NSCI 175 Exam 3
Summarize the significance of proper hypothalamic function and its relationship to homeostasis -
Answer-homeostasis: the maintenance of the body's internal environment within a narrow physiological
range
negative feedback systems are the primary homeostatic mechanisms
if a desired value, the set point, is deviated from, compensatory actions begin
the set zone refers to the range of tolerance in a system
physiological systems show redundancy - they are monitored by more than one mechanism
homeostasis examples: regulation of blood volume, blood pressure, amount of saline, blood oxygen and
glucose levels, acidity, body temp
compare and contrast hypothalamic control of and hormone release from the posterior and anterior
pituitary - Answer-neurosecretory neurons in the periventricular hypothalamus project to the pituitary
gland
,the anterior and posterior lobes of this gland are under control of the hypothalamus and both secrete
hormones
posterior pituitary (neurohormones): oxytocin and vasopressin
anterior pituitary hormones: FSH, LH, TSH, ACTH, GH, prolactin
oxytocin - Answer-"love hormone"
milk letdown reflex: stimulated by somatic sensations to trigger the release of milk (even sight or sound
of baby will stimulate cortex -> hypothalamus)
maternal behavior: oxytocin enables recognition of pup distress in mice
other functions: release during sex, social bonding, childbirth (uterus contractions and delivery)
vasopressin and oxytocin - Answer-released by posterior pituitary
receptors are expressed in the reward pathway, pair bonding
the nucleus accumbent is part of the reward pathway
mating normally induces prairie voles to form lifelong bonds, but researchers found that they could
cause the same blissful response by activating certain genes in the rodents' brains
vasopressin - Answer-antidiuretic hormone (ADH)
,regulates blood volume and salt concentration
vasopressin-containing neurons receive info about changes in salt concentration and respond by
releasing vasopressin: direct action on kidneys -> water retention and reduced urine production
anterior pituitary - Answer-"master gland"
under control of parvocellulaar neurosecretory cells
endocrine gland
these neurons communicate with the pituitary lobe via the bloodstream
cells secrete a wide-variety of hypophysiotropic hormones: FSH, LH, TSH, ACTH, GH, and prolactin
hypothalamus-pituitary portal circulation: pituitary cells secrete or stop secreting hormones
compare the actions of hormones released from the posterior and anterior pituitary - Answer-1)
hormone 2) posterior or anterior? 3) target 4) action
oxytocin, posterior, brain and uterus, milk letdown reflex, contractions, social bonding
vasopressin, posterior, kidney, angiotensin II production and thirst
FSH, anterior, gonads, ovulation and spermatogenesis
, LH, anterior, gonads, ovarian and sperm maturation
TSH, anterior, thyroid, thyroxin secretion (increases metabolic rate)
ACTH, anterior, adrenal cortex, cortisol secretion (mobilizes energy stores, inhibit immune system)
GH, anterior, all cells, stimulation of protein synthesis
Prolactin, anterior, mammary glands, growth and milk secretion
stress responses - anterior pituitary - Answer-parvocellular neurosecretory (in periventricular
hypothalamus cells) determine whether a stimulus is stressful
periventricular hypothalamus secretes CRH (corticotropin-releasing hormone) into portal circulation ->
travel to anterior pituitary
ACTH (adrenocorticotropic hormone or corticotropin) released into circulation
ACTH stimulates cortisol release from adrenal cortex (cortisol -> stress hormone)
consequences of long term stress - Answer-tension headaches and migraines
mental health problems
serious heart problems
trouble breathing, hyperventilation and panic attacks
skin and hair conditions ex. acne, hair loss
increased risk of type 2 diabetes