Nokea
Which of the following accurately describes saltatory conduction?
- A. It is faster than normal nerve conduction
- B. It occurs from one node of Ranvier to the next
- C. It only occurs in myelinated neurons
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D, 'All of the above.' Saltatory conduction is faster than normal nerve conduction, occurs from one node of Ranvier to the next, and is exclusive to myelinated neurons. This form of conduction allows for the rapid transmission of nerve impulses by the action potential jumping between the nodes of Ranvier in myelinated neurons, enhancing the efficiency of signal propagation along the axon. Choice A is correct as saltatory conduction is indeed faster than normal conduction. Choice B is accurate as it describes the mechanism of conduction 'jumping' from one node of Ranvier to the next. Choice C is correct because saltatory conduction occurs specifically in myelinated neurons where the myelin sheath insulates the axon except at the nodes of Ranvier, facilitating faster transmission of nerve impulses.
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What are apocrine and eccrine?
- A. Blood vessel
- B. Cell types
- C. Hormones
- D. Sweat glands
Correct Answer: D
Rationale: Apocrine and eccrine refer to types of sweat glands in the human body. Apocrine sweat glands are larger and located in areas like the armpits and groin, producing a thicker secretion that can be associated with body odor. Eccrine sweat glands are found throughout the skin and are responsible for regulating body temperature through the production of sweat. Understanding the functions and locations of these glands is essential in comprehending the body's thermoregulation processes.
What potential consequences can chromosomal nondisjunction have on offspring?
- A. Down syndrome, caused by an extra copy of chromosome 21.
- B. Turner syndrome, characterized by the absence of one X chromosome in females.
- C. Klinefelter syndrome, featuring one or more extra X chromosomes in males.
- D. All of the above.
Correct Answer: D
Rationale: - Chromosomal nondisjunction is the failure of homologous chromosomes or sister chromatids to separate properly during cell division, leading to an abnormal number of chromosomes in the resulting cells.
- Down syndrome is caused by an extra copy of chromosome 21, resulting from nondisjunction during meiosis. Individuals with Down syndrome have three copies of chromosome 21 instead of the usual two.
- Turner syndrome is characterized by the absence of one X chromosome in females, leading to a variety of physical and developmental features.
- Klinefelter syndrome features one or more extra X chromosomes in males, typically resulting in infertility and other physical characteristics.
Therefore, chromosomal nondisjunction can lead to various genetic disorders such as Down syndrome, Turner syndrome, and Klinefelter syndrome, making option D the correct answer.
What property of a substance refers to its ability to be drawn into thin wires?
- A. Conductivity
- B. Ductility
- C. Viscosity
- D. Malleability
Correct Answer: B
Rationale: Ductility is the property of a substance that allows it to be drawn into thin wires without breaking. Conductivity refers to the ability of a substance to conduct electricity or heat, not to be drawn into wires. Viscosity is the measure of a fluid's resistance to flow, not related to the ability to be drawn into wires. Malleability is the property of a substance that allows it to be hammered or rolled into thin sheets, not specifically related to being drawn into wires. Therefore, the correct property for the ability to be drawn into thin wires is ductility.
Bile, a yellowish-green fluid, is stored in the gallbladder and released into the small intestine during digestion. What is the primary function of bile in digestion?
- A. Break down carbohydrates
- B. Break down proteins
- C. Emulsify fats
- D. Neutralize stomach acid
Correct Answer: C
Rationale: The primary function of bile in digestion is to emulsify fats. Bile contains bile salts that help break down large fat globules into smaller droplets, increasing the surface area for enzymes to work on and aiding in the absorption of fats in the small intestine. Choices A, B, and D are incorrect because bile's main role is not to break down carbohydrates or proteins, nor to neutralize stomach acid; rather, it primarily assists in the digestion and absorption of fats through emulsification.
Dense irregular connective tissue, found in tendons and ligaments, provides:
- A. Flexibility
- B. Lubrication
- C. Insulation
- D. Tensile strength
Correct Answer: D
Rationale: Dense irregular connective tissue, found in tendons and ligaments, provides tensile strength. Tendons and ligaments need to withstand tension and forces acting upon them, and the dense irregular connective tissue helps provide this strength and support. Choice A, flexibility, is incorrect because tendons and ligaments primarily provide support and stability rather than flexibility. Choice B, lubrication, is not the main function of dense irregular connective tissue in tendons and ligaments. Choice C, insulation, is also incorrect as this tissue type is not primarily involved in providing insulation.