Free 70-question TEAS Anatomy and Physiology practice test

Answer: B. The aortic semilunar valve seals the left ventricular outflow tract during diastole to preserve systemic aortic pressure.

• A (Incorrect): The mitral valve guards the left atrioventricular opening and prevents backflow into the left atrium during systole.
• B (Correct): When left ventricular pressure falls below aortic pressure at the start of diastole, blood recoils and snaps the aortic semilunar cusps closed.
• C (Incorrect): The tricuspid valve regulates one-way flow between the right atrium and right ventricle.
• D (Incorrect): The pulmonary valve sits between the right ventricle and pulmonary trunk rather than the left ventricle and aorta.

Sources: OpenStax Anatomy and Physiology 2e, Ch. 19

Answer: D. Diaphragm contraction increases thoracic volume, reducing intra-alveolar pressure beneath ambient pressure so air moves down its gradient.

• A (Incorrect): Compression elevates pressure above atmospheric pressure and drives air outward during exhalation.
• B (Incorrect): The lungs are passive during breathing. They are pulled outward when the thoracic wall moves, and the diaphragm and intercostal muscles do the work.
• C (Incorrect): Air flows from higher pressure to lower pressure, so equal pressures would move no air. Inhalation depends on alveolar pressure falling below atmospheric pressure.
• D (Correct): By Boyle's law, diaphragm flattening and external intercostal rib elevation enlarge lung volume, lowering intrapulmonary pressure below 760 mm Hg so air flows inward.

Sources: OpenStax Anatomy and Physiology 2e, Ch. 22

Answer: A. Damage to the cerebellum causes ataxia, a loss of coordination in voluntary movements. The cerebellum also helps maintain balance and coordinate walking.

• A (Correct): The cerebellum compares the motor command from the cerebrum with feedback from the body and corrects the movement, so damage to it shows up as ataxia.
• B (Incorrect): Paralysis with lost muscle tone (flaccid paralysis) follows damage to the lower motor neurons, the cells that carry the command from the spinal cord to skeletal muscle. Cerebellar damage disturbs coordination instead.
• C (Incorrect): Pain and temperature signals travel in the spinothalamic pathway, so this loss points to damage along that sensory pathway, not to the cerebellum.
• D (Incorrect): Expressive aphasia, in which speech production is compromised, is associated with Broca's area in the frontal lobe of the cerebrum, not with the cerebellum.

Sources: OpenStax Anatomy and Physiology 2e, 16.2, 16.4, and 16.5

Answer: B. Glucagon from the alpha cells stimulates the liver to convert stored glycogen and non-carbohydrate precursors into circulating glucose.

• A (Incorrect): Insulin lowers elevated blood glucose after meals by promoting cellular uptake and glycogen synthesis in the liver.
• B (Correct): Falling blood glucose stimulates islet alpha cells to release glucagon, mobilizing liver glycogen stores and new glucose synthesis.
• C (Incorrect): Pancreatic somatostatin is an inhibiting hormone. It inhibits release of both insulin and glucagon rather than moving glucose out of the liver.
• D (Incorrect): Aldosterone is a mineralocorticoid regulating renal sodium reabsorption and potassium excretion, not fasting blood glucose.

Sources: OpenStax Anatomy and Physiology 2e, Ch. 17

Answer: A. Calcium ions from the sarcoplasmic reticulum bind to troponin, and tropomyosin slides away from the myosin-binding sites on actin so cross-bridges can form.

• A (Correct): The action potential triggers release of calcium ions from the sarcoplasmic reticulum. Calcium binds to troponin, and tropomyosin slides away from the binding sites so myosin heads can attach.
• B (Incorrect): ATP is needed for contraction, but its binding makes the myosin head detach from actin. Uncovering the binding sites depends on calcium and troponin.
• C (Incorrect): Sodium ions entering the fiber start the action potential. The action potential then triggers calcium release, and calcium is the ion that binds to troponin.
• D (Incorrect): Acetylcholine binds to receptors in the fiber's membrane at the motor end plate; it is the signal that starts the sequence. Troponin's binding site is for calcium ions.

Sources: OpenStax Anatomy and Physiology 2e, Ch. 10

Answer: C. Liver cells secrete bile, and its bile salts emulsify fats in the small intestine, which increases the surface area available to lipid-digesting enzymes.

• A (Incorrect): The gallbladder only stores bile, concentrates it, and releases it toward the small intestine when needed. The liver is the organ that secretes bile.
• B (Incorrect): Bile emulsifies fats, which is not the same as digesting them. The enzyme that splits triglycerides into fatty acids and monoglycerides is pancreatic lipase.
• C (Correct): Liver cells (hepatocytes) secrete bile. Its bile salts have one region that interacts with fat and one that interacts with water, so large fat globules are pulled apart into tiny droplets, giving lipid-digesting enzymes more surface area to work on.
• D (Incorrect): The pancreas makes pancreatic juice, a fluid with digestive enzymes and bicarbonate ions. Bile comes from the liver.

Sources: OpenStax Anatomy and Physiology 2e, Ch. 23