Nokea
Which of the following statements best describes endocrine glands?
- A. They secrete chemicals into the blood
- B. They secrete enzymes into ducts
- C. They produce sweat
- D. They produce saliva
Correct Answer: A
Rationale: Endocrine glands are ductless glands that release hormones directly into the bloodstream. These hormones are then carried to target organs and tissues throughout the body, where they regulate various physiological functions. The statement 'They secrete chemicals into the blood' accurately describes the function of endocrine glands. Choices B, C, and D are incorrect because endocrine glands do not secrete enzymes into ducts, produce sweat, or produce saliva. These functions are typically associated with exocrine glands, sweat glands, and salivary glands, respectively.
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Which organ is responsible for the production of hormones during stress?
- A. Parathyroid gland
- B. Adrenal cortex
- C. Posterior pituitary gland
- D. Hypothalamus
Correct Answer: B
Rationale: The adrenal cortex is the organ responsible for producing stress hormones like cortisol and aldosterone, which play a crucial role in the body's stress response. During stress, the adrenal cortex releases cortisol, a hormone that helps the body deal with stress by increasing blood sugar, suppressing the immune system, and aiding in metabolism. Parathyroid gland is responsible for calcium regulation, the posterior pituitary gland secretes hormones like oxytocin and vasopressin which are not directly related to the stress response, and the hypothalamus plays a role in regulating hormonal balance and various bodily functions but is not primarily responsible for producing stress hormones.
Which structure in the ear is responsible for balance?
- A. Cochlea
- B. Semicircular canals
- C. Ossicles
- D. Eustachian tube
Correct Answer: B
Rationale: The semicircular canals in the inner ear are responsible for maintaining balance by detecting changes in head position and movement. These structures contain fluid and hair cells that send signals to the brain regarding the body's orientation in space, helping us stay balanced and navigate our surroundings. The cochlea is responsible for hearing, the ossicles are involved in sound transmission, and the Eustachian tube helps equalize pressure in the middle ear, but they are not directly related to balance.
Which of the following is not a principal organ of the nervous system?
- A. Brain
- B. Thymus
- C. Ganglia
- D. Spinal cord
Correct Answer: B
Rationale: The correct answer is B. The thymus is not a principal organ of the nervous system; it is part of the immune system. The brain, spinal cord, and ganglia are principal organs of the nervous system. The brain is responsible for processing information, the spinal cord helps transmit signals between the brain and the rest of the body, and ganglia are clusters of nerve cells that support the nervous system's functions. Therefore, the thymus is the correct answer as it is not directly involved in nervous system functions.
Which muscle is responsible for breathing?
- A. Diaphragm
- B. Intercostal muscles
- C. Rectus abdominis
- D. Pectoralis major
Correct Answer: A
Rationale: The diaphragm is the primary muscle responsible for breathing. It is a large, dome-shaped muscle located at the base of the chest cavity. When it contracts, it flattens, increasing the volume of the chest cavity and causing inhalation. When it relaxes, it returns to its dome shape, decreasing the volume of the chest cavity and causing exhalation. The intercostal muscles, located between the ribs, assist the diaphragm in breathing by expanding and contracting the chest cavity. The rectus abdominis and pectoralis major are not directly involved in the process of breathing.
What is the primary role of the liver in the body?
- A. Producing insulin
- B. Detoxifying harmful substances
- C. Digesting food
- D. Storing energy
Correct Answer: B
Rationale: The correct answer is B: Detoxifying harmful substances. While the liver does produce bile for digestion and stores nutrients like glycogen, its primary function is to filter and detoxify blood coming from the digestive tract before passing it to the rest of the body. Therefore, choices A, C, and D are incorrect. Producing insulin is mainly done by the pancreas, digesting food is primarily the role of the stomach and intestines, and storing energy is a function of various organs like muscles and fat cells.