Nursing Elites

1. What is the waxy or oily substance produced by sebaceous glands that helps lubricate the skin and hair?

• A. Keratin
• B. Melanin
• C. Sebum
• D. Sweat

Correct answer: C

Rationale: Sebum is the waxy or oily substance produced by sebaceous glands. It helps lubricate the skin and hair, keeping them moisturized and protected. Keratin is a protein that makes up hair, skin, and nails, providing structure and strength. Melanin is a pigment that gives color to the skin, hair, and eyes, providing protection against UV radiation. Sweat is a watery fluid produced by sweat glands to help regulate body temperature by cooling the body through evaporation.

2. Which hormone is released by the pituitary gland?

• A. Estrogen
• B. Luteinizing Hormone
• C. Progesterone
• D. Testosterone

Correct answer: B

Rationale: The correct answer is B: Luteinizing Hormone. The pituitary gland releases luteinizing hormone, which plays a crucial role in reproductive functions by stimulating ovulation in females and testosterone production in males. Choice A, Estrogen, is incorrect as estrogen is mainly produced by the ovaries. Choice C, Progesterone, is incorrect as progesterone is produced by the corpus luteum in the ovaries and the placenta during pregnancy. Choice D, Testosterone, is incorrect as testosterone is produced primarily in the testes in males and in smaller amounts in the ovaries and adrenal glands in females.

3. Cartilage, found in joints and the ear, is a type of:

• A. Epithelial tissue
• B. Connective tissue
• C. Muscle tissue
• D. Nervous tissue

Correct answer: B

Rationale: Cartilage is a type of connective tissue that provides support and flexibility to various parts of the body, such as joints and the ear. It is composed of cells called chondrocytes embedded in a matrix of collagen and proteoglycans. Epithelial tissue covers body surfaces, muscle tissue is involved in movement, and nervous tissue transmits signals. The correct answer is connective tissue because cartilage serves a supportive function in the body.

4. What is the difference between isometric and isotonic muscle contractions?

• A. Isometric involves movement, while isotonic does not.
• B. Isotonic involves shortening of muscle, while isometric maintains length.
• C. Isometric uses more energy, while isotonic uses less.
• D. Isotonic involves smooth muscle, while isometric involves skeletal muscle.

Correct answer: B

Rationale: The correct answer is B. Isometric contractions occur when the muscle generates tension without changing its length, while isotonic contractions involve the muscle changing length to move a load. In isotonic contractions, the muscle shortens to move a load, whereas in isometric contractions, the muscle contracts to hold a position without movement. Choice A is incorrect because isometric contractions do not involve movement, while choice C is incorrect as isotonic contractions typically require more energy due to movement. Choice D is incorrect because the type of muscle involved (smooth or skeletal) is not the defining factor between isometric and isotonic contractions.

5. Which statement confirms that the cell membrane is selectively permeable?

• A. Receptors are found on a cell's surface.
• B. Cells communicate with each other using cell signals.
• C. Environmental changes can cause a cell to expand or shrink.
• D. Sodium ions must travel through ion channels to enter the cell.

Correct answer: D

Rationale: The correct answer is D because selective permeability is demonstrated by the fact that specific ions, such as sodium, require ion channels to cross the cell membrane. This process allows the cell to control what substances can enter or exit, highlighting the selective nature of the cell membrane. Choices A, B, and C do not directly relate to the concept of selective permeability of the cell membrane. Receptors on a cell's surface (Choice A) are involved in cell signaling rather than selective permeability. Cell communication through signals (Choice B) and environmental changes affecting cell size (Choice C) are not directly related to the selective permeability of the cell membrane, which specifically refers to the regulation of substances passing through the membrane.

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