Module 4: Sleep and Homeostasis - Hormones, ANS, and Diffuse Systems

Practice flashcards covering the communication patterns of the nervous system, homeostatic regulation by the hypothalamus, the autonomic nervous system divisions, and the diffuse modulatory systems of the brain.

Homeostasis

The maintenance of the body’s internal environment within a narrow physiological range to allow body cells to conduct chemical reactions.

Magnocellular neurosecretory cells

Hypothalamic neurons that extend axons down the stalk of the pituitary gland to release chemicals directly into the capillaries of the posterior lobe.

Oxytocin

A neurohormone released by the hypothalamus that promotes social bonding, facilitates uterus contractions during childbirth, and stimulates milk ejection from mammary glands.

Vasopressin

A neurohormone released by salt concentration sensitive cells in kidneys that regulates salt concentration by causing water retention and decreasing urine production.

Renin

A substance that increases blood pressure and leads to the production of angiotensin, which causes the subfornical organ to produce intense thirst.

Parvocellular neurosecretory cells

Neurons that control the secretion of hormones in the anterior pituitary but do not extend axons all the way to the anterior lobe.

CRH

A peptide released by neurons in the periventricular hypothalamus that travels to the anterior pituitary gland within about $15\,sec$ to facilitate a stress response.

ACTH

A hormone produced by the anterior pituitary that enters general circulation to stimulate the release of cortisol from the adrenal cortex within a few minutes.

Cortisol

A hormone released by the adrenal cortex during a stress response when stimulated by ACTH.

Sympathetic division

A division of the autonomic nervous system (ANS) that reacts to the outside world for survival, associated with the fight/flight response.

Parasympathetic division

A division of the autonomic nervous system (ANS) associated with the rest/digest state, active during relaxation.

Autonomic ganglia

Clusters of cells in the ventral horn of the spinal cord and brain stem where the cell bodies of autonomic lower motor neurons are located.

Diffuse modulatory systems

Systems of cells within the brain/CNS that modulate assemblies of postsynaptic neurons, typically arising from a small core of neurons in the brain stem.

Locus coeruleus

A noradrenergic point of origin located in the pons that projects axons to essentially every part of the brain.

Raphe nuclei

The point of origin for the serotonergic system, located on both sides of the midline of the brain stem with rostral projections in the pons/midbrain and caudal projections in the medulla.

Substantia nigra (SN)

A dopaminergic point of origin in the midbrain that projects axons to the striatum.

Ventral tegmental area (VTA)

A dopaminergic point of origin in the midbrain that projects to the frontal cortex and parts of the limbic system.

Basal forebrain complex

The cholinergic point of origin in the core of the telencephalon that projects to the entire cerebral cortex.

Hallucinogens

Psychoactive drugs chemically close to serotonin that act as strong agonists at serotonin receptors in the raphe neurons.

Stimulants

Drugs associated with the dopaminergic and noradrenergic systems that cause increased alertness, high self-confidence, decreased appetite, and increased BP and HR.