Nokea
Which type of muscle is found in the heart?
- A. Smooth muscle
- B. Cardiac muscle
- C. Skeletal muscle
- D. Striated muscle
Correct Answer: B
Rationale: Cardiac muscle is a specialized type of muscle found only in the heart. It is responsible for the rhythmic contractions that pump blood throughout the body. Unlike smooth and skeletal muscle, cardiac muscle has its own unique structure and function to meet the demands of the heart's continuous pumping action. Smooth muscle is found in the walls of internal organs and blood vessels, not in the heart. Skeletal muscle is attached to bones and helps in movement but is not found in the heart. Striated muscle is a broader term that includes both cardiac and skeletal muscle, but specifically, cardiac muscle refers to the muscle tissue of the heart.
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Which type of muscle is found in the walls of hollow organs?
- A. Skeletal muscle
- B. Cardiac muscle
- C. Smooth muscle
- D. Striated muscle
Correct Answer: C
Rationale: Smooth muscle tissue is found in the walls of hollow organs, such as the intestines, blood vessels, and bladder. It contracts involuntarily, allowing for movements like peristalsis in the intestines and regulation of blood flow in blood vessels. Skeletal muscle (Choice A) is attached to bones and helps in voluntary movements. Cardiac muscle (Choice B) is found in the heart and contracts involuntarily to pump blood. Striated muscle (Choice D) refers to both skeletal and cardiac muscles, which have a striped appearance due to the organization of their filaments. However, smooth muscle (Choice C) is specifically the type found in hollow organs.
What is the most visible part of the ear?
- A. Pinna
- B. Organ of Corti
- C. Cochlea
- D. Ear canal
Correct Answer: A
Rationale: The pinna, also known as the auricle, is the external part of the ear that is most visible. It helps in collecting sound waves and directing them into the ear canal for further processing by the ear structures. The pinna's visible location makes it easily identifiable as the prominent external feature of the ear. Choices B, C, and D are incorrect. The Organ of Corti is located within the cochlea and is responsible for converting sound vibrations into electrical signals. The cochlea is a spiral-shaped, fluid-filled structure in the inner ear that plays a crucial role in hearing. The ear canal is a passage that leads to the eardrum and is not the most visible part of the ear.
Which hormone regulates blood sugar levels?
- A. Insulin
- B. Glucagon
- C. Cortisol
- D. Thyroxine
Correct Answer: A
Rationale: Insulin is the hormone that regulates blood sugar levels by promoting the uptake of glucose into cells. It is produced by the pancreas and helps to lower blood sugar levels when they are too high. Glucagon, on the other hand, works in opposition to insulin by raising blood sugar levels when they are too low. Cortisol and thyroxine play different roles in the body and are not primarily responsible for regulating blood sugar levels.
What type of tissue forms the outer layer of the skin?
- A. Connective tissue
- B. Epithelial tissue
- C. Muscle tissue
- D. Nervous tissue
Correct Answer: B
Rationale: Epithelial tissue is the correct answer. It forms the outer layer of the skin, serving as a protective barrier against pathogens and environmental damage. This tissue type is essential for maintaining skin integrity and plays a crucial role in skin function. Connective tissue (Choice A), although important for providing support and structure, does not form the outer layer of the skin. Muscle tissue (Choice C) is responsible for movement and is not the primary tissue in the skin. Nervous tissue (Choice D) is involved in transmitting signals but is not the main component of the skin's outer layer.
Which hormone is released by the posterior pituitary gland?
- A. Oxytocin
- B. Thyroxine
- C. Insulin
- D. ADH
Correct Answer: A
Rationale: Oxytocin is the correct answer. It is released by the posterior pituitary gland and plays a vital role in childbirth and lactation. Oxytocin promotes uterine contractions during labor and milk ejection during breastfeeding. Choice B, Thyroxine, is incorrect as it is produced by the thyroid gland. Choice C, Insulin, is incorrect as it is produced by the pancreas. Choice D, ADH (Antidiuretic Hormone), is also released by the posterior pituitary gland, but it is not the hormone primarily associated with childbirth and lactation.