a verb must match its subject in number — a singular subject takes a singular verb.

suffix

A word part added to the end of a root, often marking a condition or part of speech, such as -itis (inflammation).

supporting detail

A specific fact or example that backs up the main idea; never the main idea itself.

tone

The author's attitude toward the subject, conveyed through word choice (neutral, critical, enthusiastic, cautionary).

transverse plane

Divides the body into top (superior) and bottom (inferior).

tricuspid valve

The right atrioventricular valve with three cusps (the R in LAB RAT).

valence electron

An outer-shell electron that drives chemical bonding.

velocity

Displacement divided by time; a vector with both size and direction (speed is the scalar version).

Free HESI A2 Study Materials & Resources

Everything you need to prepare for the HESI A2 is free here — no paywall, no sign-up. This guide is the foundation; pair it with the rest of our free HESI A2 study materials:

• HESI A2 Practice Test — realistic, timed questions with explanations, by section.
• HESI A2 Flashcards — active-recall decks for the high-yield facts.

HESI A2 Study Guide FAQ

References

1. 1.Elsevier / HESI. “Admission Assessment Exam Review, 6th Edition (HESI).” Elsevier. ↑
2. 2.Elsevier. “HESI Exam Solutions for Nursing (Admission Assessment Overview).” Elsevier. ↑
3. 3.Elsevier Evolve. “HESI A2 and à la carte Exams (Modular Section Selection).” Elsevier Evolve. ↑
4. 4.Elsevier Evolve. “Official HESI A2 Student Guide (Own Device).” Elsevier Evolve. ↑
5. 5.Elsevier Evolve. “How to Study for Entrance Exams (Student Life Blog).” Elsevier Evolve. ↑
6. 6.National Heart, Lung, and Blood Institute (NIH). “How the Heart Works: Blood Flow.” nhlbi.nih.gov. ↑
7. 7.National Cancer Institute SEER Training (NIH). “Cardiovascular System and Anatomical Terminology.” training.seer.cancer.gov. ↑
8. 8.MedlinePlus, U.S. National Library of Medicine (NIH). “Endocrine Glands, Hormones, and Medical Word Parts.” medlineplus.gov. ↑
9. 9.National Human Genome Research Institute (NIH). “Cell Biology, Organelles, DNA, and Cell Division (Genetics Glossary).” genome.gov. ↑
10. 10.National Center for Biotechnology Information (NIH). “Cellular Respiration and Photosynthesis (Biochemistry).” ncbi.nlm.nih.gov. ↑
11. 11.National Institute of Standards and Technology (NIST). “Atomic Structure, Bonding, and the pH Scale (Periodic Table).” nist.gov. ↑
12. 12.National Institute of Standards and Technology (NIST). “The Metric System, Ratios, and Unit Conversion.” nist.gov. ↑
13. 13.National Library of Medicine (NIH), Bookshelf. “Dosage Calculation and Safe Medication Administration.” ncbi.nlm.nih.gov. ↑
14. 14.Purdue Online Writing Lab (Purdue University). “Reading Comprehension: Main Idea, Inference, and Author's Purpose.” owl.purdue.edu. ↑
15. 15.Purdue Online Writing Lab (Purdue University). “Grammar, Sentence Structure, Agreement, and Punctuation.” owl.purdue.edu. ↑
16. 16.Purdue Online Writing Lab (Purdue University). “Commonly Confused Words and Spelling Conventions.” owl.purdue.edu. ↑
17. 17.MedlinePlus, U.S. National Library of Medicine (NIH). “Understanding Medical Words: Prefixes, Roots, and Suffixes.” medlineplus.gov. ↑
18. 18.NASA Glenn Research Center. “Motion, Forces, Energy, and Waves (Physics Basics).” nasa.gov. ↑

Sources for the concept answers

Every answer in the HESI A2 concept questions above is drawn from an official or authoritative primary source:

1. National Cancer Institute SEER Training (NIH). “Anatomical Terminology, Planes, and Directions.” training.seer.cancer.gov, accessed 18 June 2026.

Career Employer

Career Employer is the ultimate resource to help you get started working the job of your dreams. We cover topics from general career information, career searching, exam preparation with free study materials, career interviewing, and becoming successful in your career of choice.

Follow Us:

All Posts