Test your knowledge of human endocrine system, hormones, and their functions with these multiple-choice questions.
First, read the main notes on Human Physiology, then try to answer the questions below without looking back!
Test Your Knowledge
Showing questions 1 - 20 of 47
1. According to the classical definition, hormones are chemical messengers produced by endocrine glands and released into the blood. What is the key characteristic that distinguishes the current scientific definition of hormones from the classical one?
The current scientific definition defines hormones as **non-nutrient chemicals which act as intercellular messengers and are produced in trace amounts**. This broadens the definition beyond just organised endocrine glands and distant target organs.
2. The neural system and the endocrine system jointly coordinate and regulate physiological functions in the body. Which of the following best describes the nature of coordination provided by the neural system compared to the endocrine system?
The **neural system provides a point-to-point rapid coordination** among organs, but it is **fast but short-lived**. The **endocrine system provides chemical integration through hormones**, which generally offers a **slower but more prolonged coordination** by continuously regulating cellular functions.
3. Which of the following sets correctly lists organised endocrine glands in the human body?
**Pituitary, pineal, thyroid, adrenal, pancreas, parathyroid, thymus and gonads (testis in males and ovary in females) are the organised endocrine bodies in our body**. Liver, kidney, heart, and gastrointestinal tract also produce hormones but are not exclusively classified as organised endocrine glands in this context.
4. The hypothalamus, a crucial part of the brain for endocrine regulation, is located at which specific region?
The **hypothalamus is the basal part of diencephalon, forebrain**, and regulates a wide spectrum of body functions.
5. Hypothalamic hormones are primarily involved in regulating the synthesis and secretion of hormones from which other gland?
The neurosecretory cells in the hypothalamus produce hormones that **regulate the synthesis and secretion of pituitary hormones**.
6. What is the primary action of Gonadotrophin Releasing Hormone (GnRH), secreted by the hypothalamus?
A hypothalamic hormone called **Gonadotrophin releasing hormone (GnRH) stimulates the pituitary synthesis and release of gonadotrophins**.
7. How is the posterior pituitary regulated by the hypothalamus?
The **posterior pituitary is under the direct neural regulation of the hypothalamus**, unlike the anterior pituitary which is regulated by hypothalamic hormones via a portal circulatory system.
8. The pituitary gland is situated in a specific bony cavity. What is the name of this cavity?
The **pituitary gland is located in a bony cavity called sella tursica** and is attached to the hypothalamus by a stalk.
9. The adenohypophysis of the pituitary gland consists of which two portions?
**Adenohypophysis consists of two portions, pars distalis and pars intermedia**. Pars distalis is commonly called the anterior pituitary, and pars nervosa (neurohypophysis) is the posterior pituitary.
10. Which hormone is primarily secreted by the pars intermedia in humans, although it is almost merged with pars distalis?
**Pars intermedia secretes only one hormone called melanocyte stimulating hormone (MSH)**. However, in humans, the pars intermedia is almost merged with pars distalis.
11. Which of the following hormones are synthesised by the hypothalamus but are stored and released by the posterior pituitary (neurohypophysis)?
**Neurohypophysis (pars nervosa) also known as posterior pituitary, stores and releases two hormones called oxytocin and vasopressin, which are actually synthesised by the hypothalamus and are transported axonally to neurohypophysis**.
12. Excess secretion of growth hormone (GH) in adults, particularly in middle age, leads to which condition characterised by severe disfigurement of the face and other complications?
**Excess secretion of growth hormone in adults especially in middle age can result in severe disfigurement (especially of the face) called Acromegaly**. Gigantism results from over-secretion of GH during growth period, and pituitary dwarfism from low secretion.
13. What is the primary function of Prolactin (PRL)?
**Prolactin regulates the growth of the mammary glands and formation of milk in them**.
14. In males, which pituitary hormones are called gonadotrophins, and what are their primary functions?
**LH and FSH stimulate gonadal activity and hence are called gonadotrophins**. In males, **LH stimulates the synthesis and secretion of hormones called androgens from testis. In males, FSH and androgens regulate spermatogenesis**.
15. Oxytocin acts on smooth muscles in the body. In females, what are its key roles during and after childbirth?
**Oxytocin acts on the smooth muscles of our body and stimulates their contraction. In females, it stimulates a vigorous contraction of uterus at the time of child birth, and milk ejection from the mammary gland**.
16. Vasopressin, also known as Anti-Diuretic Hormone (ADH), primarily acts on which organ and what is the consequence of its impaired synthesis or release?
**Vasopressin acts mainly at the kidney and stimulates resorption of water and electrolytes by the distal tubules and thereby reduces loss of water through urine (diuresis). An impairment affecting synthesis or release of ADH results in a diminished ability of the kidney to conserve water leading to water loss and dehydration. This condition is known as Diabetes Insipidus**.
17. The pineal gland is located on the dorsal side of the forebrain and secretes a hormone that regulates the body's 24-hour rhythm. What is this hormone?
The **pineal gland is located on the dorsal side of forebrain. Pineal secretes a hormone called melatonin. Melatonin plays a very important role in the regulation of a 24-hour (diurnal) rhythm of our body**, including sleep-wake cycle and body temperature.
18. The thyroid gland is composed of two lobes interconnected by a thin flap of connective tissue. What is this connective tissue structure called?
The thyroid gland is composed of two lobes which are located on either side of the trachea. **Both the lobes are interconnected with a thin flap of connective tissue called isthmus**.
19. Which element is essential for the normal rate of hormone synthesis in the thyroid gland?
**Iodine is essential for the normal rate of hormone synthesis in the thyroid**. Deficiency leads to hypothyroidism and goitre.
20. Hypothyroidism during pregnancy can cause several developmental issues in the growing baby. Which of the following is NOT a consequence of this condition?
**Hypothyroidism during pregnancy causes defective development and maturation of the growing baby leading to stunted growth (cretinism), mental retardation, low intelligence quotient, abnormal skin, deaf-mutism, etc.**. Therefore, increased intelligence quotient is incorrect.