Nokea
Which of the following is NOT a tissue layer found in skeletal bone?
- A. periosteum
- B. bone marrow
- C. enamel
- D. cancellous bone
Correct Answer: C
Rationale: Enamel is a hard, outer layer that covers the crown of a tooth and is not a tissue layer found in skeletal bone. The other options, periosteum, bone marrow, and cancellous bone, are all tissue layers or components found in skeletal bone. Periosteum is the connective tissue layer covering the bone surface, bone marrow is found within the bone cavities, and cancellous bone is a spongy, porous bone tissue.
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Which of the following distinguishes the isotopes of an element?
- A. Isotopes are atoms of the same element that have different ionic charges.
- B. Isotopes are atoms of elements within the same group on the periodic table.
- C. Isotopes are atoms of the same element that have different numbers of neutrons.
- D. Isotopes are atoms of the same element with different electron configurations.
Correct Answer: C
Rationale: Isotopes are defined as atoms of the same element that have the same number of protons in their nucleus but different numbers of neutrons. This leads to variations in atomic mass for isotopes of an element. The different number of neutrons in isotopes results in differences in their atomic mass and properties while still belonging to the same element. Choice A is incorrect because isotopes do not have different ionic charges, they have the same chemical properties. Choice B is incorrect because isotopes are not atoms of elements within the same group on the periodic table; they are variants of the same element. Choice D is incorrect because isotopes of an element have the same electron configuration, differing only in the number of neutrons in the nucleus.
Which of the following is NOT a function of the liver?
- A. nutrient processing
- B. blood filtration and detoxification
- C. cholesterol and lipoprotein production
- D. insulin production and blood sugar regulation
Correct Answer: D
Rationale: The correct answer is D. The liver does not produce insulin; instead, insulin is produced by the pancreas. The liver plays a crucial role in regulating blood sugar levels by storing and releasing glucose but does not directly produce insulin. Choices A, B, and C are functions of the liver. Nutrient processing, blood filtration, detoxification, cholesterol, and lipoprotein production are essential roles performed by the liver to maintain overall metabolic balance and health.
What term describes a series of muscle contractions that transports food down the digestive tract in a wave-like fashion?
- A. digestion
- B. deglutition
- C. defecation
- D. peristalsis
Correct Answer: D
Rationale: Peristalsis is the correct term for the series of muscle contractions that move food down the digestive tract in a wave-like manner. This process helps propel food through the esophagus, stomach, and intestines, facilitating digestion and nutrient absorption. Digestion (Choice A) refers to the breakdown of food into smaller components, deglutition (Choice B) is the act of swallowing, and defecation (Choice C) is the elimination of waste from the body. Therefore, peristalsis is the most appropriate term to describe the described muscle contractions in the digestive system.
Which of the following is specialized tissue in the right atrium that acts as the heart's natural pacemaker by generating the electrical signal for the heartbeat?
- A. sinus venosus
- B. sinoatrial node
- C. atrioventricular node
- D. tricuspid valve
Correct Answer: B
Rationale: The sinoatrial node, often referred to as the SA node, is specialized tissue located in the right atrium of the heart. It functions as the heart's natural pacemaker by generating the electrical signal that initiates each heartbeat. This electrical signal spreads to the atrial muscles and then to the atrioventricular node, causing the heart to contract rhythmically and efficiently. The other options listed do not serve as the heart's natural pacemaker responsible for generating the electrical signal for the heartbeat. Sinus venosus is a developmental structure in fetal hearts, the atrioventricular node delays the electrical signal, and the tricuspid valve is a heart valve that prevents backflow of blood from the right ventricle to the right atrium.
Which of the following is an example of adaptive immunity?
- A. Inflammation
- B. Fever
- C. Antibodies
- D. Phagocytosis
Correct Answer: C
Rationale: Antibodies are produced by the adaptive immune system in response to specific antigens. They play a crucial role in targeting and neutralizing pathogens, providing long-lasting immunity against future infections. In contrast, options A (inflammation), B (fever), and D (phagocytosis) are examples of innate immunity, the body's immediate, non-specific defense mechanisms. Inflammation is a response to tissue damage, fever is a systemic response to infection, and phagocytosis is a process where cells engulf and digest pathogens, all part of the innate immune response.