Chapter 15 Flashcards
Homeostasis
The balanced functioning of physiological processes and maintenance of an organism’s internal environment within a narrow range.
Periventricular Zone
A hypothalamic region that lies most medially, bordering the third ventricle.
Magnocellular Neurosecretory Cell
A large neuron of the periventricular and supraoptic nuclei of the hypothalamus that projects to the posterior pituitary and secretes oxytocin or vasopressin into the blood.
neurohormones
A hormone released by neurons into the bloodstream.
Vasopressin
A small peptide hormone released from the posterior pituitary by magnocellular neurosecretory cells; promotes water retention and decreased urine production by the kidney; also called antidiuretic hormone (ADH).
Parvocellular neurosecretory cells
A small neuron of the medial and periventricular hypothalamus that secretes hypophysiotropic peptide hormones into the hypothalamo-pituitary portal circulation to stimulate or inhibit the release of hormones from the anterior pituitary.
Hypophysiotropic hormone
A peptide hormone, such as corticotropin-releasing hormone or gonadotropin-releasing hormone, released into the blood by the parvocellular neurosecretory cells of the hypothalamus; stimulates or inhibits the secretion of hormones from the anterior pituitary.
Hypothalamo-pituitary portal circulation
A system of blood vessels that carries hypophysiotropic hormones from the hypothalamus to the anterior pituitary.
Adrenal cortex
The outer segment of the adrenal gland; releases cortisol when stimulated by the pituitary adrenocorticotropic hormone.
Adrenal medulla
The inner segment of the adrenal gland, innervated by preganglionic sympathetic fibers; releases epinephrine.
Cortisol
A steroid hormone released by adrenal cortex; mobilizes energy reserves, suppresses the immune system, and has direct actions on some CNS neurons.
Autonomic nervous system (ANS)
A system of central and peripheral nerves that innervates the internal organs, cardiovascular system, and glands; also called visceral PNS. It consists of sympathetic, parasympathetic, and enteric divisions.
Sympathetic division
A division of the autonomic nervous system that in fight-or-flight situations activates physiological responses, including increased heart rate, respiration, blood pressure, and energy mobilization and decreased digestion and reproductive functions; its peripheral axons emerge from the thoracic and lumbar spinal cord.
Parasympathetic division
A division of the autonomic nervous system that maintains heart rate and respiratory, metabolic, and digestive functions under normal conditions; its peripheral axons emerge from the brain stem and sacral spinal cord.
Autonomic ganglia
Peripheral ganglia of the sympathetic and parasympathetic divisions of the ANS.
Postganglionic neurons
A peripheral neuron of the sympathetic and parasympathetic divisions of the ANS; its cell body lies in autonomic ganglia, and its axons terminate on peripheral organs and tissues.
Preganglionic neurons
A neuron of the sympathetic and parasympathetic divisions of the ANS; its cell body lies in the CNS (spinal cord or brain stem), and its axons extend peripherally to synapse on postganglionic neurons in the autonomic ganglia.
Sympathetic chain
A series of interconnected sympathetic ganglia of the ANS, adjacent to the vertebral column, that receive input from preganglionic sympathetic fibers and project postganglionic fibers to target organs and tissues.
Enteric division
A division of the ANS that innervates the digestive organs; consists of the myenteric and submucous plexuses.
Nucleus of the solitary tract
A brain stem nucleus that receives sensory input and uses it to coordinate autonomic function via its outputs to other brain stem and forebrain nuclei and to the hypothalamus.
Diffuse modulatory systems
One of several systems of CNS neurons that project widely and diffusely onto large areas of the brain and use modulatory neurotransmitters, including dopamine, norepinephrine, serotonin, and ACh.
locus coeruleus
A small nucleus located bilaterally in the pons; using NE as their neurotransmitter, its neurons project widely to all levels of the CNS.
Raphe nuclei
Clusters of serotonergic neurons that lie along the midline of the brain stem from the midbrain to the medulla and project diffusely upon all levels of the CNS.
Basal forebrain complex
Several cholinergic nuclei of the telencephalon, including the medial septal nuclei and basal nucleus of Meynert.
