TEAS Version 7 Science Section Practice 2026–2027: Comprehensive Study Guide, Test Bank & Practice Questions

A trauma patient requires an immediate red blood cell transfusion, but there is insufficient time to determine the patient’s ABO blood group. Ignoring the Rh factor, which blood group is considered the universal red blood cell donor? A. Type A B. Type B C. Type AB D. Type O Correct Answer: D. Type O Rationale: Type O red blood cells lack both A and B surface antigens, making them least likely to trigger an ABO incompatibility reaction. Type A cells carry A antigens, type B cells carry B antigens, and type AB cells carry both. When the Rh factor is considered, O-negative blood is the preferred universal red blood cell donor. Question 2 A blood sample is collected from a cardiac chamber that has just received blood returning from the systemic circulation. In which chamber would the blood oxygen concentration most likely be lowest? A. Left atrium B. Left ventricle C. Right atrium D. Aorta Correct Answer: C. Right atrium Rationale: The right atrium receives oxygen-poor blood returning from body tissues through the superior and inferior venae cavae. The blood then travels to the right ventricle and lungs for oxygenation. The left atrium, left ventricle, and aorta normally contain oxygen-rich blood that has returned from the pulmonary circulation. Question 3 A membrane receptor binds an extracellular hormone and activates the production of a second messenger inside the plasma membrane. Where does this newly formed intracellular signal travel? A. To another part of the same cell B. Directly into a neighboring cell C. Into the bloodstream D. Outside the cell to bind the hormone Correct Answer: A. To another part of the same cell Rationale: Second messengers transmit signals from membrane receptors to intracellular targets within the same cell. They may activate enzymes, alter ion channels, or influence gene expression. They do not normally enter the bloodstream or neighboring cells. The extracellular hormone serves as the first messenger, while the intracellular molecule carries the signal internally. Question 4 After a person chews food and mixes it with saliva to form a bolus, which structure does the bolus enter immediately after leaving the oral cavity? A. Esophagus B. Pharynx C. Stomach D. Larynx Correct Answer: B. Pharynx Rationale: The bolus moves from the oral cavity into the pharynx during swallowing. It then passes through the esophagus before reaching the stomach. The larynx is part of the respiratory tract and is protected during swallowing by the epiglottis. Therefore, the pharynx is the next digestive structure encountered. Question 5 A patient has extensive damage to the intestinal villi and microvilli. Which digestive function would be most directly impaired? A. Mechanical breakdown of food in the mouth B. Absorption of most nutrients into blood and lymph C. Storage of fecal material D. Production of hydrochloric acid Correct Answer: B. Absorption of most nutrients into blood and lymph Rationale: Most nutrient absorption occurs in the small intestine, where villi and microvilli greatly increase the available surface area. Damage to these structures reduces the diffusion and active transport of nutrients into blood and lymphatic vessels. The mouth performs mastication, the rectum stores feces, and the stomach produces hydrochloric acid. Question 6 A microorganism enters the body and causes tissue damage and disease. Which term most accurately describes this invading organism? A. Antibody B. Pathogen C. Cytokine D. Platelet Correct Answer: B. Pathogen Rationale: A pathogen is a disease-causing organism or infectious agent, such as a bacterium, virus, fungus, or parasite. Antibodies are immune proteins that recognize antigens. Cytokines are signaling molecules used by immune cells, while platelets participate primarily in blood clotting rather than causing infectious disease. Question 7 A patient is rehabilitating after an injury to muscles that voluntarily move the lower limbs. Which type of muscle tissue is primarily involved? A. Cardiac muscle attached to tendons B. Smooth muscle within bones C. Skeletal muscle attached to bones D. Epithelial muscle surrounding joints Correct Answer: C. Skeletal muscle attached to bones Rationale: Skeletal muscles are usually attached to bones by tendons and produce voluntary body movements. Cardiac muscle is found only in the heart, while smooth muscle is located in organs and blood vessels. Epithelial tissue covers surfaces and forms glands; it is not classified as muscle tissue and does not produce limb movement. Question 8 When a person first detects the sweet smell of freshly baked bread, how is this information initially classified by the nervous system? Motor information Sensory information Endocrine feedback Autonomic output Correct Answer: B. Sensory information Rationale: Smell receptors detect chemical molecules and convert them into sensory nerve impulses that travel toward the central nervous system. Motor information travels from the nervous system to muscles or glands. Endocrine feedback involves hormones, while autonomic output regulates involuntary organs rather than initially detecting environmental stimuli. Question 9 A hiker suddenly encounters a bear. Her heart rate increases, her pupils dilate, and her palms become sweaty. Which division of the nervous system is primarily responsible for these changes? A. Parasympathetic division B. Somatic sensory division C. Sympathetic division D. Enteric division Correct Answer: C. Sympathetic division Rationale: The sympathetic division activates the fight-or-flight response during stressful or dangerous situations. It increases heart rate, redirects blood to skeletal muscles, dilates pupils, and stimulates sweating. The parasympathetic division promotes rest and digestion. The somatic sensory system detects stimuli, while the enteric system primarily regulates gastrointestinal activity. Question 10 A histology student examines a tissue containing red blood cells, white blood cells, platelets, and a fluid extracellular matrix. How should this tissue be classified? A. Epithelial tissue B. Nervous tissue C. Muscle tissue D. Connective tissue Correct Answer: D. Connective tissue Rationale: Blood is classified as connective tissue because its cells are suspended in an extracellular matrix called plasma. White blood cells also perform immune functions within this tissue. Epithelial tissue covers surfaces, muscle tissue contracts, and nervous tissue conducts electrical impulses. Blood connects body systems by transporting gases, nutrients, wastes, hormones, and immune cells.