Nokea
Which of the following bones is the only movable bone of the skull?
- A. Maxilla
- B. Zygomatic
- C. Lacrimal
- D. Mandible
Correct Answer: D
Rationale: The mandible (D) is the only movable bone of the skull. It forms the lower jaw and is crucial for functions like chewing and speaking. The maxilla, zygomatic, and lacrimal bones (options A, B, and C) are not movable bones within the skull.
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Which of the following hormones decreases the concentration of blood glucose?
- A. insulin
- B. glucagon
- C. growth hormone
- D. glucocorticoids
Correct Answer: A
Rationale: Insulin is the hormone responsible for decreasing the concentration of blood glucose levels by promoting the uptake and storage of glucose in cells. When blood glucose levels rise, insulin is released to help cells absorb excess glucose, thereby lowering its concentration in the bloodstream. Glucagon, growth hormone, and glucocorticoids, in contrast, all play roles in increasing blood glucose levels through different mechanisms.
Which of the following are tropic hormones? (Select one that doesn't apply.)
- A. Somatotropin
- B. Follicle-stimulating hormone
- C. Antidiuretic hormone
- D. Thyroid-stimulating hormone
Correct Answer: C
Rationale: Tropic hormones are hormones that stimulate other endocrine glands to release their hormones. Antidiuretic hormone (C) is not a tropic hormone; it acts on the kidneys to regulate water balance. Somatotropin (A), follicle-stimulating hormone (B), and thyroid-stimulating hormone (D) are all tropic hormones that stimulate the release of hormones from other glands.
What type of synovial joint is the elbow?
- A. Pivot
- B. Hinge
- C. Ball and socket
- D. Toddle
Correct Answer: B
Rationale: The correct answer is B: Hinge. The elbow joint is classified as a hinge joint because of its structure and movement capabilities. Hinge joints allow movement in only one plane, similar to a door hinge, enabling flexion and extension movements. In contrast, pivot joints allow rotational movement, ball and socket joints offer a wide range of motion in multiple directions, and toddle is not a recognized joint type.
What is the name of the outermost layer of the skin?
- A. dermis
- B. epidermis
- C. subcutaneous tissue
- D. hypodermis
Correct Answer: B
Rationale: The correct answer is B, 'epidermis.' The epidermis is the outermost layer of the skin, providing a protective barrier against environmental factors and regulating water loss. The dermis is located beneath the epidermis and contains important structures like blood vessels and glands. Subcutaneous tissue, also known as the hypodermis, is located below the dermis and serves functions such as insulation and energy storage.
Which structure of the nervous system carries action potentials in the direction of a synapse?
- A. cell body
- B. axon
- C. neuron
- D. myelin
Correct Answer: B
Rationale: The correct answer is the axon. The axon is a long, slender projection of a neuron that carries nerve impulses away from the cell body towards other neurons, muscles, or glands. Action potentials travel along the axon to the axon terminals where they lead to the release of neurotransmitters at the synapse, allowing communication with other neurons or target cells. The cell body contains the nucleus and organelles of the neuron but does not transmit action potentials. Neurons are the functional unit of the nervous system composed of the cell body, dendrites, and axon. Myelin is a fatty substance that surrounds and insulates axons, helping to speed up the transmission of nerve impulses but does not carry action potentials towards the synapse.