Neuroendocrine Qs - Campbell

Which of the following statements about hormones and the endocrine system is true? a) Hormones result in short-term responses as compared with nervous responses. b) Hormones only affect specific cells having the appropriate receptors. c) Hormones are stored in the mitochondria of hormone-secreting cells. d) Hormones are produced by specialized blood cells and secreted into the blood.

Answer: Hormones only affect specific cells having the appropriate receptors. - Hormones convey information via the bloodstream to cells throughout the body. Cells are unresponsive to a particular signal if they lack the appropriate receptors.

The posterior pituitary is a component of the pituitary gland that _____. a) is composed of nerve tissue that connects directly to the brain. b) produces the endorphins, which are the body's natural painkillers. c) secretes the hormone prolactin (PRL), which has different effects in different species. d) is composed of endocrine cells synthesizing numerous hormones.

Answer: a) Posterior Pituitary is composed of nerve tissue that connects directly to the brain. - Conversely, Anterior Pituitary is composed of endocrine cells synthesizing numerous hormones.

In their mechanism of action, a difference between steroid and nonsteroid hormones is that _____. a) steroid hormones enter the nucleus of the target cell, whereas nonsteroid hormones do not. b) non-steroid hormones cross the plasma membrane more readily than do steroid hormones. c) steroid hormones use a signal transduction pathway. d) non-steroid hormones bind reversibly to DNA.

Answer: a) Steroid hormones enter the nucleus of the target cell, whereas nonsteroid hormones do not. - Conversely, Nonsteroid hormones use a signal transduction pathway.

A characteristic of every animal hormone is that the hormone _____. a) acts as a regulatory message or signal between cells. b) is a protein. c) enters a cell and interacts with DNA. d) is under the control of the pituitary gland.

Answer: a) acts as a regulatory message or signal between cells. - Hormones are secreted into body fluids, usually blood, and communicate regulatory signals throughout the body.

Steroid hormones, such as the sex hormones, _____. a) can diffuse across the phospholipid membrane of cells. b) can affect DNA directly to stimulate transcription of certain genes. c) are peptides, which are small molecules containing 3 to 30 amino acids. d) bind to receptors in the plasma membrane.

Answer: a) can diffuse across the phospholipid membrane of cells. - Steroid hormones are small, nonpolar molecules that easily move across cell membranes.

Which statement about the endocrine and nervous systems is true? a) Some specialized nerve cells, such as neurosecretory cells, perform functions of both systems. b) Both transmit signals to and from the brain and spinal cord. c) The responses of the endocrine and nervous systems to stimuli take about the same amount of time. d) Chemicals produced by the endocrine system transmit signals through the nervous system.

Answer: a) Some specialized nerve cells, such as neurosecretory cells, perform functions of both systems. - neurosecretory cells conduct nerve signals and also make and secrete hormones.

Which of these hormones make up an antagonistic pair? a) calcitonin ... parathyroid hormone b) ACTH ... FSH c) glucagon ... testosterone d) endorphins ... prolactin

Answer: a) calcitonin ... parathyroid hormone. Explanation: d) Endorphins are natural painkillers - Prolactin stimulates the mammary glands to produce milk.

A lack of _____ is responsible for type I diabetes mellitus. a) insulin b) oxytocin c) prolactin d) thyroxine

Answer: a) insulin. - An autoimmune disease, in which pancreatic beta cells are destroyed, is responsible for type I diabetes mellitus.

Which of the following is considered to be a major endocrine gland? a) lens of the eye b) heart c) salivary gland d) adrenal gland

Answer: d) adrenal gland. - The adrenal gland secretes hormones, such as glucocorticoids.

Jet lag occurs when a person moves rapidly from one time zone to another, causing conflict between the body's biological rhythm and the new cycle of light and dark. Some scientists suspect that jet lag may result from disruption of a daily hormone cycle related to the hormone _____. a) insulin b) oestrogen c) epinephrine d) melatonin

Answer: d) melatonin. - Melatonin is produced by the pineal gland, which has either light-sensitive cells or nervous connections to the eyes; its production is regulated to some extent by day length.