Target cells respond to hormones because ____________.
- A. they sit next to the cell that makes the hormone
- B. they made the hormone they are responding to
- C. they have receptors for that hormone
- D. all cells in the body respond to all hormones
Correct Answer: C
Rationale: The correct answer is C because target cells respond to hormones by possessing specific receptors for that hormone. These receptors bind to the hormone, initiating a cellular response. Option A is incorrect as proximity to hormone-producing cells is not the reason for response. Option B is incorrect as target cells do not make the hormones they respond to. Option D is incorrect as not all cells respond to all hormones; only target cells with specific receptors do.
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A congenital condition that includes mental retardation, short disproportional body size, and a thick tongue and neck is caused by __________.
- A. insulin deficiency
- B. deficiency of thymosin
- C. deficiency of thyroxin
- D. excess of synthetic growth hormone
Correct Answer: C
Rationale: Step 1: The congenital condition described points towards a disorder affecting growth and development.
Step 2: The symptoms of mental retardation, short body size, and thick neck suggest hypothyroidism.
Step 3: Thyroxin is a hormone produced by the thyroid gland that regulates metabolism and growth.
Step 4: A deficiency of thyroxin in congenital hypothyroidism leads to the described symptoms.
Step 5: Therefore, the correct answer is C: deficiency of thyroxin.
Summary:
A: Insulin deficiency does not match the symptoms described.
B: Thymosin deficiency is not related to growth and mental retardation.
D: Excess of synthetic growth hormone would not cause mental retardation and thick neck.
The structure leading to the stomach is called?
- A. Pharynx
- B. Epiglottis
- C. Oesophagus
- D. Larynx
Correct Answer: C
Rationale: The correct answer is C: Oesophagus. The oesophagus is the structure leading to the stomach that carries food from the mouth to the stomach through peristalsis. The pharynx (A) is the throat cavity, the epiglottis (B) is a flap that prevents food from entering the trachea during swallowing, and the larynx (D) is the voice box. Therefore, the oesophagus is the correct answer as it specifically functions to transport food to the stomach.
Hyposecretion of adrenal cortex hormones can lead to ___.
- A. Addison disease.
- B. diabetes mellitus.
- C. Cushing syndrome.
- D. cretinism.
Correct Answer: A
Rationale: The correct answer is A: Addison disease. Hyposecretion of adrenal cortex hormones can lead to Addison disease, characterized by fatigue, weight loss, low blood pressure, and skin discoloration. This is because insufficient cortisol and aldosterone production from the adrenal cortex can disrupt the body's stress response and electrolyte balance.
Summary of why other choices are incorrect:
B: Diabetes mellitus is primarily related to insulin regulation issues, not adrenal cortex hormones.
C: Cushing syndrome is caused by hypersecretion, not hyposecretion, of adrenal cortex hormones.
D: Cretinism is associated with thyroid hormone deficiency, not adrenal cortex hormone deficiency.
Selective β2 agonists produce all of the following EXCEPT:
- A. Stimulate β2 > β1
- B. Bronchodilation
- C. Decrease of blood pressure
- D. Stimulate uterine contraction
Correct Answer: D
Rationale: The correct answer is D: Stimulate uterine contraction. Selective β2 agonists primarily target β2 receptors in the lungs, leading to bronchodilation. They have minimal effect on β1 receptors, thus do not significantly impact heart rate or blood pressure. However, β2 receptors in the uterus can cause uterine relaxation, not contraction. Therefore, selective β2 agonists do not stimulate uterine contractions. Choices A, B, and C are incorrect as they align with the typical effects of selective β2 agonists.
Several hormones are synthesized in the hypothalamus and transported to the anterior pituitary gland. The mechanism of transportation from hypothalamus to anterior pituitary gland is through the ________.
- A. hepatic portal system
- B. general circulatory system
- C. hypophyseal portal system
- D. feedback loop
Correct Answer: C
Rationale: The correct answer is C: hypophyseal portal system. This system involves a direct blood vessel connection between the hypothalamus and the anterior pituitary gland, allowing hormones synthesized in the hypothalamus to be rapidly transported to the anterior pituitary without being diluted in the general circulation. The hepatic portal system (A) involves blood flow from the digestive system to the liver. The general circulatory system (B) would dilute the hormones before reaching the anterior pituitary. A feedback loop (D) is a mechanism that regulates hormone levels but is not the primary mode of transportation between the hypothalamus and anterior pituitary.