TORTORA ENDOCRINE

• What significant changes occur in boys and girls during puberty?

  They develop striking differences in physical appearance and behavior.
• How does the endocrine system impact development during puberty?

  It directs development and regulates body functions.
• What role do estrogens play in girls during puberty?

  Estrogens promote accumulation of adipose tissue in the breasts and hips.
• What changes occur in boys due to increasing levels of testosterone during puberty?

  Testosterone helps build muscle mass and enlarge the vocal cords.
• What is the overall influence of endocrine secretions during puberty?

  They have a powerful influence on physical and behavioral changes.
• How do hormones contribute to homeostasis?

  They regulate the activity of smooth muscle, cardiac muscle, and some glands.
• What are some functions of hormones in the body?

  They alter metabolism, spur growth, and influence reproductive processes.
• What is the role of the suprachiasmatic nucleus in the endocrine system?

  It participates in circadian rhythms.
• What are the two types of glands in the body?

  Exocrine glands and endocrine glands.
• How do exocrine glands differ from endocrine glands?

  Exocrine glands secrete products into ducts, while endocrine glands secrete hormones into interstitial fluid.
• What are some examples of exocrine glands?


  Sweat, oil, mucous, and digestive glands.
• What is the primary function of endocrine glands?

  To secrete hormones into the interstitial fluid.
• Which glands are classified as endocrine glands?

  Pituitary, thyroid, parathyroid, adrenal, and pineal glands.
• What is the significance of the vascular nature of endocrine glands?

  They depend on the cardiovascular system to distribute hormones.
• How do hormones reach their target cells?

  They diffuse into blood capillaries and are carried to target cells.
• What is the typical circulating level of hormones in the body?

  Circulating levels are typically low.
• What is the role of the nervous system in relation to the endocrine system?

  Both systems coordinate functions of all body systems.
• How do neurotransmitters and hormones differ in their action?

  Neurotransmitters act locally, while hormones act throughout the body.
• What is the time frame for the onset of action for the nervous system compared to the endocrine system?

  Nervous system responses are typically within milliseconds, while endocrine responses take seconds to hours.
• What is the duration of action for the nervous system compared to the endocrine system?

  Nervous system effects are generally briefer than those of the endocrine system.
• How do hormones exert their effects on target cells?

  By binding to specific protein receptors on or in target cells.
• What happens to hormone receptors when a hormone is present in excess?

  The number of target-cell receptors may decrease, a process called down-regulation.
• What is up-regulation in hormone receptors?


  It is when the number of receptors increases due to hormone deficiency.
• What is the function of synthetic hormones that block hormone receptors?

  They prevent hormones from exerting their normal effects.
• What are circulating hormones?

  Hormones that pass from secretory cells into interstitial fluid and then into the blood.
• What are local hormones?

  Hormones that act locally on neighboring cells or on the same cell that secreted them.
• What are paracrines and autocrines?

  Paracrines act on neighboring cells, while autocrines act on the same cell that secreted them.
• What is an example of a local hormone and its function?

  Interleukin-2 (IL-2) activates nearby immune cells and stimulates the same cell to proliferate.
• What is the effect of nitric oxide (NO) in the body?

  It causes relaxation of nearby smooth muscle fibers in blood vessels, leading to vasodilation.
• How are circulating hormones inactivated?

  They are inactivated by the liver and excreted by the kidneys.
• What is the study of disorders of the endocrine system called?

  Endocrinology.
• What are the functions of hormones in the body?

  They help regulate chemical composition, metabolism, muscle contraction, glandular secretions, and immune activities.
• What are the two chemical classes of hormones based on their solubility?

  Lipid-soluble hormones and water-soluble hormones.
• What are steroid hormones derived from?

  Cholesterol.
• How are thyroid hormones synthesized?

  By attaching iodine to the amino acid tyrosine.
• What is nitric oxide (NO) classified as?

  Both a hormone and a neurotransmitter.
• What are amine hormones synthesized from?

  They are synthesized by modifying certain amino acids.
• What are peptide hormones made of?

  Amino acid polymers.
• How do smaller peptide hormones differ from larger protein hormones?

  Smaller peptide hormones consist of chains of 3 to 49 amino acids, while larger protein hormones include 50 to 200 amino acids.
• What is the significance of the differences in chemical structure among steroid hormones?

  They allow for a large diversity of functions.