1. What is the main function of the endocrine system in the human body? a) To produce and secrete hormones that regulate various physiological processes b) To transport oxygen and nutrients to the cells and remove waste products c) To protect the body from foreign invaders and pathogens d) To coordinate voluntary and involuntary movements and responses Answer: A. The endocrine system consists of glands that produce and secrete hormones that regulate various physiological processes such as growth, metabolism, reproduction, stress response, etc. 2. What are the two types of hormones based on their chemical structure and how do they differ in their mode of action? a) Steroid and peptide hormones; steroid hormones are lipid-soluble and can cross the cell membrane, while peptide hormones are water-soluble and bind to receptors on the cell surface b) Amino acid and protein hormones; amino acid hormones are derived from tyrosine or tryptophan, while protein hormones are composed of chains of amino acids c) Catecholamine and thyroid hormones; catecholamine hormones are derived from tyrosine and act on adrenergic receptors, while thyroid hormones are derived from iodine and act on nuclear receptors d) All of the above Answer: D. All of the above are correct classifications of hormones based on their chemical structure and mode of action. 3. What is the difference between negative feedback and positive feedback in hormonal regulation? a) Negative feedback is when a change in a variable triggers a response that counteracts the initial change, while positive feedback is when a change in a variable triggers a response that amplifies the initial change b) Negative feedback is when a hormone inhibits its own secretion or the secretion of another hormone, while positive feedback is when a hormone stimulates its own secretion or the secretion of another hormone c) Negative feedback is when a hormone acts on its target organ to produce a desired effect, while positive feedback is when a hormone acts on its source organ to increase its production d) All of the above Answer: D. All of the above are correct definitions of negative feedback and positive feedback in hormonal regulation. 4. What are the three main categories of endocrine disorders and what are some examples of each? a) Hyposecretion, hypersecretion, and abnormal responsiveness; examples include diabetes mellitus, Cushing's syndrome, and diabetes insipidus respectively b) Primary, secondary, and tertiary; examples include Addison's disease, hypopituitarism, and hypothalamic dysfunction respectively c) Autoimmune, neoplastic, and iatrogenic; examples include Graves' disease, pituitary adenoma, and