How to Prepare for the ATI TEAS Science Test
General Information
The vast majority of questions concern the human body, its systems, and the function of these
systems. A few questions cover on topics from biology, chemistry, and physics. For some of the
questions, you will not only need to know about scientific concepts, but also be able to reason about
them using scientific methods of thought.
Human Anatomy and Physiology
The largest portion of the Science section of the ATI TEAS Test concerns the human body. This may
include questions regarding the gastrointestinal system and human metabolism, or more complex
ones that require you to identify the bodily system responsible for reproductive function, hormone
output, or the body’s electrical impulses. The questions may cover muscles and body functions,
ranging from the purpose and parts of the heart to those of the abdominal muscles. To prepare for
these questions, study all aspects of the body and its systems.
Cells: Parts and Function
Cells are the components that make up all living organisms. All animal and plant cells contain a
nucleus, cytoplasm, a cell membrane, mitochondria, and ribosomes. However, plant cells contain
three extra components: chloroplasts, a cell wall, and a permanent vacuole. Different cells are
designed to perform different functions; for example, red blood cells are designed to carry oxygen to
other cells in animals; a plant’s leaf cells are designed to absorb light.
Be sure you understand these terms and their role in cell function: eukaryotic, organelles, plasma
membrane, nucleus, cytoplasm, ribosome, rough ER, Golgi apparatus, nucleolus, lysosome,
mitochondria,centrosome, smooth ER, cilia.
Tissues
Tissues are groups of cells working together to perform a specific function. There are four main
types of tissues in the body: epithelial, connective, muscular, and nervous tissues. Epithelial tissue
exists in sheets and does not have a dedicated blood supply; instead, it relies on diffusion from
nearby capillaries. It serves two purposes: either as a covering, like skin, or to produce secretions,
like glands. Connective tissue connects different structures within the body and usually has its own
blood supply. The three types of muscle tissue( skeletal, cardiac, and smooth) are all involved in
allowing movement. Finally, nervous tissue makes up the brain and nervous system.
Be sure you know the four types of tissue, their functions, and where they are located in the
body: epithelial, connective, muscular, nervous.
Organ Systems
Just as groups of cells working together make tissues, groups of tissues working together make
organs. A group of organs working together then makes an organ system. For example, the nervous
system is made up of the brain, the spinal cord, and the nerves. There are 11 major organ systems
in the human body: the respiratory, circulatory or cardiovascular, digestive or gastrointestinal,
muscular, nervous, integumentary, endocrine, urinary, reproductive, immune and skeletal. It is
important to understand the general anatomy and physiology of all of these systems.
Respiratory System
The respiratory system comprises the nose, throat, and lungs. It also includes the trachea, bronchi,
and diaphragm. Its function is to receive and deliver oxygen and remove carbon dioxide. The
diaphragm is a sheet of muscle that enables breathing. The intercostal muscles and accessory
muscles can also be used to enable greater expansion. Inside the lungs, oxygen and carbon dioxide
are exchanged between the air and blood via diffusion. This process occurs in the alveoli. The rate
at which gas enters or leaves the lungs is called ventilation and is controlled by the autonomic
nervous system, specifically by the medulla oblongata and pons. If the level of carbon dioxide in the
blood increases, this is detected by receptors in the aorta, carotid artery, and medulla. A signal is
then sent to increase the rate of breathing to remove excess CO2.
The ATI TEAS test may also gauge your knowledge of the role of these in the respiratory
system: pharynx, epiglottis, larynx, trachea, bronchi, bronchioles, surfactant, cilia, pleura, pleural
fluid, simple diffusion, diffusion rate, ventilation rate, acidosis, alkalosis, negative pressure breathing,
total lung capacity, residual volume, vital capacity, tidal volume, inspiratory reserve volume,
inspiratory reserve volume cystic fibrosis, surfactant insufficiency, asthma, emphysema.
Cardiovascular System
The circulatory, or cardiovascular, system is composed of the heart, blood vessels, and blood. Its
function is to transport blood cells and nutrients around the body. It is important to understand the
anatomy of blood, blood cells, the circulatory system, the heart, and the cardiac cycle, as well as
issues regarding these parts and systems.
There are two circuits through which blood travels―pulmonary and systemic. The pulmonary circuit
carries deoxygenated blood away from the heart to the lungs where carbon dioxide is removed and
oxygen binds to the hemoglobin in red blood cells. The oxygenated blood is then taken back to the
heart, where it can be circulated by the systemic circuit to deliver oxygenated blood to the rest of the
body, as well as transporting nutrients and waste.
The pulse rate is the number of heartbeats per minute and a normal pulse rate for a healthy adult
should fall between 60 and 100 beats per minute. There are two types of blood pressure: systolic
and diastolic. Systolic pressure is the pressure inside the arteries when the heart contracts and
should be less than 120 mm Hg. Diastolic pressure is the pressure in the arteries when the heart
relaxes and a normal value is under 80 mm Hg.
The roles of these in cardiovascular function must be understood, as well: atria, ventricles,
atrioventricular valves, tricuspid valve, mitral valve (bicuspid valve), arteries, arterioles, capillaries,
diffusion, aorta, venules, veins, inferior vena cava, pulmonary veins, plasma, erythrocytes,
hemoglobin, anemia, sickle-cell trait, leukocytes, lymphocytes, platelets, thrombocytopenia, closed
circulatory system, systemic circuit, lymphatic system, lymph, lymph nodes, pulmonary circuit,
systole, diastole, congestive heart failure, hypertension, atherosclerosis.
Gastrointestinal or Digestive System
The gastrointestinal system is a large system of organs composed of the mouth, esophagus,
stomach, small intestine, large intestine, pancreas, liver, gall bladder, rectum, and anus. Its function
is to break down food and absorb nutrients. During digestion, the body secretes several enzymes
that help to break down food. These include pepsin, which acts on proteins, lipase, which acts on fat,
and amylase, which acts on carbohydrates. Generally, food is moved through the digestive system
via a series muscular contractions called peristalsis.
Be sure you also know the meaning and function of these: absorb, alimentary canal, salivary glands,
bolus, pharynx, stomach, esophageal sphincter, pyloric sphincter, gastric, juice, chyme, small
intestine, duodenum, bile, common bile duct, villi, microvilli, jejunum, ileum, cecum, colon, rectum,
anus, anal sphincter, mechanical digestion, chemical digestion, zymogen, hepatic portal vein,
digestive hormones and the cause of their release.
Muscular System
The muscular system works in conjunction with the skeletal system to allow movement. There are
three types of muscle in the human body: cardiac, smooth, and skeletal. Cardiac muscle is found in
the heart and is an involuntary muscle. Smooth muscle is also involuntary and is the stretchiest type
of muscle. It is found throughout the body, in blood vessels, the bladder, the eyes, and many other
areas. Skeletal muscles, such as the deltoid and biceps brachii, are the voluntary muscles attached
to bones by tendons. It is important to know the parts and structures that make up the muscular
system, including the types of muscles and muscle tissues.
Some other terms you’ll need to study are: fascicles, myofibril, sarcomeres, actin, myosin, T tubules,
ischemic, soma, dendrites, axon, action potentials, polarization, myelin, multiple sclerosis, synapse,
neurotransmitters, neuromuscular junction, acetylcholine, motor unit, atrophy, muscle fatigue, lactic
acid, muscle strain.
Nervous System
The nervous system is composed of the central nervous system, which contains the brain and spinal
cord, and the peripheral nervous system, which contains the nerves and sensory organs. The brain
is the control center of the nervous system and contains roughly 100 billion neurons. The nervous
tissue is composed of two kinds of cells―neurons or “nerve cells,” which transmit electrochemical
signals to the body, and neuroglia, which surround and help to maintain the neurons. There are
three kinds of neurons―afferent neurons, which send sensory signals to the central nervous
system, efferent neurons, which send signals from the central nervous system to the muscular
system, and interneurons, which form the network that transmits information from afferent neurons to
efferent neurons.
Be sure you also understand the role of these in nervous system function: brain, cranium, cerebrum,
corpus callosum, brain stem, cerebellum, medulla, spinal cord, spinal nerves, somatic nervous
system, autonomic nervous system, sympathetic and parasympathetic divisions, cranial nerves,
optic nerve, vagus nerve, sciatic nerve, neuropathy.
Note: Some references combine the previous two systems into one, calling it the “neuromuscular
system.”
Integumentary System
The integumentary system is composed of the skin, hair, and nails. The integumentary system acts
as a barrier and protects the body from damage. It also excretes waste substances, such as sweat,
and helps to regulate body temperature and vitamin D synthesis. Sensory receptors for the detection
of pain, pressure, and temperature are attached to integumentary system. Human skin has several
layers, including the epidermis, dermis, and hypodermis. The epidermis is the external layer; the
dermis is the middle layer and contains the muscular tissue, follicles and hair roots, nerve endings,
vessels glands, and connective tissue. The innermost layer is the hypodermis, which contains the
body fat.
Other important things related to this system are: integument, adipose, sudoriferous glands, eccrine
glands, apocrine glands, sebaceous glands, sebum, thermoregulation, hyperthermia, hypothermia.
Endocrine System
The endocrine system of the body is made up of glands that secrete hormones into the bloodstream.
These hormones travel through the circulatory system to work on particular target organs in the
body. Hormones help regulate many different bodily functions, including growth and development,
reproduction, metabolism, and stress responses. Glands of the endocrine system include the
adrenal gland, which produces adrenaline, noradrenaline, and dopamine.
Understanding the endocrine system function also requires familiarity with these
terms: homeostasis, receptors, peptide hormones, steroid hormones, positive feedback, negative
feedback, hypothalamus, posterior pituitary, oxytocin, vasopressin, anterior pituitary, direct
hormones, topic hormones, melatonin, parathyroid hormone, thyroid hormones, calcitonin, various
hormones that stimulate other body functions, hypothyroidism, hyperthyroidism, goiter, insulin,
glucagon, diabetes, epinephrine, aldosterone, estrogen, progesterone, testosterone.
Urinary System
The urinary system, or renal system, removes waste from the body and regulates the blood. It is
composed of the kidneys, ureters, bladder, and urethra. The kidneys filter the blood, converting
waste into urine. The ureters are smooth, muscular tubes, which transport urine from the kidneys to
the bladder. Urine is stored in the bladder before being passed through the urethra and expelled.
Other important terms relating to this system are: nephron, renal arteries, glomerulus, Bowman’s
capsule, renal corpuscle, afferent arteriole, efferent arteriole, renal tubule, hematuria, adrenal
glands, hormones involved in this system and the cause of their release.
*Note: Some references combine the urinary and reproductive systems into one and call it the
“genitourinary” system.
Reproductive System
Male
The male reproductive system is composed of the testes, glands, sperm ducts, urethra, and penis.
The testes are contained within the scrotum and produce sperm (male sex cells) and male sex
hormones. The primary male sex hormone is testosterone. Testosterone is secreted in males after
puberty, stimulating the production of sperm, increasing body hair growth, causing enlargement of
the larynx and thickening of the vocal cords, increasing muscle mass, and thickening of the skin and
bones.
Other terms related to the function of the male reproductive system are: seminiferous tubules,
spermatogenesis, epididymis, ejaculatory duct, seminal vesicles, prostate gland, bulbourethral
glands.
Female
The female reproductive system is composed of the ovaries, fallopian tubes, uterus, cervix, and
vagina and includes a 28-day cycle of events, known as the menstrual cycle. The ovaries contain
hundreds of eggs or ova (female sex cells). The ovaries release hormones that cause the lining of
the uterus to develop and cause an egg to mature. The main female sex hormones are estrogen,
progesterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH). These hormones
regulate the menstrual cycle;estrogen, in particular, stimulates the changes that occur during
puberty.
The female reproductive system also involves these: oogenesis, endometrium, placenta,
menstruation, follicular phase, luteal phase, ovarian follicle, ovulation, corpus luteum.
Immune System
The immune system protects the body against disease and it is divided into the innate and adaptive
immune system. White blood cells, or leukocytes, are produced and stored by the body. There are
two general types of leukocytes: phagocytes, which destroy foreign cells, and lymphocytes, which
are used to remember and recognize foreign organisms, enabling more efficient destruction.
Disorders of the immune systems can leave the body vulnerable to diseases. For example,
immunodeficiency can occur as a result of contracting human immunodeficiency virus (HIV), which
makes the immune system less effective than normal.
A thorough understanding of the immune system entails understanding the significance of
these: pathogens, innate arm, adaptive arm, flora, lysozyme, antimicrobial peptides, interferon,
memory for pathogens, granulocytes, basophils, eosinophils, neutrophils, phagocytosing,
inflammatory responses, dendritic cells, pathogen-associated molecular patterns (PAMPs), antigen,
macrophages, natural killer (NK) cells, vaccination, T cells, thymus, helper T cells, acquired
immunodeficiency syndrome (AIDS), cytotoxic T cells, B cells, plasma cells, antibodies, complement
system, active and passive immunity, self-tolerant, autoimmune disease.
Skeletal System
The skeletal system consists of the bones of the body, as well as the supporting tissues that connect
them. Bones serve multiple purposes. They provide a framework for the body itself, protect organs,
produce red and white blood cells in the marrow, and store calcium, iron, and fat. There are five
types of bones in the human body: long, flat, short, sesamoid, and irregular. Irregular bones have a
unique shape, like the vertebrae for example. Supportive tissues include cartilage, tendons, and
ligaments. It is important to know the parts of the skeletal system, including the bones and their
macroscopic and microscopic structure.
Other important terms to know and understand are: axial skeleton, appendicular skeleton, synovial
joint, fibrous joint, cartilaginous joint, arthritis, rheumatoid arthritis, antagonistic muscle and
contraction, spongy bone, bone marrow, compact bone, diaphysis, epiphyses, epiphyseal plate,
periosteum, osteoblast, osteoclast, osteocyte, osteon, lamellae, haversian canal, folkmann canal,
lacunae, canaliculi, osteoporosis, osteogenesis imperfecta, osteoarthritis.
Anatomical Planes and Terminology
To help in understanding anatomy, the human body is discussed in three planes: the coronal,
sagittal, and transverse (or horizontal) planes. If a person is standing upright and facing forward, with
their arms by their side, palms facing forward and fingers pointing down, they are in the “resting
pose.” Then, the coronal plane separates the front and back (or anterior/ventral and posterior/dorsal)
halves; the sagittal separates the left and right (or lateral and medial) halves, and the transverse
plane separates the top and bottom (or inferior and superior) halves.
Life and Physical Sciences
The newest version of the ATI TEAS (TEAS 6) has de-emphasized the area of Earth science in favor
of focusing on the biological and chemical realms of study. These are, after all, more relevant to
nursing practices. Be sure you understand the following terms and ideas before taking the test.
Macromolecules
Macromolecules are large molecules necessary for life. The major macromolecules are
carbohydrates, lipids, proteins, and nucleic acids. These perform a large range of functions involved
in survival and growth. Humans get most of the macromolecules they need from their food and are
able to synthesize some proteins from combinations of other macromolecules.
Additional terms to become familiar with include: monomer, polymer, dehydration synthesis,
hydrolysis, monosaccharide, disaccharide, polysaccharide, glycogen, starch, amylose, amylopectin,
cellulose, chitin, amino acid, peptide bond, polypeptide chain, globular protein, fibrous protein,
enzyme, activation energy, active site, hydrocarbon chain, hydrophobic, fatty acid, triglyceride,
saturated and unsaturated fatty acid chain, nucleotide, ribonucleic acid (RNA), adenosine
triphosphate (ATP).
Heredity
Heredity is the mechanism by which genetic information is passed from parent to child. This genetic
information can code for certain traits, such as eye color. The genetic information that is passed on
is held in the DNA, which is made of nucleic acids. Over many generations, the passing on of some
traits, while failing to pass on others, can lead to the evolution of a species.
DNA
DNA stands for deoxyribonucleic acid and is the fundamental genetic building block in humans and
almost all other life. Most of the DNA is held in the nucleus of the cells. It is made up of four
chemicals that match up together in pairs: adenine goes with thymine and guanine goes with
cytosine. From just these four chemicals, every gene and chromosome and protein can be made. It
is important to know that DNA can replicate itself, which allows for the creation of new cells.
Chromosomes
DNA strands in cells are very long and thin and are curled into structures called chromosomes.
Humans have 23 pairs of chromosomes (46 total chromosomes) in each cell, except for sperm and
ova which have only one set of each chromosome (23 in total). Normally, two strands of DNA are
complementary and form a double helix, but when cell division takes place, the two strands of the
helix separate and are copied, eventually resulting in two sets of double helixes and two sets of
chromosomes—one for each of the new cells.
Genes
Genes are made up of DNA and each chromosome may contain many genes. Genes contain the
genetic instructions with which to make proteins. Every person has two copies or alleles of every
gene—one inherited from each of their parents. Most genes are the same in every person, but
some, such as the genes that determine eye color, are different. Genes can either be dominant or
recessive, and if an organism has one of each, the dominant gene is the one that will be expressed.
For example, a person might have a dominant gene for green eyes and a recessive gene for grey
eyes—as a result they will have green eyes. Incomplete dominance and codominant genes also
exist.
Mendel’s Laws of Heredity
Johann Gregor Mendel discovered the laws of heredity when studying pea plants. They are as
follows:

The law of segregation: Each inherited trait comes from a pair of genes, one from each
parent.

The law of independent assortment: Genes on different chromosomes are kept separate
from each other so that the inheritance of one trait does not depend on the inheritance of
another.

The law of dominance: If a pair of genes is made up of one dominant and one recessive
gene, the dominant gene will be expressed.
Make sure you are also familiar with this additional vocabulary: mitosis, meiosis, diploid, haploid,
gamete, zygote, allele, homozygous, heterozygous, dominant, recessive, genotype, phenotype,
incomplete dominance, codominance, Punnett square, X-linked, monohybrid cross, dihybrid cross.
Chemistry
The TEAS test requires you to not only demonstrate your understanding of anatomy and biology but
also of chemistry. Through your nursing career, it will often be important to be able to understand
and implement chemistry concepts.
Basic Atomic Structure
Atoms are the building blocks of all chemicals. They are composed of three types of
particles―positively charged protons, negatively charged electrons, and neutral neutrons. Protons
and neutrons make up the nucleus, the central part of the atom. Electrons orbit the nucleus in shells
and most of the volume of the atom is taken up by the space between the nucleus and the electrons.
An element’s nuclear symbol reveals how many protons, electrons, and neutrons make up an atom.
It is important to be able to recognize atomic structure.
Characteristic Properties of Substances
Substances can be made up of pure elements or pure compounds, but not mixtures of elements or
mixtures of compounds. Substances must have a definite chemical composition and distinct
chemical properties. A pure substance cannot be made into simpler components without some
chemical change taking place.
Characteristic properties of substances include their freezing or melting point and their boiling or
condensing point, as well as properties like color and density.
Important terms include: substance, mixture, physical property, chemical property, extensive
property, intensive property, density, melting point, boiling point, specific heat capacity, malleability,
polar molecule, cohesive, adhesion, aqueous solution, solution, solvent, solute, diffusion, osmosis.
States of Matter
Matter may exist in three main states: solid, liquid, or gas. The state that matter is in is dependent on
temperature. For example, at room temperature, water is a liquid; but, below its freezing point of 0ºC,
it changes state and becomes a solid, ice. Likewise, above its boiling point of 100ºC, it changes state
and becomes a gas, steam. Other substances and mixtures also exist in these three states and have
their own freezing/melting and boiling/condensing points. When a substance or mixture goes from
one state to another, we call this a change of state. It is important to be able to compare and
contrast the changes of state in matter.
Terms to remember include: intramolecular force, intermolecular force, crystal, phase transition,
freezing point, evaporation, vapor, condensation, latent heat, latent heat of fusion, latent heat of
vaporization, calorie, phase diagram, triple point, critical point, sublimation, deposition.
Chemical Reactions
Chemical reactions can occur when particles collide with each other under the right conditions. The
minimum amount of energy required to start a reaction is known as the activation energy and is the
amount of energy required for a specific reaction to occur. The rate of a reaction can be increased
by increasing the temperature, pressure, or concentration and by adding a catalyst. In industry, iron
is added to catalyze the reaction between nitrogen and hydrogen which makes ammonia. It is
important to be able to describe chemical reactions.
Related terms are: ionic bond, covalent bond, organic molecule, reactant, product, chemical
equation, single displacement reaction, substitution reaction, double displacement reaction,
molecular ion, polyatomic ion, decomposition reaction, synthesis reaction, direct combination
reaction, combustion, oxidation reaction, exothermic, endothermic, catalyst, pH, acidity,
alkalinity/basicity.
The Periodic Table
The 118 known elements are displayed on the periodic table in a specific order. Progressing from
left to right and top to bottom on the table, the elements increase in atomic number. A row in this
table is called a period and a column is called a group. The elements in each row and group share
certain properties.
These are further associated terms: atomic number, atomic mass, atomic mass unit (amu), period,
group, noble gas, metal, element, compound, orbit, orbital, cloud orbit, isotope, neutral atom, ion,
cation, anion, shell, subshell, electron configuration, valence electron, octet rule.
Scientific Reasoning
Scientific reasoning questions on the ATI TEAS test are designed to evaluate your ability to answer
questions and problems using scientific methods and inquiry. Focused on different areas of science,
these questions require the use of logic and reason to find the correct answer. They may be
presented as a word problem, requiring scientific knowledge and math skills to respond accurately.
The Scientific Method
A key scientific reasoning concept to know is the Scientific Method. The Scientific Method involves
six steps: problem identification, question asking, hypothesis development, data collection, analysis,
and conclusion. The first two steps enable the formulation of the hypothesis. Data collection involves
the collection of facts through a scientific method, in a controlled environment, to test the hypothesis.
In the analysis step, the data are analyzed to see if they support the hypothesis. The conclusion
states whether the data analyzed are consistent with the hypothesis.
Other related terms are: experiment, null hypothesis, dependent and independent variable,
experimental group, control, control group, controlled variable, bias, reproducibility.
Lab Measurements
To collect data, some lab measurements are required. The nature of these measurements will
depend on the question that is asked. Tools such as thermometers and scales might be used to
determine the effect of temperature or weight, for example. For these measurements to be reliable
and useful, it is important that they are carried out in a methodical way. It is important to be able to
identify different lab measurements and the tools with which they would be carried out.
The Metric System
The metric system of measurement is widely used in scientific and medical settings. Each basic unit
(meter, gram, liter, etc.) is enlarged or reduced by a multiple of 10 using a certain prefix.
Numerically, measurements can be expressed in alternate units by moving the decimal point to the
left or right.
Important terms to consider are: graduated cylinder, volumetric flask, volumetric pipette, measuring
wheels, electronic balance, triple beam balance, causality.
Scientific Critique
Scientific critique is necessary to evaluate the quality of a scientific experiment. This may take the
form of deciding whether the data collected is the right kind of data with which to answer the
question, or if there is enough of it. Or it might mean carefully considering whether the conclusions
drawn from an experiment actually fit that data. For example, is the scientist making the mistake of
assuming that because two things are correlated, one must cause the other, without the necessary
information to make that assumption? Without a proper scientific critique, it is easy to draw the
wrong conclusions from research findings. It is important that you are able to critique scientific
experiments using logic and the available evidence.
Relationships
Between different variables (e.g., height, temperature, pressure), there can be several relationships.
Two variables might be correlated, i.e., when one increases, so does the other, or they might be
inversely correlated, i.e., when one increases, the other decreases. On the other hand, they might
not be correlated at all. In some cases, they might be correlated because one variable is causing the
other, but it’s important to consider what other variables might be involved that aren’t immediately
apparent. Usually, we try to remember that “correlation does not imply causation.” However, it is
important to study relationships between different variables, events, objects, and procedures and to
be able to explain these relationships logically.
Scientific Analysis
In the scientific analysis stage of a scientific experiment, the hypothesis is considered in the context
of the data and results obtained. In many cases, this is compared to a “null hypothesis” and an
attempt is made to decide which hypothesis best fits the available data. If the data demonstrate that
a hypothesis is incorrect, a new one is needed; in some cases, a new experiment must be carried
out. To decide if the data support a hypothesis or not, the experiment must have been suitably
designed so that the data gathered actually answers the question asked. It is important to be able to
analyze the design of an experiment or a scientific investigation.