TEAS 7 practice test science

Correct Answer: B

Rationale: The main organ responsible for regulating sleep is the hypothalamus. The hypothalamus plays a crucial role in controlling the body's circadian rhythm, which is the internal clock that regulates the sleep-wake cycle. It receives input from the eyes about light and darkness, aiding in determining when it's time to sleep or wake up. Additionally, the hypothalamus regulates the production of melatonin by the pineal gland, a hormone that helps control sleep patterns. While the thalamus relays sensory information to the brain, the pituitary gland is primarily responsible for hormone production and release, and the pineal gland produces melatonin under the control of the hypothalamus. Therefore, the hypothalamus is the correct choice as the main organ involved in sleep regulation.

Correct Answer: C

Rationale: A chemical change involves a chemical reaction where new substances are formed. Burning wood to produce ash is an example of a chemical change because the wood undergoes a chemical reaction to form a new substance (ash). In this process, the chemical composition of wood changes to produce ash, which is a new substance. On the other hand, melting ice to form water, dissolving sugar in water, and crushing a can to reduce its size are examples of physical changes. In these instances, the substances may change their physical state or appearance but do not undergo a chemical reaction to form new substances. Therefore, choice C is the correct answer as it represents a chemical change, while choices A, B, and D represent physical changes.

Correct Answer: B

Rationale: Peristalsis is the term used to describe the involuntary muscular contractions that move food through the digestive tract. This process involves rhythmic contractions and relaxations of the muscles in the digestive system, which help propel food from the esophagus to the stomach and through the intestines for digestion and absorption of nutrients. Segmentation refers to the mixing movements in the intestines that aid in the absorption of nutrients but is not the term for the movement of food through the digestive tract. Chylification is not a recognized term in digestive physiology. Emulsification is the process of breaking down fat globules into smaller droplets to aid in digestion, not the movement of food through the digestive tract.

Correct Answer: A

Rationale: The correct answer is simple squamous epithelium (Choice A). The inner surface of blood vessels is lined by a single layer of flattened cells, known as simple squamous epithelium. This epithelium type is thin and allows for efficient diffusion and filtration, which is essential for the exchange of gases and nutrients across blood vessel walls. Simple columnar epithelium (Choice B) is typically found in the lining of the gastrointestinal tract and is responsible for absorption and secretion. Stratified squamous epithelium (Choice C) is commonly found in the skin, providing protection against mechanical stress. Stratified columnar epithelium (Choice D) is not a characteristic epithelium type found in the lining of blood vessels, as it is more commonly present in specific regions of the body like parts of the male urethra and the conjunctiva of the eye.

Correct Answer: C

Rationale: The small intestine is the primary site for both chemical digestion and absorption of nutrients in the digestive system. The lining of the small intestine is equipped with villi and microvilli, which significantly increase the surface area available for absorption. Enzymes from the pancreas and bile from the liver play crucial roles in further breaking down food into absorbable molecules that can pass through the intestinal wall into the bloodstream. While the stomach assists in mechanical breakdown and initial protein digestion, it is not the main site of nutrient absorption. The large intestine, on the other hand, mainly absorbs water and electrolytes from undigested food particles. The mouth aids in initial mechanical breakdown and some carbohydrate digestion, but the majority of nutrient absorption occurs in the small intestine, making it the correct answer.