Thyroid gland produces a hormone called "Thyroxine" which
- A.controls blood glucose levels.
- B.controls ovulation.
- C.controls metabolic rate.
- D.maintains pregnancy.
Correct answer
Explanation
The correct answer is C, controls metabolic rate.. Thyroxine sets the body's basal metabolic rate, that is, how fast cells use oxygen and food to release energy.
The thyroid is a butterfly-shaped gland in the neck. Its hormone thyroxine contains iodine, so a diet short of iodine leads to goitre, a swelling of the gland; this is why table salt is iodised. Too little thyroxine in children causes cretinism, with stunted growth and mental retardation, and in adults it causes myxoedema. Too much causes exophthalmic goitre, with bulging eyes, weight loss and a fast heartbeat. The pituitary controls the thyroid through thyroid-stimulating hormone.
A is wrong because blood glucose is controlled by insulin and glucagon from the pancreas.
B is wrong because ovulation is triggered by luteinising hormone from the pituitary.
D is wrong because pregnancy is maintained by progesterone from the corpus luteum and later the placenta.
Exam tip: thyroxine → metabolic rate, needs iodine; deficiency → goitre, cretinism (children), myxoedema (adults).
Practice Questions
View allWhich one of the following is not true for anodizing process?
- A.It makes aluminium corrosion resistant.
- B.Metals like aluminium, titanium and magnesium can be anodized.
- C.Clean aluminium article is the anode and oxygen gas is evolved at the cathode.
- D.It is used in aircraft industry.
Show answer
In anodizing the clean aluminium article is indeed the anode, but oxygen is released at the anode, not at the cathode; hydrogen is released at the cathode.
Read the full explanation →Which one of the following statements is not correct?
- A.The response of the ear to sound of increasing intensity is approximately logarithmic.
- B.The sensitivity of the human ear does not vary with the frequency of the sound.
- C.When two or more waves traverse the same medium, the displacement of any element of the medium is the algebraic sum of the displacements due to each wave.
- D.Longitudinal waves can travel in all media—solids, liquids and gases.
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The statement that the sensitivity of the human ear does not vary with frequency is false, because the ear is far more sensitive to some frequencies than to others.
Read the full explanation →Kwashiorkor disease in children is caused by
- A.sufficient carbohydrates but less fats in diet
- B.sufficient carbohydrates and fats but deficient proteins in diet
- C.sufficient vitamins but deficient fats in diet
- D.sufficient fats but deficient vitamins in diet
Show answer
Kwashiorkor is a disease of protein deficiency in a child who still gets enough calories. It usually appears when a child is weaned from breast milk onto a starchy diet with little protein.
Read the full explanation →Which one of the following is the correct order of pH for the given substances?
- A.Coffee < Lemon juice < Milk of magnesia < Blood
- B.Milk of magnesia < Blood < Coffee < Lemon juice
- C.Lemon juice < Blood < Coffee < Milk of magnesia
- D.Lemon juice < Coffee < Blood < Milk of magnesia
Show answer
Arranged from most acidic to most basic, the four substances fall in exactly this order. Lemon juice, rich in citric acid, has a pH of about 2 to 2.5.
Read the full explanation →Which one of the following diseases may be caused by the deficiency of vitamin C?
- A.Rickets
- B.Rabies
- C.Hepatitis
- D.Scurvy
Show answer
Scurvy is caused by a lack of vitamin C, or ascorbic acid, which the body needs to make collagen, the protein that holds skin, gums and blood vessels together.
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