Page 1 - Science Study Guide for the TEAS

General Information

The topics covered by the 47 questions on the ATI TEAS Science Test fall into three main categories, with the largest emphasis on human anatomy and physiology. Here are the approximate percentages of questions from each tested area of science:

\[\begin{array}{ll} \text{Human Anatomy and Physiology} & {68\%} \\ \text{Life and Physical Science} & {17\% } \\ \text{Scientific Reasoning} & {15\%} \\ \end{array}\]

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 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 \(CO_2\).

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


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.


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.

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